Abstract: AIM: To study the cytotoxic activity of bortezomib against gastric cancer and its action mechanism.METHODS: MTT assay was used to detect the cytotoxic activity of bortezomib against gastric cancer SGC-7901 cells. The apoptosis were detected by Annexin V-FITC/PI staining and flow cytometry analysis. The protein expressions were determined by Western blot analysis.RESULTS: The IC₅₀ value of bortezomib against SGC-7901 cells was (54.6± 4.1) nmol/L. After treatment with 0, 50, and 100 nmol/L bortezomib for 48 h, the percents of apoptosis were (1.8±0.7)% ,(26.5±4.6)%,(41.7±5.8) % , respectively. There was significant difference among the different treatments(P<0.01). After treatment with 50 and 100 nmol/L bortezomib for 48 h, the cleaved-Parp and cleaved-caspase-3 were detected by Western blot analysis. After treatment with 50 and 100 nmol/L bortezomib for 48 h, the protein expression of Bmi-1 was downregulated.CONCLUSION: Bortezomib shows significant anticancer activity against gastric cancer SGC-7901 cells. The downregulation of Bmi-1 protein may played an important role in its apoptotic pathway.

Key words: Gastric cancer, Bortezomib, Apoptosis, Bmi-1