Establishment And Characteristic Of Imatinib Mesylate-resistant Gastrointestinal Stromal Tumor Cell

Object: Imatinib mesylate is the specific targeted drug of gastrointestinal stromal tumor. It is the standard treatment for GIST patients whose tumor are unresectable or metastasis. However, recent clinical practice show that the rug-resistance to IM limits its efficacy in the therapy of GIST. And it became a major problem of treating GIST. For that reason, we using GIST-T1 cell with imatinib mesylate to establish drug resistant cell line and compare the different biological characteristics between two. Then we discuss on the gastrointestinal stromal tumor drug resistance situation preliminarily and lays the foundation for downstream resistance reversal researches and supply a new treatment strategy for the GIST patients.Method: 1.In vitro gastrointestinal stromal tumor cells are selected by increasing concentration of drug IM, which is added into the culture medium when the cells are in logarithmic phase. Most sensitive cells die after 48 h culturing and then replace the drug medium into drug-free medium. Passage the cells when they grow up and repeat the produces above and increase concentration until achieve cells which are resistance to IM.2. Compare the different biological characteristics between parent cell GIST-T1 and resistant cell line GIST-T1 IR including changes in the morphology of two cell, the cell growth curve and calculating the doubling time, cell migration ability, the cell cycle and the half inhibitory concentration(IC50) and calculate the resistance index by using CCK-8 method.Result: 1. Successfully established resistant cell lines GIST- T1 IR which resistance to IM within 6 months. 2. The doubling time respectively are 26.59±1.34 h and 33.63±2.82 h on average, and the difference was statistically significant. HE-staining shows that the GIST-T1 cell morphology is long and narrow and cell volume is larger. There are only one or two nucleus in the cell. The cytoplasm has little particle. Compared to GIST-T1, GIST-T1 IR’s volume is smaller. There are three or more nucleus in most cells. We can see the nuclear fission and nuclear/cytoplasmic ratios obviously increased, and so does the cytoplasmic granules. Its migration ability of experiment has shown that compared with parental cells, the drug resistant cells have a stronger ability of migration. The IC50 are 10.5±0.12μmol/L and 42.0±0.32μmol/L, the RI is 4.0,which suggest us that it belong to low resistance. And cell cycle of resistant cells and its parent cell are different. The cells in S phase respectively are 16.46% and 20.72% respectively.G0/G1 phase are 33.45% and 39.88% respectively.G2/M phase are 28.48% and 19.01% respectively. The GIST- T1 IR cells in S increased about 4.26% and G0/G1 increased about 6.43%, but in the G2/M phase the proportion reduced about 9.47%.Conclusion: Successfully established a stable human gastrointestinal stromal tumor cells which resistant to IM GIST-T1 IR it can serve as a further study as a cell model, we lay a solid foundation for the following research including tumor drug resistance reversal, and we hope we can provide new strategies for patients.