FIELD OF THE DISCLOSURE

The disclosure generally relates to inhibitors of CaMKK2. More particularly, the disclosure relates to small molecule inhibitors of CaMKK2.

BACKGROUND OF THE DISCLOSURE

Ca2+is the most pervasive second messenger in cell-based signaling and many proteins are involved in mediating calcium signaling. Of these, the Ca2+/Calmodulin kinases (CaM kinases) have multiple roles many of which remain to be elucidated. The most upstream of these are the CaM-kinase kinases (CaMKKs) which consist of two known isoforms (α/β or 1/2). Both isoforms act as upstream activators of CaMK1 and CaMK4. Intriguingly, CaMKK2 has constituitive or autonomous activity, while CaMKK1 is dependent upon Ca2+/CaM binding. The entire list of substrates of CaMKK2 is not yet known but, in addition to CaMK1 and CaMK4, this kinase has been shown to act as an upstream activator of Akt and AMPK.

Over the last decade there have been numerous studies implicating CaMKK2 in diseases. Recently CaMKK2 has been shown to play an important role in cancers, such as, for example, hepatocellular carcinoma, prostate cancer, glioma; in neurological diseases such as, for example, Alzheimer's Disease, depression and bipolar disorder; and in metabolic disorders, such as, for example, bone loss; diabetes, metabolic syndrome and obesity. In each of these cases, a high quality pharmacological probe would help elucidate the biology or potentially be a therapeutic agent.

The activity of CaMKK2 in neurodegenerative diseases is especially prominent in the literature, and suggests that a drug-like CaMKK2 inhibitor may be a therapeutic entity for treating these diseases. Accumulation of Aβ42 oligomers (42-amino acid-long amyloid beta [Aβ42o] peptide fibrils forming amyloid plaques), Tau phosphorylation (and ultimately accumulation of hyper-phosphorylated Tau in tangles [NFT]), increased/defective autophagy, abnormal calcium homeostasis and defective mitochondrial structure/function have all independently been implicated in the pathophysiology of Alzheimer's Disease (AD). Over-activation of the CAMKK2-AMPK kinase pathway represents a novel and unique unifying ‘stress-response’ pathway, since this kinase dyad is over-activated by Aβ42o in a calcium-dependent manner and triggers phosphorylation and activation of a myriad of downstream effectors such as Tau, MFF (mitochondria fission factor), and ULK2 (mitophagy inducing kinase) and, therefore, links at least 5 of the landmark defects reproducibly involved in early stages of AD pathophysiology. Before the formation of amyloid plaques and NFT, amyloidogenic processing of amyloid precursor protein (APP) by β- and γ-secretase produces abnormal accumulation of Aβ42 peptides, which have a strong ability to oligomerize and form dimers, trimers, and higher-order oligomers that ultimately fibrillate to form Aβ plaques. Soluble, oligomeric forms of Aβ42 (Aβ42o) lead to early loss of excitatory synapses (synaptotoxic effects) in cortical and hippocampal pyramidal neurons (PNs) before plaque formation and without compromising neuronal viability, strongly suggesting that synaptotoxicity is an early event in the disease progression triggered by soluble Aβ42o. A second class of pathological cellular events reported in brain of AD patients are thought to affect mitochondrial structure and function, including altered axonal mitochondria motility, defective mitochondrial function and imbalanced mitochondrial fission and fusion. Aβ42o overactivates the stress-response AMP-activated kinase (AMPK) in a CAMKK2-dependent manner and inhibition of CAMKK2 or AMPK protects hippocampal PNs from Aβ42-mediated loss of excitatory synapses observed in the hAPPSWE,INDtransgenic AD mouse model (J20) in vivo. Importantly, the effects of Aβ42o-dependent CAMKK2-AMPK over-activation on synaptic loss require the ability of AMPK to phosphorylate Tau on a specific Serine residue (S262) providing the first link between Aβ42o and Tau phosphorylation in early stages of AD pathophysiology. In addition, upon AMPK-dependent phosphorylation, mitochondrial fission factor (MFF) enhances the recruitment of the mitochondrial fission effector Drp1, suggesting a connection to neuronal mitophagy (autophagy of mitochondria) and that blocking CAMKK2-AMPK blocks the ability of Aβ42o to induce synaptic loss. AMPK is ubiquitously expressed by all cells in the body, but CAMKK2 expression is largely restricted to neurons in the central nervous system and, thus, constitutes a drug target for AD. The CAMKK2-AMPK-phosphoTau pathway is, thus, the only pathway known that links Aβ to tau phosphorylation, suggesting that this unique pathway is not just a surrogate of Aβ but an actual pathophysiological mechanism of AD development and maintenance. This effect may apply to other neurodegenerative diseases, as CAMKK2 overactivation appears also to be associated with prion disease maintenance.

The most well-known inhibitor of CaMKK2 is STO-609. This agent, while reasonably potent biochemically, has poor potency in cells. For example, it was previously used at 100 to 1000-fold over it is known IC50to observe effects in cells. The selectivity of this agent over other kinases is poor and, at such high concentrations as have been used in cells in published studies, other targets are being engaged, confounding interpretation to some extent. It has therefore been acknowledged in the extant literature that a dose of caution should be employed when interpreting the results of experiments with this agent, due to its poor selectivity. Furthermore, STO-609 has poor permeability. These issues may disqualify STO-609 from use in vivo evaluation.

As of yet, no licensed drug specifically targets CAMKK2, and an in vivo CAMKK2 chemical probe (a selective, pharmacokinetically suitable agent that can be used in animal studies to draw conclusions about in vivo phenotype of CAMKK2 inhibition) does not currently exist, yet such a probe is required for preclinical studies. As a serine/threonine kinase, CAMKK2 falls within the druggable genome: over 25 kinase inhibitors targeting a variety of kinases already are FDA-approved drugs, many of which have revolutionized the treatment of multiple diseases. In a published PK study, STO-609 fails to enter the brain despite achieving plasma concentrations >30 μM with a 9.4 mg/kg ip dose. In fact, this agent displayed generally poor tissue penetration with Cmaxvalues at or below 1 μM with elimination completed in 8 hour (h) or less. This is well below the putative cell-based IC50of this agent. The effects of plasma protein binding were not considered but would undoubtedly render these concentrations insufficient to deliver efficacious free concentrations of this agent. The poor permeability of STO-609 is in large part due to the carboxylate moiety which is required for CaMKK2 potency. A previously published paper on the Phase I clinical trial of the TORC1/2 inhibitor OSI-027 which, like STO-609, has a pendent free carboxylate moiety, demonstrated poor tissue and tumor penetration despite achieving high plasma concentrations. Although drugs with carboxylic acids are known, they are not common and are generally considered a liability for entry into the central nervous system (CNS). STO-609 is also a potent agonist of the ArH receptor (43 nM) leading to the induction of CYP1A1, 1B1 and other ArH target genes in multiple cell lines. It was demonstrated that STO-609 also activates CaMK1 through ArH activity—an especially confounding observation as CaMK1 is a substrate of CaMKK2 and should be indirectly inhibited. Taken together, these data rules out STO-609 for CNS applications. A CaMKK2 inhibitor was previously disclosed by scientists at the University of North Carolina; however, this agent, like STO-609, also has a carboxylate on which its potency depends. It observed that it has even poorer cell-based activity that STO-609. In short, while CaMKK2 is an important target, no suitable in vivo probe exists for this target in AD, and other diseases/pathologies associated with CaMKK2.

Based on the foregoing, there exists an ongoing and unmet need for improved CaMKK2 inhibitors.

SUMMARY OF THE DISCLOSURE

The present disclosure provides compounds suitable for inhibiting CaMKK2. Also provided are compositions and methods of treating diseases associated with CaMKK2.

In an aspect, the present disclosure provides compounds. The compounds may be inhibitors of CaMKK2. The compounds comprise an indazole core. The indazole core is substituted at the 3-position and the 5-position. The indazole core may have additional substitution as described herein.

In an aspect, the present disclosure provides compositions comprising one or more compound of the present disclosure. The compositions may comprise one or more pharmaceutically acceptable carrier.

In an aspect, the present disclosure provides methods of using one or more compounds of the present disclosure. For example, the compounds can be used to treat an individual having cancer, a neurologic disease, a metabolic condition, an orthopedic condition, a mental health condition, a viral infection, or a combination thereof.

For example, a method of treating comprises administering to an individual one or more compound of the present disclosure or a composition comprising one or more compounds of the present disclosure.

The method may be carried out in an individual who has been diagnosed with or is suspected of having cancer (e.g., prostate cancer, ovarian cancer, pymphoma, lung, colorectal, glioma, hepatocellular, and the like, and combinations thereof), neurologic diseases (e.g., neurodegenerative diseases such as, for example, Alzheimer's Disease and the like), metabolic conditions (e.g., obesity, type-2 diabetes, non-alcoholic fatty liver disease (NAFLD), and the like, and combinations thereof), orthopedic conditions (e.g., for treating fractures, for treating muscle atrophy, and the like, and combinations thereof), mental health conditions (e.g., anxiety, depression, obsessive compulsive disorder, bipolar disorder, schizophrenia, and the like, and combinations thereof), a viral infection (i.e., therapeutic use) (e.g., human immunodeficiency virus (HIV), tuberculosis (TB), and the like, and combinations), or a combination thereof.

A method of the present disclosure comprises administering to an individual in need of treatment one or more compounds or a composition comprising one or more compounds of the present disclosure. Compositions comprising the compounds described herein may be administered to an individual using any known method and route, including oral, parenteral, subcutaneous, intraperitoneal, intrapulmonary, intranasal, and intracranial injections. Parenteral infusions include, but are not limited to, intramuscular, intravenous, intraarterial, intraperitoneal, subcutaneous administration, and the like. Administration may also include, but is not limited to, topical and/or transdermal administrations.

