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 8

SIRT5 promotes histone acetylation in melanoma.

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SIRT5 promotes histone acetylation in melanoma. (A) Heatmap of z scores ...
(A) Heatmap of z scores calculated from metabolic reaction fluxes predicted by genome-scale modeling to be differentially active (P < 0.01) after SIRT5 KD. (B) Total histone acetylation is reduced 96 hours after transduction with shRNAs SIRT5-KD1 or -KD2 compared with a nontargeting control in melanoma cell lines. Lanes were run on the same gel but are noncontiguous. (C) Immunoblot demonstrating loss of H3K9ac and H4K16ac 96 hours after transduction with shRNAs SIRT5-KD1 or -KD2 compared with a nontargeting control in A2058 cells. (D) H3K9ac is reduced within the promoter regions of MITF and c-Myc in SIRT5-depleted A2058 cells via CUT&RUN followed by qRT-PCR. Signal (Ct values) relative to input DNA were normalized to control samples for each primer set. Graphed are averages of n = 9 replicates. Error bars represent standard deviation. Significance calculated using 1-way ANOVA. Acetylation (E) and MITF expression (F) are restored in A2058 cells lacking SIRT5 after 4 weeks of continual culture in puromycin. (G) Total cellular acetyl-CoA levels are increased in A2058, A375 and SK-MEL-2 cells 96 hours after SIRT5 depletion. Acetyl-CoA abundance was quantified by liquid chromatography–high resolution mass spectrometry and normalized to cell number. Plotted are average (n = 5) acetyl-CoA levels as pmol acetyl-CoA/105 cells. Error bars represent standard deviation. Significance calculated using 1-way ANOVA. C, control.