Preliminary Study Of The Relation Between Multidrug Resistance And Metastasis Of Epithelial-mesenchymal Transition In Gastric Cancer Cell Lines

【Objective】Through the establishment of a human gastric cancer cisplatin-resistant cell strainSGC7901/CDDP, we observed and analyzed its biological characteristics. The correlationproperties of drug resistant gastric cancer cells and the EMT phenotype were detected inorder to explore the relationship between EMT, MDR and metastasis in gastric cancer,which will provide a theoretical basis for the development of new targeted drugs forgastric cancer and provide effective therapeutic strategies for clinical patients.【Method】1. Select human gastric carcinoma cells SGC7901as parental cells and cisplatin asinducing agent. The parental cells SGC7901carried out by the initial induction ofconcentration that is1/10IC50of cisplatin and using a concentration gradient incrementmethod for12months. The human gastric cancer cisplatin-resistant cell lines named toSGC7901/CDDP.2. The morphological characteristics of both cell lines were observed underinverted phase contrast optical microscopy. The cell growth curve was drawed and thepopulation doubling time was calculated in accordance with MTT colorimetric assay.Comparison of the resistant cells and the parental cell colony forming ability by theplate colony sphere formation. To assess the ability of migration and invasion in vitro,transwell chambers for cell migration experiments and the reconstituted basementmembrane for invasion assay was adopted.3. The drug resistance index and drug susceptibility for different chemotherapy reagents of parental cell line SGC7901and multidrug resistant cell line SGC7901/CDDPof gastric carcinoma was detected by MTT assay.Annexin V/PI staining was used toevaluate apoptosis in cisplatin of both cell line; Adriamycin retention and accumulationwere adopted to compare the resistance characteristics of the cells4. Protein expression levels of MRP, Bcl-2, Bax and EMT-related phenotypesproteins such as E-cadherin and vimentin in parental cells SGC7901and multidrugresistant cells SGC7901/CDDP of gastric carcinoma were detected by Western blot.【Result】1. There was successfully constructed the stable human gastric cancercisplatin-resistant cell lines SGC7901/CDDP。2. Drug-resistant cell lines SGC7901/CDDP showed a spindle-shaped adherentgrowth, widen the cell gap, obtain the morphological characteristics of the interstitialcells, diminish the ability to appreciation, slow the growth, but cell migration andinvasion capacity was obvious enhanced（p<0.05）。3. The resistance index of other chemotherapy have different mechanisms forSGC7901/CDDP were also significantly increased, significantly reduced drug sensitivity（p<0.05）.After48hours cisplatin treatment, the resistant cell apoptosis index of twocell lines were55.4%and39.7%,compared with parental cells increasedsignificantly.Adriamycin accumulation and retention experiments show a significantincrease in the rate of resistant cells in drug pump（p<0.05）.4. In the resistant cell line SGC7901/CDDP, such as the MRP, Bcl-2, vimentin, theexpression of this protein was obviously enhanced, meanwhile, such as the E-cadherin,Bax, this protein’s expression was lowered significantly.【Conclusion】1. Establishing cisplatin resistant cell line SGC7901/CDDP of human gastric cancerby increasing concentration gradient will provide a good experimental model for cancerresearch in vitro.2. The resistance of cisplatin-resistant cell lines SGC7901/CDDP of human gastric cancer relate to MRP, Bcl-2, bax. The process of resistance of gastric cancer cellsaccompanied by the occurrence of EMT which resulting the gastric cancer cells enhancedtheir invasion and migration ability, thus contributing to the metastasis of gastric cancer.