RELATIONSHIP BETWEEN MDR-1 MESSENGER-RNA EXPRESSION AND ANTICANCER DRUG-SENSITIVITY IN HUMAN HEPATOCELLULAR-CARCINOMA CELL-LINES

We examined the relationship between chemosensitivity and the expression of mdr-1 and P-gp in ten human HCC cell lines. Expression of P-gp was detected immunohistochemically and the expression of mdr-1 mRNA by the reverse transcriptase polymerase chain reaction (RT-PCR). Chemosensitivity was determined by the MTT assay. P-gp was positive in nine of the ten lines. mdr-1 mRNA expression was found in five. All cells lines positive for mdr-1 mRNA expression expressed P-gp. We could not demonstrate a correlation between mdr-1 or P-gp expression and drug resistance. We conclude that drug-resistance in HCC cells depends not only on mdr-1 but also on other factor(s).