AIM： To investigate the c-kit expression in biliary tract cancer cell lines and histological sections from patients with extrahepatic cholangiocarcinoma （CC） and to evaluate the efficacy of in vitro and in vitro tr...AIM： To investigate the c-kit expression in biliary tract cancer cell lines and histological sections from patients with extrahepatic cholangiocarcinoma （CC） and to evaluate the efficacy of in vitro and in vitro treatment with imatinib mesilate. METHODS： The protein expression of c-kit in the human biliary tract cancer cell lines Mz-ChA-2 and EGI-1 and histological sections from 19 patients with extrahepatic CC was assessed by immunoblotting, immunocytochemistry, and immunohistochemistry. The anti-proliferative effect of imatinib mesilate on biliary tract cancer cell lines Mz-ChA-2 and EGI-1 was studied in vitro by automated cell counting. In addition, immunodeficient NMRI mice （Taconic^TM） were subcutaneously injected with 5 × 10^6 cells of cell lines MzChA-2 and EGI-1. After having reached a tumour volume of 200 mm^3, daily treatment was started intraperitoneally with imatinib mesilate at a dose of 50 mgikg or normal saline （NS）. Tumor volume was calculated with a Vernier caliper. After 14 d, mice were sacrificed with tumors excised and tumor mass determined.RESULTS： Immunoblotting revealed presence of c-kit in Mz-ChA-2 and absence in EGI-1 cells. Immunocytochemistry with c-kit antibodies displayed a cytoplasmatic and membraneous localization of receptor protein in Mz-ChA-2 cells and absence of c-kit in EGI-1 cells, c-kit was expressed in 7 of 19 （37%） extrahepatic humanCC tissue samples, 2 showed a moderate and 5 a rather weak immunostaining. Imatinib mesilate at a low concentration of 5 μmoliL caused a significant growth inhibition in the c-kit positive cell line Mz-ChA-2 （31%）, but not in the c-kit negative cell line EGI-1 （0%） （P〈0.05）. Imatinib mesilate at an intermediate concentration of 10 μmoliL inhibited cellular growth of both cell lines （51% vs 57%）. Imatinib mesilate at a higher concentration of 20 μmoliL seemed to have a general toxic effect on both cell lines. The IC50 values were 9.7 μmoliL and 11 μmoliL, respectively. After 14 d of in vitro treatment with imatinib mesilate, using the chimeric mouse model, c-kit positive Mz-ChA-2 tumors had a significantly reduced volume and mass as compared to NS treatment （P〈 0.05）. In contrast to that, treatment of mice bearing c-kit negative EGI-1 tumors did not result in any change of tumor volume and mass as compared to NS treatment. CONCLUSION： c-kit expression is detectable at a moderate to low protein level in biliary tract cancer. Imatinib mesilate exerts marked effects on tumor growth in vitro andin vitro dependent on the level of c-kit expression.展开更多
基金Supported by the Deutsche Krebshilfe, No. 10-2106-Wi1
文摘AIM： To investigate the c-kit expression in biliary tract cancer cell lines and histological sections from patients with extrahepatic cholangiocarcinoma （CC） and to evaluate the efficacy of in vitro and in vitro treatment with imatinib mesilate. METHODS： The protein expression of c-kit in the human biliary tract cancer cell lines Mz-ChA-2 and EGI-1 and histological sections from 19 patients with extrahepatic CC was assessed by immunoblotting, immunocytochemistry, and immunohistochemistry. The anti-proliferative effect of imatinib mesilate on biliary tract cancer cell lines Mz-ChA-2 and EGI-1 was studied in vitro by automated cell counting. In addition, immunodeficient NMRI mice （Taconic^TM） were subcutaneously injected with 5 × 10^6 cells of cell lines MzChA-2 and EGI-1. After having reached a tumour volume of 200 mm^3, daily treatment was started intraperitoneally with imatinib mesilate at a dose of 50 mgikg or normal saline （NS）. Tumor volume was calculated with a Vernier caliper. After 14 d, mice were sacrificed with tumors excised and tumor mass determined.RESULTS： Immunoblotting revealed presence of c-kit in Mz-ChA-2 and absence in EGI-1 cells. Immunocytochemistry with c-kit antibodies displayed a cytoplasmatic and membraneous localization of receptor protein in Mz-ChA-2 cells and absence of c-kit in EGI-1 cells, c-kit was expressed in 7 of 19 （37%） extrahepatic humanCC tissue samples, 2 showed a moderate and 5 a rather weak immunostaining. Imatinib mesilate at a low concentration of 5 μmoliL caused a significant growth inhibition in the c-kit positive cell line Mz-ChA-2 （31%）, but not in the c-kit negative cell line EGI-1 （0%） （P〈0.05）. Imatinib mesilate at an intermediate concentration of 10 μmoliL inhibited cellular growth of both cell lines （51% vs 57%）. Imatinib mesilate at a higher concentration of 20 μmoliL seemed to have a general toxic effect on both cell lines. The IC50 values were 9.7 μmoliL and 11 μmoliL, respectively. After 14 d of in vitro treatment with imatinib mesilate, using the chimeric mouse model, c-kit positive Mz-ChA-2 tumors had a significantly reduced volume and mass as compared to NS treatment （P〈 0.05）. In contrast to that, treatment of mice bearing c-kit negative EGI-1 tumors did not result in any change of tumor volume and mass as compared to NS treatment. CONCLUSION： c-kit expression is detectable at a moderate to low protein level in biliary tract cancer. Imatinib mesilate exerts marked effects on tumor growth in vitro andin vitro dependent on the level of c-kit expression.
