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The development of resistance to treatments of melanoma is commonly associated with an upregulation of the MAPK pathway and the development of an undifferentiated state. Previous studies have suggested that melanoma with these resistance characteristics may be susceptible to innate death mechanisms such as pyroptosis triggered by the activation of inflammasomes. In this study, we have taken cell lines from patients before and after the development of resistance to BRAF V600 inhibitors and exposed the resistant melanoma to temozolomide (a commonly used chemotherapy) with and without chloroquine to inhibit autophagy. It was found that melanoma with an inflammatory undifferentiated state appeared susceptible to this combination when tested in vitro and in vivo against xenografts in nonobese diabetic scid gamma mice. Translation of the latter results into patients would promise durable responses in patients treated by the combination. The inflammasome and death mechanism involved appeared to vary between melanoma and involved either AIM2 or NLRP3 inflammasomes and gasdermin D or E. These preliminary studies have raised questions as to the selectivity for different inflammasomes in different melanoma and their selective targeting by chemotherapy. They also question whether the inflammatory state of melanoma may be used as biomarkers to select patients for inflammasome-targeted therapy., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: Patients with melanoma and early stable disease (SD) with pembrolizumab have unclear prognosis. We present post hoc analyses of long-term outcomes for patients with early SD, partial response (PR) or complete response (CR) with pembrolizumab., Patients and Methods: Patients who received pembrolizumab in the KEYNOTE-001 and KEYNOTE-006 studies and had SD, PR or CR at weeks 12 or 24 were included., Results: Of 294 patients in the week 12 analysis, 107 (36.4%) had SD at week 12, of whom 7 (6.5%) had a best overall response of CR, 43 (40.2%) had PR and 57 (53.3%) had SD. Forty-eight-month overall survival (OS) rates were 95.2%, 73.0% and 47.7%, respectively, for patients with CR, PR and SD at week 12. Similar results were observed in the 241 patients in the week 24 analysis. Forty-eight-month OS rates were 72.1% for patients with SD at week 12 followed by subsequent response and 75.0% for patients with PR at week 12 followed by no change in response or progression. Thirty-six-month and 48-month OS rates were 11.6% and not reached, respectively, for patients with SD at week 12 followed by progression before week 24., Conclusions: A substantial proportion of patients (46.7%) with early (week 12) SD with pembrolizumab achieved subsequent PR or CR. Patients with SD at week 12 and subsequent CR/PR had similar survival to those who maintained PR. In contrast, patients with SD at week 12 and subsequent progression had poor survival outcomes. These findings may guide treatment decisions for patients achieving early SD., Trial Registration: Clinicaltrials.gov: NCT01295827 (KEYNOTE-001); NCT01866319 (KEYNOTE-006)., Competing Interests: Conflict of interest statement The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: O.H. is a consultant advisor for Aduro, Akeso, Amgen, Array, BeiGene, BMS, Genentech, GSK, Immunocore, Incyte, Janssen, Merck, NextCure, Novartis, Sanofi, Regeneron, Seattle Genetics, Tempus and Zelluna. He is a speaker for Array, BMS, Novartis, Pfizer, Sanofi and Regeneron. He has contracted research for his institution from Aduro, Akeso, Amgen, Arcus, Array, BMS, CytomX, Exelixis, Genentech, GSK, Immunocore, Incyte, Io-vance, Merck, Merck Serono, Moderna, NextCure, Novartis, Regeneron, Sanofi, Seattle Genetics, Torque and Zelluna. S.J.D., B.H.M. and E.J. are employees of Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA, and S.J.D. owns stock in Merck & Co., Inc., Kenilworth, NJ, USA. A.A. is a consultant advisor for Amgen, BMS, Merck, Novartis, Pierre Fabre, Roche, Sanofi and Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA. M.S.C. is a consultant advisor for Amgen, BMS, Eisai, IDEAYA, MSD, Merck Serono, Nektar, Novartis, Pierre Fabre, QBiotics, OncoSec, Regeneron, Roche and Sanofi. He has also received honoraria from BMS, MSD and Novartis. T.M. has served on advisory boards for Merck, BMS and OncoSec. A.D. has received grants from BMS, Merck, Pfizer/Array and Xencor. He also served on an advisory board meeting for Xencor. J.J.G. has served on advisory boards for BMS, Merck, MSD, Novartis, Pfizer, Pierre Fabre, Roche, Sanofi and Sun Pharma. He has also received personal fees from BMS, MSD, Novartis and Pierre Fabre for travel as well as personal fees for serving as a speaker for MSD, Novartis and Pierre Fabre. P.H. has no disclosures to report. F.S.H. is a consultant advisor for Aduro, Bristol Myers Squibb, Eisai, EMD Serono, Genentech/Roche, Idera, Merck, Novartis, Pieris Pharmaceutical, Sanofi and Takeda. He reports grants and royalties paid to his institution by Bristol Myers Squibb and Novartis, as well as personal fees from Gossamer. He also holds equity in Apricity, Bicara, Pionyr and Torque. He has served on advisory boards for Apricity, Bicara, Bioentre, Checkpoint Therapeutics, Compass Therapeutics, Iovance, Pionyr, Surface and Torque. His pending patents include Methods for Treating MICA-Related Disorders (#20100111973; includes royalties), Angiopoietin-2 Biomarkers Predictive of Anti-Immune Checkpoint Response (#20170248603), Compositions and Methods for Identification, Assessment, Prevention, and Treatment of Melanoma Using PD-L1 Isoforms (#20160340407), Therapeutic Peptides (#20160046716, #20140004112, #20170022275, #20170008962), Methods of Using Pembrolizumab and Trebananib and Anti-Galectin Antibody Biomarkers Predictive of Anti-Immune Checkpoint and Anti-Angiogenesis Responses (#20170343552). He has been issued patents for Tumor Antigens and Uses Thereof (#7250291), Therapeutic Peptides (#9402905), Vaccine Compositions and Methods for Restoring NKG2D Pathway Function Against Cancers (#10279021) and Antibodies that Bind to MHC Class I Polypeptide-Related Sequence A (#10106611). A.M.J. has received institutional support from MSD. L.M. has no disclosures to report. A.R. is a consultant for Amgen, Chugai, Merck, Novartis, Nurix, Sanofi and Vedanta. He is a current scientific advisory board member and stockholder in 4C Biomed, Apricity, Arcus, Compugen, Highlight, ImaginAb, Isoplexis, Lutris Pharma, MapKure, Merus, PACT Pharma, Rgenix and Tango Therapeutics and is a past scientific advisory board member and stockholder in Advaxis, Cytomx, Five Prime, Kite-Gilead and RAPT. He has also received grants paid to his institution from Agilent and Bristol Myers Squibb. C.R. is a consultant advisor for Amgen, AstraZeneca, BMS, Merck, MSD, Novartis, Pierre Fabre, Roche and Sanofi. J.S. has no disclosures to report. J.S.W. has received grants paid to his institution from Merck. He has been issued a PD-1 biomarker patent with Biodesix unrelated to the submitted work. J.D.W. is a non-compensated consultant for Merck. He is also a consultant for Amgen, Apricity, Arsenal IO, Ascentage Pharma, Astellas, AstraZeneca, Bayer, BeiGene, Boehringer Ingelheim, Bristol Myers Squibb, Celgene, Chugai, Eli Lilly, Elucida, F Star, Georgiamune, Imvaq, Kyowa Hakko Kirin, Linneaus, Merck, Neon Therapeutics, Polynoma, Psioxus, Recepta, Sellas, Serametrix, Surface Oncology, Syndax, Syntalogic, Takara Bio, Tizona Pharmaceuticals, Trieza, Truvax and Werewolf Therapeutics. He reports equity in Adaptive Biotech, Apricity, Arsenal IO, Belgene, Georgiamune, Imvaq, Linneaus and Tizona Pharmaceuticals. He has received research grants from Bristol Myers Squibb and Sephora. He has licensed patents for xenogeneic DNA vaccines (Merial; includes royalties), a myeloid-derived suppressor cell (MDSC) assay (Serametrix; includes royalties), an anti–PD-1 antibody (Agenus), anti-CTLA4 antibodies (Agenus) and anti-GITR antibodies and method of use thereof (Agenus/Incyte). He has also been issued patents for alphavirus replicon particles expressing Newcastle disease viruses for cancer therapy, phosphatidylserine targeting agents and uses thereof for adoptive T-cell therapies, immunosuppressive follicular help-like T cells modulated by immune checkpoint blockade, identifying and treating subjects at risk for checkpoint blockade therapy–associated colitis, CAR+ T cells targeting differentiation antigens as means to treat cancer, anti-CD40 agonist mAB fused to monophosphoryl lipid A (MPL) for cancer therapy and engineered vaccinia viruses for cancer immunotherapy. G.V.L. is consultant advisor for Aduro Biotech Inc, Amgen Inc, Array Biopharma inc, Boehringer Ingelheim International GmbH, Bristol Myers Squibb, Evaxion Biotech A/S, Hexel AG, Highlight Therapeutics S.L., Merck Sharp & Dohme, Novartis Pharma AG, OncoSec, Pierre Fabre, QBiotics Group Limited, Regeneron Pharmaceuticals Inc, SkylineDX B.V., and Specialised Therapeutics Australia Pty Ltd., (Copyright © 2021 Merck Sharp & Dohme Corp., The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Dysregulation of epigenetic modifiers is a frequent event in melanoma and underlies many aspects of melanoma biology, including resistance to targeted therapy and immunotherapies. Here, we report that dual targeting of BET and CDK9 proteins have synergistic effects against melanoma cells in vitro and in vivo. The BET inhibitor (IBET151) and CDK9 inhibitor (CDKI73) synergistically killed melanoma cells in vitro independent of their BRAF or NRAS mutation status. The combination of drugs markedly inhibited the growth of human melanoma C002M cells in vitro in three-dimensional spheroids and in vivo in NOD-SCID gamma mice compared with vehicle control and the individual drugs (P < 0.05). Cell death was associated with mitochondrial depolarization, caspase-dependent apoptosis with cleavage of PARP1, and downregulation of anti-apoptotic proteins BCL2, BCLXL, and MCL1. Gene set enrichment analysis revealed downregulation of hallmark gene sets associated with E2F, G2M checkpoint, and c-MYC. Survival analysis showed worse prognosis with high G2M, E2F, or c-MYC gene signatures, suggesting biomarkers of response of BET and CDK9 inhibitors in melanoma. This combination of epigenetic inhibitors targets multiple downstream genes, leading to cell death of melanoma cells in vitro and in vivo, and warrants further investigation for treatment of melanoma in patients not responding to current therapies., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: Long-term safety of pembrolizumab in melanoma was analyzed in KEYNOTE-001, KEYNOTE-002, and KEYNOTE-006., Patients and Methods: Analysis involved patients who received ≥1 pembrolizumab dose. Lead-time bias was addressed via landmark analyses in patients who were progression-free before day 147., Results: Adverse events (AEs) were analyzed for 1567 patients (median follow-up, 42.4 months). Most AEs were mild/moderate; grade 3/4 treatment-related AEs occurred in 17.7% of patients. Two pembrolizumab-related deaths occurred. Any-grade immune-mediated AEs (imAEs) occurred in 23.0%, most commonly hypothyroidism (9.1%), pneumonitis (3.3%), and hyperthyroidism (3.0%); grade 3/4 imAEs occurred in 6.9% of patients. Most imAEs occurred within 16 weeks of treatment. In landmark analysis, patients who did (n = 79) versus did not (n = 384) develop imAEs had similar objective response rates (ORRs) (64.6% versus 63.0%); median time to response (TTR), 5.6 months for both; median duration of response (DOR), 20.0 versus 25.3 months; median progression-free survival (PFS), 17.0 versus 17.7 months; median overall survival (OS), not reached (NR) versus 43 months (p = 0.1104). Patients who did (n = 17) versus did not (n = 62) receive systemic corticosteroids had similar ORRs (70.6% vs. 62.9%) and median TTR (6.4 vs. 5.6 months) but numerically shorter median PFS (9.9 vs. 17.0 months); median DOR, 14.2 months versus NR; median OS, NR for both., Conclusions: These results enhance the knowledge base for pembrolizumab in advanced melanoma, with no new toxicity signals after lengthy follow-up of a large population. In landmark analyses, pembrolizumab efficacy was similar regardless of imAEs or systemic corticosteroid use., Clinical Trial Registry: NCT01295827, NCT01704287, NCT01866319., Competing Interests: Conflict of interest statement C.R. has participated in advisory boards for Roche; Pierre Fabre; Merck; Novartis; Amgen; Bristol-Myers Squibb; Novartis; Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, U.S.A. (MSD); and Sanofi. O.H. reports personal fees from Merck for consulting during the conduct of the study; as well as contracted research for his institution from Arcus, Aduro, Akeso, Amgen, Array, Bristol-Myers Squibb, CytomX, Exelixis, Genentech, GSK, Immunocore, Incyte, Iovance, Merck, Moderna, Merck Serono, NextCure, Novartis, Regeneron, Roche, Seattle Genetics, Torque, and Zelluna outside the submitted work. A.R. has received personal fees as honoraria for consulting from Amgen, Chugai, Genentech-Roche, Novartis, and Merck; and personal fees, as a scientific advisory member and stockholder from Arcus, Bi-oncotech, Compugen, CytomX, Five Prime, FLX-Bio, Merus, Rgenix, PACT Pharma, and Tango Therapeutics, outside the submitted work. J.S.W. reports personal fees for honoraria for advisory boards and transportation from Merck, Bristol-Myers Squibb, Genentech, Celldex, Pfizer, and AstraZeneca, outside the submitted work. In addition. J.S.W. has a patent named on a PD-1 biomarker patent by Biodesix issued. I.D. reports grants from Merck, Bristol-Myers Squibb, Incyte, OncoSec, and Regeneron, and personal fees from Regeneron, during the conduct of the study. F.S.H. reports other from Merck to their institution for clinical trial support during the conduct of the study; grants, personal fees, and consulting from Bristol-Myers Squibb; personal fees from Merck, EMD Serono, Genentech/Roche, Bayer, Partners Therapeutics, Sanofi, Pfizer, and Kairos for consulting; grants and personal fees from Novartis for consulting; personal fees from Takeda, Surface, Compass Therapeutics, Verastem, and Rheos for advisory boards; personal fees from Apricity and Bicara for scientific advisory board and equity; personal fees from Aduro for advisor consulting; personal fees from Pionyr for advisory board and equity; personal fees from 7 Hills Pharma for advisor; other from Torque for scientific advisory board and equity; outside the submitted work. In addition, F.S.H. has a patent for Methods for Treating MICA-Related Disorders (#20100111973) with royalties paid, a patent for Tumor antigens and uses thereof issued (#7250291), a patent for Angiopoieten-2 Biomarkers Predictive of Anti-immune checkpoint response pending (#20170248603), a patent for Compositions and Methods for Identification, Assessment, Prevention, and Treatment of Melanoma using PD-L1 Isoforms pending (#20160340407), five patents for Therapeutic peptides pending (#20160046716, #20140004112, #20170022275, #20170008962, #9402905), and a patent for “methods of using pembrolizumab and trebananib.” J.D.W. reports personal fees for consulting from Adaptive Biotech, Amgen, Apricity, Ascentage Pharma, Astellas, AstraZeneca, Bayer, BeiGene, Bristol-Myers Squibb, Celgene, Chugai, Eli Lilly, F-star, Imvaq, Kyowa Hakko Kirin, Linnaeus, MedImmune, Merck, Neon Therapeutics, Ono, Polaris Pharma, Polynoma, PsiOxus, Puretech, Recepta, Takara Bio, Trieza, Truvax, Serametrix, Surface Oncology, Syndax, and Syntalogic; research support from Bristol-Myers Squibb and AstraZeneca; and equity in Potenza Therapeutics, Tizona Pharmaceuticals, Adaptive Biotechnologies, Imvaq, BeiGene, Trieza, and Linnaeus. T.C.M. reports personal fees for honorarium from Bristol-Myers Squibb, Aduro, Merck, and Incyte outside the submitted work. R.W.J. reports other from Bristol-Myers Squibb, and Gilead for consulting, outside the submitted work. C.B. reports personal fees from Bristol-Myers Squibb (board advisor), speaker fees from Merck, and travel fees from Amgen and Sandoz outside the submitted work. GVL is consultant advisor for Aduro Biotech Inc, Amgen Inc, Array Biopharma inc, Boehringer Ingelheim International GmbH, Bristol-Myers Squibb, Highlight Therapeutics S.L., MSD, Novartis Pharma AG, Pierre Fabre, QBiotics Group Limited, Regeneron Pharmaceuticals Inc, SkylineDX B.V. I.P. is a consultant for Amgen, Merck, and Iovance, outside the submitted work. R.Dummer reports intermittent, project focused consulting and/or advisory relationships with Novartis, MSD, Bristol-Myers Squibb, Roche, Amgen, Takeda, Pierre Fabre, Sun Pharma, Sanofi, Catalym, Second Genome, Regeneron, Alligator, MaxiVAX SA and touchIME outside the submitted work. J.L. reports employment at MSD, and GSK. S.J.D. reports personal fees as an employee of MSD, and shareholder inMerck & Co., Inc., Kenilworth, NJ, USA. M.S.C. has served on advisory boards for Bristol-Myers Squibb, MSD, Amgen, Novartis, Pierre Fabre, Roche, Sanofi, Merck, Ideaya, Regeneron, Nektar, Eisai, Oncosec and Qbiotics., outside the submitted work. A.J. reports consulting and/or advisory role for Neolukin, Janssen Oncology, Ipsen, AstraZeneca, Sanofi, Noxopharm, IQvia, Pfizer, Novartis, Bristol-Myers Squibb, and Merck Serono, outside the submitted work. A.J. also reports research funding from Bristol-myers Squibb, Janssen Oncology, MSD, Mayne Pharma, Roche/Genentech, Bayer, Macrogenics, Lilly, Pfizer, AstraZeneca, and Corvus Pharmaceuticals. All remaining authors have declared no conflicts of interest., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The histone methylase EZH2 is frequently dysregulated in melanoma and is associated with DNA methylation and silencing of genes involved in tumor suppression. In this study, we used chromatin immunoprecipitation and sequencing to identify key suppressor genes that are silenced by histone methylation in constitutively active EZH2 (Y641) mutant melanoma and assessed whether these regions were also sites of DNA methylation. The genes identified were validated by their re-expression after treatment with EZH2 and DNA methyltransferase inhibitors. The expression of putative EZH2 target genes was shown to be highly relevant to the survival of patients with melanoma in clinical datasets. To determine correlates of response to EZH2 inhibitors, we screened a panel of 53 melanoma cell lines for drug sensitivity. We compared RNA sequencing profiles of sensitive to resistant melanoma cells and performed pathway analysis. Sensitivity was associated with strong downregulation of IFN-γ and IFN-α gene signatures that were reversed by treatment with EZH2 inhibitors. This is consistent with EZH2-driven dedifferentiated invasive states associated with treatment resistance and defects in antigen presentation. These results suggest that EZH2 inhibitors may be most effectively targeted to immunologically cold melanoma to both induce direct cytotoxicity and increase immune responses in the context of checkpoint inhibitor immunotherapy., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

The treatment of melanoma has been markedly improved by the introduction of targeted therapies and checkpoint blockade immunotherapy. Unfortunately, resistance to these therapies remains a limitation. Novel anticancer therapeutics targeting the MCL1 anti-apoptotic protein have shown impressive responses in haematological cancers but are yet to be evaluated in melanoma. To assess the sensitivity of melanoma to new MCL1 inhibitors, we measured the response of 51 melanoma cell lines to the novel MCL1 inhibitor, S63845. Additionally, we assessed combination of this drug with inhibitors of the bromodomain and extra-terminal (BET) protein family of epigenetic readers, which we postulated would assist MCL1 inhibition by downregulating anti-apoptotic targets regulated by NF-kB such as BCLXL, BCL2A1 and XIAP, and by upregulating pro-apoptotic proteins including BIM and NOXA. Only 14% of melanoma cell lines showed sensitivity to S63845, however, combination of S63845 and I-BET151 induced highly synergistic apoptotic cell death in all melanoma lines tested and in an in vivo xenograft model. Cell death was dependent on caspases and BAX/BAK. Although the combination of drugs increased the BH3-only protein, BIM, and downregulated anti-apoptotic proteins such as BCL2A1, the importance of these proteins in inducing cell death varied between cell lines. ABT-199 or ABT-263 inhibitors against BCL2 or BCL2 and BCLXL, respectively, induced further cell death when combined with S63845 and I-BET151. The combination of MCL1 and BET inhibition appears to be a promising therapeutic approach for metastatic melanoma, and presents opportunities to add further BCL2 family inhibitors to overcome treatment resistance., (© 2020 UICC.)

Melanoma, as for many other cancers, undergoes a selection process during progression that limits many innate and adaptive tumor control mechanisms. Immunotherapy with immune checkpoint blockade overcomes one of the escape mechanisms but if the tumor is not eliminated other escape mechanisms evolve that require new approaches for tumor control. Some of the innate mechanisms that have evolved against infections with microorganisms and viruses are proving to be active against cancer cells but require better understanding of how they are activated and what inhibitory mechanisms may need to be targeted. This is particularly so for inflammasomes which have evolved against many different organisms and which recruit a number of cytotoxic mechanisms that remain poorly understood. Equally important is understanding of where these mechanisms will fit into existing treatment strategies and whether existing strategies already involve the innate killing mechanisms., (© 2020 The Authors. Pigment Cell & Melanoma Research published by John Wiley & Sons Ltd.)

Background: Anti-programmed cell death protein 1 (PD-1) antibodies (PD1) prolong recurrence-free survival in high-risk resected melanoma; however, approximately 25%-30% of patients recur within 1 year. This study describes the pattern of recurrence, management and outcomes of patients who recur with adjuvant PD1 therapy., Patients and Methods: Consecutive patients from 16 centres who recurred having received adjuvant PD1 therapy for resected stage III/IV melanoma were studied. Recurrence characteristics, management and outcomes were examined; patients with mucosal melanoma were analysed separately., Results: Melanoma recurrence occurred in 147 (17%) of ∼850 patients treated with adjuvant PD1. In those with cutaneous melanoma (n = 136), median time to recurrence was 4.6 months (range 0.3-35.7); 104 (76%) recurred during (ON) adjuvant PD1 after a median 3.2 months and 32 (24%) following (OFF) treatment cessation after a median 12.5 months, including in 21 (15%) who ceased early for toxicity. Fifty-nine (43%) recurred with locoregional disease only and 77 (57%) with distant disease. Of those who recurred locally, 22/59 (37%) subsequently recurred distantly. Eighty-nine (65%) patients received systemic therapy after recurrence. Of those who recurred ON adjuvant PD1, none (0/6) responded to PD1 alone; 8/33 assessable patients (24%) responded to ipilimumab (alone or in combination with PD1) and 18/23 (78%) responded to BRAF/MEK inhibitors. Of those who recurred OFF adjuvant PD1, two out of five (40%) responded to PD1 monotherapy, two out of five (40%) responded to ipilimumab-based therapy and 9/10 (90%) responded to BRAF/MEK inhibitors., Conclusions: Most patients who recur early despite adjuvant PD1 develop distant metastases. In those who recur ON adjuvant PD1, there is minimal activity of further PD1 monotherapy, but ipilimumab (alone or in combination with PD1) and BRAF/MEK inhibitors have clinical utility. Retreatment with PD1 may have activity in select patients who recur OFF PD1., Competing Interests: Disclosure CNO reports non-financial support from Merck Sharp Dohme (MSD), outside the submitted work. ANS reports grants and personal fees from Bristol-Myers Squibb (BMS), during the conduct of the study; grants and personal fees from Immunocore, grants from Xcovery, grants, personal fees and non-financial support from Castle Biosciences, outside the submitted work. DC reports personal fees from BMS, personal fees from Novartis, outside the submitted work. JM reports other from Merck/Pfizer, other from MSD, other from Pierre Fabre, grants and other from Ultrasun, L'Oreal, Pierre Fabre, MSD, BMS, outside the submitted work. VA reports personal fees and non-financial support from BMS, personal fees from MSD, personal fees from Novartis, personal fees and non-financial support from Pierre Fabre, personal fees from Merck Serono, personal fees from Roche, non-financial support from Onco-sec, outside the submitted work. AY reports grants from National Heart, Lung, And Blood Institute of the National Institutes of Health under Award Number R38HL143619. CH reports personal fees from Amgen, personal fees from BMS, personal fees from Incyte, personal fees from MSD, personal fees from Novartis, personal fees from Pierre Fabre, personal fees from Roche, outside the submitted work. RD has intermittent, project focused consulting and/or advisory relationships with Novartis, MSD, BMS, Roche, Amgen, Takeda, Pierre Fabre, Sun Pharma, Sanofi, Catalym, Second Genome outside the submitted work. MM reports personal fees and non-financial support from MSD, personal fees and non-financial support from BMS, personal fees and non-financial support from AstraZeneca, personal fees and non-financial support from Roche, personal fees from Novartis, outside the submitted work. SPP reports personal fees from Merck & Co, Incyte, Castle Biosciences and Cardinal Health, and institutional clinical trial support from Provectus, Ideaya and BMS outside the submitted work. AH reports personal fees from BMS, personal fees from Pierre Fabre, personal fees from Merck, outside the submitted work. DBJ reports other from Array Biopharma, grants and other from BMS, grants and other from Incyte, other from Merck, other from Novartis, other from Genentech, outside the submitted work. CUB reports personal fees from BMS, MSD, GSK, Lilly, Roche, Novartis, Pfizer, GenMab, AZ, Pierre Fabre, grants from BMS, NanoString, Novartis, outside the submitted work; and stockownership Unitit Cars, Neon Therapeutics. SS reports grants and other from MSD, grants and other from BMS, grants from Amgen, grants from Endocyte, grants from Astra Zeneca, other from Roche, outside the submitted work. MSC reports personal fees from BMS, personal fees from MSD, personal fees from Novartis, personal fees from Roche, personal fees from Amgen, personal fees from Pierre Fabre, personal fees from Ideaya, outside the submitted work. JMGL reports grants and personal fees from Achilles therapeutics, personal fees from AstraZeneca, personal fees from Boston Biomedical, grants and personal fees from BMS, personal fees from Eisai, personal fees from EUSA Pharma, personal fees from GSK, personal fees from Ipsen, personal fees from Imugene, personal fees from Incyte, personal fees from iOnctura, personal fees from Kymab, personal fees from Merck Sorono, grants and personal fees from MSD, grants and personal fees from Nektar, grants and personal fees from Novartis, personal fees from Pierre Fabre, grants and personal fees from Pfizer, grants and personal fees from Roche/Genetech, personal fees from Secarna, personal fees from Vitaccess, personal fees from Covance, grants and personal fees from Immunocore, grants from Aveo, grants from Pharmacyclics, outside the submitted work. AMM reports personal fees from BMS, personal fees from MSD, personal fees from Novartis, personal fees from Roche, personal fees from Pierre Fabre, outside the submitted work. GVL is a Consultant Advisor and reports the following outside of the submitted work; personal fees from Aduro, personal fees from Amgen, personal fees from Array, personal fees from BMS, personal fees from MSD, personal fees from Novartis, personal fees from Pierre Fabre, personal fees from Oncosec, personal fees from Roche, personal fees from Sandoz. All other authors have declared no conflicts of interest., (Copyright © 2020 European Society for Medical Oncology. Published by Elsevier Ltd. All rights reserved.)

It is estimated that ~50% of patients with melanoma harbour B‑Raf (BRAF)V600 driver mutations, with the most common of these being BRAFV600E, which leads to the activation of mitogen‑activated protein kinase proliferative and survival pathways. BRAF inhibitors are used extensively to treat BRAF‑mutated metastatic melanoma; however, acquired resistance occurs in the majority of patients. The effects of long‑term treatment with PLX4032 (BRAFV600 inhibitor) were studied in vitro on sensitive V600E BRAF‑mutated melanoma cell lines. After several weeks of treatment with PLX4032, the majority of the melanoma cells died; however, a proportion of cells remained viable and quiescent, presenting senescent cancer stem cell‑like characteristics. This surviving population was termed SUR cells, as discontinuing treatment allowed the population to regrow while retaining equal drug sensitivity to that of parental cells. RNA sequencing analysis revealed that SUR cells exhibit changes in the expression of 1,415 genes (P<0.05) compared with parental cells. Changes in the expression levels of a number of epigenetic regulators were also observed. These changes and the reversible nature of the senescence state were consistent with epigenetic regulation; thus, it was investigated as to whether the senescent state could be reversed by epigenetic inhibitors. It was found that both parental and SUR cells were sensitive to different histone deacetylase (HDAC) inhibitors, such as SAHA and MGCD0103, and to the cyclin‑dependent kinase (CDK)9 inhibitor, CDKI‑73, which induced apoptosis and reduced proliferation both in the parental and SUR populations. The results suggested that the combination of PLX4032 with HDAC and CDK9 inhibitors may achieve complete elimination of SUR cells that persist after BRAF inhibitor treatment, and reduce the development of resistance to BRAF inhibitors.

Purpose: Immune components of the tumor microenvironment (TME) have been associated with disease outcome. We prospectively evaluated the association of an immune-related gene signature (GS) with clinical outcome in melanoma and non-small cell lung cancer (NSCLC) tumor samples from two phase III studies., Experimental Design: The GS was prospectively validated using an adaptive signature design to optimize it for the sample type and technology used in phase III studies. One-third of the samples were used as "training set"; the remaining two thirds, constituting the "test set," were used for the prospective validation of the GS., Results: In the melanoma training set, the expression level of eight Th1/IFNγ-related genes in tumor-positive lymph node tissue predicted the duration of disease-free survival (DFS) and overall survival (OS) in the placebo arm. This GS was prospectively and independently validated as prognostic in the test set. Building a multivariate Cox model in the test set placebo patients from clinical covariates and the GS score, an increased number of melanoma-involved lymph nodes and the GS were associated with DFS and OS. This GS was not associated with DFS in NSCLC, although expression of the Th1/IFNγ-related genes was associated with the presence of lymphocytes in tumor samples in both indications., Conclusions: These findings provide evidence that expression of Th1/IFNγ genes in the TME, as measured by this GS, is associated with clinical outcome in melanoma. This suggests that, using this GS, patients with stage IIIB/C melanoma can be classified into different risk groups., (©2019 American Association for Cancer Research.)

Background: To compare the clinical efficacy of New York Esophageal squamous cell carcinoma-1 (NY-ESO-1) vaccine with ISCOMATRIX adjuvant versus ISCOMATRIX alone in a randomized, double-blind phase II study in participants with fully resected melanoma at high risk of recurrence., Methods: Participants with resected stage IIc, IIIb, IIIc and IV melanoma expressing NY-ESO-1 were randomized to treatment with three doses of NY-ESO-1/ISCOMATRIX or ISCOMATRIX adjuvant administered intramuscularly at 4-week intervals, followed by a further dose at 6 months. Primary endpoint was the proportion free of relapse at 18 months in the intention-to-treat (ITT) population and two per-protocol populations. Secondary endpoints included relapse-free survival (RFS) and overall survival (OS), safety and NY-ESO-1 immunity., Results: The ITT population comprised 110 participants, with 56 randomized to NY-ESO-1/ISCOMATRIX and 54 to ISCOMATRIX alone. No significant toxicities were observed. There were no differences between the study arms in relapses at 18 months or for median time to relapse; 139 vs 176 days (p=0.296), or relapse rate, 27 (48.2%) vs 26 (48.1%) (HR 0.913; 95% CI 0.402 to 2.231), respectively. RFS and OS were similar between the study arms. Vaccine recipients developed strong positive antibody responses to NY-ESO-1 (p≤0.0001) and NY-ESO-1-specific CD4 + and CD8 + responses. Biopsies following relapse did not demonstrate differences in NY-ESO-1 expression between the study populations although an exploratory study demonstrated reduced (NY-ESO-1) + /Human Leukocyte Antigen (HLA) class I + double-positive cells in biopsies from vaccine recipients performed on relapse in 19 participants., Conclusions: The vaccine was well tolerated, however, despite inducing antigen-specific immunity, it did not affect survival endpoints. Immune escape through the downregulation of NY-ESO-1 and/or HLA class I molecules on tumor may have contributed to relapse., Competing Interests: Competing interests: IDD, WC and JSC are coinventors on International Patent Application No: PCT/US2004/032147 ('In vivo efficacy of NY-ESO-1 plus adjuvant'). JFT has received honoraria for advisory board participation from Merck Sharpe Dohme Australia and Bristol-Myers Squibb Australia. He has also received honoraria and travel expenses from GSK and Provectus Inc. GAM has received research funding from Pfizer, Celgene and Ventana; acted as a consultant/advisor for Provectus; and received travel funding from Roche and Novartis. EW serves as consultant/advisor for Eli Lilly and Merck Serono, and has received travel funding from Roche. PN has received non-financial support from Novartis, as well as personal fees from Novartis and GlaxoSmithKline for advisory board participation. MPNF serves as consultant for, and has received travel funding from Sirtex. PGC has received payment for attending BMS advisory boards. RV declares stock or other ownership at Agenus, Dynavax and Soligenix. EM is an employee of, and holds stock in CSL Limited. ID is supported by an NHMRC Practitioner Fellowship (APP1102604). PRD is a founder and shareholder in SapVax which provides research funding to his laboratory., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

The development of changes in T cells, referred to as T cell exhaustion, has been suggested as a cause of primary or acquired resistance to immunotherapy by immune checkpoint blockade (ICB). A limited number of studies, largely performed on tumor infiltrating lymphocytes (TILs), has provided evidence in support of this hypothesis, but whether similar changes occur in circulating blood lymphocytes has received little attention. In the present study, a comprehensive analysis of peripheral blood leukocytes from 42 patients taken over the course of treatment with anti-PD-1 was undertaken. The patients included those grouped as responders (who did not progress), primary non-responders (primary resistance) and those with acquired resistance (who initially responded then subsequently progressed). Analysis included surface markers of exhaustion, production of cytokines following in vitro stimulation, and assessment of transcription factor levels associated with T cell exhaustion. There were differences in innate cell populations between responders and non-responders at baseline and maintained throughout therapy. Frequencies of total and classical CD14 + CD16 - monocytes were higher and the major subset of NK cells (CD16 hi CD56 + ) was significantly smaller in the primary resistance group compared with responders. However, differences in peripheral blood expression of exhaustion markers were not evident between the treatment groups. T cell exhaustion markers were expressed in practically all patients and the major observation was an increase in CD39 on CD4 T cells during treatment. The results confirm the association of Eomes transcription factor with T cell exhaustion but levels of expression and the ratio with T-bet over Eomes did not differ between the patient groups. Thus, peripheral blood expression of T cell exhaustion markers does not distinguish between responders and non-responders to anti-PD-1 therapy. CD4 T cell expression of IFNγ also differed in pre-treatment samples, indicating that predictors of response unrelated to exhaustion may be present in peripheral blood. The association of response with innate cell populations and CD4 T cell responses requires further study., (Copyright © 2020 Pirozyan, McGuire, Emran, Tseng, Tiffen, Lee, Carlino, Menzies, Long, Scolyer, Fazekas de St Groth and Hersey.)

Methylation of DNA at CpG sites is the most common and stable of epigenetic changes in cancer. Hypermethylation acts to limit immune checkpoint blockade immunotherapy by inhibiting endogenous interferon responses needed for recognition of cancer cells. By contrast, global hypomethylation results in the expression of programmed death ligand 1 (PD-L1) and inhibitory cytokines, accompanied by epithelial-mesenchymal changes that can contribute to immunosuppression. The drivers of these contrasting methylation states are not well understood. DNA methylation also plays a key role in cytotoxic T cell 'exhaustion' associated with tumor progression. We present an updated exploratory analysis of how DNA methylation may define patient subgroups and can be targeted to develop tailored treatment combinations to help improve patient outcomes., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Pembrolizumab demonstrated robust antitumor activity and safety in the phase Ib KEYNOTE-001 study (NCT01295827) of advanced melanoma. Five-year outcomes in all patients and treatment-naive patients are reported herein. Patients whose disease progressed following initial response and who received a second course of pembrolizumab were also analyzed., Patients and Methods: Patients aged ≥18 years with previously treated or treatment-naive advanced/metastatic melanoma received pembrolizumab 2 mg/kg every 3 weeks, 10 mg/kg every 3 weeks, or 10 mg/kg every 2 weeks until disease progression, intolerable toxicity, or patient/investigator decision to withdraw. Kaplan-Meier estimates of overall survival (OS) and progression-free survival (PFS) were calculated. Objective response rate and PFS were based on immune-related response criteria by investigator assessment (data cut-off, September 1, 2017)., Results: KEYNOTE-001 enrolled 655 patients with melanoma; median follow-up was 55 months. Estimated 5-year OS was 34% in all patients and 41% in treatment-naive patients; median OS was 23.8 months (95% CI, 20.2-30.4) and 38.6 months (95% CI, 27.2-not reached), respectively. Estimated 5-year PFS rates were 21% in all patients and 29% in treatment-naive patients; median PFS was 8.3 months (95% CI, 5.8-11.1) and 16.9 months (95% CI, 9.3-35.5), respectively. Median response duration was not reached; 73% of all responses and 82% of treatment-naive responses were ongoing at data cut-off; the longest response was ongoing at 66 months. Four patients [all with prior response of complete response (CR)] whose disease progressed during observation subsequently received second-course pembrolizumab. One patient each achieved CR and partial response (after data cut-off). Treatment-related AEs (TRAEs) occurred in 86% of patients and resulted in study discontinuation in 7.8%; 17% experienced grade 3/4 TRAE., Conclusions: This 5-year analysis of KEYNOTE-001 represents the longest follow-up for pembrolizumab to date and confirms the durable antitumor activity and tolerability of pembrolizumab in advanced melanoma., Clinical Trial Registry: ClinicalTrials.gov, NCT01295827., (© The Author(s) 2019. Published by Oxford University Press on behalf of the European Society for Medical Oncology.)

Background: Primary findings from the METRIC (TMT212A2301) study demonstrated that trametinib improved progression-free survival (PFS) and overall survival (OS) compared with chemotherapy in patients with unresectable or metastatic cutaneous melanoma with a BRAF V600 E/K mutation. However, clinical data characterising the long-term use of these therapies in combination with BRAF inhibitors or as monotherapies are limited., Methods: In this open-label, phase 3 study, 322 patients with BRAF V600 E/K-mutant metastatic melanoma were randomised in a 2:1 ratio to receive trametinib (2 mg orally, once daily; n = 214) or chemotherapy (dacarbazine [1000 mg/m 2 ] or paclitaxel [175 mg/m 2 ] intravenously, every 3 weeks; n = 108). Patients who progressed on chemotherapy were allowed to cross over and receive trametinib. Five-year results of efficacy and safety analyses are reported., Results: The median PFS was 4.9 months in the trametinib arm versus 1.5 months in the chemotherapy arm (hazard ratio, 0.54; 95% confidence interval, 0.41-0.73). Landmark OS rates for trametinib versus chemotherapy arms at 1 year, 2 years and 5 years were 60.9% versus 49.6%, 32.0% versus 29.4% and 13.3% versus 17.0%, respectively. Most patients (n = 70 [65%]) from the chemotherapy arm crossed over to the trametinib arm early in their treatment. No unexpected adverse events were reported., Conclusions: This 5-year follow-up of patients with BRAF V600 E/K-mutant metastatic melanoma on a targeted therapy demonstrates that long-term use of trametinib is possible with no new or unexpected adverse events. Some patients experienced long-term survival benefit with trametinib monotherapy (METRIC ClinicalTrials.gov number, NCT01245062.)., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

While multiple mechanisms of BRAF V600 -mutant melanoma resistance to targeted MAPK signaling inhibitors (MAPKi) have been reported, the epigenetic regulation of this process remains undetermined. Here, using a CRISPR-Cas9 screen targeting chromatin regulators, we discover that haploinsufficiency of the histone deacetylase SIRT6 allows melanoma cell persistence in the presence of MAPKi. Haploinsufficiency, but not complete loss of SIRT6 promotes IGFBP2 expression via increased chromatin accessibility, H3K56 acetylation at the IGFBP2 locus, and consequent activation of the IGF-1 receptor (IGF-1R) and downstream AKT signaling. Combining a clinically applicable IGF-1Ri with BRAFi overcomes resistance of SIRT6 haploinsufficient melanoma cells in vitro and in vivo. Using matched melanoma samples derived from patients receiving dabrafenib + trametinib, we identify IGFBP2 as a potential biomarker for MAPKi resistance. Our study has not only identified an epigenetic mechanism of drug resistance, but also provides insights into a combinatorial therapy that may overcome resistance to standard-of-care therapy for BRAF V600 -mutant melanoma patients.

Purpose: Therapeutic blockade of immune checkpoints has revolutionized cancer treatment. Durable responses, however, occur in less than half of those treated, and efforts to improve treatment efficacy are confounded by a lack of understanding of the characteristics of the cells that initiate antitumor immune response. Patients and Methods: We performed multiparameter flow cytometry and quantitative multiplex immunofluorescence staining on tumor specimens from immunotherapy-naïve melanoma patients and longitudinal biopsy specimen obtained from patients undergoing anti-PD-1 therapy. Results: Increased numbers of CD69 + CD103 + tumor-resident CD8 + T cells were associated with improved melanoma-specific survival in immunotherapy-naïve melanoma patients. Local IL15 expression levels strongly correlated with these tumor-resident T-cell numbers. The expression of several immune checkpoints including PD-1 and LAG3 was highly enriched in this subset, and these cells significantly expanded early during anti-PD-1 immunotherapy. Conclusions: Tumor-resident CD8 + T-cell numbers are more prognostic than total CD8 + T cells in metastatic melanoma. In addition, they are likely to initiate response to anti-PD-1 and anti-LAG-3 treatments. We propose that the immune profile of these cells prior to treatment could inform strategies for immune checkpoint blockade. Clin Cancer Res; 24(13); 3036-45. ©2018 AACR ., (©2018 American Association for Cancer Research.)

Background: Despite newly approved treatments, metastatic melanoma remains a life-threatening condition. We aimed to evaluate the efficacy of the MAGE-A3 immunotherapeutic in patients with stage IIIB or IIIC melanoma in the adjuvant setting., Methods: DERMA was a phase 3, double-blind, randomised, placebo-controlled trial done in 31 countries and 263 centres. Eligible patients were 18 years or older and had histologically proven, completely resected, stage IIIB or IIIC, MAGE-A3-positive cutaneous melanoma with macroscopic lymph node involvement and an Eastern Cooperative Oncology Group performance score of 0 or 1. Randomisation and treatment allocation at the investigator sites were done centrally via the internet. We randomly assigned patients (2:1) to receive up to 13 intramuscular injections of recombinant MAGE-A3 with AS15 immunostimulant (MAGE-A3 immunotherapeutic; 300 μg MAGE-A3 antigen plus 420 μg CpG 7909 reconstituted in AS01B to a total volume of 0·5 mL), or placebo, over a 27-month period: five doses at 3-weekly intervals, followed by eight doses at 12-weekly intervals. The co-primary outcomes were disease-free survival in the overall population and in patients with a potentially predictive gene signature (GS-positive) identified previously and validated here via an adaptive signature design. The final analyses included all patients who had received at least one dose of study treatment; analyses for efficacy were in the as-randomised population and for safety were in the as-treated population. This trial is registered with ClinicalTrials.gov, number NCT00796445., Findings: Between Dec 1, 2008, and Sept 19, 2011, 3914 patients were screened, 1391 randomly assigned, and 1345 started treatment (n=895 for MAGE-A3 and n=450 for placebo). At final analysis (data cutoff May 23, 2013), median follow-up was 28·0 months [IQR 23·3-35·5] in the MAGE-A3 group and 28·1 months [23·7-36·9] in the placebo group. Median disease-free survival was 11·0 months (95% CI 10·0-11·9) in the MAGE-A3 group and 11·2 months (8·6-14·1) in the placebo group (hazard ratio [HR] 1·01, 0·88-1·17, p=0·86). In the GS-positive population, median disease-free survival was 9·9 months (95% CI 5·7-17·6) in the MAGE-A3 group and 11·6 months (5·6-22·3) in the placebo group (HR 1·11, 0·83-1·49, p=0·48). Within the first 31 days of treatment, adverse events of grade 3 or worse were reported by 126 (14%) of 894 patients in the MAGE-A3 group and 56 (12%) of 450 patients in the placebo group, treatment-related adverse events of grade 3 or worse by 36 (4%) patients given MAGE-A3 vs six (1%) patients given placebo, and at least one serious adverse event by 14% of patients in both groups (129 patients given MAGE-A3 and 64 patients given placebo). The most common adverse events of grade 3 or worse were neoplasms (33 [4%] patients in the MAGE-A3 group vs 17 [4%] patients in the placebo group), general disorders and administration site conditions (25 [3%] for MAGE-A3 vs four [<1%] for placebo) and infections and infestations (17 [2%] for MAGE-A3 vs seven [2%] for placebo). No deaths were related to treatment., Interpretation: An antigen-specific immunotherapeutic alone was not efficacious in this clinical setting. Based on these findings, development of the MAGE-A3 immunotherapeutic for use in melanoma has been stopped., Funding: GlaxoSmithKline Biologicals SA., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Purpose Pembrolizumab provides durable antitumor activity in metastatic melanoma, including complete response (CR) in about 15% of patients. Data are limited on potential predictors of CR and patient disposition after pembrolizumab discontinuation after CR. We describe baseline characteristics and long-term follow-up in patients who experienced CR with pembrolizumab in the KEYNOTE-001 study ( ClinicalTrials.gov identifier: NCT01295827). Patients and Methods Patients with ipilimumab-naive or -treated advanced/metastatic melanoma received one of three dose regimens of pembrolizumab. Eligible patients who received pembrolizumab for ≥ 6 months and at least two treatments beyond confirmed CR could discontinue therapy. Response was assessed every 12 weeks by central Response Evaluation Criteria in Solid Tumors version 1.1. For this analysis, CR was defined per investigator assessment, immune-related response criteria, and potential predictors of CR were evaluated using univariate and multivariate analyses. Results Of 655 treated patients, 105 (16.0%) achieved CR after median follow-up of 43 months. At data cutoff, 92 patients (87.6%) had CR, with median follow-up of 30 months from first CR. Fourteen (13.3%) patients continued to receive treatment for a median of ≥ 40 months. Pembrolizumab was discontinued by 91 patients (86.7%), including 67 (63.8%) who proceeded to observation without additional anticancer therapy. The 24-month disease-free survival rate from time of CR was 90.9% in all 105 patients with CR and 89.9% in the 67 patients who discontinued pembrolizumab after CR for observation. Tumor size and programmed death-ligand 1 status were among the baseline factors independently associated with CR by univariate analysis. Conclusion Patients with metastatic melanoma can have durable complete remission after discontinuation of pembrolizumab, and the low incidence of relapse after median follow-up of approximately 2 years from discontinuation provides hope for a cure for some patients. The mechanisms underlying durable CR require further investigation.

Mutations in BRAF activate oncogenic MAPK signalling in almost half of cutaneous melanomas. Inhibitors of BRAF (BRAFi) and its target MEK are widely used to treat melanoma patients with BRAF mutations but unfortunately acquired resistance occurs in the majority of patients. Resistance results from mutations or non-genomic changes that either reactivate MAPK signalling or activate other pathways that provide alternate survival and growth signalling. Here, we show the histone deacetylase inhibitor (HDACi) panobinostat overcomes BRAFi resistance in melanoma, but this is dependent on the resistant cells showing a partial response to BRAFi treatment. Using patient- and in vivo-derived melanoma cell lines with acquired BRAFi resistance, we show that combined treatment with the BRAFi encorafenib and HDACi panobinostat in 2D and 3D culture systems synergistically induced caspase-dependent apoptotic cell death. Key changes induced by HDAC inhibition included decreased PI3K pathway activity associated with a reduction in the protein level of a number of receptor tyrosine kinases, and cell line dependent upregulation of pro-apoptotic BIM or NOXA together with reduced expression of anti-apoptotic proteins. Independent of these changes, panobinostat reduced c-Myc and pre-treatment of cells with siRNA against c-Myc reduced BRAFi/HDACi drug-induced cell death. These results suggest that a combination of HDAC and MAPK inhibitors may play a role in treatment of melanoma where the resistance mechanisms are due to activation of MAPK-independent pathways., (© 2017 UICC.)

Effective treatment or prevention of immune side effects associated with checkpoint inhibitor therapy of cancer is an important goal in this new era of immunotherapy. Hepatitis due to immunotherapy with antibodies against PD-1 is uncommon and generally of low severity. We present an unusually severe case arising in a melanoma patient after more than 6 months uncomplicated treatment with anti-PD-1 in an adjuvant setting. The hepatitis rapidly developed resistance to high-dose steroids, requiring anti-thymocyte globulin (ATG) to achieve control. Mass cytometry allowed comprehensive phenotyping of circulating lymphocytes and revealed that CD4 + T cells were profoundly depleted by ATG, while CD8 + T cells, B cells, NK cells and monocytes were relatively spared. Multiple abnormalities in CD4 + T cell phenotype were stably present in the patient before disease onset. These included a population of CCR4 - CCR6 - effector/memory CD4 + T cells expressing intermediate levels of the Th1-related chemokine receptor CXCR3 and abnormally high multi-drug resistance type 1 transporter (MDR1) activity as assessed by a rhodamine 123 excretion assay. Expression of MDR1 has been implicated in steroid resistance and may have contributed to the severity and lack of a sustained steroid response in this patient. The number of CD4 + rhodamine 123-excreting cells was reduced > 3.5-fold after steroid and ATG treatment. This case illustrates the need to consider this form of steroid resistance in patients failing treatment with corticosteroids. It also highlights the need for both better identification of patients at risk and the development of treatments that involve more specific immune suppression.

Aim: Sarcoidosis is a multisystem granulomatous disease. This condition has a documented association with the diagnosis of melanoma and can be induced in melanoma patients receiving anti-neoplastic therapy. We evaluated a case series of melanoma patients who developed immunotherapy-induced sarcoidosis., Methods: Three patients with melanoma (n = 1 resected Stage III, n = 2 metastatic) treated with anti-programmed cell death (PD)-1 antibody therapy at two institutions developed biopsy-proven sarcoidosis. We used mass cytometry to determine expression of the relevant chemokine receptors (CR) by peripheral blood mononuclear cells for two of the three patients who developed sarcoidosis and 13 melanoma patients who did not. Blood samples were collected before receiving PD-1 checkpoint inhibitor therapy., Results: Immunophenotypic analysis demonstrated abnormally high numbers of circulating Th17.1 (CCR6 + CCR4 - CXCR3 + CCR10 - ) cells prior to commencing PD-1 checkpoint inhibitor therapy in five of 15 melanoma patients, including both the patients who developed sarcoidosis during the course of therapy., Conclusion: Our findings support prior literature implicating Th17.1 cells in the pathogenesis of sarcoidosis. However, we demonstrate these findings in patients with melanoma prior to administration of checkpoint therapy and before the onset of clinically symptomatic sarcoidosis. The identification of elevated Th17.1 cells in melanoma patients who have not developed sarcoidosis may reflect the established association between melanoma and sarcoidosis. With some patients receiving these agents over a prolonged period, the clinical course of immunotherapy-induced sarcoidosis is uncertain., (© 2017 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.)

Background: Sentinel-lymph-node biopsy is associated with increased melanoma-specific survival (i.e., survival until death from melanoma) among patients with node-positive intermediate-thickness melanomas (1.2 to 3.5 mm). The value of completion lymph-node dissection for patients with sentinel-node metastases is not clear., Methods: In an international trial, we randomly assigned patients with sentinel-node metastases detected by means of standard pathological assessment or a multimarker molecular assay to immediate completion lymph-node dissection (dissection group) or nodal observation with ultrasonography (observation group). The primary end point was melanoma-specific survival. Secondary end points included disease-free survival and the cumulative rate of nonsentinel-node metastasis., Results: Immediate completion lymph-node dissection was not associated with increased melanoma-specific survival among 1934 patients with data that could be evaluated in an intention-to-treat analysis or among 1755 patients in the per-protocol analysis. In the per-protocol analysis, the mean (±SE) 3-year rate of melanoma-specific survival was similar in the dissection group and the observation group (86±1.3% and 86±1.2%, respectively; P=0.42 by the log-rank test) at a median follow-up of 43 months. The rate of disease-free survival was slightly higher in the dissection group than in the observation group (68±1.7% and 63±1.7%, respectively; P=0.05 by the log-rank test) at 3 years, based on an increased rate of disease control in the regional nodes at 3 years (92±1.0% vs. 77±1.5%; P<0.001 by the log-rank test); these results must be interpreted with caution. Nonsentinel-node metastases, identified in 11.5% of the patients in the dissection group, were a strong, independent prognostic factor for recurrence (hazard ratio, 1.78; P=0.005). Lymphedema was observed in 24.1% of the patients in the dissection group and in 6.3% of those in the observation group., Conclusions: Immediate completion lymph-node dissection increased the rate of regional disease control and provided prognostic information but did not increase melanoma-specific survival among patients with melanoma and sentinel-node metastases. (Funded by the National Cancer Institute and others; MSLT-II ClinicalTrials.gov number, NCT00297895 .).

Melanoma of the skin is a common cancer only in Europeans, whereas it arises in internal body surfaces (mucosal sites) and on the hands and feet (acral sites) in people throughout the world. Here we report analysis of whole-genome sequences from cutaneous, acral and mucosal subtypes of melanoma. The heavily mutated landscape of coding and non-coding mutations in cutaneous melanoma resolved novel signatures of mutagenesis attributable to ultraviolet radiation. However, acral and mucosal melanomas were dominated by structural changes and mutation signatures of unknown aetiology, not previously identified in melanoma. The number of genes affected by recurrent mutations disrupting non-coding sequences was similar to that affected by recurrent mutations to coding sequences. Significantly mutated genes included BRAF, CDKN2A, NRAS and TP53 in cutaneous melanoma, BRAF, NRAS and NF1 in acral melanoma and SF3B1 in mucosal melanoma. Mutations affecting the TERT promoter were the most frequent of all; however, neither they nor ATRX mutations, which correlate with alternative telomere lengthening, were associated with greater telomere length. Most melanomas had potentially actionable mutations, most in components of the mitogen-activated protein kinase and phosphoinositol kinase pathways. The whole-genome mutation landscape of melanoma reveals diverse carcinogenic processes across its subtypes, some unrelated to sun exposure, and extends potential involvement of the non-coding genome in its pathogenesis.

Purpose Expression of programmed death-ligand 1 (PD-L1) is a potential predictive marker for response and outcome after treatment with anti-programmed death 1 (PD-1). This study explored the relationship between anti-PD-1 activity and PD-L1 expression in patients with advanced melanoma who were treated with pembrolizumab in the phase Ib KEYNOTE-001 study (clinical trial information: NCT01295827). Patients and Methods Six hundred fifty-five patients received pembrolizumab10 mg/kg once every 2 weeks or once every 3 weeks, or 2 mg/kg once every 3 weeks. Tumor response was assessed every 12 weeks per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 by independent central review. Primary outcome was objective response rate. Secondary outcomes included progression-free survival (PFS) and overall survival (OS). Membranous PD-L1 expression in tumor and tumor-associated immune cells was assessed by a clinical trial immunohistochemistry assay (22C3 antibody) and scored on a unique melanoma (MEL) scale of 0 to 5 by one of three pathologists who were blinded to clinical outcome; a score ≥ 2 (membranous staining in ≥ 1% of cells) was considered positive. Results Of 451 patients with evaluable PD-L1 expression, 344 (76%) had PD-L1-positive tumors. Demographic and staging variables were equally distributed among PD-L1-positive and -negative patients. An association between higher MEL score and higher response rate and longer PFS (hazard ratio, 0.76; 95% CI, 0.71 to 0.82) and OS (hazard ratio, 0.76; 95% CI, 0.69 to 0.83) was observed ( P < .001 for each). Objective response rate was 8%, 12%, 22%, 43%, 57%, and 53% for MEL 0, 1, 2, 3, 4, and 5, respectively. Conclusion PD-L1 expression in pretreatment tumor biopsy samples was correlated with response rate, PFS, and OS; however, patients with PD-L1-negative tumors may also achieve durable responses.

Direct treatments of cancer such as chemotherapy, radiotherapy and targeted therapy have been shown to depend on recruitment of the immune system for their effectiveness. Recent studies have shown that development of resistance to direct therapies such as BRAF inhibitors in melanoma is associated with suppression of immune responses. We point to emerging data that implicate activation of the polycomb repressive complex 2 (PRC2) and its catalytic component-enhancer of zeste homolog 2 (EZH2)-in progression of melanoma and suppression of immune responses. EZH2 appears to have an important role in differentiation of CD4 T cells and particularly in the function of T regulatory cells, which suppress immune responses to melanoma. We review mechanisms of EZH2 activation at the genomic level and from activation of the MAP kinase, E2F or NF-kB2 pathways. These studies are consistent with activation of EZH2 as a common mechanism for induction of immune suppression in patients failing direct therapies and suggest EZH2 inhibitors may have a role in combination with immunotherapy and targeted therapies to prevent development of immunosuppression., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Purpose: We evaluated atypical response patterns and the relationship between overall survival and best overall response measured per immune-related response criteria (irRC) and Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST v1.1) in patients with advanced melanoma treated with pembrolizumab in the phase Ib KEYNOTE-001 study (clinical trial information: NCT01295827)., Patients and Methods: Patients received pembrolizumab 2 or 10 mg/kg every 2 weeks or every 3 weeks. Atypical responses were identified by using centrally assessed irRC data in patients with ≥ 28 weeks of imaging. Pseudoprogression was defined as ≥ 25% increase in tumor burden at week 12 (early) or any assessment after week 12 (delayed) that was not confirmed as progressive disease at next assessment. Response was assessed centrally per irRC and RECIST v1.1., Results: Of the 655 patients with melanoma enrolled, 327 had ≥ 28 weeks of imaging follow-up. Twenty-four (7%) of these 327 patients had atypical responses (15 [5%] with early pseudoprogression and nine [3%] with delayed pseudoprogression). Of the 592 patients who survived ≥ 12 weeks, 84 (14%) experienced progressive disease per RECIST v1.1 but nonprogressive disease per irRC. Two-year overall survival rates were 77.6% in patients with nonprogressive disease per both criteria (n = 331), 37.5% in patients with progressive disease per RECIST v1.1 but nonprogressive disease per irRC (n = 84), and 17.3% in patients with progressive disease per both criteria (n = 177)., Conclusion: Atypical responses were observed in patients with melanoma treated with pembrolizumab. Based on survival analysis, conventional RECIST might underestimate the benefit of pembrolizumab in approximately 15% of patients; modified criteria that permit treatment beyond initial progression per RECIST v1.1 might prevent premature cessation of treatment., Competing Interests: Authors' disclosures of potential conflicts of interest are found in the article online at www.jco.org. Author contributions are found at the end of this article., (© 2016 by American Society of Clinical Oncology.)

Importance: The programmed death 1 (PD-1) pathway limits immune responses to melanoma and can be blocked with the humanized anti-PD-1 monoclonal antibody pembrolizumab., Objective: To characterize the association of pembrolizumab with tumor response and overall survival among patients with advanced melanoma., Design, Settings, and Participants: Open-label, multicohort, phase 1b clinical trials (enrollment, December 2011-September 2013). Median duration of follow-up was 21 months. The study was performed in academic medical centers in Australia, Canada, France, and the United States. Eligible patients were aged 18 years and older and had advanced or metastatic melanoma. Data were pooled from 655 enrolled patients (135 from a nonrandomized cohort [n = 87 ipilimumab naive; n = 48 ipilimumab treated] and 520 from randomized cohorts [n = 226 ipilimumab naive; n = 294 ipilimumab treated]). Cutoff dates were April 18, 2014, for safety analyses and October 18, 2014, for efficacy analyses., Exposures: Pembrolizumab 10 mg/kg every 2 weeks, 10 mg/kg every 3 weeks, or 2 mg/kg every 3 weeks continued until disease progression, intolerable toxicity, or investigator decision., Main Outcomes and Measures: The primary end point was confirmed objective response rate (best overall response of complete response or partial response) in patients with measurable disease at baseline per independent central review. Secondary end points included toxicity, duration of response, progression-free survival, and overall survival., Results: Among the 655 patients (median [range] age, 61 [18-94] years; 405 [62%] men), 581 had measurable disease at baseline. An objective response was reported in 194 of 581 patients (33% [95% CI, 30%-37%]) and in 60 of 133 treatment-naive patients (45% [95% CI, 36% to 54%]). Overall, 74% (152/205) of responses were ongoing at the time of data cutoff; 44% (90/205) of patients had response duration for at least 1 year and 79% (162/205) had response duration for at least 6 months. Twelve-month progression-free survival rates were 35% (95% CI, 31%-39%) in the total population and 52% (95% CI, 43%-60%) among treatment-naive patients. Median overall survival in the total population was 23 months (95% CI, 20-29) with a 12-month survival rate of 66% (95% CI, 62%-69%) and a 24-month survival rate of 49% (95% CI, 44%-53%). In treatment-naive patients, median overall survival was 31 months (95% CI, 24 to not reached) with a 12-month survival rate of 73% (95% CI, 65%-79%) and a 24-month survival rate of 60% (95% CI, 51%-68%). Ninety-two of 655 patients (14%) experienced at least 1 treatment-related grade 3 or 4 adverse event (AE) and 27 of 655 (4%) patients discontinued treatment because of a treatment-related AE. Treatment-related serious AEs were reported in 59 patients (9%). There were no drug-related deaths., Conclusions and Relevance: Among patients with advanced melanoma, pembrolizumab administration was associated with an overall objective response rate of 33%, 12-month progression-free survival rate of 35%, and median overall survival of 23 months; grade 3 or 4 treatment-related AEs occurred in 14%., Trial Registration: clinicaltrials.gov Identifier: NCT01295827.

The epigenetic modifier EZH2 is in the center of a repressive complex controlling differentiation of normal cells. In cancer EZH2 has been implicated in silencing tumor suppressor genes. Its role in melanoma as well as target genes affected by EZH2 are poorly understood. In view of this we have used an integrated systems biology approach to analyze 471 cases of skin cutaneous melanoma (SKCM) in The Cancer Genome Atlas (TCGA) for mutations and amplifications of EZH2. Identified changes in target genes were validated by interrogation of microarray data from melanoma cells treated with the EZH2 inhibitor GSK126. We found that EZH2 activation by mutations, gene amplification and increased transcription occurred in about 20% of the cohort. These alterations were associated with significant hypermethylation of DNA and significant downregulation of 11% of transcripts in patient RNASeq data. GSK126 treatment of melanoma lines containing EZH2 activation reversed such transcriptional repression in 98 candidate target genes. Gene enrichment analysis revealed genes associated with tumor suppression, cell differentiation, cell cycle inhibition and repression of metastases as well as antigen processing and presentation pathways. The identified changes in EZH2 were associated with an adverse prognosis in the TCGA dataset. These results suggest that inhibiting of EZH2 is a promising therapeutic avenue for a substantial fraction of melanoma patients., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

Melanoma patients with sentinel lymph node metastases have variable 5-year survival rates (39-70%). The prognostic significance of tumor-infiltrating lymphocytes in sentinel lymph node metastases from such patients is currently unknown. Anti-PD-1/PD-L1 inhibitors have significantly improved clinical outcome in unresectable AJCC stage IIIC/IV metastatic melanoma patients, and are being trialed in the adjuvant setting in advanced stage disease, however, their role in early stage (sentinel lymph node positive) metastatic disease remains unclear. The aims of this study were to characterize, in sentinel lymph nodes, the subpopulations of lymphocytes that interact with metastatic melanoma cells and analyze their associations with outcome, and to determine tumor PD-L1 expression as this may provide a rational scientific basis for the administration of adjuvant anti-PD-1/PD-L1 inhibitors in sentinel lymph node positive metastatic melanoma patients. Sentinel lymph nodes containing metastatic melanoma from 60 treatment-naive patients were analyzed for CD3, CD4, CD8, FOXP3, PD-1, and PD-L1 using immunohistochemistry on serial sections. The results were correlated with clinicopathologic features and outcome. Positive correlations between recurrence-free/overall survival with the number of CD3+ tumor-infiltrating lymphocytes (hazard ratio=0.36 (0.17-0.76), P=0.005; hazard ratio=0.29 (0.14-0.61), P=0.0005, respectively), the number of CD4+ tumor-infiltrating lymphocytes (hazard ratio=0.34 (0.15-0.77), P=0.007; hazard ratio=0.32 (0.14-0.74), P=0.005, respectively), and the number of CD8+ tumor-infiltrating lymphocytes (hazard ratio =0.42 (0.21-0.85), P=0.013; hazard ratio =0.32 (0.19-0.78), P=0.006, respectively) were observed. There was also a negative correlation with the number of peritumoral PD-1+ lymphocytes (hazard ratio=2.67 (1.17-6.13), P=0.016; hazard ratio=2.74 (1.14-6.76), P=0.019, respectively). Tumoral PD-L1 expression was present in 26 cases (43%) but did not correlate with outcome. The findings suggest that T-cell subsets in sentinel lymph node metastases can predict melanoma patient outcome. In addition, the relatively high number of PD-L1 positive sentinel lymph node melanoma metastases provides a rationale for anti-PD-1 therapy trials in sentinel lymph node positive melanoma patients, particularly those with peritumoral PD-1+ lymphocytes.

The epigenetic modifier EZH2 is part of the polycomb repressive complex that suppresses gene expression via histone methylation. Activating mutations in EZH2 are found in a subset of melanoma that contributes to disease progression by inactivating tumor suppressor genes. In this study we have targeted EZH2 with a specific inhibitor (GSK126) or depleted EZH2 protein by stable shRNA knockdown. We show that inhibition of EZH2 has potent effects on the growth of both wild-type and EZH2 mutant human melanoma in vitro particularly in cell lines harboring the EZH2Y646 activating mutation. This was associated with cell cycle arrest, reduced proliferative capacity in both 2D and 3D culture systems, and induction of apoptosis. The latter was caspase independent and mediated by the release of apoptosis inducing factor (AIFM1) from mitochondria. Gene expression arrays showed that several well characterized tumor suppressor genes were reactivated by EZH2 inhibition. This included activating transcription factor 3 (ATF3) that was validated as an EZH2 target gene by ChIP-qPCR. These results emphasize a critical role for EZH2 in the proliferation and viability of melanoma and highlight the potential for targeted therapy against EZH2 in treatment of patients with melanoma.

Histone acetylation marks have an important role in controlling gene expression and are removed by histone deacetylases (HDACs). These marks are read by bromodomain and extra-terminal (BET) proteins and novel inhibitiors of these proteins are currently in clinical development. Inhibitors of HDAC and BET proteins have individually been shown to cause apoptosis and reduce growth of melanoma cells. Here we show that combining the HDAC inhibitor LBH589 and BET inhibitor I-BET151 synergistically induce apoptosis of melanoma cells but not of melanocytes. Induction of apoptosis proceeded through the mitochondrial pathway, was caspase dependent and involved upregulation of the BH3 pro-apoptotic protein BIM. Analysis of signal pathways in melanoma cell lines resistant to BRAF inhibitors revealed that treatment with the combination strongly downregulated anti-apoptotic proteins and proteins in the AKT and Hippo/YAP signaling pathways. Xenograft studies showed that the combination of inhibitors was more effective than single drug treatment and confirmed upregulation of BIM and downregulation of XIAP as seen in vitro. These results support the combination of these two classes of epigenetic regulators in treatment of melanoma including those resistant to BRAF inhibitors.

Purpose: To evaluate the expression of tumor PD-L1 and changes in tumor-infiltrating lymphocyte (TIL) populations in patients with metastatic melanoma treated with targeted MAPK inhibitors., Experimental Design: Ninety-three tumors were analyzed from 40 patients treated with a BRAF inhibitor alone (BRAFi; n = 28) or combination of BRAF and MEK inhibitors (Combi; n = 12). Tumors were excised before treatment (PRE), early during treatment (EDT), and at progression (PROG). Immunohistochemical staining was performed for CD4, CD8, CD68, FOXP3, LAG3, PD-1, and PD-L1 and correlated with clinical outcome., Results: Patients' tumors that were PD-L1 positive at baseline showed a significant decrease in PD-L1 expression at PROG (P = 0.028), whereas patients' tumors that were PD-L1 negative at baseline showed a significant increase in PD-L1 expression at PROG (P = 0.008) irrespective of treatment with BRAFi or Combi. Overall PD-L1 expression highly correlated with TIL immune markers. BRAFi-treated patients showed significant increases in CD4(+), CD8(+), and PD-1(+) lymphocytes from PRE to EDT (P = 0.001, P = 0.001, P = 0.017, respectively), and Combi-treated patients showed similar increases in CD4(+) and CD8(+) lymphocytes from PRE to EDT (P = 0.017, P = 0.021)., Conclusions: The addition of MEKi to BRAFi did not result in significant reduction in immune infiltration in EDT biopsies. This provides support for conducting trials that combine MAPKi with immune checkpoint inhibitors in the hope of improving complete and durable response rates. PD-L1 expression at PROG on MAPK inhibitors varied according to baseline expression suggesting that combining MAPKi with immunotherapies concurrently may be more effective in patients with PD-L1 expression and TILs in baseline melanoma samples., (©2015 American Association for Cancer Research.)

Prior studies have shown that combinations of histone deacetylase (HDAC) and BRAF inhibitors (BRAFi) have synergistic effects on BRAFi-resistant melanoma through enhanced apoptosis and inhibition of the cAMP-dependent drug resistance pathway. However, little is known about the expression of various HDACs and their associations with BRAF/NRAS mutation status, clinicopathologic characteristics, and patient outcome. The present study extensively profiled HDAC class 1 and their targets/regulators utilizing immunohistochemistry in human melanoma samples from patients with stage IV melanoma, known BRAF/NRAS mutational status, and detailed clinicopatholgical data. HDAC8 was increased in BRAF-mutated melanoma (P=0.016), however, no association between expression of other HDACs and NRAS/BRAF status was identified. There was also a correlation between HDAC1, HDAC8 expression, and phosphorylated NFκb p65 immunoreactivity (P<0.001). Increased cytoplasmic HDAC8 immunoreactivity was independently associated with an improved survival from both diagnosis of primary melanoma and from first detection of stage IV disease to melanoma death on multivariate analysis (HR 0.992, 95% CI 0.987-0.996; P<0.001 and HR 0.993, 95% CI 0.988-0.998; P=0.009, respectively). These results suggest not only that HDAC8 may be a prognostic biomarker in melanoma, but also provide important data regarding the regulation of HDACs in melanoma and a rational basis for targeting them therapeutically.

This study evaluated the expression of PD-L1 in immunotherapy-naïve metastatic melanoma patients to determine longitudinal intrapatient concordance and correlate PD-L1 status with clinicopathologic characteristics and outcome. PD-L1 expression was assessed by immunohistochemistry in 58 patients (43 primary tumors, 96 metastases). Seventy-two percent of patients had at least one specimen expressing PD-L1 in ≥ 1% of tumor cells. Median positive tumor cell count overall was low (8% in nonzero specimens). PD-L1 expression was frequently discordant between primary tumors and metastases and between intrapatient metastases, such that 23/46 longitudinal patient specimens were discordant. PD-L1 was associated with higher TIL grade but not with other known prognostic features. There was a positive univariate association between PD-L1 expression in locoregional metastases and melanoma-specific survival, but the effect was not observed for primary melanoma. In locoregional lymph node metastasis, PD-L1+/TIL+ patients had the best outcome, and PD-L1+/TIL- patients had poor outcome., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Monoclonal antibodies against immune checkpoint blockade have proven to be a major success in the treatment of melanoma. The programmed death receptor-1 ligand-1 (PD-L1) expression on melanoma cells is believed to have an inhibitory effect on T cell responses and to be an important escape mechanism from immune attack. Previous studies have shown that PD-L1 can be expressed constitutively or can be induced by IFN-γ secreted by infiltrating lymphocytes. In the present study we have investigated the mechanism underlying these two modes of PD-L1 expression in melanoma cells including cells that had acquired resistance to the BRAF inhibitor vemurafenib. PD-L1 expression was examined by flow cytometry and immunoblotting. Specific inhibitors and siRNA knockdown approaches were used to examine the roles of the RAF/ MEK, PI3K, NF-κB, STAT3 and AP1/ c-Jun pathways. IFN-γ inducible expression of PD-L1 was dependent on NF-κB as shown by inhibition with BMS-345541, an inhibitor of IκB and the BET protein inhibitor I-BET151, as well as by siRNA knockdown of NF-κB subunits. We were unable to implicate the BRAF/MEK pathway as major regulators in PD-L1 expression on vemurafenib resistant cells. Similarly the PI3K/AKT pathway and the transcription factors STAT3 and c-Jun had only minor roles in IFN-γ induced expression of PD-L1. The mechanism underlying constitutive expression remains unresolved. We suggest these results have significance in selection of treatments that can be used in combination with monoclonal antibodies against PD1, to enhance their effectiveness and to reduce inhibitory effects melanoma cells have against cytotoxic T cell activity.

As the incidence of melanoma continues to increase worldwide, the search for new therapies for advanced (stage IV) melanoma brings with it new patterns of toxicity to contend with. This review covers the toxicity profiles of new treatments for advanced melanoma currently in development. Therefore, the latest literature on melanoma treatment was surveyed for data on reported toxicities. The new types of treatments can be roughly divided into targeted tyrosine kinase inhibitors and immunomodulating agents. Each has its own set of toxicities particular to type and to individual drug. Targeted tyrosine kinase inhibitors generally cause fatigue, whereas immunomodulatory agents induce a specific set of adverse events known as immune-related adverse events (irAEs). Despite the incidence of adverse events, these agents hold promise for the treatment of stage IV melanoma. With new treatment opportunities come increased chance of toxic reactions. The key to successful melanoma treatment in the future is likely to be novel combinations of new therapeutic agents.

Pembrolizumab (MK-3475) is a monoclonal antibody that binds to the PD-1 receptor on T cells and prevents binding to its ligands PD-L1 and PD-L2. Blocking this receptor frees T cells from the inhibitory effects of PD-L1 and allows them to mediate antitumor effects against cancer cells. In a large Phase I study of 411 patients with melanoma, high durable response rates over a range of doses and schedules have been shown with very little toxicity. A Phase III study of pembrolizumab comparing two schedules of administration with the current standard treatment with the anti-CTLA-4 monoclonal antibody is in progress. Combinations with other checkpoint inhibitors as well as other anticancer agents are also being evaluated. Approval of pembrolizumab for the treatment of melanoma is expected.

Histone modifications are increasingly being recognized as important epigenetic mechanisms that govern chromatin structure and gene expression. EZH2 is the catalytic subunit of the polycomb repressive complex 2 (PRC2), responsible for tri-methylation of lysine 27 on histone 3 (H3K27me3) that leads to gene silencing. This highly conserved histone methyltransferase is found to be overexpressed in many different types of cancers including melanoma, where it is postulated to abnormally repress tumor suppressor genes. Somatic mutations have been identified in approximately 3% of melanomas, and activating mutations described within the catalytic SET domain of EZH2 confer its oncogenic activity. In the following review, we discuss the evidence that EZH2 is an important driver of melanoma progression and we summarize the progress of EZH2 inhibitors against this promising therapeutic target., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Risk factors for melanoma are well known and have guided plans for primary and secondary prevention. The presentation of the disease, however, varies widely depending on the geographic area, ethnicity, and socioeconomic status. For this reason, many countries have developed specific strategies to increase public awareness and favor early diagnosis. Awareness campaigns, doctor education, and screening of high-risk subjects have all contributed to improve disease outcome in developed countries. The role of primary care physicians is particularly relevant in this regard. Developing countries are trying to implement similar measures. Future efforts to further improve the efficacy of preventive strategies should focus on populations that usually escape campaigns, such as elderly men and people with low socioeconomic status. Fast-growing tumors also require specific attention.

Epigenetic changes are widespread in melanoma and contribute to the pathogenic biology of this disease. In the present study, we show that I-BET151, which belongs to a new class of drugs that target the BET family of epigenetic "reader" proteins, inhibits melanoma growth in vivo and induced variable degrees of apoptosis in a panel of melanoma cells. Apoptosis was caspase dependent and associated with G1 cell cycle arrest. All melanoma cells tested had increased levels of the BH3 proapoptotic protein BIM, which appeared to be regulated by the BRD2 BET protein and to some extent by BRD3. In contrast, knockdown experiments indicated that inhibition of BRD4 was associated with decreased levels of BIM. Apoptosis was dependent on BIM in some but not all cell lines, indicating that other factors were determinants of apoptosis, such as downregulation of antiapoptotic proteins revealed in gene expression arrays. G1 cell cycle arrest appeared to be mediated by p21 and resulted from inhibition of the BRD4 protein. The activity of BET protein inhibitors appears independent of the BRAF and NRAS mutational status of melanoma, and further studies to assess their therapeutic role in melanoma are warranted.

The transcription factor NF-kappaB (NF-kB) is a key regulator of cytokine and chemokine production in melanoma and is responsible for symptoms such as anorexia, fatigue, and weight loss. In addition, NF-kB is believed to contribute to progression of the disease by upregulation of cell cycle and anti-apoptotic genes and to contribute to resistance against targeted therapies and immunotherapy. In this study, we have examined the ability of the bromodomain and extra-terminal (BET) protein inhibitor I-BET151 to inhibit NF-kB in melanoma cells. We show that I-BET151 is a potent, selective inhibitor of a number of NF-kB target genes involved in induction of inflammation and cell cycle regulation and downregulates production of cytokines such as IL-6 and IL-8. SiRNA studies indicate that BRD2 is the main BET protein involved in regulation of NF-kB and that I-BET151 caused transcriptional downregulation of the NF-kB subunit p105/p50. These results suggest that BET inhibitors may have an important role in treatment of melanoma where activation of NF-kB may have a key pathogenic role., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Macrophage migration inhibitory factor (MIF) is a widely expressed cytokine involved in a variety of cellular processes including cell cycle regulation and the control of proliferation. Overexpression of MIF has been reported in a number of cancer types and it has previously been shown that MIF is upregulated in melanocytic tumours with the highest expression levels occurring in malignant melanoma. However, the clinical significance of high MIF expression in melanoma has not been reported., Methods: MIF expression was depleted in human melanoma cell lines using siRNA-mediated gene knockdown and effects monitored using in vitro assays of proliferation, cell cycle, apoptosis, clonogenicity and Akt signalling. In silico analyses of expression microarray data were used to correlate MIF expression levels in melanoma tumours with overall patient survival using a univariate Cox regression model., Results: Knockdown of MIF significantly decreased proliferation, increased apoptosis and decreased anchorage-independent growth. Effects were associated with reduced numbers of cells entering S phase concomitant with decreased cyclin D1 and CDK4 expression, increased p27 expression and decreased Akt phosphorylation. Analysis of clinical outcome data showed that MIF expression levels in primary melanoma were not associated with outcome (HR = 1.091, p = 0.892) whereas higher levels of MIF in metastatic lesions were significantly associated with faster disease progression (HR = 2.946, p = 0.003 and HR = 4.600, p = 0.004, respectively in two independent studies)., Conclusions: Our in vitro analyses show that MIF functions upstream of the PI3K/Akt pathway in human melanoma cell lines. Moreover, depletion of MIF inhibited melanoma proliferation, viability and clonogenic capacity. Clinically, high MIF levels in metastatic melanoma were found to be associated with faster disease recurrence. These findings support the clinical significance of MIF signalling in melanoma and provide a strong rationale for both targeting and monitoring MIF expression in clinical melanoma.

Increased global protein synthesis and selective translation of mRNAs encoding proteins contributing to malignancy is common in cancer cells. This is often associated with elevated expression of eukaryotic translation initiation factor 4 (eIF4E), the rate-limiting factor of cap-dependent translation initiation. We report here that in human melanoma downregulation of miR-768-3p as a result of activation of the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway has an important role in the upregulation of eIF4E and enhancement in protein synthesis. Melanoma cells displayed increased nascent protein production and elevated eIF4E expression, which was associated with the downregulation of miR-768-3p that was predicted to target the 3'-untranslated region of the eIF4E mRNA. Overexpression of miR-768-3p led to the downregulation of the endogenous eIF4E protein, reduction in nascent protein synthesis and inhibition of cell survival and proliferation. These effects were efficiently reversed when eIF4E was co-overexpressed in melanoma cells. On the other hand, introduction of anti-miR-768-3p into melanocytes upregulated endogenous eIF4E protein expression and increased global protein synthesis. Downregulation of miR-768-3p appeared to be mediated by activation of the MEK/ERK pathway, in that treatment of BRAF(V600E) melanoma cells with the mutant BRAF inhibitor PLX4720 or exposure of either BRAF(V600E) or wild-type BRAF melanoma cells to the MEK inhibitor U0126 resulted in the upregulation of miR-768-3p and inhibition of nascent protein synthesis. This inhibition was partially blocked in cells cointroduced with anti-miR-768-3p. Significantly, miR-768-3p was similarly downregulated, which was inversely associated with the expression levels of eIF4E in fresh melanoma isolates. Taken together, these results identify downregulation of miR-768-3p and subsequent upregulation of eIF4E as an important mechanism in addition to phosphorylation of eIF4E responsible for MEK/ERK-mediated enhancement of protein synthesis in melanoma.

Acquired resistance to BRAF inhibitors often involves MAPK re-activation, yet the MEK inhibitor trametinib showed minimal clinical activity in melanoma patients that had progressed on BRAF-inhibitor therapy. Selective ERK inhibitors have been proposed as alternative salvage therapies. We show that ERK inhibition is more potent than MEK inhibition at suppressing MAPK activity and inhibiting the proliferation of multiple BRAF inhibitor resistant melanoma cell models. Nevertheless, melanoma cells often failed to undergo apoptosis in response to ERK inhibition, because the relief of ERK-dependent negative feedback activated RAS and PI3K signalling. Consequently, the combination of ERK and PI3K/mTOR inhibition was effective at promoting cell death in all resistant melanoma cell models, and was substantially more potent than the MEK/PI3K/mTOR inhibitor combination. Our data indicate that a broader targeting strategy concurrently inhibiting ERK, rather than MEK, and PI3K/mTOR may circumvent BRAF inhibitor resistance, and should be considered during the clinical development of ERK inhibitors., (Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.)

Intralesional immunotherapy of melanoma has two complementary aims. One is to cause regression of the injected metastasis. The other is to incite or modulate systemic immune responses in such a way that non-injected metastases will also undergo regression. A number of phase 1 and phase II studies with cytokines, viral, or bacterial agents have been conducted but their use has remained sporadic and has not progressed to become established treatments. Two treatments have progressed to randomized phase III studies. The most promising of these is based on intralesional injection of a genetically modified herpes simplex virus (HSV) (T-Vec). Initial results have shown a significant effect on durable response rates (DRR) but effects on overall survival remain under study. The second involved injection of plasmids coding for the HLA B7 antigen (Allovectin). Despite encouraging early results the treatment did not reach its endpoints and its use has been discontinued. A phase II study involving intralesional injection of oncolytic A21 coxsackie virus (Cavatak) is also under way and is showing promise., (© 2013 Wiley Periodicals, Inc.)

The purpose of this study is to profile the changes in the serum levels of a range of chemokines, cytokines, and growth and angiogenic factors in MAPK inhibitor-treated metastatic melanoma patients and to correlate these changes with clinical outcome and changes in melanoma tissue biopsies taken from the same patients. Forty-two chemokine, cytokine, angiogenic, and growth factors were measured in the sera of 20 BRAF inhibitor-treated and four combination BRAF and MEK inhibitor-treated metastatic melanoma patients using a multiplex chemokine assay. The changes were correlated with Ki-67 and CD8(+) tumor-infiltrating lymphocytes in the tumor biopsies taken at the same time points, as well as clinical outcome, including response rate, progression-free survival, and overall survival. Serum levels of IFN-γ, CCL4, and TNF-α were significantly increased, whereas CXCL8 significantly decreased from pretreatment (PRE) to early during treatment (EDT) serum samples. The decrease in serum CXCL8 levels from PRE to EDT significantly correlated with decreases in markers of melanoma proliferation (Ki-67) and increases in cytotoxic tumor-infiltrating T cells in corresponding tumor biopsies. In addition, a greater fold reduction in CXCL8 serum levels from PRE to EDT serum samples was associated with decreased overall survival. These results suggest that BRAF inhibition causes decreased CXCL8 secretion from melanoma cells and induce an immune response against the tumor associated with increased IFN-γ, CCL4, and TNF-α. Further studies are needed to determine if CXCL8 is predictive of response and to confirm the functions of these chemokine and cytokine in BRAF-mutant melanoma under BRAF inhibition.

Cancer cells commonly undergo chronic endoplasmic reticulum (ER) stress, to which the cells have to adapt for survival and proliferation. We report here that in melanoma cells intrinsic activation of the ER stress response/unfolded protein response (UPR) is, at least in part, caused by increased outputs of protein synthesis driven by oncogenic activation of mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (MEK/ERK) and promotes proliferation and protects against apoptosis induced by acute ER stress. Inhibition of oncogenic BRAF(V600E) or MEK-attenuated activation of inositol-requiring enzyme 1 (IRE1) and activating transcription factor 6 (ATF6) signaling of the UPR in melanoma cells. This was associated with decreased phosphorylation of eukaryotic initiation factor 4E (eIF4E) and nascent protein synthesis and was recapitulated by knockdown of eIF4E. In line with this, introduction of BRAF(V600E) into melanocytes led to increases in eIF4E phosphorylation and protein production and triggered activation of the UPR. Similar to knockdown of glucose-regulated protein 78 (GRP78), inhibition of XBP1 decelerated melanoma cell proliferation and enhanced apoptosis induced by the pharmacological ER stress inducers tunicamycin and thapasigargin. Collectively, these results reveal that potentiation of adaptation to chronic ER stress is another mechanism by which oncogenic activation of the MEK/ERK pathway promotes the pathogenesis of melanoma.