Phosphatidylethanolamine binding protein 1 enhances sensitivity of gastric cancer cell to 5-fluorouracil via inhibition of cell proliferation, migration and invasion

摘要

Purpose: To determine the association between phosphatidylethanolamine binding protein 1, which is an Raf kinase inhibitor protein (RKIP), and 5-fluorouracil (5-FU) via analysis of the association between RKIP and clinical responses in individuals treated using fluorouracil-based chemotherapy. Methods: Human gastric cancer cell lines MGC-803 and SGC-7901 were used in this study. Cell viability was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis and migration were determined with flow cytometry and Transwell chamber assays, respectively. The mRNA and protein ex pressions of apoptosis-related factors were assayed using real-time polymerase chain reaction (RT-PCR) and Western blotting, respectively, while the ex pression of RKIP was determined by immunohistochemical staining. Results: Chemotherapeutic drug (5-FU) treatment induced low RKIP ex pression levels in tumorigenic GC cells, thereby sensitizing the cells to apoptosis (8.57 vs 1.25 %, p 0.01). The highest RKIP level correlated well with initiation of apoptosis (4.20 vs 1.25 %, p 0.01). Following in vitro downregulation of RKIP, there was increase in the viability and proliferation of RKIP-inhibited cells over time, and these changes were linked to alterations in cell cycle phases and increased optical density in MTT proliferation assay (1.55 vs 1.18, p 0.01). In vitro Transwell assay measurement revealed an association between RKIP downregulation and enhancement of cell migration potential (652 vs 436, p 0.01). Ectopic RKIP ex pression restored the apoptotic sensitivity of resistant cells (14.30 vs 1.36 %, p 0.01). This sensitization was annulled by upregulation of survival routes. Reduction of RKIP by ex pression of antisense and siRNA conferred resistance on cancer cells sensitive to 5-FU-mediated apoptosis (6.88 vs 2.13 %, p 0.01). Conclusion: Thus, RKIP is a promising therapeutic strategy for improving the efficacy of clinically relevant chemotherapeutic drugs for GC.