SIRT6 Haploinsufficiency Induces BRAF Melanoma Cell Resistance to MAPK Inhibitors Via IGF Signalling
Overview
Authors
Affiliations
While multiple mechanisms of BRAF-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-mutant melanoma patients.
Biersack B, Nitzsche B, Hopfner M Cancer Drug Resist. 2025; 8:6.
PMID: 39935431 PMC: 11810460. DOI: 10.20517/cdr.2024.125.
Age-Related Increases in IGFBP2 Increase Melanoma Cell Invasion and Lipid Synthesis.
Alicea G, Patel P, Portuallo M, Fane M, Wei M, Chhabra Y Cancer Res Commun. 2024; 4(8):1908-1918.
PMID: 39007351 PMC: 11295880. DOI: 10.1158/2767-9764.CRC-23-0176.
ALDH1A3-acetaldehyde metabolism potentiates transcriptional heterogeneity in melanoma.
Lu Y, Travnickova J, Badonyi M, Rambow F, Coates A, Khan Z Cell Rep. 2024; 43(7):114406.
PMID: 38963759 PMC: 11290356. DOI: 10.1016/j.celrep.2024.114406.
H2A.Z chaperones converge on E2F target genes for melanoma cell proliferation.
Jostes S, Vardabasso C, Dong J, Carcamo S, Singh R, Phelps R Genes Dev. 2024; 38(7-8):336-353.
PMID: 38744503 PMC: 11146596. DOI: 10.1101/gad.351318.123.
The CoREST repressor complex mediates phenotype switching and therapy resistance in melanoma.
Wu M, Hanly A, Gibson F, Fisher R, Rogers S, Park K J Clin Invest. 2024; 134(6).
PMID: 38300709 PMC: 10940100. DOI: 10.1172/JCI171063.