WDR76 regulates 5-fluorouracil sensitivity in colon cancer via HRAS

Abstract

BackgroundWD repeat domain 76 (WDR76) has been reported in multiple tumors, while without relation to chemotherapy resistance. 5-fluorouracil (5-FU) is widely adopted in treating colon cancer. However, the resistance of WDR76 and 5-FU in colon cancer remains unclear.MethodsLimma package in R software was employed to analyze the differentially expressed genes. Western blot or quantitative real-time PCR (qRT-PCR) were run to assessed the gene expression. The cytotoxic effect was determined according to cell viability assay, colony formation assay in vitro. Cell apoptosis was assayed using flow cytometry. GSEA analysis was performed to identify pathways related to the target gene. Xenografted mice model was employed to evaluate the tumor growth.ResultsBioinformatic analysis revealed the higher expression of WDR76 in 5-FU sensitive colon cancer cells compared to resistant colon cancer cells, accompanied by the decreased mRNA expression of WDR76 in 5-FU resistant colon cancer cells. The overexpressed WDR76 resulted in the apoptosis and the downregulated colony numbers in 5-FU resistant colon cancer cells, leading to the elevated sensitivity of 5-FU. Meanwhile, knockdown of WDR76 enhances the resistance of 5-FU in colon cancer both in vitro and vivo, which was reversed by a specific inhibitor of HRAS, Kobe006. An important molecular mechanism of 5-FU resistance lies the degradation of HRAS induced by WDR76.ConclusionOur findings demonstrated a role of WDR76 as a promising target for reversing the resistance of colon cancer to 5-FU.