Increase of cell viability and P-glycoprotein expression in Chinese hamster ovary cells after 24 hours' exposure to vincristine

Abstract Cell viability and P-glycoprotein expression in Chinese hamster ovary cells have been measured following incubation in a range of vincristine concentrations for 24 h. An increase of 12% in cell viability was observed with increasing drug concentrations in a drug-sensitive cell line (E29) and a lesser increase of 5% in a multidrug-resistant cell line (VRA15). The increased cell viability corresponded to a rise of P-glycoprotein level. Slot blots showed that there was an increase in P-glycoprotein mRNA with all drug concentrations tested in E29, although there was only partial correlation of mRNA levels with P-glycoprotein levels viability.