KLF5 Is Activated by Gene Amplification in Gastric Cancer and Is Essential for Gastric Cell Proliferation

Gastric cancer is the third leading cause of cancer death worldwide. In this study, we tried to clarify the function of KLF5 in gastric cancer. Copy number variation (CNV) and the expression of KLF5 were interrogated in public datasets. The clinical significance of KLF5 amplification and gene expression in gastric cancer were evaluated. The function of KLF5 in cell proliferation was studied in gastric cancer cell lines and organoids. We found that KLF5 amplification mainly occurred in the chromosome instable tumors (CIN) and was significantly associated with TP53 mutation. In addition, higher KLF5 expression correlated with more locally invasive gastric cancer and higher T stage. Next, a KLF5 gene expression signature was curated. The genes in the signature were involved in cell development, cell cycle regulation, cell death, suggesting potential roles played by KLF5. Functional studies using siRNAs revealed that KLF5 was essential for the proliferation of gastric cancer cells. Finally, using gastric organoid models, we revealed that the proliferation of organoids was significantly inhibited after the down regulation of KLF5. Our study revealed that KLF5 was amplified and over-expressed in gastric cancer, and it may play an oncogene-like role in gastric cancer by supporting cell proliferation.