The deacylase SIRT5 supports melanoma viability by influencing chromatin dynamics
William Giblin, … , Costas A. Lyssiotis, David B. Lombard
William Giblin, … , Costas A. Lyssiotis, David B. Lombard
Published May 4, 2021
Citation Information: J Clin Invest. 2021;131(12):e138926. https://doi.org/10.1172/JCI138926.
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Research Article Cell biology Metabolism

The deacylase SIRT5 supports melanoma viability by influencing chromatin dynamics

Abstract

Cutaneous melanoma remains the most lethal skin cancer, and ranks third among all malignancies in terms of years of life lost. Despite the advent of immune checkpoint and targeted therapies, only roughly half of patients with advanced melanoma achieve a durable remission. Sirtuin 5 (SIRT5) is a member of the sirtuin family of protein deacylases that regulates metabolism and other biological processes. Germline Sirt5 deficiency is associated with mild phenotypes in mice. Here we showed that SIRT5 was required for proliferation and survival across all cutaneous melanoma genotypes tested, as well as uveal melanoma, a genetically distinct melanoma subtype that arises in the eye and is incurable once metastatic. Likewise, SIRT5 was required for efficient tumor formation by melanoma xenografts and in an autochthonous mouse Braf Pten–driven melanoma model. Via metabolite and transcriptomic analyses, we found that SIRT5 was required to maintain histone acetylation and methylation levels in melanoma cells, thereby promoting proper gene expression. SIRT5-dependent genes notably included MITF, a key lineage-specific survival oncogene in melanoma, and the c-MYC proto-oncogene. SIRT5 may represent a druggable genotype-independent addiction in melanoma.

Authors

William Giblin, Lauren Bringman-Rodenbarger, Angela H. Guo, Surinder Kumar, Alexander C. Monovich, Ahmed M. Mostafa, Mary E. Skinner, Michelle Azar, Ahmed S.A. Mady, Carolina H. Chung, Namrata Kadambi, Keith-Allen Melong, Ho-Joon Lee, Li Zhang, Peter Sajjakulnukit, Sophie Trefely, Erika L. Varner, Sowmya Iyer, Min Wang, James S. Wilmott, H. Peter Soyer, Richard A. Sturm, Antonia L. Pritchard, Aleodor A. Andea, Richard A. Scolyer, Mitchell S. Stark, David A. Scott, Douglas R. Fullen, Marcus W. Bosenberg, Sriram Chandrasekaran, Zaneta Nikolovska-Coleska, Monique E. Verhaegen, Nathaniel W. Snyder, Miguel N. Rivera, Andrei L. Osterman, Costas A. Lyssiotis, David B. Lombard

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Figure 9

SIRT5 promotes histone methylation and reduced cellular ROS levels in melanoma.

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SIRT5 promotes histone methylation and reduced cellular ROS levels in me...
(A) LC-MS/MS-based metabolite profiling followed by MetaboAnalyst pathway analysis demonstrate alterations in glycine and serine and methionine biosynthesis pathways in melanoma cells upon SIRT5 depletion. (B) Perturbations in 1C metabolite levels in response to SIRT5 loss in the cell lines shown. Each column represents the mean of 3 independently prepared biological replicates. Metabolite levels in SIRT5-depleted (KD1 and KD2, as indicated) samples are normalized to control. SAM, S-adenosyl-methionine; SAH, S-adenosylhomocysteine; GSH, reduced glutathione; GSSG, glutathione disulfide. (C) H3K4me3 and H3K9me3 immunoblot in melanoma cells 96 hours after transduction with shRNAs SIRT5-KD1 or -KD2 compared with a nontargeting control. (D) H3K4me3 and H3K9me3 levels are restored in A2058 cells lacking SIRT5 after 4 weeks of continual culture in puromycin. (E) Flow cytometric analysis of DCFDA-stained A2058 cells 96 hours after transduction with shRNAs SIRT5-KD1 or -KD2 reveals increased ROS compared with a nontargeting control, P < 0.005. Left panel, average mean fluorescence intensity of DCFDA positive populations in n = 3 samples. Error bars represent standard deviation. Significance calculated using 1-way ANOVA. Right panel, representative (n = 6) flow cytometric analysis of A2058 cells stained with DCFDA. (F) SIRT5 interacts with MTHFD1L in A2058 cells. Increasing amounts of anti-SIRT5 antibody increases SIRT5-MTHFD1L coprecipitation compared with normal rabbit IgG control. Basal expression of SIRT5 and MTHFD1L in whole-cell extract (1% of initial amount used for immunoprecipitation) is shown for comparison. (G) Proposed model of promotion of MITF and c-MYC expression via SIRT5-dependent chromatin modifications in human melanoma. Me, methylation; Ac, acetylation. C, control.