RNA mis-splicing sensitizes SETD2-mutant kidney cancer cells to DNMTi (Methylation)

The dysregulation of the histone H3 lysine 36 (H3K36) methyltransferase, SETD2, is associated with worse clinical outcomes and metastasis in clear cell Renal Cell Carcinoma (ccRCC). Here, we reveal that kidney cancer cells displaying diminished H3K36me3 levels (SETD2 deficiency) show increased sensitivity to the anti-tumor effects of the DNA hypomethylating agent 5-aza-2’-deoxycytidine (Decitabine/DAC). DAC treatment induced stronger viral mimicry activation and immunostimulatory signals by higher transposable element (TE) expression in SETD2-mutant cancer cells. Surprisingly, we demonstrate that the increased TE abundance in SETD2-knockout (SETD2-KO) kidney cancer cells is substantially derived from mis-spliced products induced by DAC treatment. Epigenetic profiling suggests that differential DNA methylation, H3K36me3, and H3K9me3 marks across exons and intronic TEs might contribute to elevated mis-splicing rates specifically in the SETD2 loss context. Finally, SETD2 dysregulation also sensitized tumors in vivo to combinatorial therapy of DAC and immune checkpoint inhibitors highlighting the translational potential for this precision medicine. Infinium MethylationEPIC BeadChip assay generated for  786-O (EV) and 786-O (SETD2 KO) treated with 300nM Decitabine.