Incidence rate of cancer is estimated to increase by 40% in 2030. Furthermore, the development of resistance against currently available treatment strategies has contributed to the cancer-associated mortality. Scientists are now looking for the solutions that could help prevent the disease occurrence and could provide a pain-free treatment alternative for cancers. Therefore, efforts are now put to find a potent natural compound that could sever this purpose. Ursolic acid (UA), a triterpene acid, has potential to inhibit the tumor progression and induce sensitization to conventional treatment drugs has been documented. Though, UA is a hydrophobic compound therefore it is usually chemically modified to increase its bioavailability prior to administration. However, a thorough literature indicating its mechanism of action and limitations for its use at clinical level was not reviewed. Therefore, the current study was designed to highlight the potential mechanism of UA, its anti-cancer properties, and potential applications as therapeutic compound. This endeavour is a valuable contribution in understanding the hurdles preventing the translation of its potential at clinical level and provides foundations to design new studies that could help enhance its bioavailability and anti-cancer potential for various cancers. Cancer is a major public health issue and the second leading cause of death worldwide . AccordiResearchers worldwide have been driven to evaluate the anticancer effect of biomolecules derived from natural sources due to the lack of effective chemo-preventive methods that are ideal for improving the therapeutic outcomes during an anticancer treatment. Owing to their enhanced safety, phytochemicals obtained from natural sources have the potential to be effectively used as a potent therapeutic agents against cancers . One sucTherefore, in current study, the detailed review of UA therapeutic potential in different cancers is provided that highlighted its role as chemo-preventive and treatment compound for the cancer. Similarly, the mechanism of action of UA in cancers is also brought to limelight that also facilitated in the identification of disease pathogenesis. This endeavour provided significant insight of UA potential for treatment of cancers in combination with conventional treatments.30H48O3, molecular weight 456.7 g/mol, and melting point of 283–285°C [Ursolic acid (UA), a common secondary metabolite, belongs to ursane-type pentacyclic triterpenoids, is found in the pomace, cork, flower, sprout, leaf, and bark of different medicinal plants . UA was 83–285°C . Owing t83–285°C . The bio83–285°C . The enz83–285°C . The synRosmarinus officinalis are known as the commercial source of UA and contains its contents up to 2.95%. Recently, UA has been detected in commercially available dry fruits and edible wild-mushrooms for the first time [UA is a five-ring triterpenoid compound present in many botanical sources –23. Famirst time , 25. DifCuticular wax on leaves and fruits are also tremendous source of UA which protect the fruits from herbivore and bacterial, and mechanical stress . Leaves eucalyptus trees can also be different source of UA [UA has also been extracted from leftover of rosemary after carnosic acid extraction . Moreovece of UA . The conce of UA . Severalce of UA .eucalyptus trees present in the Temperate and the Mediterranean regions have higher concentrations of UA compared to the Eucalyptus trees present in the tropical and sub-tropical locations [Studies have showed that the contents UA from different sources differ in a significant manner. For instance, the fruits and leaves of Vaccinium species have highest contents of free UA compared to the lower stems, roots and rhizomes, that contain bound form of UA . Furtherocations , 42.The therapeutic potential of UA is hindered by its limited solubility, bioavailability, and fast metabolism. The poor solubility of UA in water results in low absorption, and short half-life of drug in the body. These obstacles limit the pharmacological applications of UA, and it has been placed in Class IV in biological drug classification system . ResearcN-methylpiperazine, alkane-1, 6-diamines, alkane-1, 4-diamines and alkane-1, and 2-diamines. The study showed that the derivatives of UA bearing primary amines showed more antiproliferative activities than that of derivatives with secondary and tertiary amines [Tian and his group studied the anticancer activities of UA derivatives containing diamine moieties at C-28 on three different human cancer cell lines using MTT assay. The nitrogen containing UA derivatives were primarily synthesized by esterification at position C-28 using 2-hydroxyacetic acid. This C-28 modification was then followed by amidation reaction using amines including piperazine, y amines .UA derivatives bearing oxidazole, triazolone, and piperazone moieties were synthesized and their antitumor potential was evaluated. The result revealed that compound 11b inhibited HIF1- α expression and enhanced antiproliferative activity by blocking the progression of cell cycle at G1 phase . SimilarTo enhance the bioavailability and anticancer activities, UA was chemically modified by Li et al. Using a nitrogenous heterocyclic scaffold and a privileged fragment at C-28, they synthesized a new derivative FZU3010. The results of Sulforhodimine B assay and flow cytometry showed that FZU3010 inhibited proliferation and induced apoptosis in SUM149PT and HCC1937 cell lines .To enhance the hydrophilicity of UA to increase its clinical utility a simple synthetic approach was used to synthesize a series of new ionic UA derivatives. The results revealed a higher water solubility and improved anticancer activities of these novel UA ionic derivatives .A total of six novel derivatives were synthesized through inducing modifications at C-3 position of UA. The UA derivative bearing amine moity at position C-3 showed the highest activity against leukemia cells. Moreover, the 2c showed high selectivity index for cancerous cells over normal cells. The mechanism of anticancer activities of 2c was studied and the results showed that the 2c derivative induces apoptosis through caspase 3, and 8; and causes cell cycle arrest. Furthermore, the synergistic effects of 2c and imatinib, which is a standard kinase inhibitor, was found when used in combination .Shao et al. attempted to modify UA at C-3 and C-28 positions to synthesize a total of twenty-three derivatives with improved anticancer activities. They first performed acetylation of UA, resulting in the formation of 3-O-acetylursolic which was further treated with bromo-diolefine to obtain fatty esters. They also synthesized amides and ester derivatives of UA. The anticancer properties of UA derivatives were evaluated using MTT assay which revealed improved antiproliferative activities against the control group .Wenfeng and colleagues prepared a series of UA derivatives and compared their anticancer activities with UA. They found that UA232 a novel derivative of UA possesses significantly higher anticancer activities against A549 and H460 cells than that of UA. Further expression analysis and flow cytometry revealed that UA232 induce G0/G1 phase arrest and apoptosis in lung cancer cell lines through endoplasmic reticulum mediated stress pathway .UA has been under study for its various therapeutic effects in multiple diseases particularly in various types of cancers . InvestiIn 2019, Jin et al. were successfully able to synthesize UA derivatives bearing moieties like thiadiazol, hydrazide, and oxadiazole and these compounds were studied on different cancer`s cell lines. One of the compounds, 4d was able to induce apoptosis in HeLa cells, and arrested the cell cycle at G0/G1 phase. Interestingly, this compound was also found to inhibit the MAPK pathway, as it was directly inhibiting the MEK1 activity, consequentially obstructing the RAS/RAF/MEK/ERK signal transduction pathway . In anotUA can also effectively inhibit the proliferation and EMT in the gastric cancer cells via regulating the IKK/NF-KB pathway . The stuUA plays an essential role in the inhibition of JAK/STAT pathway. This compound inhibits the activation of src and JAK kinases by suppressing the phosphorylation, preventing the STAT3 activation in prostate cancer cells. Furthermore, UA also inhibited the xenografted prostate cancer in mouse model by inhibiting the activation of STAT3 . UA alsoUA is also being used against ovarian cancer. In the current investigation, UA was used to treat ovarian cancer cells, and the inhibitory effects were clearly seen. By suppressing the activity of both PI3K and AKT molecules as well as their phosphorylated versions, UA blocked the PI3k/AKT pathway. Apoptosis and cell cycle arrest are caused by this as well as the elevated reactive oxygen species . In caseStaphylococcus aureus (MRSA) [Bacillus, Klebsiella, Escherichia, Shigella species. Furthermore, when these derivatives were combined with kanamycin, their antimicrobial activity was enhanced and their minimum inhibitory concentration was also reduced to 8 μg/mL from 128 μg/mL [Bacterial infections impose a huge risk on public health, including the development antibiotics resistant strains. Now public health officials are considering to use the naturally occurring products and their derivatives as the potential therapeutic options against the microbial pathogens . Scientis (MRSA) . Studies28 μg/mL .. extracted UA from leaves of Ilex hainanensis and form their derivatives to assess their activity against both gram-positive and gram-negative microbes, which showed that those compounds showed a significant levels of activity against gram-positive microbes, however their activity against gram-negative microbes was trivial [E. coli for 24 h at the concentration of 10 μg/mL [Acanthamoeba spp. demonstrating the role as amoebicidal drug [Complexes of UA with metals such as copper, iron, zinc, antimony, and tin were shown to have antibacterial activity against both gram-positive and gram-negative microbes. The dimethyl tin derivative of UA was found to have excellent antibacterial activity with the MIC value of 8 μg/mL. However, the metal derivatives of copper and zinc did not demonstrated any activity in this regard –82. In 2 trivial . The ext10 μg/mL . In anotdal drug . In the dal drug , 87.Several modern studies have implied that the excessive use of antimicrobial agents, during and after the treatment of cancer can also cause undesirable consequences. As it is now known that antimicrobial agents have adverse effect on human gut microbiota, which can persist for massive period of time . This caC. elegans from the injurious effects of reactive oxygen species [Inflammation in the neuron can lead towards serious neurological disorders which can dangerously impact an individual’s health. When any neurotoxin, pathogen or indigenous source cause the microglial cells to activate, it results in the activation of inflammatory response mediated by prostaglandins, ROS, NO, cytokines, chemokines, ultimately leading towards neurodegenerative diseases , 91, 92. species .P. incarnata was shown to have a neuroprotective role Alzheimer’s disease which is characterize by the accumulation of amyloid-β plagues. When Aβ-induced mice model were administered with UA (56 mg/kg), there was significant decrease in the accumulation of the amyloid plagues with the improvement in performance of spatial memory [C. elegens which showed that at the concentration of 100 μM, UA significantly inhibited the amyloid-β by augmenting the ubiquitin proteosome system which is essential for the maintenance of proteostasis [UA extract from l memory . In anoteostasis . Protecteostasis , 99.Increased global incidence of obesity and diabetes have inflicted a tremendous risk to the well-being of human. Diabetes mellitus is characterize by the deficiency and resistance to insulin, resulting in hyperglycemia, moreover obesity has a strong association with diabetes and insulin resistance –103. ThiThe bioactive activity of UA extracts from asparagus wild was observed which showed that UA inhibit the activity of two key metabolic enzymes α-glucosidase and α-amylase which are involved in type II diabetes . In a stM. tuberculosis [Inflammation is a response of body against pathogenesis induced by any harmful agent or microbes to maintain tissue homeostasis. However, when the inflammatory response is prolonged and become chronic, it causes damage to the tissues and malfunctioning of the organs , 117. Chrculosis . Zhou etrculosis . UA has rculosis .Further, the UA derivates  were designed and accessed for their anti-inflammatory activity. It was depicted that the compounds were inhibiting the Cox-1 and Cox-2 enzymes and reducing the inflammation by the inhibition of prostaglandins biosynthesis , 121. ThNumerous studies have confirmed the anticancer properties of UA in vitro. However, its mechanism of action varies from cancer to cancer. The molecular players targeted by UA in different cancers is illustrated in Fig. UA (UA) shows potent anti-cancer properties against breast cancer (BC) cells by inducing apoptosis and autophagy, cell cycle and cell proliferation arrest and suppressing angiogenesis and metastasis. . It was The chemo-preventive effect of UA was also elucidated in metastatic BC cell lines through inactivation of Jun N-terminal kinase, Akt and mammalian target of rapamycin phosphorylation and lowering NF-κB levels in the nucleus , 125. InTherapeutic potential of UA has also been studied in colorectal cancer (CRC) with positive results. STAT3 signal transduction pathway is involved in CRC progression and its inhibition has been linked with decreased cancer cell growth , 130. UAEffect of UA on CRC cells in mice models revealed that UA reduced tumor volume without affect body weight of mice, which indicates its anti-tumor activity without toxicity to normal body cells. US also halted the expression of angiogenic factors such as vascular endothelial growth factor A and basic fibroblast growth factor in addition to suppression of sonic hedgehog (SHH), STAT3, Akt and p70S6K pathways , 12. In Impact of UA in prostate cancer (PCa) has also been explored and it has been seen in a recent study that UA promotes apoptosis in PCa via ROCK/PTEN pathway. Rho associated protein kinase (ROCK) interacts with microtubules and is essential for maintenance of epithelial cell polarity . UA inhiRising chemoresistance rates for prostate cancer cases has exacerbated the need to find safer treatment options. It was observed that UV induced anti-tumor effects trough increased ER stress and autophagy in pancreatic cancer cells. Levels of ER stress-related proteins such as CHOP, p-eIF2α, BiP, and Calpain1 were increased upon UA administration leading reduced cell viability. It was also seen that UA induced autophagy through ATG5/LC3 II-dependent signaling. Administration of UA with Gemcitabine (GEM) increased cell death and improved chemo-sensitivity to GEM in pancreatic cancer cells . Role ofIn case of hepatocellular carcinoma (HCC), up-regulated cholesterol and lipid metabolism promote tumor growth through stimulation of oncogenic signaling pathways . LoweredIn addition to having anti-cancerous properties, UA and its derivatives can also block G + and G– bacteria as well as a few viral actions . UA has UA is a naturally occurring substance that has been used in a variety of ways due to its biological properties and demonstrates its potential to be effective in the treatment and prevention of several diseases. As a result, in both cellular and animal models, the pharmacological effects of UA demonstrated anti-cancer, anti-diabetic, neuroprotective, and anti-inflammatory mechanisms. Despite the great advances that have been made in elucidating the role of UA in various pathologies and its pharmacological properties, there are still gaps in the research that need to be filled. UA is a multi-dimensional molecule that targets many different pathways within cells by regulating transcription factors, protein kinases and metabolites etc. One of the major concerns regarding UA is its poor bioavailability and low solubility and intestinal permeability despite its strong pharmacological properties . UA is cBy structurally altering the original UA skeleton, researchers have produced synthetic UA derivatives with improved medicinal benefits to overcome the problems of poor bioavailability and intestinal uptake . When coA natural compound, ursolic acid, can be isolated from several commonly consumed fruits and vegetables. Its ability to simultaneously target multiple signalling proteins has capacitated it to be used as chemo preventive or therapeutic agent for cancers. It inhibits or promotes the activity of numerous proteins belonging to cell growth and cell apoptosis, respectively. Despite the availability of the tons of data, there is a need to perform more proteomics-based research to understand its potential as therapeutic agent. Similarly, the impact of UA on the metabolism of a cancer cell must also be investigated. There is also a need to integrate nanotechnology to enhance the bioavailability and anti-cancer potential of UA. Studies at cell level has shown the promising outcomes. Therefore, future investigations must be focused on evaluating its cytotoxicity in animal models and determining its pharmacological dose in different cancers. Through more investigations UA can be delineated as pain-free therapeutic option for cancers.


Nigeria’s population is projected to increase from 200 million in 2019 to 450 million in 2050 if the fertility level remains at the current level. Thus, we examined the shifts in the age pattern of fertility, timing of childbearing and trend in fertility levels from 2003 and 2018 across six regions of Nigeria.This study utilised the 2003, 2008, 2013, and 2018 Nigeria Demographic and Health Survey datasets. Each survey was a cross-sectional population-based design, and a two-stage cluster sampling technique was used to select women aged 15–49 years. The changes in the timing of childbearing were examined by calculating the corresponding mean ages at the birth of different birth orders for each birth order separately to adjust the Quantum effect for births. The Gompertz Relational Model was used to examine the age pattern of fertility and refined fertility level.In Nigeria, it was observed that there was a minimal decline in mean children ever born (CEB) between 2003 and 2018 across all maternal age groups except aged 20–24 years. The pattern of mean CEB by the age of mothers was the same across the Nigeria regions except in North West. Nigeria’s mean number of CEB to women aged 40–49 in 2003, 2008, 2013 and 2018 surveys was 6.7, 6.6, 6.3 and 6.1, respectively. The mean age (years) at first birth marginally increased from 21.3 in 2003 to 22.5 in 2018. In 2003, the mean age at first birth was highest in South East (24.3) and lowest in North East (19.4); while South West had the highest (24.4) and both North East and North West had the lowest (20.2) in 2018. Similar age patterns of fertility existed between 2003 and 2018 across the regions. Nigeria’s estimated total fertility level for 2003, 2008, 2013 and 2018 was 6.1, 6.1, 5.9 and 5.7, respectively.The findings showed a reducing but slow fertility declines in Nigeria. The decline varied substantially across the regions. For a downward change in the level of fertility, policies that will constrict the spread of fertility distribution across the region in Nigeria must urgently be put in place. The world population will increase from nearly 7.7 billion in 2019 to 8.5 billion in 2030 and further increase to about 9.7 billion by 2050 [In SSA, countries such as South Africa, Ghana, Kenya, Gabon, and several others have progressed in the demographic transition process, but Nigeria is still struggling to lower its fertility level despite taking various measures to reduce it . NigeriaThe age pattern of fertility is essential in understanding the fertility situation in Nigeria because the likelihood of a woman having a child in a given time interval is strongly varied by age –7. For iThe knowledge about the effects of changes in the timing of fertility at all birth orders is essential for understanding the past and the future trajectories of reproductive behaviour . SubstanA similar shift in the age pattern of fertility was observed in many Asian countries and Latin America at the early stage of their fertility decline . Also, for fertility transition in Brazil, postponement in the second birth was identified without postponement in the first birth . LikewisA study in Nigeria showed that the maternal age of a mother at first childbirth across all the regions in Nigeria ranged from 17.7 to 21 years and concluded that adolescent first birth is widespread in Nigeria . This siNigeria is a multi-ethnic country with diverse socio-cultural differences, so the indicators of fertility at the national level may be inadequate to explain childbearing behaviour in sub-population. It is essential to know if these indicators are the same across the regions of Nigeria. Although many works have focused on fertility in Nigeria; however, the age pattern of fertility and timing of childbearing has not been sufficiently considered in the analysis of fertility. Since changes in the level of fertility over time result from shifts in age patterns and timing of fertility, there is a need for a detailed assessment of the recent changes in the age pattern of fertility and the timing of childbearing. Therefore, this study aims to examine changes over the years in the age pattern of fertility, timing of childbearing and fertility levels in Nigeria as a whole and across its region.Nigeria has the largest population in Africa and the 14th largest in landmass. According to the 2006 Population and Housing Census conducted in Nigeria, the country’s population was 140,431,790 , 18, butThe study utilized data from the 2003, 2008, 2013 and 2018 Demographic and Health Surveys (NDHS). Each survey was a cross-sectional population-based design, and a two-stage cluster sampling technique was used to select women aged 15–49 years. The 2003 NDHS programme made use of the sampling frame designed for the 1991 population census, while the sampling frame designed for the 2006 population and housing census was used for 2008, 2013 and 2018 NDHS but with modification due to expansion in the number of households between the census period and the survey years defined in all the survey rounds, the primary sampling unit (PSU) was a cluster tagged as the Enumeration Areas (EAs) from the 1991 and 2006 EA census sampling frames. Samples for the 2003 and 2008 surveys were selected using a stratified two-stage cluster design consisting of 365 clusters in 2003 NDHS and 888 clusters in 2008 NDHS. While 2013 and 2018 NDHS were conducted at three and two stages, respectively. For 2013, 893 localities were selected at the first stage with probability proportional to the size and with an independent selection from each sampling stratum. In the second stage, one EA was randomly selected from most of the selected localities. In a few larger localities, more than one EA was selected. In total, 904 EAs were selected. After selecting the EAs and before the main survey, a household listing operation was carried out in all the selected EAs. For 2018 NDHS, at the first stage, 1400 EAs were selected; and a household listing which served as a sampling frame was conducted on the selected EAs. In the second stage, 30 households were selected from each cluster by an equal probability of systematic sampling. The number of households interviewed in 2003, 2008, 2013, and 2018 was 7864, 34070, 40680 and 42000, respectively. The number of women aged 15–49 years interviewed for these year periods used in the study is given as 7620, 33385, 38948, and 41821, respectively. A detailed description of the methodology of the data set used for this study may be found in NDHS main report [μ is the mean age of childbearing that measures the timing of childbearing; x(i) is the central age-point in the age interval, and I is the age group containing the upper age limit of the childbearing span; and f(i) denotes the fertility rate experienced by women in each age group.The changes in the timing of childbearing were examined by calculating the corresponding mean ages at the birth of different birth orders of the study periods. The mean was calculated for each birth order separately to adjust the Quantum effect for births. The level of fertility is influenced by changes in the timing of childbearing (Tempo) and children ever born (Quantum) .μ=∑i=IThe shifts in the age pattern of fertility can be examined by looking at observed or model age-specific fertility rates. However, due to reporting errors and the truncation effect; observed age-specific fertility may be inappropriate to describe the age pattern of fertility . Thus, i5Px, of women in each age group  for x = 15, 20, ------- 45, were calculated. Then the fertility standard developed by Booth [Two sets of data were used in the study. These are the women’s data set  and children’s data set (child recode). All the variables needed in both the women’s data set and children’s data set for the study were extracted using SPSS. The variables used to estimate the numerator of TFR, the month and year of the child’s birth, were extracted from the children’s data set with the ID variable and matched with the women’s data. The observed ASFRs as presented in Fig 2 was obtained through direct estimation as described by Moultrie et al. . While tThe plots of z(x)–e(x) against g(x) and z(i)–e(i) against g(i) (on the same set of axes) that were almost on the same line was used to fit the model. The values of α (intercept) and β (slope) are the parameters. The level of fertility (TFR) was estimated indirectly by applying the above-derived parameters (α & β) to the current fertility gompits. The parameters α & β for the periods were compared; α indicates the location of fertility, and β shows the spread in relation to the standard.Sample weights were applied to each case to adjust for differences in the probability of selection. Weighting is important to increase the sample’s extent of representativeness and reduce the errors associated with sample selection bias.Since the authors of this manuscript did not collect the data, we sought permission from the MEASURE DHS website and access to the data was provided after our intent for the request was assessed and approved on the 10th of March 2021. The DHS surveys are ethically accepted by the ORC Macro Inc. Ethics Committee and the Ethics Boards of partner organizations in different countries, such as the Ministries of Health. The women who were interviewed gave either written or verbal consent during each of the surveys.The mean number of children ever born by the age of mothers across the Nigeria regions between 2003 and 2018 was presented in Women of the South West region have consistently had the lowest fertility levels across all the survey years, though fertility stalled between 2003 and 2013 in the region. In North Central, a fertility decline was observed between 2003 and 2013 but stalled between 2013 and 2018. Between 2003 and 2018, while the mean CEB for women aged 15–49 only decreased from 2.5 to 2.4 in South-South, it increased from 2.4 to 2.5 in South East. Also, across the six geopolitical zones, fertility decline was observed among women aged 40–49 except in North West. The mean number of children born to women aged 40–49 in North West rose from 6.78 in 2003 to 8.27, about a 22% increase. The highest decrease in average cumulative fertility among women who had completed their fertility was found in SS (30%) and the lowest in NE (3%). At the national level, only a 9% fertility decline was observed among older women.Nonetheless, there was at least a marginal increase in mean age at first birth order across the regions. The mean age at second birth marginally increased in Nigeria between 2003 and 2018. In NE, NW, and NC, the mean age at second birth was static. Meanwhile, a persistent increase in mean age at second birth was observed in SS, whereas, in SE, it rose between 2003 and 2013 but fell between 2013 and 2018. In SW, it increased between 2003 and 2018; but the rate of increase was minimal compared to that of SS.In Nigeria, the mean age at third birth order increased between 2003 and 2008; but stalled between 2008 and 2018. The same pattern was observed in NC. Furthermore, the mean age of NE and NW were differentiated in the third birth order. An increase in mean age at third birth was observed in NE between 2003 and 2018, while in NW, the timing of childbearing at third birth order remains unchanged. In 2003, the mean age at the third birth order was almost the same in SW and SE; however, while there was an increase between 2003 and 2018 in SW, but it decreased between 2003 and 2018 in SE. Also, there was a steady increase in SS between 2003 and 2018. At birth order four, inconsistency was observed in the trend of the timing of childbearing in Nigeria, NC, SS, and SE. However, the mean age at fourth birth was clearly highest in SW, while NW and NE had the lowest. Between 2003 and 2018, the timing of childbearing did not change in Nigeria and across the regions except SW, where a marginal increase was observed.According to the curve, the SE estimated ASFRs for 2018, 2013, 2008 and 2003 were almost the same at younger ages but varied at older ages. As expected, in later years, the 2003 estimated ASFRs were the highest, while that of 2013 and 2008 were closed. The estimated ASFRs for 2018 were the lowest. It shows there have been shifts in the age pattern of fertility in the SE between 2003 and 2018. For SS, the curve of the estimated ASFRs for the periods revealed inconsistency in the shifts of age pattern. For instance, the older ages ASFRs in 2013 were lower than that in 2008; in fact, that of 2003 was higher than in 2008. However, a shift in the age pattern of fertility was observed in SS between 2003 and 2018. Lastly, in SW, the curve of the estimated ASFRs for the periods differs at the older ages, with ASFRs in 2018 being the lowest and 2003 being the highest. This indicates a shift in the age pattern of fertility between 2003 and 2018 in SW.The difference between the observed and estimated figures may be due to the quality of the data. Estimation of fertility indicators remains a challenge in many developing countries due to uncertainty about data quality . FertiliThe beta values of SW, SE, and SS were greater than one in 2018, while they are less than one in other regions. Furthermore, the alpha values are negative for each of the survey years in all the regions, with the exception of NW and NE in 2003. The result depicts a relatively widespread fertility distribution in northern regions and national as well. Likewise, the alpha values indicate later onset and termination of childbearing in southern regions when compared with the northern region. Also, it appears from the Gompertz parameters that Nigeria has two distinct age patterns of fertility distribution. The values of β suggest similar age patterns of fertility exist between 2003 and 2018 in the northern regions and Nigeria; however, it appears that there have been shifts in the age pattern of fertility in southern regions.Also, the estimated total fertility rates of the model, as shown in The In the SE, fertility decline was rapid between 2003 and 2013 but stalled between 2013 and 2018. Also, accelerated fertility decline was observed in SS and NC compared to other regions. Inconsistency was observed in NW. However, the level of fertility has been consistently lowest in the SW, and highest in the NW, except in 2003, where NE was the highest. The general trend is that regions with higher fertility had experienced a more gradual decline, while regions with low fertility had a more rapid decline, thus increasing the regional differentials in fertility.Considering the demographic shifts and overall population growth, Nigeria will face many challenges in meeting basic demands, such as housing, education, and health care of the country. Nigeria is faced with a population explosion that is expected to push the population past 450 million people by the middle of the century if nothing is done about her fertility level. Since changes in the level of fertility over time result from shifts in age patterns and timing of fertility. Thus, this study described the shifts in the age pattern of fertility between 2003 and 2018 across six regions of Nigeria.A shift in age patterns and timing of fertility is pertinent to changes in the level of fertility over time. A similar age pattern of fertility in Nigeria between 2003 and 2018 was established in this study. This pattern was also observed in all the regions in the northern part of Nigeria between 2003 and 2018. However, a marginal shift in the age pattern of fertility was found in the regions in the south regions . Age patterns of fertility between 2003 and 2018 indicate the early onset of childbearing in the Northern regions and the late termination of fertility in the Southern regions of Nigeria. This finding corroborates the outcome of previous studies conducted in Nigeria . The difThe age pattern of fertility where women continue childbearing as long as they are able such as in Nigeria is noted for high fertility. Fertility decline begins as fertility decreases at both early and later ages of reproductive years . Across In Nigeria, the total fertility rate estimated indirectly due to errors in birth reporting minimally declined from 6.1 in 2003 to 5.7 in 2018; the change of 0.4 recorded in our findings corroborates with the change documented in NDHS reports. However, our estimated TFR was inconsistent with that of NDHS reports, this may be due to errors associated with the surveys , which oThe values of Gompertz relation model parameters (α and β) used to provide a good-fit fall within the estimated the recommended ranges by Moultrie and colleagues . Except The postponement of first birth has not changed significantly, and the mean age at first birth obtained in this study echoes the slow pace of fertility transition in Nigeria. The mean age at first birth only increased slightly from 21.3 years in 2003 to 22.5 years in 2018, with the Southern and Northern regions having mean age at first birth of 24 years and 20 years, respectively. This finding agreed with the outcome of Fagbamigbe and Idemudia , which rAs documented in the literature, several factors explain the persistence of high fertility in Nigeria. Early marriage and contraceptive use are among the main factors responsible for high fertility . FindingThe shifts in the age pattern of fertility and changes in the timing of childbearing are to be examined using observed age-specific fertility rates over time. Due to the incompleteness of the vital registration system in Nigeria, observed age-specific fertility may not be suitable for this study. However, a model designed to circumvent this problem was used in this study; and it was used successfully to fit the age-specific fertility rates in different populations. The strength of this study is the use of large national representative cross-sectional datasets across 15 years conducted in Nigeria to estimate future fertility level trajectories.The study has several implications for policy and research in Nigeria. Fertility level estimates will inform the choice of policy that will be recommended and also make specific group policies to avert the danger of unplanned fertility in the country. The study also informed research by estimating one of the vital components of population studies and presenting new findings that future studies can reference.The indirect techniques and mathematical models adopted in this study provided plausible estimates of fertility levels and clearly described the future trajectory of fertility in Nigeria. The similarity of a relatively widespread fertility distribution exists in Nigeria as an entity and Northern regions. There have not been substantial shifts in the age patterns of fertility between 2003 and 2018 in Nigeria. Slight shifts in age patterns of fertility were observed in Southern regions, but in the core North of the country, there were no shifts. Also, the study demonstrated that the timing of childbearing has not changed in Nigeria; this is evident in the change in the fertility level observed in the country. This study has also revealed that fertility levels are still high in Nigeria. There were regional differentials in fertility levels and trends. Notably, Southern regions are moving to the point of transiting to the second phase of transition, that is where TFR equals 4.0, while fertility levels are above 6 children per woman in NW and NE. The level of fertility in Nigeria, as indicated by TFR, implies that, if the current trend persists, Nigeria is faced with a population explosion that is expected to make its population size above 450 million people by 2050. To avoid the crises that may arise due to population explosion due to high fertility levels and population growth, immediate actions to reduce fertility drastically should be put in place. With a consistent and rapid fertility decline, Nigeria will have fewer children to cater for; and a larger proportion will be in the economically productive age bracket. This is the demographic dividend that Nigeria can benefit from if something urgent is done about its fertility level. For a downward change in the level of fertility, policies that will constrict the spread of fertility distribution across the region in Nigeria must urgently be put in place.S1 Appendix(DOCX)Click here for additional data file.


In the past decade, the focus of bottom-up synthetic biology has shifted from the design of complex artificial cell architectures to the design of interactions between artificial cells mediated by physical and chemical cues. Engineering communication between artificial cells is crucial for the realization of coordinated dynamic behaviours in artificial cell populations, which would have implications for biotechnology, advanced colloidal materials and regenerative medicine. In this review, we focus our discussion on molecular communication between artificial cells. We cover basic concepts such as the importance of compartmentalization, the metabolic machinery driving signaling across cell boundaries and the different modes of communication used. The various studies in artificial cell signaling have been classified based on the distance between sender and receiver cells, just like in biology into autocrine, juxtacrine, paracrine and endocrine signaling. Emerging tools available for the design of dynamic and adaptive signaling are highlighted and some recent advances of signaling-enabled collective behaviours, such as quorum sensing, travelling pulses and predator-prey behaviour, are also discussed. Living cells are compartmentalized chemical systems that continuously sense their environment and interact with other cells . CommuniBiologists commonly exploit signaling pathways to control cellular behaviours using well-established biomolecular tools, such as genome engineering . EmerginIn that context, the design and construction of artificial cells offers avenues to the bottom-up engineering of precisely controlled communication pathways between synthetic chemical compartments. Artificial cells designate man-made functional micro-compartments inspired by living cells and assembled from a small number of well-defined building blocks . AlthougOver the past few years, research has gradually moved from the design of single artificial cells towards the study of populations of artificial cells able to interact, cooperate, or compete via chemical signaling. Artificial cells provide a unique opportunity to strip-out the complexity of cell signaling, build robust, rationally designed communication pathways, and develop a quantitative theoretical framework of molecular communication by testing hypothesis in well-defined systems. Advances geared towards controlling synthetic cell communication have recently been reviewed . The conAfter introducing general concepts of cell signaling, we discuss in this review recent studies on communication between artificial cells through the prism of the mode of communication and signaling distance. Emerging directions geared at dynamically controlling artificial cell signaling are also presented, together with the achievement of collective behaviours and future challenges in the field.Communication in artificial cells builds upon well-established phenomenological knowledge of biological cell signaling, which is the capacity of a cell to receive, process and transmit signals . While s(i) The communication chain includes signal generation, encoding, transmission, propagation, reception and decoding  Bradsha. In livi(ii) Cell signaling also depends on the distance between sender and receiver cells  Bradsha, and is (iii) Last, cell signaling is dynamic and adaptive  Figure . Living Chemical signaling in living cells can be characterized by (i) the communication chain and mode of communication, (ii) the distance between sender and receiver  and (iii) the adaptive nature of signaling networks:Building upon these well-established characteristics of biological cell signaling, we discuss below examples of their realization in artificial cells.Artificial cells are man-made, cell-sized compartmentalized chemical systems. Compartmentalization is central to localize chemical species and reactions and sustain chemical gradients . In the Signal transmission and reception will therefore differ depending on which compartment is used to assemble artificial cells. For instance, continuous membranes may require the insertion of channels (e.g. protein pores) to allow diffusion of molecules. In contrast, the need for insertion of pores can be eliminated if the membrane is porous enough . For insH2O2 ∼ 2 × 10–5 cm2 s−1 while DdsDNA ∼ 5 × 10–7 to 0.81 × 10–8 cm2 s−1 for ∼20 bp)  .Importantly, compared to other types of signals that may require frequency or intensity modulation to encode a message, molecules may readily encode information in their nature or structure: their specificity will induce a specific response in the receiver compartment. For instance, small molecular substrates selectively activate their matching enzyme to produce a desired product, sequence-defined polynucleotide strands will selectively bind to their complementary partner, etc. The binding constant between signaling molecules and their target will also impact the efficiency of communication. Additional encoding of information can be obtained by modulating the concentration of molecules signals, the level or frequency of protein activation, etc., although this has not yet been thoroughly demonstrated in artificial cells.L as the distance between the sender and receiving cell, and d as the typical cell size. Accordingly, autocrine signaling occurs for τ = L2/D, where D is the diffusion coefficient of the signaling molecules. For instance, if we compare autocrine (L < d–let’s fix L = 0.2d) and paracrine (L ≥ d–let’s fix L = 2d) signaling for a given diffusible molecule , we get: τparacrine ∼ 100 × τautocrine, namely, the characteristic timescale for paracrine signalling is ca. 100-fold longer than for autocrine signaling. Although this very simplistic consideration does not take into account permeation of signaling molecules through membranes, their concentration or binding constant to their target, it is consistent with theoretical modelling of autocrine and paracrine trajectories  that frequently occurs in biological systems.The first type of autocrine signaling corresponds to artificial cells hosting enzyme cascades, since the product of enzymatic transformation acts as a signaling molecule for the next enzyme in the cascade . In a sein situ alkaline phosphatase-driven production of Fmoc-TyrOH hydrogel network  as a signal that is received by another colloidosome to assist in the formation of a polymer membrane  genetic circuits as the biological machinery for driving signalling. For example, Tang et al. described the design and assembly of a gene-mediated chemical communication pathway between lipid vesicle transmitters and proteinosome receivers . In anotDuring paracrine signaling, signal dilution may limit the distance over which communication takes place. Recent studies have been geared towards signal amplification to circumvent such limitation . BuddingOther than the size of the signaling molecule, there are other factors that influence the length scales involved in paracrine signaling such as receiver cell density, consumption rate of signaling molecule by receiver cells, signal degradation and permeability of receiver cell to signaling molecule. Tom de Greef and coworkers have looked into the details of the effects of all the above parameters on paracrine signaling by using DNA-strand displacement reactions which can be triggered by light, microfluidic traps to control receiver cell density, concentration of immobilized DNA strands within proteinosomes to control signal consumption per receiver cell and the presence of exonuclease to control signal degradation .2/Ag nanoparticles that can produce Hydrogen peroxide (H2O2) as a signaling molecule by photocatalytic reduction of dioxygen. The signaling molecule was transported unidirectionally from sender to receiver colony with the help of a subtle flow induced by placing a filter paper at one end of the hydrogel colony and adding water slowly at the opposite end. In the receiver cell colony, coacervates were sequestered with G4-hemin DNAzyme that processed the signaling molecule to produce the red fluorescent product resorufin by oxidation of Amplex red. Further oxidation of resorufin to resazurin which is non fluorescent allowed the demonstration of signaling front in the form of a travelling fluorescence band.Endocrine signaling is another distance-based communication between cells where sender and receiver cells are very distant from one another ydrogels . The senThe development of microfluidics tools will open new perspectives to study endocrine signaling in articifical cells. Microfluidics has indeed already offered ways to study living cell-cell signaling and biochemical cross-talk between cells by hosting them in spatially defined regions, separating them using different types of porous barriers and connecting different colonies via flow in microfluidic channels. These studies have garnered a lot of attention leading to rapid development of Organ-on-a-Chip (OoC) and human-on-a-chip devices for toxicity screening, drug metabolism, pharmacokinetics, cancer metastasis and ADMET profiling (ADMET: Absorption/Distribution/Metabolism/Excretion/Toxicity) . With thChemical signaling in living cells is adaptive. The design of stimuli-responsive assemblies and the development of new tools to program and manipulate artificial cells provides a first step towards dynamic signaling regulation in synthetic micro-compartments. In this section, we exemplify such emerging strategies by classifying them depending on which element of the communication chain  they act on.in situ biochemical reactions, which either diffuse out of the cell passively  or are excreted via specific processes  precisely synchronized in space and time. In artificial cells, remote control over signal production and release can be achieved using stimuli-responsive reactions and assemblies , this has been recently shown by Haylock et al., who demonstrated regulation of communication between ternary network of droplet interface bilayers via controlled activation of protein pores using a chemical activator . In situignaling . Bayley ignaling . Tang etignaling . Using aignaling . Going aignaling .Release of molecules through lipid or polymer membranes has also been realized by perturbing the membrane organization in response to environmental stimuli. In an example, Lecommandoux and colleagues spatially separated incompatible enzymes involved in a cascade reaction into distinct polymer-based compartments, and temperature was used to selectively activate one cascade over the other by membrane fluidization . Ces and2+-nitrilotriacetic acid and His-tagged proteins to exercise a high level of control over the loading of biologically relevant macromolecules  exposed on their surface could be harnessed to control a cascade enzyme reaction. The distance between the catalytic nanocompartments within a cluster could be easily controlled by modifying the length of DNA strands which affects the overall performance of the cascade reaction . Such a Moving towards more autonomous systems, artificial cell motility could also be exploited to control population density and therefore tune the distance between sender and receiver cells. Examples of artificial cells capable of motility include catalase-containing organoclay/DNA semipermeable microcapsule, which in the presence of hydrogen peroxide exhibits enzyme-powered oxygen gas bubble-dependent buoyancy ; layer-bTo achieve a desired response and ensure proper signal transduction, the signal needs to be interpreted by the receiver. Living cells rely on complex transduction cascades to decode molecular signals binding to receptors, and ultimately produce a precise response at a specific location, such as expression of a given gene in the nucleus. Signal transduction also often includes an amplification step to relay low concentrations of secreted chemical signals into an effective intracellular process . Such coRegarding specific addressing of signals, sub-compartmentalization is used by cells for sustaining the multiplexed circuitry enabling complex signal processing and generation of integrated responses. Cells can shift metabolic flux in response to diverse signals by redistributing existing enzymes into organelles without affecting total enzyme quantities. The idea of engineering synthetic organelles to co-localize the components of an engineered metabolism has gained considerable interest in recent years. Reproducing such complex pathways in artificial cells can be achieved by building multi-compartmentalized ensembles . In a rein vivo metabolic control  that was captured by RNA present in receiver droplets to trigger fluorescence, but this also activated a dsDNA template which displaced DFHBI to cause the fluorescence to decay. This activation and deactivation of fluorophore propagated a fluorescent pulse through the array of receiver droplets . Chemical signaling is yet usually short range (except when flows of the surrounding medium are involved), slow, and stochastic due to the possible degradation of molecules, their diffusion, and the presence of a high background molecular noise . These pFurther systematic studies, e.g., of the impact of sender-receiver geometry on signaling, should be performed. Precise or targeted manipulation of artificial cells using magnetic field, optical tweezers, ultrasound waves, micromanipulators or 3D printers are promising tools for such a purpose. The design of new types of compartments with variable membrane permeability is also an interesting perspective to gain deeper insight into molecular communication.2+) and lactose as input signal that produced a fluorescence output in endonuclease EcoRI containing droplet and glucose production β-galactosidase containing water droplet, respectively. We anticipate that future studies will be geared towards developing more intricate signaling networks among consortia of artificial cells by a finer programmability and remote control over signal production, transmission or reception.Although most of the studies on artificial cell communication have been based on linear or cascade modes of communication, we have seen above that recent works try to increase the complexity of the signaling pathway by programming feedback, e.g., based on DNA strand displacement and genetic circuits. Future steps would be achieving orthogonal signaling, namely processing multiple signals at the same time without cross-talk, combining different types of signaling , or understanding how competition for the signal among homogenous or heterogenous colloidal communities affects signal transmission. Recently, Bayley and coworkers took a step in this direction by developing a three-compartment multisome system stabilised by lipids in aqueous environment that has ability to receive and process signals in parallel . This paComplexification of signaling responses may also come with complexification of the compartments themselves, e.g., via the design of dynamical systems capable of reconfiguration, restructuration, division, growth, differentiation , etc., bIn this review, we have illustrated how this rapidly emerging field of communication in artificial cells has progressed in the last decade with a majority of the strides being taken in the last 5 years alone. It started with more conventional self-modification of behaviour , progressed to paracrine/juxtacrine signaling and went further to achieve dynamic adaptive signaling at a population level to enable complex collective behaviours such as quorum sensing, travelling waves and pulses and differentiation of artificial cells. Different modes of communication were also explored such as linear, cascade, bidirectional and networked communication. Nevertheless, artificial cell signaling is still in its infancy when compared to its counterpart in living cells where complex signaling networks operate to control and coordinate behaviour at different length scales enabling organization, maintenance and multiplication of multicellular organisms or architectures. The importance of signaling in living systems is representative of its role in the development of artificial cell systems, to make them more autonomous, exhibit complex spatiotemporal patterning, differentiation and functional regulation. It could lead to the development of a new generation of smart colloidal agents, such as theranostic agents capable of smart multi-cycle delivery of payloads upon receiving appropriate biological cues. Though we have not reviewed the research regarding artificial cell communicating with living cells in this review, it also presents an important facet for artificial cell technologies. We can also envision a future where living cells are cultured in the presence of artificial cells to fabricate hybrid implants for regenerative medicine where the integrated artificial cells can perform functions of support, maintenance and regulation of the living cells in the implant and in the vicinity.


The report is not a review or a summary. In a manner, it is a perspective but an unusual one. It looks back to the years my colleagues and I (RG) began preparing for human retroviruses (beginning in 1970), how they evolved, and attempts to bring to light or simply to emphasize many exceptional characteristics of a retrovirus known as HTLV-1 and some fortuitous coincidences, with emphasis on the needs of the field. These events cover over one half a century. We have had many reviews on HTLV-1 disease, epidemiology, and basic aspects of its replication, genome, gene functions, structure, and pathogenesis, though continued updates are needed. However, some of its truly exceptional features have not been highlighted, or at least not in a comprehensive manner. This article attempts to do so. Journal of Virology with hostile comments from the editor that more or less concluded that everyone knows there are no human retroviruses and such reports, even such work, must stop.The first unusual feature mentioned is not exactly science-based, but it has been a recurrent one. The first submitted encompassing major manuscript describing this cancer virus (to be known as HTLV-1 later), the first known human leukemia virus, and the first human retrovirus was immediately rejected by the U.S. Proceedings of the National Academies of Science, which accepted the first few papers , attention to HTLV-1 quickly faded. This includes both knowledge about it and research support for it. This is not easy to understand. Though HTLV-1 is not widespread in the United States, most of Europe, China, and India, which form the largest centers for publicity and most of the world science support, it is very prominent in select places such as Japan; in Native Australians; in parts of Indonesia, Romania, and Iran; in several countries in South America but especially Peru and Brazil; in parts of equatorial Africa and migrants originating from Africa to Europe; in the United States; and especially in the islands of the Caribbean . The oddOne of us (RG) decided on two simultaneous efforts in a search for human retroviruses. One was to develop a sure surrogate marker for a retrovirus far more sensitive than electron microscopy because the titer of any putative retrovirus, if present, must be very low because of difficulty in finding one, a situation very different from the well-studied and well-known animal retroviruses that replicated to high levels. At the same time, we wanted this surrogate assay to allow frequent sampling of cultures because the virus may be expressed only in a “pulse”. Both were true, and our selection proved worthy. Indeed, very recent findings suggest that the plus-strand of the HTLV-1 provirus including tax remains transcriptionally silent, and only intermittently as bursts by cellular stress such as hypoxia and glycolysis –23. In 1After years of studies, we could make retrovirus assay sensitive  [the detail of the assay and its development was reviewed in ref ], readilThe second approach was attempted to grow primary human blood cells in sufficient amounts and over sufficient time to attempt proper culture. This would require growth factors, and a few were only recently discovered from conditional media. One key result we made was the discovery of a T-cell growth factor, later termed interleukin-2 (IL-2), which became the first studied cytokine –28. DuriSoon we found the second human retrovirus, HTLV-2, in a leukemic cell from a patient with a T-cell variant of having hairy cell leukemia . This viin vitro transformation and in vivo transfection studies that lead to transformed cells that look and act like human adult T-cell leukemia/lymphoma (ATL) cells. Alone among known tumor viruses, HTLV-1 infection apparently does it all. Sometimes, the issue has been raised as to why so many do not get leukemia when infected. My hypothesis is that the HTLV-1 provirus drives the proliferation of infected cells for its survival since HTLV-1 is so poorly infectious and transmission comes mostly from infected cells. It is also plausible that the establishment of the in vivo leukemia may require the accumulation of somatic mutations in infected T cells, which is driven by the clastogenic nature of HTLV-1 with time. Recent whole-genome analyses of the ATL cells from many patients indeed demonstrate convergent patterns of genetic mutations  cells , 43, or Above, it was already noted that HTLV-1 causes more than ATL. It also induces spastic paralytic disease  immune mechanisms –54. AddiAs noted above, in the 1970s, there was broad and strong resistance even to the possible existence of human retroviruses. The discoveries of the HTLVs (HTLV-1 reported in 1980 and HTLV-2 in 1982) were just being accepted when AIDS was first recognized in 1981, opening up the idea that AIDS might have a similar origin. However, by the time a patient was recognized as having AIDS, usually, the patient had many microbial infections. The question was which one was the cause? It turned out to be quite challenging; a hidden retrovirus was suggested and shown to be the cause. We can say with confidence that without the HTLV experience, this would have been thought of as a wild and unacceptable notion. Further, the key technology utilized for the discovery of HIV came out of HTLV research, namely, the growth of primary human blood T cells with IL-2 and a very sensitive and specific assay for a retrovirus (proper assays of RT), which were key to the findings on HIV.In vitro transformation of umbilical cord T cells  which holds the patent and intellectual property for the BNZ-1 peptide mentioned in this article.The remaining author declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Primary open-angle glaucoma is one of the leading causes of blindness worldwide. With limited therapeutics targeting the pathogenesis at the trabecular meshwork (TM), there is a great need for identifying potential new targets. Recent evidence has implicated Toll-like receptor 4 (TLR4) and it is signaling pathway in augmenting the effects of transforming growth factor beta-2 (TGFβ2) and downstream extracellular matrix production. In this review, we examine the role of TLR4 signaling in the trabecular meshwork and the interplay between endogenous activators of TLR4 (damage-associated molecular patterns (DAMPs)), extracellular matrix (ECM), and the effect on intraocular pressure Glaucoma is a progressive neurodegenerative disease and is the second leading cause of blindness worldwide, affecting over sixty million people . PrimaryIncreases in outflow resistance through the TM can be contributed to multiple factors, such as actin cytoskeletal rearrangement in the TM and changes to the inner wall endothelium of Schlemm’s canal . AdditioTLR4 polymorphisms are indicated to be involved with slower responses to infection, reduced autoimmunity, and glaucoma  in the development of glaucomatous trabecular meshwork damage. In human glaucomatous donor eyes several toll-like receptors, including TLR4, have been shown to have upregulated expression in the retina after IOP elevation . Additioglaucoma . Specifiglaucoma . These dToll-like receptors (TLRs) play a significant role in the detection of pathogen associated molecular patterns (PAMPs) and damage associated molecular patterns (DAMPs) . FunctioTLR4 was first identified as the receptor for lipopolysaccharide (LPS) and was shown to play a vital role in innate immunity . Activatin situ because of cell damage, cell injury, and remolding of the ECM  . DAMPs a the ECM . DAMPs cignaling . Endogenignaling . The speignaling . Specifiignaling . In patiignaling . An extrignaling . Like HMBambi expression enhances TGFβ signaling  and fibroblast growth factors (FGFs)  and helpAs mentioned, TGFβ2 signaling increases the production of ECM proteins, including FN. We and others have identified FN, a dimeric multidomain ECM glycoprotein, to be elevated in glaucomatous TM tissues and aqueous humor . FibroneTlr4. Here we found that TGFβ2-induced ocular hypertension and ECM production is dependent on both EDA and Tlr4, and in mice constitutively expressing FN-EDA the effects of TGFβ2 are amplified (Bambi in the TM resulted in increased ECM deposition and development of ocular hypertension, likely due to uninhibited TGFβ2 signaling. In addition, we also tested the role of NF-κB, an upstream regulator of Bambi expression, in TGFβ2-induced ocular hypertension and found that mutation in the p50 subunit of NF-κB prevented TGFβ2-induced ocular hypertension (Recently, utilizing a selective inhibitor of TLR4 signaling, TAK-242, we showed TGFβ2 induced ECM production in the TM was inhibited . Notablymplified . To furtrtension . These dWe have also examined ways to attenuate the downstream fibrotic signaling initiated by TGFβ2–TLR4 signaling crosstalk. Since NF-κB is necessary for this fibrotic response, we examined how a suppressor of NF-κB signaling, A20, may be able to rescue the effects of TGFβ2 and TLR4 activators, such as FN-EDA, within the TM. Previous work showed that A20 is downregulated in human TM cells that expressed constitutively active α5β3 integrin . The actThis review summarizes the involvement of the TGFβ2-TLR4 signaling pathways in augmenting the pathogenesis of ocular hypertension at the trabecular meshwork. The TLR4 pathway is a fibroinflammatory pathway that can modulate the function of the TM, specifically by altering the TM’s rate of deposition of ECM, leading to the impairment of aqueous humor outflow and the progression of glaucoma. Identification of additional DAMPs and regulators of TLR4 signaling may allow us to identify potential therapeutic targets for POAG. Further investigation of TGFβ2-TLR4 crosstalk in the TM will help to explain the mechanisms involved in the development of glaucomatous TM damage.


Lung cancer is the leading cause of cancer-related deaths globally. Despite current treatment approaches that include surgery, chemotherapy, radiation and immunotherapies, lung cancer accounted for 1.79 million deaths worldwide in 2020, emphasizing the urgent need to find novel agents and approaches for more effective treatment. Traditionally, chemicals derived from plants, such as paclitaxel and docetaxel, have been used in cancer treatment, and in recent years, research has focused on finding other plant-derived chemicals that can be used in the fight against lung cancer. Ursolic acid is a polyphenol found in high concentrations in cranberries and other fruits and has been demonstrated to have anti-inflammatory, antioxidant and anticancer properties. In this review, we summarize recent research examining the effects of ursolic acid and its derivatives on lung cancer. Data from in vitro cell culture and in vivo animal studies show potent anticancer effects of ursolic acid and indicate the need for clinical studies. Cancer is characterized by enhanced proliferative signaling and its ability to resist programed cell death/apoptosis, evade growth suppressors and induce angiogenesis, leading to survival, growth, tumor formation and metastasis . Lung caExcessive growth factor receptor signaling is well established as a significant contributor driving cancer cell survival, proliferation and metastasis . For exaDuring stressful cellular events, such as DNA damage, tumor suppressor p53 initiates cell cycle arrest to allow for DNA repair, and when repair is not possible, cellular apoptosis occurs . MutatioOther signaling molecules that play a role in carcinogenesis include the nuclear factor kappa-light-chain enhancer of activated B cells (NF-kB). NF-kB acts as a transcription factor and is activated by tumor necrosis factor (TNF-a) and several ligands that bind to transmembrane protein receptors, such as growth factor receptors. NF-kB activation results in the activation/release of antiapoptotic factors, cell cycle regulators, cytokines and chemokines, leading to cell survival, proliferation, inflammation and angiogenesis . IncreasInitiation of death receptor signaling activates the proapoptotic protein BID, which leads to the release of cytochrome C from mitochondria; the activation of effector caspases that cleave PARP; and the activation of other proteins responsible for cell shrinkage, DNA fragmentation and chromatin condensation, resulting in apoptosis ,23, undeCurrent treatments for lung cancer include surgery, chemotherapy, radiation therapy and immunotherapy . MedicatTaxus brevifolia and Taxus baccata, respectively) [Traditionally, plant-derived chemicals have been developed into agents used to treat cancer, including lung cancer. Such examples of plant-derived chemotherapy agents include paclitaxel and docetaxel, which are derived from the bark of the Pacific and European yew tree (ctively) ,29. Lungctively) ,31, and ctively) ,33.30H48O3) [Ursolic acid (UA) is a pentacyclic triterpenoid  (chemica30H48O3)  found in30H48O3) ,46,47,4830H48O3) ,50. FruiThere is evidence that UA exhibits a wide range of biological activities ,37,51,52A few published reviews summarize the effects of UA in cancer prevention and treatment ,63,64, bStudies that have examined the effects of UA in cultured human lung cancer cells are summarized below and in L were significantly reduced, whereas Bax protein levels were increased. Treatment with UA induced p21/WAF1 and Fas/APO-1 signaling [Human A549 adenocarcinoma lung cancer cells treated with ursolic acid (2–40 µM) had significantly reduced proliferation, G1-phase cell cycle arrest and induction of apoptosis (determined via DNA fragmentation), . Westernignaling ,  1, 2, 3, 9 and 10, as well as an increase in glucocorticoid receptor (GR) cytosolic localization. These data suggest that members of the MMP family may be involved not only in invasion but also apoptosis of cancer cells and that cytosolic localization of GR may be an important factor in the upregulation of MMP during ursolic-acid-induced apoptosis of H460 cells .+-K+-ATPase and PKC activities were reduced. Taken together, these data suggest that UA treatment increases apoptosis and decreases viability and migration of human lung cancer cells [Treatment of A549, H3255 and Calu-6 human lung cancer cells with UA decreased cell viability, migration and invasion and increased DNA fragmentation and apoptosis. Treatment with UA led to decreased protein expression of angiogenic factors vascular endothelial growth factor (VEGF) and transforming growth factor beta1 (TGF-beta1), both of which are biomarkers associated with cancer cell metastasis. In addition, mRNA levels of intercellular adhesion molecule-1 (ICAM-1) fibronectin and matrix metalloproteinases (MMP) 2 and 9, all important for cell adhesion, migration and invasion, were reduced. The levels of lactate dehydrogenase (LDH) in the medium, an indicator of plasma membrane damage, were increased, whereas Naer cells . AlthougApart from examining the effects of UA on lung cancer cells, researchers have examined the potential of UA to counteract the effects of cigarette smoke in lung cells. Normal human bronchial epithelial (NHBE) cells were exposed to cigarette smoke extract (CSE) to induce cytotoxicity and cell death in order to mimic the in vivo conditions of cigarette smoking. Treatment with UA resulted in reversal of many of the negative effects of CSE, including reduced CSE-induced cytotoxicity, reduced CSE-induced lactate dehydrogenase efflux and recovery of CSE-induced glutathione loss. CSE activated the Nrf2 pathway, as shown by the increased levels of NQO1, GST and Nrf2 proteins. Treatment with UA normalized these results to near-control levels and reduced the CSE-induced DNA damage. In this cell model, UA alleviated the cytotoxic effects of CSE and recovered the intracellular redox balance, suggesting that UA has a protective effect against CSE-induced cell injury. The authors concluded that UA has a potential role in both the prevention and treatment of lung tumors caused by cigarette smoking . The modA549 cells treated with UA showed reduced proliferation, as well as reduced adhesion, wound healing and transwell migration, indicating inhibition of metastasis. Western blot analysis revealed an upregulation of E-cadherin and a downregulation of N-cadherin and vimentin, indicating an inhibition of epithelial–mesenchymal transition (EMT). Furthermore, decreased expression of astrocyte-elevated gene-1 (AEG-1) correlated with repression of NF-kB signaling was observed in cells treated with UA .Treatment of A549 and H460 human lung cancer cells with UA significantly decreased cell viability and proliferation. UA increased chromatin condensation and induced apoptosis. Flow cytometry revealed an increase in cell cycle arrest in the G0/G1 phase. Western blot analysis revealed an increase in cleaved caspases 3 and 9, increased phosphorylation of the proapoptotic protein Bax and a decrease in phosphorylated Bcl-2, an anti-apoptotic protein, suggesting that UA induces apoptosis in these cells via a caspase-dependent pathway. Treatment with UA increased phosphorylation/activation of AMP-activated protein kinase (AMPK) and inhibited the phosphorylation/activation of mTOR and p70S6K proteins, which are involved in protein synthesis and cell growth. In addition, the levels and activity of the lipogenic enzymes acetyl-CoA carboxylase (ACC) and fatty acid synthase (FASN) were decreased due to increased AMPK activation [Treatment of A549 human lung cancer cells with ursolic acid (0–50 µM) resulted in reduced cell viability and increased DNA damage associated with inhibition of vaccinia-related kinase 1 (VRK1) autophosphorylation and reduced phosphorylation of its downstream substrates, CREB and histone H3. This UA treatment also decreased cyclin D1 mRNA levels, a downstream effector of CREB and histone H3. Nuclear magnetic resonance (NMR) titration experiments and in silico modeling showed that UA is able to bind directly to VRK1, causing inhibition of kinase activity. A combination of UA with doxorubicin resulted in greater reduction in cell viability compared to either compound alone, indicating a synergic effect. Furthermore, when UA was combined with the PARP-1 inhibitor veliparib, a significant reduction in cell viability was observed compared to UA alone, indicating that UA exerts synergistic effects when combined with drugs that target DNA damage repair genes . The finWu et al. reported significantly reduced cell viability and induction of apoptosis in NSCLC  cells treated with UA (5–80 µM). UA treatment increased phosphorylation/activation of stress-activated protein kinases/Jun amino-terminal kinases (SAPK/JNK) while simultaneously decreasing the protein levels of SP1, DNMT1 and EZH2. Detection of caspase 3/7 activity was increased by UA treatment, as observed with a Caspase 3/7 assay kit. Use of the SAPK/JNK inhibitor SP600125 abolished the effects of UA on SP1, DNMT1 and EZH2, confirming the involvement of this signaling pathway. Exogenous expression of SP1 or DNMT1 also abolished the UA-induced effects, providing strong evidence of their involvement. Based on these data, the authors concluded that UA inhibits NSCLC cell growth via SAPK/JNK-mediated inhibition of SP1, DNMT1 and EZH2 .Treatment of mesothelioma cells  with 10–40 µM UA inhibited proliferation and colony formation in a dose-dependent manner. Cell-cycle analysis showed an accumulation in the sub-G1 phase compared to untreated controls, indicating induction of apoptosis. Western blot analysis showed reduced total PARP and reduced caspase 3, both of which are apoptosis-related proteins. UA treatment attenuated the levels of EMT-related proteins; E-cadherin expression was increased, whereas levels of vimentin, N-cadherin, twist, B-catenin and pGSK3a/b were decreased. The expression of the survival genes cyclin D1, p-AKT and NF-kB were also reduced with UA treatment. MicroRNA array and qRT-PCR results indicated that let7b was upregulated in H2452 and H28 cells treated with UA. Overall, the data reported in this study suggest that UA treatment can induce apoptosis in lung cancer cells through inhibition of EMT and increased expression of let7b . DownregSong et al. (2017) examined the ability of UA to increase the radiosensitivity of H1299 NSCLC cells . They esTreatment of A549 cells with UA (10–100 µM) for 24 h inhibited cell proliferation and induced apoptosis. UA decreased the number of cells in the G0/G1 phase in a dose-dependent manner and increased the number of cells in the S and G2/M phases, suggesting UA-induced cell cycle arrest in the S and G2/M phase. This UA treatment decreased protein expression of Bcl-2 and total PARP, increased levels of cleaved-PARP and increased markers for autophagy, including the LC3-II/LC3-I ratio and p62 protein expression .Human lung cancer A549 cells treated with UA  for 24 or 48 h showed reduced cell viability, as well as increased autophagy and mitophagy. Treatment with UA increased the levels of autophagy-associated protein LC3-II and increased the LC3-II/LC-I ratio. In addition, the mitochondria of cells treated with UA appeared to be fragmented, and the levels of p62 protein, which is required for mitophagy, were increased and colocalized with fragmented mitochondria. Furthermore, treatment with UA increased ROS production, increased Nrf2 and PTEN-induced kinase 1 (PINK1) protein levels and reduced phosphorylated Akt and mTOR levels . The datUrsolic acid treatment of NSCLC H1975 cells with an EGFR T790M mutation, a major cause of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI/erlotinib) resistance, resulted in inhibition of proliferation and motility, as well as induction of apoptosis. UA treatment resulted in inhibition of CT45A2 expression via β-catenin/TCF4 inhibition. These data show that UA may be a potential treatment for NSCLC with the EGFRl858R/T790M mutation . This stChen et al. constructed a paclitaxel resistance cell line, A549-PR, with increased expression of stemness markers CD133, Oct-4, Notch3, Nanog and Sox2. Treating these chemotherapy-resistant cells with UA resulted in decreased expression of these marker proteins, reduced aldehyde dehydrogenase 1 (ALDH1) activity and, importantly, increased sensitivity to paclitaxel. Treatment of A549-PR cells with UA resulted in reduced miR-149-5/MyD88 signaling. The UA-mediated inhibition of chemoresistance and stemness was partially reversed by overexpression of miR-149 and knockdown of MyD88 . PaclitaHuman NSCLC cells (H1975) treated with UA exhibited inhibited mesenchymal-like responses, such as migration, invasion and matrix metallopeptidase (MMP) 2 and 9 activity . FurtherHuman lung cancer cells (NCI-H292) treated with UA showed significantly reduced viability and increased apoptosis, as evidenced by increased levels of cleaved PARP and increased cytochrome C levels. Western blotting analysis revealed increased levels of endonuclease G (Endo G) and apoptosis inducing factor (AIF), whereas levels of the antiapoptotic proteins B-cell lymphoma 2 (BCL2) and BH3 interacting domain death agonist (BID) were reduced with UA treatment. In these cells, UA increased intracellular calcium levels by causing a time-dependent release and reduced mitochondrial membrane potential without affecting ROS levels. Taken together, these results suggest that UA treatment can induce apoptosis through AIF and Endo G release via a mitochondria-dependent pathway .A variety of lung cancer cells , when treated with UA, exhibited significantly reduced cell proliferation, whereas apoptosis was induced, as evidenced by an annexin V-FITC/PI double staining assay. UA treatment increased levels of cleaved PARP and decreased levels of Bcl-2, both indicators of apoptosis. In addition, treatment of H460, H1975 and A549 lung cancer cells with UA induced autophagy, as revealed by the elevation in the protein levels of the autophagy marker LC-3-II. Furthermore, UA treatment decreased phosphorylation/activation of Akt and its downstream targets, p70S6K and 4EBP1. Inhibition of autophagy, using siRNA for autophagy-related gene 5 (ATG5) or chloroquine, enhanced the effects of UA (inhibition of proliferation and induction of apoptosis), suggesting that the autophagy observed following UA treatment acts as a pro-survival mechanism in these cells .Human A549 and H460 lung cancer cells treated with UA exhibited reduced proliferation, as well as reduced CDK4, cyclin D1 and cyclin E protein and mRNA levels, whereas the levels of p21 and p27 tumor suppressor proteins were increased. In addition, treatment with UA resulted in decreased VEGFR and pSTAT3 levels, suggesting inhibition of angiogenesis. Decreases in cell invasion and wound healing/migration were observed, suggesting antimetastatic activity of UA in NSCLC cells. Cancer stem cell (CSC) proliferation was inhibited with UA treatment, as evidenced by a significant reduction in the levels of CSC markers . Molecular binding studies showed a high-affinity interaction between UA and EGFR, suggesting that UA interferes with EGFR signaling. This was further tested by treating cells with human recombinant EGF combined with 20 µM of UA. In the presence of UA, the EGF-mediated EGFR phosphorylation was reduced, and the downstream targets of the EGFR pathway, JAK2 and STAT3, showed reduced phosphorylation, whereas the total protein levels remained unchanged. Chromatin DNA extracted from NSCLC cells that had been treated with UA exhibited a significant reduction in the binding of STAT3 to promoters MMP2 and PD-L1. Based on these results, the authors concluded that UA has anticancer activity dependent on STAT3 signaling, that STAT3 acts as a bridge between EGFR and PD-L1 and that UA may be a drug candidate for PD-L1-based targeted cancer therapies . Althoug50 values) of proliferation of different lung cancer cell lines.According to the results of the studies presented above, it is evident that the effects of UA were examined in a variety of lung cancer cells representing distinct subtypes of the disease. Small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) adenocarcinoma, squamous cell carcinoma and large cell carcinoma cell lines were utilized. The effective concentration of UA appears to be in the range of 20–50 µM in the majority of the studies reviewed herein. Unfortunately, no studies have been conducted that examine and directly compare the UA concentration required for half-maximum inhibition  for 1 week, followed by subcutaneous injection of A549 lung cancer cells in their right flank in the second week. Four weeks following cancer cell injection, the excised tumors showed reduced volumes compared to the control group that received no UA pretreatment. The tumor volumes observed following UA pretreatment were comparable to those in mice treated with the established chemotherapy drug cyclophosphamide . However7 cells/mouse) in their flank were treated intraperitoneally with UA (100 mg/kg), etoposide (6 mg/kg) or a combination of UA and etoposide for 14 days. Both UA and etoposide treatment showed a trend toward reduced tumor weight; however, tumor weights did not significantly differ from those of non-treated animals in the control group. When UA and etoposide were administered in combination, a significant decrease in tumor volume was observed, indicating a synergistic effect. UA was also injected in combination with doxorubicin (2 mg/kg) to the xenografted mice for 10 days; this combination showed synergistic effects, resulting in reduced tumor size compared to each treatment alone [C57 BL/6 mice injected with Lewis lung carcinoma (LLC)-luciferase cells  7 days prior to UA treatment, which was administered every other day for two weeks. Animals were sacrificed on experimental day 23; immunohistochemistry of tumor tissue samples from the high-dose UA group showed decreased protein expression of Ki-67, MMP-2 and CD34, as well as increased expression of Bid. The decreased levels of Ki-67 indicate decreased proliferation of cancer cells, the increased levels of Bid show induction of apoptosis and the reduced CD34 levels indicate reduced angiogenesis. The reduced proliferation, reduced angiogenesis and induction of apoptosis may explain the reduced tumor volume and weight. Although the reduction in MMP-2 suggests reduced metastasis, researchers found that liver metastasis was not prevented by UA treatment. Furthermore, the nude mice used in the study were found to have detectable levels of functional immune cells (T and NK cells); therefore, it is possible that UA increased the cancer-killing ability of the intrinsic immune system of the animals. Further studies are required to examine the role of UA in the immune system of animals and humans with lung cancer [Subcutaneous injection of 50 or 100 mg/kg UA (extracted from the leaves of wild loquat E. fragrans Champ) to female Balb/c nude mice xenografted with A549 human lung cancer cells resulted in reduced tumor volume and weight compared to the vehicle control group . Animalsg cancer .6), expressing the EGFR T790M mutation which confers resistance to erlotinib (EGFR-TKI), in their flank and administered UA (25 mg/kg) via daily injection for 18 days. This treatment reduced tumor growth and weight when compared to the vehicle control group [Athymic nude mice were injected with H1975 human lung cancer cells  had the greatest anticancer effect. Accordingly, UA derivatives with electron-donating groups (UA-9) were suggested to have the most potent anticancer activity . HoweverUrsolic acid-triazolyl derivatives with o-bromo, o-chloro or o-methoxy substitutions on the aromatic ring showed inhibition of cell growth of cancer cells, including A549 lung cancer cells . These UA group of ursolic acid benzylidene derivatives were created through an oxidation/condensation procedure and tested against cultured cancer cells, including A549 lung cancer cells . Each of+/+). UA with a cleaved A-ring and a secondary amide at C3 (compound 17) was found to be the most active in inducing apoptosis. Treatment of lung cancer cells with this UA derivative induced apoptosis, as evidenced by the increased cleaved caspase-8 and caspase-7 levels and the decrease in Bcl-2 protein levels. Increased levels of Beclin-1 and LC3A/B-II suggested an induction of autophagy with this UA-derivative treatment. Decreases in mTOR and p62 protein levels were also observed. Based on these findings, UA derivative compound 17 may be a potential candidate for lung cancer treatment and should be further researched [A series of A-ring cleaved UA derivatives were prepared and evaluated in NSCLC cells  treatment with the UA derivative UA232 resulted in reduced cell proliferation and induction of apoptosis. These effects were more prominent with UA232 than treatment with the parent UA compound, whereas the cytotoxic effects on normal cells (HEK293T) were the same. UA232 treatment of lung cancer cells caused the cells to arrest in the G0/G1 phase of the cell cycle in association with downregulation of cyclin D1 and CDK4. This novel UA derivative significantly increased apoptosis and increased cleaved-PARP1 protein levels compared to standard UA treatment. There was no significant change in the levels of Bax, Bcl-2 or caspase-8, indicating that apoptosis was not induced through either the mitochondrial apoptosis pathway or the death receptor pathway. UA232 treatment increased expression of CHOP, indicating a mechanism involving the ER stress pathway. Pretreatment with 4-PBA, an ER stress inhibitor, attenuated the UA232-induced apoptosis, a further indication of the role of ER stress .Another UA derivative with functionalized aniline or amide side chains was synthesized and used to treat lung adenocarcinoma NCI-H460 cells. Compound 5Y8 had the most potent antiproliferative activity, which was significantly higher than that associated with treatment with the UA parent compound. Molecular docking studies revealed that compound 5Y8 had a key interaction with the active site of NF-kB, blocking the activity and signaling pathway, which led to apoptosis. These findings indicate that the 5Y8 UA derivative has potential as a new class of NF-kB inhibitor for the treatment of lung cancer and may contribute to overcoming chemotherapy resistance .50 values in a micromolar range (5.22–8.95 μM) [50: 5.22 μM) and caused G1 phase cell cycle arrest and increased caspase 3 cleavage, an indicator of apoptosis. In addition, cancer cell migration was inhibited, suggesting that this compound may help to prevent metastasis. Treatment with UA compound 8C inhibited the NF-kB signaling pathway, as evidenced by the significantly reduced levels of phosphorylated IKKα/β and IKBα and reduced NF-kB levels. Furthermore, molecular docking studies showed a key interaction between compound 8C and the active site of NF-kB, blocking its activity [Treatment of A549 lung cancer cells with a number of UA derivatives containing long-chain diamine moieties resulted in significant inhibition of viability, with IC8.95 μM) . The UA activity . Activatactivity  shows clAlthough the parent ursolic acid compound has been shown to be an effective anticancer agent, the above-described studies have shown that derivatives of the parent UA compound have enhanced potency, indicating that modification may be an effective approach to drug development.2) had increased plasma concentration with the peak UA concentration of 3404.6 ng/mL (7454.78 nM) four hours post infusion, followed by a rapid decline between hours 4 and 6. The concentration slowly declined from post-infusion hour six (approximately 300 ng/mL (656.89 nM)) to hour sixteen (approx. 30 ng/mL (65.69 nM)) [UA has limited bioavailability ,91 due, .69 nM)) .Collectively, the limited animal studies indicate that oral administration of UA can result in plasma UA levels in the nano-to-micromolar range, at concentrations close to those used in the majority of the in vitro studies showing potent anticancer effects.Another point that deserves consideration is the role of the gut microbiome in UA-induced effects. The gut microbiota may influence UA metabolism and result in the generation of UA metabolites with potent anticancer properties. Unfortunately, the anticancer properties of UA metabolites have not been studied to date.GooglePatents.com, accessed on 9 September 2022) revealed that in the past 10 years, 25,638 patent applications have been filed globally pertaining to UA, of which 5793 were related to UA use in cancer. In Canada, 354 applications were filed for UA patents, with 140 related to cancer. In the US, the numbers were higher, with a total of 1341 applications related to UA and 542 specifically related to UA and cancer. A search of European Union (EU) Clinical Trials Registry and the Government of Canada clinical trials registry yielded no registered trials related to ursolic acid use specifically for cancer treatment or any other use.A search of patent applications  related to ursolic acid revealed four trials: three completed and one withdrawn. Among the completed clinical trials, one (NCT02401113) examined the effect of ursolic acid (derived from loquat extract) in preventing sarcopenia in 54 adults, although no data/results have been published . Another trial examined the bioavailability of ursolic acid in 18 healthy male adult participants (NCT04421716); although the study was completed in April 2021, no results have been published. The third trial  examined the effects of 12-week ursolic acid administration  in 24 adult participants with metabolic syndrome [A search of syndrome , with fiThese data clearly indicate that although there is evidence from in vitro studies and limited in vivo animal studies of the anticancer potential of ursolic acid, interest from the scientific community to perform clinical trials is limited, possibly due to a lack of strong in vivo animal studies, leading to a lack of funding.2, administered by a 4 h intravenous infusion), was investigated in a group of 63 volunteer subjects. The DLT was found to be between 74–130 mg/m2 and mainly consisted of diarrhea and hepatotoxicity, and the MTD was determined to be 98 mg/m2 [One potential limitation of clinical translation of UA is its low bioavailability due to its low water solubility. An innovation that can combat this limitation would be to successfully encapsulate UA into micelles, nanoparticles or liposomes. These encapsulation strategies can increase the water solubility of UA, hopefully resolving the low bioavailability issue. In one preliminary clinical trial, the maximum tolerated dose (MTD), as well as the dose-limiting toxicity (DLT) of ursolic acid liposomes (11–130 mg/m98 mg/m2 . The abo98 mg/m2  and the 98 mg/m2  describe98 mg/m2  describeAlthough few UA derivatives have been found to be more effective than the parent compound in cell culture studies (studies presented in In vitro studies reported here suggest that treatment of lung cancer cells with UA reduces proliferation and viability while increasing apoptosis and autophagy. Some studies showed cell cycle arrest in the G0/G1 phase, as well as reduced cell migration. Several studies showed inhibition of NF-kB and/or mTOR pathways, which are involved in cell proliferation and survival. In most of the studies examined herein, apoptosis was confirmed through increased levels of cleaved PARP, as well as caspases 3, 7 and 9. Some studies showed an increase in the expression of the proapoptotic protein Bax and a significant decrease in the expression of the antiapoptotic protein Bcl-2, highlighting the apoptotic effects of ursolic acid on lung cancer cells.In vivo studies revealed that treatment of lung cancer xenografted animals with UA resulted in a decrease in tumor volume and weight; however, it is not yet clear whether the mechanisms involved are the same as those reported with cell cultures.A number of UA derivatives and analogs have been developed and tested for their effect against lung cancer, with some showing higher anticancer effects than the parent UA compound. Further studies with derivatives are needed to examine the signaling pathways involved.Drugs currently used for the treatment of lung cancer include cisplatin, gemcitabine, docetaxel, etoposide, paclitaxel and vinorelbine. Only a few studies have compared the effects of UA to the effects of currently used lung cancer drugs. Kim et al.  found thIn vivo animal studies have shown that UA treatment of animals xenografted with lung cancer cells had a similar effect in reducing tumor volume as cyclophosphamide , etoposiOverall, the studies summarized in the present review collectively show that treatment of lung cancer cells with ursolic acid considerably reduces key cancer features, including cell viability, proliferation, colony formation and migration, in addition to inducing cancer cell death. Treatment of animal models of lung cancer with UA resulted in reduced tumor volume. Future research is required to further determine the effects of UA on both cancerous and normal tissues, as well as to elucidate the cellular signaling pathways involved.It should be noted that UA has low water solubility and limited bioavailability. Future studies should be conducted to better understand the best route of administration, pharmacokinetics, bioavailability and tumor-reducing potential of UA, its derivatives and metabolites.Importantly, to further investigate the anticancer potential of UA in cancer patients, clinical trials are necessary.