Inhibitory mechanism of timosaponin B-Ⅱagainst proliferation and migration of human gastric cancer cells / 第二军医大学学报

ABSTRACT

Objective To explore the inhibitory mechanism of timosaponin B-Ⅱ against the proliferation and migration of human gastric cancer cell lines BGC-823 and MGC-803. Methods BGC-823 and MGC-803 cells were treated with timosaponin B-Ⅱ (50 ng/mL) for 48 h, and the mRNA and protein expressions of scavenger receptor A5 (SCARA5) were measured by qPCR and Western blotting, respectively. The binding site of hsa-miRNA-766-3p in SCARA5 gene 3′UTR was predicted by bioinformatics, and was validated by luciferase report assay. After transfecting with hsa-miRNA-766-3p mimic or siRNA-SCARA5 for 24 h, the BGC-823 and MGC-803 cells were treated with timosaponin B-Ⅱ(50 ng/mL) for 48 h. The relative levels of hsamiRNA-766-3p and SCARA5 protein expression were detected by qPCR and Western blotting, respectively. The proliferation and migration abilities of cells were determined by MTT. Results The expressions of SCARA5 protein in BGC-823 and MGC-803 cells treated with timosaponin B-Ⅱ (50 ng/mL) for 48 h were significantly increased versus the control group (P0.01), while no significant difference was found in relative mRNA level of SCARA5 between the timosaponin B-Ⅱ treated cell group and the control group (P0.05). Compared with transfection of reporter gene expression vector alone group, the luciferase activity was significantly inhibited or enhanced in the cells co-transfected with hsa-miRNA-766-3p mimic or hsa-miRNA-766-3p inhibitor and wild-type luciferase reporter gene (P0.05, P0.01). No change was observed between the cells co-transfected with hsa-miRNA-766-3p mimic or hsa-miRNA-766-3p inhibitor and mutant-type luciferase reporter gene expression vector and the cells transfected with reporter gene expression vector alone (P0.05). Hsa-miRNA-766-3p levels were significantly decreased and SCARA5 protein expressions were significantly increased in BGC-823 and MGC-803 cells treated with 50 ng/mL timosaponin B-Ⅱ (P0.01). Compared with the timosaponin B-Ⅱ treatment group, hsa-miRNA-766-3p levels were significantly increased and SCARA5 protein expressions were significantly decreased in the BGC-823 and MGC-803 cells of the hsa-miRNA-766-3p mimic transfection＋ timosaponin B-Ⅱ treatment group (P0.01). There were no differences in the hsa-miRNA-766-3p levels between the hsa-miRNA-766-3p mimic transfection＋timosaponin B-Ⅱtreatment group and the timosaponin B-Ⅱ treatment group (P0.05), but SCARA5 protein expressions were significantly decreased (P0.01). Compared with cell control group and vehicle control group, the proliferation and migration abilities of BGC-823 and MGC-803 cells were significantly inhibited by timosaponin B-Ⅱ (P0.01). Compared with the timosaponin B-Ⅱ treatment group, the proliferation and migration abilities of BGC-823 and MGC-803 cells were significantly increased in the siRNA-SCARA5 transfection＋timosaponin B-Ⅱ treatment group (P0.01). Conclusion Timosaponin B-Ⅱ can inhibit the proliferation and migration of BGC-823 and MGC-803 cells via suppressing hsamiRNA-766-3p and upregulating the target gene SCARA5.