The Role of Tumoral FOXP3 on Cell Proliferation, Migration, and Invasion in Gastric Cancer.

BACKGROUND/AIMS: There is little published data on the role of FOXP3 in gastric cancer.

METHODS: FOXP3 expression and localization in gastric cancer tissues and cells were examined by immunohistochemistry, RT-PCR, flow cytometry, western blot, and laser confocal microscopy. CCK8, plate clone, wound healing, and transwell insert assays were performed for gastric cancer cells. Potential molecules and signaling pathways were screened using high-throughput transcriptome sequencing.

RESULTS: FOXP3 expression in gastric cancer tissues was higher than that in para-carcinoma tissues. It was restricted to the cytoplasm of para-carcinoma tissues, but was observed in the cytoplasm or/and nuclei of gastric cancer tissues. FOXP3 expression was positively correlated with pathological grading, and was detected in gastric cancer and GES-1 cells, where it was expressed in the cytoplasm alone, or in both the cytoplasm and the nucleus. FOXP3 overexpression promoted cell proliferation, migration, and invasion, while FOXP3 knockdown suppressed these effects. Furthermore, RT-PCR and ELISA confirmed that FOXP3 upregulation resulted in increased TGF-β expression and secretion in gastric cancer cells.

CONCLUSION: FOXP3 expression was associated with degree of gastric cancer differentiation. In addition, upregulated and ectopic tumoral FOXP3 can promote gastric cancer proliferation, migration, and invasion, partly through the TGF-β pathway.