Bilirubin Restrains the Anticancer Effect of Vemurafenib on BRAF-Mutant Melanoma Cells Through ERK-MNK1 Signaling.
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ABSTRACT:
SUBMITTER: Tan Y
PROVIDER: S-EPMC8250144 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundApproximately 50% of melanomas harbor activating (V600) mutations in the serine-threonine protein kinase B-RAF (BRAF). The oral BRAF inhibitor vemurafenib (PLX4032) frequently produced tumor regressions in patients with BRAF V600-mutant metastatic melanoma in a phase 1 trial and improved overall survival in a phase 3 trial.MethodsWe designed a multicenter phase 2 trial of vemurafenib in patients with previously treated BRAF V600-mutant metastatic melanoma to investigate the efficacy of vemurafenib with respect to overall response rate (percentage of treated patients with a tumor response), duration of response, and overall survival. The primary end point was the overall response rate as ascertained by the independent review committee; overall survival was a secondary end point.ResultsA total of 132 patients had a median follow-up of 12.9 months (range, 0.6 to 20.1). The confirmed overall response rate was 53% (95% confidence interval [CI], 44 to 62; 6% with a complete response and 47% with a partial response), the median duration of response was 6.7 months (95% CI, 5.6 to 8.6), and the median progression-free survival was 6.8 months (95% CI, 5.6 to 8.1). Primary progression was observed in only 14% of patients. Some patients had a response after receiving vemurafenib for more than 6 months. The median overall survival was 15.9 months (95% CI, 11.6 to 18.3). The most common adverse events were grade 1 or 2 arthralgia, rash, photosensitivity, fatigue, and alopecia. Cutaneous squamous-cell carcinomas (the majority, keratoacanthoma type) were diagnosed in 26% of patients.ConclusionsVemurafenib induces clinical responses in more than half of patients with previously treated BRAF V600-mutant metastatic melanoma. In this study with a long follow-up, the median overall survival was approximately 16 months. (Funded by Hoffmann-La Roche; ClinicalTrials.gov number, NCT00949702.).
| S-EPMC3724515 | biostudies-literature
Project description:The combination of JQ1 and Vemurafenib acted synergistically in BRAF-mutant cell lines, resulting in marked apoptosis in vitro, with up-regulation of pro-apoptotic proteins. In vivo, combination treatment suppressed tumor growth and significantly improved survival compared to either drug alone. RNA sequencing of tumor tissues revealed almost four thousand genes that were uniquely modulated by the combination, with several anti-apoptotic genes significantly down-regulated.
2016-06-21 | GSE83592 | GEO
Project description:BackgroundRAF inhibitors are an effective therapy for patients with BRAF-mutant melanoma and brain metastasis. Efficacy data are derived from clinical studies enriched with physiologically fit patients; therefore, it is of interest to assess the real-world experience of vemurafenib in this population. Tumor-specific genetic variants that influence sensitivity to RAF kinase inhibitors also require investigation.MethodsRecords of patients with BRAF-mutant melanoma and brain metastases who were treated with vemurafenib were reviewed. Clinical data were extracted to determine extracranial and intracranial objective response rates, progression-free survival (PFS), overall survival (OS), and safety. A bait-capture, next-generation sequencing assay was used to identify mutations in pretreatment tumors that could explain primary resistance to vemurafenib.ResultsAmong patients with intracranial disease treated with vemurafenib, 27 were included in survival analyses and 22 patients were assessable for response. The extracranial and intracranial objective response rates were 71% and 50%, respectively. Discordant responses were observed between extracranial and intracranial metastatic sites in 4 of 19 evaluable patients. Median PFS was 4.1 months (95% confidence interval [CI]: 2.6-7.9); median intracranial PFS was 4.6 months (95% CI: 2.7-7.9), median OS was 7.5 months (95% CI: 4.3-not reached), with a 30.4% 1-year OS rate. Outcomes were influenced by performance status. Vemurafenib was tolerable, although radiation-induced dermatitis occurred in some patients who received whole-brain radiotherapy. Adequate samples for next-generation sequencing analysis were available for seven patients. Melanomas categorized as "poorly sensitive" (?20% tumor growth, new lesions, or ?50% shrinkage for <4 months) harbored co-occurring mutations in genes predicted to activate the phosphatidylinositol 3-kinase-AKT (PI3K-AKT) pathway.ConclusionVemurafenib is highly active in BRAF-mutant melanoma brain metastases but has limited activity in patients with poor performance status. The safety and efficacy of concurrent radiotherapy and RAF inhibition requires careful clinical evaluation. Combination strategies blocking the MAPK and PI3K-AKT pathway may be warranted in a subset of patients.Implications for practiceVemurafenib is active for BRAF-mutant intracranial melanoma metastases in an unselected patient population typical of routine oncologic practice. Patients with poor performance status appear to have poor outcomes despite vemurafenib therapy. Preliminary data indicate that co-occurring or secondary alterations in the phosphatidylinositol 3-kinase-AKT (PI3K-AKT) pathway are involved in resistance to RAF inhibition, thus providing a rationale for dual MAPK and PI3K-AKT pathway inhibition in this patient population.
| S-EPMC4492223 | biostudies-literature
Project description:Recently, we identified that PREX1 overexpression is critical for metastatic but not tumorigenic growth in a mouse model of NRAS-driven melanoma. In addition, a PREX1 gene signature correlated with and was dependent on ERK MAPK activation in human melanoma cell lines. In the current study, the underlying mechanism of PREX1 overexpression in human melanoma was assessed. PREX1 protein levels were increased in melanoma tumor tissues and cell lines compared with benign nevi and normal melanocytes, respectively. Suppression of PREX1 by siRNA impaired invasion but not proliferation in vitro PREX1-dependent invasion was attributable to PREX1-mediated activation of the small GTPase RAC1 but not the related small GTPase CDC42. Pharmacologic inhibition of ERK signaling reduced PREX1 gene transcription and additionally regulated PREX1 protein stability. This ERK-dependent upregulation of PREX1 in melanoma, due to both increased gene transcription and protein stability, contrasts with the mechanisms identified in breast and prostate cancers, in which PREX1 overexpression was driven by gene amplification and HDAC-mediated gene transcription, respectively. Thus, although PREX1 expression is aberrantly upregulated and regulates RAC1 activity and invasion in these three different tumor types, the mechanisms of its upregulation are distinct and context dependent.ImplicationsThis study identifies an ERK-dependent mechanism that drives PREX1 upregulation and subsequent RAC1-dependent invasion in BRAF- and NRAS-mutant melanoma. Mol Cancer Res; 14(10); 1009-18. ©2016 AACR.
| S-EPMC5065759 | biostudies-literature
Project description:Targeted inhibition of oncogenic pathways can be highly effective in halting the rapid growth of tumors but often leads to the emergence of slowly dividing persister cells, which constitute a reservoir for the selection of drug-resistant clones. In BRAFV600E melanomas, RAF and MEK inhibitors efficiently block oncogenic signaling, but persister cells emerge. Here, we show that persister cells escape drug-induced cell-cycle arrest via brief, sporadic ERK pulses generated by transmembrane receptors and growth factors operating in an autocrine/paracrine manner. Quantitative proteomics and computational modeling show that ERK pulsing is enabled by rewiring of mitogen-activated protein kinase (MAPK) signaling: from an oncogenic BRAFV600E monomer-driven configuration that is drug sensitive to a receptor-driven configuration that involves Ras-GTP and RAF dimers and is highly resistant to RAF and MEK inhibitors. Altogether, this work shows that pulsatile MAPK activation by factors in the microenvironment generates a persistent population of melanoma cells that rewires MAPK signaling to sustain non-genetic drug resistance.
| S-EPMC8009031 | biostudies-literature
Project description:Understanding the impact of BRAF signaling inhibition in human melanoma on key disease mechanisms is important for developing biomarkers of therapeutic response and combination strategies to improve long-term disease control. This work investigates the downstream metabolic consequences of BRAF inhibition with vemurafenib, the molecular and biochemical processes that underpin them, their significance for antineoplastic activity, and potential as noninvasive imaging response biomarkers. 1H NMR spectroscopy showed that vemurafenib decreases the glycolytic activity of BRAF-mutant (WM266.4 and SKMEL28) but not BRAFWT (CHL-1 and D04) human melanoma cells. In WM266.4 cells, this was associated with increased acetate, glycine, and myo-inositol levels and decreased fatty acyl signals, while the bioenergetic status was maintained. 13C NMR metabolic flux analysis of treated WM266.4 cells revealed inhibition of de novo lactate synthesis and glucose utilization, associated with increased oxidative and anaplerotic pyruvate carboxylase mitochondrial metabolism and decreased lipid synthesis. This metabolic shift was associated with depletion of hexokinase 2, acyl-CoA dehydrogenase 9, 3-phosphoglycerate dehydrogenase, and monocarboxylate transporters (MCT) 1 and 4 in BRAF-mutant but not BRAFWT cells and, interestingly, decreased BRAF-mutant cell dependency on glucose and glutamine for growth. Further, the reduction in MCT1 expression observed led to inhibition of hyperpolarized 13C-pyruvate-lactate exchange, a parameter that is translatable to in vivo imaging studies, in live WM266.4 cells. In conclusion, our data provide new insights into the molecular and metabolic consequences of BRAF inhibition in BRAF-driven human melanoma cells that may have potential for combinatorial therapeutic targeting as well as noninvasive imaging of response. Mol Cancer Ther; 15(12); 2987-99. ©2016 AACR.
| S-EPMC5136471 | biostudies-literature
Project description:BRAF V600 mutations occur in a wide range of tumor types, and RAF inhibition has become standard in several of these cancers. Despite this progress, BRAF V600 mutations have historically been considered a clear demonstration of tumor lineage context-dependent oncogene addiction, based predominantly on the insensitivity to RAF inhibition in colorectal cancer. However, the true broader activity of RAF inhibition pan-cancer remains incompletely understood. To address this, we conducted a multicohort "basket" study of the BRAF inhibitor vemurafenib in non-melanoma BRAF V600 mutation-positive solid tumors. In total, 172 patients with 26 unique cancer types were treated, achieving an overall response rate of 33% and median duration of response of 13 months. Responses were observed in 13 unique cancer types, including historically treatment-refractory tumor types such as cholangiocarcinoma, sarcoma, glioma, neuroendocrine carcinoma, and salivary gland carcinomas. Collectively, these data demonstrate that single-agent BRAF inhibition has broader clinical activity than previously recognized. SIGNIFICANCE: These data suggest that BRAF V600 mutations lead to oncogene addiction and are clinically actionable in a broad range of non-melanoma cancers, including tumor types in which RAF inhibition is not currently considered standard of care.See related commentary by Ribas and Lo, p. 640.This article is highlighted in the In This Issue feature, p. 627.
| S-EPMC7196502 | biostudies-literature
Project description:Autophagy is a dynamic cell survival mechanism by which a double-membrane vesicle, or autophagosome, sequesters portions of the cytosol for delivery to the lysosome for recycling. This process can be inhibited using the antimalarial agent chloroquine (CQ), which impairs lysosomal function and prevents autophagosome turnover. Despite its activity, CQ is a relatively inadequate inhibitor that requires high concentrations to disrupt autophagy, highlighting the need for improved small molecules. To address this, we screened a panel of antimalarial agents for autophagy inhibition and chemically synthesized a novel series of acridine and tetrahydroacridine derivatives. Structure-activity relationship studies of the acridine ring led to the discovery of VATG-027 as a potent autophagy inhibitor with a high cytotoxicity profile. In contrast, the tetrahydroacridine VATG-032 showed remarkably little cytotoxicity while still maintaining autophagy inhibition activity, suggesting that both compounds act as autophagy inhibitors with differential effects on cell viability. Further, knockdown of autophagy-related genes showed no effect on cell viability, demonstrating that the ability to inhibit autophagy is separate from the compound cytotoxicity profiles. Next, we determined that both inhibitors function through lysosomal deacidification mechanisms and ultimately disrupt autophagosome turnover. To evaluate the genetic context in which these lysosomotropic inhibitors may be effective, they were tested in patient-derived melanoma cell lines driven by oncogenic BRAF (v-raf murine sarcoma viral oncogene homolog B). We discovered that both inhibitors sensitized melanoma cells to the BRAF V600E inhibitor vemurafenib. Overall, these autophagy inhibitors provide a means to effectively block autophagy and have the potential to sensitize mutant BRAF melanomas to first-line therapies.
| S-EPMC4091172 | biostudies-literature
Project description:There have been significant advances in the treatment of malignant melanoma with the U.S. Food and Drug Administration approval of two drugs in 2011, the first drugs approved in 13 years. The developments of immune checkpoint modulation via cytotoxic T-lymphocyte antigen-4 blockade, with ipilimumab, and targeting of BRAF(V600), with vemurafenib or dabrafenib, as well as MEK, with trametinib, have been paradigm changing both for melanoma clinical practice and for oncology therapeutic development. These advancements, however, reveal new clinical questions regarding combinations and optimal sequencing of these agents in patients with BRAF mutant disease. We review the development of these agents, putative biomarkers, and resistance mechanisms relevant to their use, and possibilities for sequencing and combining these agents.
| S-EPMC4063399 | biostudies-literature
Project description:BRAF inhibitor vemurafenib achieves high response rate and an improvement in survival in patients with BRAF-mutated metastatic melanoma. However, median progression-free survival is only 6.9 months in the phase 3 study. Retrospective analyses suggest that treatment with BRAF inhibitors beyond initial progression might be associated with improved overall survival. We aimed to prospectively investigate the activity of prolonged treatment with vemurafenib and the addition of fotemustine in patients with systemic progression on prior single-agent BRAF inhibitor.In this two-centres, single-arm Phase 2 trial, we enrolled patients with systemic progressive disease during single-agent vemurafenib treatment. Participants received vemurafenib 960 mg twice daily or dose administered at time of disease progression with vemurafenib previous treatment and fotemustine 100 mg/m2 intravenously every three weeks. The primary endpoint was PFS.Thirty-one patients were enrolled in the study; 16 patients had brain metastases at baseline. Median PFS was 3.9 months and 19 patients (61.3%) achieved disease control (1 CR, 4 PR, 14 SD). For patients achieving disease control, median duration of treatment was 6 months. Median OS was 5.8 months from enrolment and 15.4 months from start of previous vemurafenib. Five patients (16.1%) had a G3-4 AE, the most common being thrombocytopenia, which occurred in 3 patients.This trial is registered with ClinicalTrials.gov number NCT01983124.The combination of vemurafenib plus fotemustine has clinical activity and an acceptable safety profile in BRAF-refractory patients.
| S-EPMC5844757 | biostudies-literature