GSE192489
Phosphorylation and stabilization of EZH2 by VprBP trigger aberrant gene silencing in colon cancer
Our recent work has shown that VprBP is overexpressed in colon cancer and phosphorylates histone H2AT120 to drive epigenetic gene inactivation and oncogenic transformation. We have extended these observations by investigating whether VprBP also phosphorylates non-histone proteins as an additional mechanism linking its kinase activity to colon cancer development. We now demonstrate that VprBP directly phosphorylates EZH2 at T367 to augment its nuclear stabilization and enzymatic activity in colon cancer cells. Consistent with this mechanistic role, VprBP-mediated EZH2 phosphorylation leads to elevated levels of H3K27me3 and altered expression of growth regulatory genes in cancer cells. Furthermore, our preclinical studies using organoid and xenograft models revealed that EZH2 requires phosphorylation for its oncogenic function, which may have therapeutic implications for gene reactivation in colon cancer cells. Together, our data define a new mechanism underlying VprBP-driven colonic tumorigenesis by linking VprBP-mediated EZH2 phosphorylation to EZH2 stability that is crucial for establishing H3K27me3 and gene silencing program. Overall design: mRNA-seq of EZH2-knocked down (n=3) in colon cancer cell line (SW620)