Abstract B017: SETD2-loss mediated H3K36me3 causes disruptions in topologically associated domains (TADs) to promote oncogenic expression in clear cell renal cell carcinoma

Abstract SETD2 is an RNA Polymerase II (Pol II)-associated histone methyltransferase that catalyzes the co-transcriptional methylation of H3K36me2 to create H3K36me3 marks in gene bodies of actively transcribed genes. SETD2 is one of the most frequently mutated chromatin-modifying genes across different cancer types, with the highest prevalence (13%) in clear cell renal cell carcinoma (ccRCC). ccRCC has been recognized as a VHL loss-driven disease in which VHL is mutated or silenced in up to 80-90% of tumors, and the heterozygous loss of chromosome 3p where VHL resides is identified in >90% of ccRCC. The other three top mutated genes in ccRCC are also located at chromosome 3p, including PBRM1 (~40%), SETD2 (8-13%), and BAP1 (6-10%). Notably, deletion of Vhl alone is insufficient to induce kidney cancer in mice, whereas combined deletion of Vhl and Pbrm1 results in multifocal, transplantable non-metastatic clear cell kidney cancer. Human ccRCC genomics and cancer evolution studies revealed that SETD2 mutations often co-occur with VHL and PBRM1 mutations and SETD2 mutations associate with tumor progression. Previously, using VHLMT PBRM1MT SETD2MT metastatic ccRCC patient-derived cell line and xenograft models we found that H3K36me3 restoration reduced distant metastases of ccRCC in mice, establishing SEDT2 as a metastatic tumor suppressor in kidney cancer. An integrated ATAC-seq, ChIP-seq, and transcriptome analysis uncovered a tumor suppressor model of SETD2 in which loss of SETD2-mediated H3K36me3 creates an epigenetic landscape consisting of widespread open chromatin that amplifies oncogenic transcriptional output through aberrant activation of enhancers. Here, we hypothesize that loss of SETD2-mediated H3K36me3 alters 3D chromosome architecture to increase chromatin accessibility and enhancer-promoter interactions, which in turn activates oncogenic transcription, including pro-metastatic genes such as MMP1, HGF, MYC, and ETV1. Here, we performed chromosome conformation capture (Hi-C) to interrogate 3D chromatin architecture in kidney cancer with defined mutations in VHL, PBRM1, or SETD2 for the first time. Our preliminary global analysis comparing SETD2 mutant and wildtype HiC samples showed disruptions in Topologically Associated Domains (TADs) and increased long-range interaction with loss of SETD2 function. Further understanding of how dysregulated epigenetics conferred by SETD2 loss promotes tumor initiation and metastasis will allow the discovery of novel therapeutic vulnerabilities associated with the loss of SETD2. Citation Format: Amrita M. Nargund, Rui Yang. SETD2-loss mediated H3K36me3 causes disruptions in topologically associated domains (TADs) to promote oncogenic expression in clear cell renal cell carcinoma [abstract]. In: Proceedings of the AACR Special Conference: Advances in Kidney Cancer Research; 2023 Jun 24-27; Austin, Texas. Philadelphia (PA): AACR; Cancer Res 2023;83(16 Suppl):Abstract nr B017.