Overexpression of Rictor protein and Rictor-H. pylori interaction impact on tumor progression and prognosis in patients with gastric cancer.

Introduction. Growing evidence indicates that Rictor (Rapamycin-insensitive companion of mTOR) is overexpressed across several malignancies and associated with poor survival. However, only limited data indicate that Rictor plays a role in gastric cancer (GC). We sought to explore the prognostic value of Rictor in GC and present interaction analysis between Rictor expression and H pylori status regarding their effects over the prognosis of GC patient. Materials and methods. 250 GC tissues and 124 lymph node metastases were collected for the detection of Rictor by immunohistochemistry. Cox regression model was used to assess the association between Rictor expression and patient prognosis. Functional experiments were examined in transfected cells using Rictor siRNA. Additive and multiplicative interactions of Rictor and H. pylori were evaluated. Results. In this study, the positive rate of Rictor was 51.6% (129/150) in GC tissues. Multivariate analyses showed that Rictor was independent unfavorable predictor for OS (HR = 1.554, 95% CI = 1.076-2.244, P = 0.019) and DFS (HR = 1.556, 95% CI = 1.081-2.240, P = 0.017). Patients with upregulated Rictor in the primary tumor and lymph node metastases had the worst prognosis. We observed significant additive and multiplicative interactions between Rictor expression and H. pylori status for OS and DFS (P < 0.05). Our in vitro experiment showed that knockdown of Rictor could suppress cell proliferation, induce apoptosis and inhibit tumor migration and invasion. Conclusion. Our results demonstrate that Rictor, acting as an oncogene, might be a potential prognostic biomarker and therapeutic target in GC. We suggest that Rictor expression and H. pylori status may be a prognostic marker in gastric cancer.