Establishment of imatinib-resistant gastrointestinal stromal tumor cell subline and investigation of its sensitivity to the chemomotherapeutic agents

Aim. To establish the subline of imatinib-resistant gastrointestinal stromal tumor (GISTs) cells and to evaluate its sensitivity to various types of chemotherapeutic agents. Methods. To establish imatinib-resistant subline, tumor cells of GIST T-1 line were cultured with gradually increasing doses of imatinib for 18 months. Sensitivity of GIST T-1 cells to imatinib was comparably evaluated every 3 months by using MTS-based colorimetric assay. Level of expression of proteins serving as apoptotic markers, was examined by Western blotting with appropriate monoclonal antibodies. After establishment of GIST T-1 cell line with the signs of resistance to target medication imatinib, its sensitivity to various groups of chemotherapy (doxorubicin, etoposide, vinblastine, paclitaxel and cys-platinum) was evaluated. Sensitivity of imatinib-resistant GIST T-1 cells to chemotherapy as well as the level of expression of proteins serving as apoptotic markers, was evaluated by using MTS-based colorimetric assay and Western blotting. Results. After 18 month of culturing GIST T1 cells in the presence of gradually increasing doses of imatinib, the sings of resistance to this drug were observed. The obtained subline of GIST T1 IM-108R cells was sensitive to all used chemotherapeutic agents. Doxorubicin, vinblastine and etoposide were found to be the most potent cytostatic agents against imatinib-resistant GIST T1 IM-108R cells. Conclusion. Imatinib-resistant GIST T1 subline cells are sensitive to various types of chemotherapeutic agents; the established GIST T1 IM-108R cell subline might be further used for screening for the most effective chemotherapeutic agents and novel synthesized compounds.