In this study, Falletta et al. show that microenvironmental cues, including inflammation-mediated resistance to adoptive T-cell immunotherapy, transcriptionally repress MITF via ATF4 in response to inhibition of translation initiation factor eIF2B.,Their results suggest that translation reprogramming, an evolutionarily conserved starvation response, has been hijacked by microenvironmental stress signals in melanoma to drive phenotypic plasticity and invasion and determine therapeutic outcome.,The intratumor microenvironment generates phenotypically distinct but interconvertible malignant cell subpopulations that fuel metastatic spread and therapeutic resistance.,Whether different microenvironmental cues impose invasive or therapy-resistant phenotypes via a common mechanism is unknown.,In melanoma, low expression of the lineage survival oncogene microphthalmia-associated transcription factor (MITF) correlates with invasion, senescence, and drug resistance.,However, how MITF is suppressed in vivo and how MITF-low cells in tumors escape senescence are poorly understood.,Here we show that microenvironmental cues, including inflammation-mediated resistance to adoptive T-cell immunotherapy, transcriptionally repress MITF via ATF4 in response to inhibition of translation initiation factor eIF2B.,ATF4, a key transcription mediator of the integrated stress response, also activates AXL and suppresses senescence to impose the MITF-low/AXL-high drug-resistant phenotype observed in human tumors.,However, unexpectedly, without translation reprogramming an ATF4-high/MITF-low state is insufficient to drive invasion.,Importantly, translation reprogramming dramatically enhances tumorigenesis and is linked to a previously unexplained gene expression program associated with anti-PD-1 immunotherapy resistance.,Since we show that inhibition of eIF2B also drives neural crest migration and yeast invasiveness, our results suggest that translation reprogramming, an evolutionarily conserved starvation response, has been hijacked by microenvironmental stress signals in melanoma to drive phenotypic plasticity and invasion and determine therapeutic outcome.
This retrospective study aimed to identify prognostic factors in patients with brain metastases from cutaneous melanoma.,In all, 265 patients under regular screening according to valid national surveillance guidelines were included in the study.,Kaplan-Meier analyses were performed to estimate and to compare overall survival.,Cox modeling was used to identify independent determinants of the overall survival, which were used in explorative classification and regression tree analysis to define meaningful prognostic groups.,In total, 55.5% of our patients presented with two or less brain metastases, 82.6% had concurrent extracranial metastasis and 64% were asymptomatic and diagnosed during surveillance scans.,In all, 36.7% were candidates for local treatment (neurosurgery or stereotactic radiosurgery (SRS)).,The median overall survival of the entire collective was 5.0 months (95% confidence interval: 4.3-5.7).,Favourable independent prognostic factors were: normal pre-treatment level of serum lactate dehydrogenase (P<0.001), administered therapy (neurosurgery or SRS vs other, P=0.002), number of brain metastases (single vs multiple, P=0.032) and presence of bone metastasis (false vs true, P=0.044).,Three prognostic groups with significantly different overall survival were identified.,Candidates for local treatment (group I) had the longer median survival (9 months).,Remaining patients could be further classified in two groups on the basis of serum lactate dehydrogenase.,Applied treatment and serum lactate dehydrogenase levels were independent predictors of survival of patients with brain metastases from cutaneous melanoma.,Patients receiving local therapy have overall survival comparable with general stage IV melanoma patients.