SRPX2 is overexpressed in gastric cancer and promotes cellular migration and adhesion.

SRPX2 (Sushi repeat containing protein, X-linked 2) was first identified as a downstream molecule of the E2A-HLF fusion gene in t(17;19)-positive leukemia cells and the biological function of this gene remains unknown. We found that SRPX2 is overexpressed in gastric cancer and the expression and clinical features showed that high mRNA expression levels were observed in patients with unfavorable outcomes using real-time RT-PCR. The cellular distribution of SRPX2 protein showed the secretion of SRPX2 into extracellular regions and its localization in the cytoplasm. The introduction of the SRPX2 gene into HEK293 cells did not modulate the cellular proliferative activity but did enhance the cellular migration activity, as shown using migration and scratch assays. The conditioned-medium obtained from SRPX2-overexpressing cells increased the cellular migration activity of a gastric cancer cell line, SNU-16. In addition, SRPX2 protein remarkably enhanced the cellular adhesion of SNU-16 and HSC-39 and increased the phosphorylation levels of focal adhesion kinase (FAK), as shown using western blotting, suggesting that SRPX2 enhances cellular migration and adhesion through FAK signaling. In conclusion, the overexpression of SRPX2 enhances cellular migration and adhesion in gastric cancer cells. Here, we report that the biological functions of SRPX2 include cellular migration and adhesion to cancer cells.