Objective:To establish multidrug resistant human hepatoma cell subline(HepG2/DOX) and study its biological features.Methods:Doxorubincin-resistant human hepatoma cell subline (HepG2/DOX) was induced by doxorubincin-gradually increasing concentration.To observe cells by light microscope and analyze number and structure of chromosomes of these tumor cells.Sensitivity of anticancer drugs was screened in HepG2

HepG2/DOX cells by MTT method.The immunohistochemistry method was used to measure MDR-1 gene product Pgp expression.Results:HepG2/DOX and HepG2 were different in shape

growth speed.The number and structure of their chromosomes were also different.The value of 50% inhibitory concentration(IC50

μg/ml) for DOX

CDDP

MMC

5-FU

and MTX in HepG2

HepG2/DOX cells was (0.070 and 1.161)

(0.214 and 1.317)

(0.162 and 0.498)

(0.313 and 1.683)

(0

007 and 0.217) respectively.MDR-l gene product Pgp170 expression was found either in HepG2/DOX or HepG2 cells.Pgp170 exprssion in HepG2/DOX was higher than in HepG2.Once HepG2/DOX had been cultured in DOX free RPMl1640 medium for 5 weeks

the IC50(μg/ml)for DOX in HepG2/DOX reduced to 0.684.Conclusion:HepG2/DOX has the characteristics of MDR.The drug-resistance was correlated with over expression of MDR-1 gene product Pgp 170 and slow growth.