Increased mdr gene expression and decreased drug accumulation in a human colonic cancer cell line resistant to hydrophobic drug |
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| Authors: | C C Chao C M Ma P W Cheng S Lin-Chao |
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| Institution: | Tumor Biology Laboratory, Department of Biochemistry, Chang Gung Medical College, Taiwan, Republic of China. |
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| Abstract: | An adriamycin-resistant human colonic cancer cell line was characterized. This clone exhibits the classical multidrug resistance (MDR) phenotype, being cross-resistant to hydrophobic drugs such as colchicine, and vinblastine. In contrast, this clone shows a normal response to DNA-damaging agents. The appearance of MDR in these cells was linked to a decreased accumulation of the drug 3H]colchicine as compared to the drug-sensitive cells. This MDR line expressed 80-100 fold increased levels of the specific 4.5-kb mdr mRNA, and a gene amplification. Our results indicate that MDR in human colonic cancer cells can result from increased expression of at least one member of the mdr gene family. |
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