ATPase inhibitory factor 1 is a prognostic marker and contributes to proliferation and invasion of human gastric cancer cells.

ATPase inhibitory factor 1 (IF1) has recently been considered as a potential oncogene in human cancers. Recently, increasing evidences have shown that IF1 is overexpressed in human cancers and promotes tumor growth and metastasis. In this study, we found that the expression levels of IF1 protein and mRNA in gastric cancer tissues were significantly higher than those in matched adjacent nontumor tissues. Clinical association analysis revealed that the positive expression of IF1 was correlated with large tumor size, lymph node metastasis, venous infiltration and advanced TNM tumor stage in gastric cancer. Furthermore, IF1 was an independent prognostic marker for predicting 5-year overall survival and disease-free survival of gastric cancer patients. In vitro studies found that IF1 knockdown significantly inhibited cell proliferation and induced apoptosis in SGC-7901 cells. In a nude mouse xenograft model, IF1 knockdown prominently slowed down tumor growth with reduced number of Ki-67 positive cancer cells and elevated number of TUNEL positive cancer cells. Otherwise, IF1 knockdown evidently reduced SGC-7901 cell migration and invasion. In conclusion, these results indicate that IF1 may serve as a prognostic marker and promotes tumor growth and metastasis in gastric cancer.