| BackgroundGastric cancer is the fourth high incidence of cancer in the world, the mortality rate of gastric cancer accounted for two in cancer mortality. Currently in the treatment of advanced gastric cancer has reached a preliminary consensus:surgery alone can not achieve radical biological significance, even extended resection and lymph node dissection. Therefore, neoadjuvant chemotherapy emerged. According to the guidelines, platinum combined with fluorouracil drugs still as the main program in the treatment of gastric cancer. But for advanced gastric cancer, the total effective rate of chemotherapy was no more than50%, while chemotherapy-resistant of tumors acted the main reason. Through the research of the biological behavior of gastric cancer cell lines and resistance gene, try to find the relationship between resistance gene and the effectiveness of chemotherapy, then we could guide patients choosing chemotherapy drugs in advance, in order to achieve individualized chemotherapy.ObjectiveTo establish drug-resistant gastric cancer cell lines by increasing concentration method and high-dose method. Then we successfully induced two resistant cell lines, comparing the similarities and differences between the biological behavior of the two cell lines, and the initial exploration the expression levels of drug-related genes, provide a theoretical basis for clinical chemotherapy medication. Provide the basis for the next reversal of drug resistance. MethodologyUsing increasing concentrations and high-dose cisplatin methods induced gastric cancer drug-resistent cell lines BGC823/CDDPi, BGC823/CDDPh. The changes of biological characteristics between two cell lines were observed using light microscopy. The resistance index was detected by CCK-8assay. The cell growth curve was draw by CCK-8assay. The cell cycle of drug-resistant cells was detected by flow cytometry. The cell invasion ability was detected by Transwell assay. The density of CEA and CA-199in the cell culture medium was detected by immune luminescence. Western blot detection the resistance-associated protein ERCC1, MDR1, GSTÏ€, and PCR detection the resistance-associated genes erccl, mdrl, gst p1.Results(1) Comparing with BGC823cell, the BGC823/cDDP cell turned to be a little big and irregular shape, and some giant cells could be seen.(2) BGC823/CDDPi cell resistance index was7.63, BGC823/CDDPh cell resistance index was4.54, the doubling time of drug-resistant cell lines compared with normal cells extend, compared with BGC823/CDDPi, the cell doubling time of BGC823/CDDPh relative shorter.(3) From the results of flow cytometry, the cell numbers of G1phase increased while in S, G2phase decreased in BGC823/cDDP cell.(4) The invasion ability was stronger in BGC823/cDDP cell, while the BGC823/CDDPh cell more obvious.(5) The density of CEA and CA-199had no significant difference between BGC823and BGC823/cDDP.(6) The resistant associated protein ERCC1, GSTÏ€ expression higher in BGC823/cDDP than normal gastric cancer cells, which BGC823/CDDPi higher expression than BGC823/CDDPi, and there was no MDR1protein expression. The situation of the genes expression was the same.Conclusion(1) The cisplatin-resistant cell lines BGC823/CDDPh and BGC823/CDDPi was different in biological characteristics.(2) Comparing with BGC823i cells, the BGC823/cDDPh cells have lower RI and shorter double time, but its invasion ability was stonger. The research of the BGC823/CDDPh cell had more clinically meaningful. It could provide the basis research for the next drug resistance genes and reversal the drug-resistant.(3) The drug-resistant of BGC823cells were related to ERCC1, GST proteins. With the increase in protein expression, cell resistance index also increased. |
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