Knockdown of TRIM65 suppressed the proliferation and invasiveness of gastric cancer cells by restricting the ubiquitin degradation of PPM1A

Gastric cancer is a type of serious malignant tumors all around the world. TCGA data showed that the expression of TRIM65 (E3 ubiquitin ligase) was enhanced in the gastric cancer tissues. The role of TRIM65 in the tumorigenesis of gastric cancer remains unclear. In this study, we successfully established TRIM65-knockdown gastric cancer cells. Next, CCK-8, colony formation assays and transwell assays were performed to detect the cell proliferation and invasion. The results showed that suppression of TRIM65 inhibited the proliferation and invasion of gastric cancer cells. Interestingly, the Western blot assay confirmed that downregulation of TRIM65 increased the level of PPM1A and decreased the level of p-TBK1 in gastric cancer cells. Mechanistically, immunoprecipitation assay revealed that knockdown of TRIM65 inhibited the ubiquitin degradation of PPM1A. In rescue experiments, suppression of PPM1A promoted the proliferation and invasion of gastric cancer cells transfected with sh-TRIM65. Therefore, our results suggested that knockdown of TRIM65 inhibited the proliferation and invasion of gastric cancer cells by suppressing the ubiquitin degradation of PPM1A and phosphorylation of TBK1.