ObjectiveTo established a mouse model of multi-drug resistant (MDR) colon carcinoma and initially explore the mechanism of drug resistance.MethodsThe mouse models were generated by subcutaneous inoculation of drug-sensitive colon cancer HCT-8 cells and drug-resistant colon cancer HCT-8/VCR cells in mice. Their drug-resistance properties were assessed by vincristine (VCR) and cyclophosphamide (CTX) in vivo. The expression levels of multi-drug resistance gene 1 (P-gp/MDR1) and multi-drug resistance-associated protein 1 (MRP1) were detected by real-time PCR and Western blotting in tumor tissues of the mouse models.ResultsThe speed of tumor growth was not significantly different between the MDR and sensitive mouse models. There was a more intense drug-resistance in the MDR mouse models than in the sensitive mouse models. Real-time PCR and Western blotting showed that the expression level of P-gp/MDR1 in the MDR mouse models was enhanced, but the MRP1 expression did not show significant differences. ConclusionsA mouse model of MDR colon carcinoma has been successfully established. The mechanism of MDR in the mouse models is related to the overexpression of P-gp/MDR1 gene. 