| Background and objectiveCancer remains a serious threat to human survival and health. Gastric cancer is one of the highest morbidity and mortality of malignant tumor all around the world. Currently, Surgery, radiation therapy, chemotherapy, as well as targeted therapy are the main treatment strategies for gastric cancer. Due to the low diagnostic rate of early gastric cancer, the great majority of patients are diagnosed at late stage, losing the opportunities of radical surgery. Chemotherapy is the main treatment of advanced gastric cancer and postoperative recurrence. Common chemotherapeutics include platinum-based drugs, fluorouracil, taxanes topoisomerase ? inhibitors etc. Compared with the combination chemotherapy of traditional drugs, the above-mentioned drugs of multi-drug combination chemotherapy regimens greatly improve the curative effect and patient survival. In spite of advances in diagnosis and treatment, gastric cancer has lower 5-year survival rate.5-Fluorouracil (5-Fu), as a fundamental medicine for gastric cancer, plays a role of anti-cancer by interfering DNA synthesis. However, it is limited by multidrug resistance (MDR) and serious adverse reactions. Therefore, it is very important to develop a combination of chemotherapy drugs with enhanced efficacy and reduced toxicity. Proton pump inhibitors, used in the treatment of gastric acid-related diseases, have been shown to represent a model of drugs which can elevate sensitization of drug-resistant gastric cancer cells to anti-cancer drugs recently. But the underlying mechanisms remain not fully understood. One report showed thatomeprazole (OPZ) combined with antiemetics could prevent gastrointestinal side reaction caused by cisplatin or 5-Fu chemotherapy. Thus, in this study, we investigated the anti-tumor efficacy and possible action mechanisms of combination treatment of omeprazole and 5-Fu in human gastric cancer cells (SGC-7901 cells) in vitro.MethodsThe inhibitory effects of combination treatment or single treatment of OPZ and/or 5-Fu on the proliferation of SGC-7901 cells were determined using MTT assay and colony formation assays. Hoechst 33342 nuclear staining assay was used to analyze the morphology changes of cell apoptosis. The Annexin V-FITC/PI double-staining assay was used to detect the apoptotic cell number. Then effects of combination treatment or single treatment of OPZ and 5-Fu on cell cycle distribution of SGC-7901 cells were detected using PI staining by flow cytometry. The effects of OPZ and 5-Fu combination treatment or single treatment in SGC-7901 cells on cell migration and invasion were investigated by transwell migration assay and/or wound scratch assay. The expression of related proteins was determined by western blotting assay.Results1. Compared with 5-Fu treatment alone, the inhibition rate of OPZ and 5-Fu combination treatment on the proliferation of SGC-7901 cells for 48 or72 hours was much higher, while the inhibition rate for 24 hours was lower. And 40?g/ml OPZ combined with 10 or 20 or 40?g/ml 5-FU showed obviously synergistic effects on the growth of SGC-7901 cells.2. Combination treatment of OPZ with 5-Fu induced G0/G1 phase arrest in SGC-7901 cells, which was due to the decrease of expressions of cyclinD1, cyclinE1 and CDK2.3. Compared with 5-Fu treatment alone, OPZ and 5-Fu combination treatment induced apoptosis of SGC-7901 cells with obvious shrinked peripheral nucleus, and increased the population of early apoptotic cells markedly.4. In western blotting assay, results showed that OPZ and 5-Fu combination treatment increased the ratio of Bax/Bcl-2 expression, cleaved-PARP expression and the expression of cleaved caspase-3 and cleaved caspase-9 proteins compared with 5-Fu treatment alone.5. OPZ and 5-Fu combination treatment showed more potent inhibition on the migration of SGC-7901 cells than 5-FU treated alone.6. OPZ and 5-Fu combination treatment showed more potent inhibition on the invasion of SGC-7901 cells than 5-FU treated alone.7. The migration and invasion inhibitory effects of combination treatment of OPZ and 5-FU were related to the inhibition of active matrix metalloproteinase-2 (MMP-2) protein expression.ConclusionCombination treatment of OPZ and 5-Fuinduced synergistic effects on the growth of SGC-7901 cells in vitro through induction of apoptosis and cell cycle G0/G1 phase arrest. And compared with 5-Fu treatment alone, combination treatment of OPZ and 5-FU showed stronger inhibition on the migration and invasion of SGC-7901 cells via inhibiting the expression of active MMP-2 protein. |
PDF Full Text Request