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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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 2

SIRT5 is required for melanoma cell growth and survival.

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SIRT5 is required for melanoma cell growth and survival. (A) The BRAF or...
(A) The BRAF or NRAS mutant melanoma cell lines indicated were infected with a nontargeting shRNA (control) or 1 of 2 SIRT5 shRNAs (KD1 or KD2). Equivalent cell numbers were then plated 48 hours after transduction into 96-well plates in the presence of puromycin. Cell mass was determined at the indicated time points via WST-1 assay, with absorbance measured at 450 nm. Average results (n = 6/time point) are graphed. Error bars represent standard deviation. Representative of 5 of 5 SIRT5 shRNAs tested (see also Figure 3B). (B) SIRT5 KD results in significantly (P < 0.0001, 1-way ANOVA) impaired colony formation by A2058 and SK-MEL-2 cells 12 days after transduction. Cell mass was assayed using crystal violet staining, with absorbance measured at 590 nm. Average of n = 12 technical replicates is plotted. Error bars represent standard deviation. Representative (n = 4) crystal violet–stained wells are shown. Bottom, representative immunoblot analysis demonstrating SIRT5 KD. (C) Top, viability of A2058 cells transfected with the indicated CRISPR guide RNA (Control or G1–G4). Cell mass was assayed using crystal violet staining, with absorbance measured at 590 nm. Average of n = 9 technical replicates is plotted. Error bars represent standard deviation. Significance calculated using 1-way ANOVA. Bottom, representative immunoblot analysis confirming CRISPR-mediated SIRT5 loss (Control: empty vector).