Preliminary study on mechanism of drug resistance in human colon cancer cell line HCTV2000

AIM: To investigate the mechanisms of multidrug resistance in human colon cancer cell line HCT_V2000.METHODS: P-glycoprotein (P-GP) was detected by immunocytochemical staining. Expression and amplification of mdr1 gene were detected by nucleic acid hybridization. Cytotoxicity was measured by MTT method.RESULTS: HCT_V2000 cells showed a positive response to monoclonal antibodies against P-GP encoded by the mdr1 gene. Overexpression of mdr1 mRNA was found, but no evidence of mdr1 gene amplification or rearrangement was suggested. Verapamil increased the accumulation of ³H-VCR inside the cells and partially reversed drug resistance to VCR.CONCLUSION: Overexpression of mdr1 mRNA is one of the important mechanisms of drug resistance in HCT_V2000 cell line; however, there may be some other mechanisms which are also involved in this.