INCREASE OF CELL VIABILITY AND P-GLYCOPROTEIN EXPRESSION IN CHINESE-HAMSTER OVARY CELLS AFTER 24 HOURS EXPOSURE TO VINCRISTINE

Cell viability ind P-glycoprotein expression in Chinese hamster ovary cells have been measured following incubation in a range of vincristin e concentrations for 24 h. An increase of 12% in cell viability was ob served with increasing drug concentrations in a drug-sensitive cell li ne (E29) and a lesser increase of 5% in a multidrug-resistant cell lin e (VRA15). The increased cell viability corresponded to a rise of P-gl ycoprotein level. Slot blots showed that there was an increase in P-gl ycoprotein mRNA with all drug concentrations tested in E29, although t here was only partial correlation of mRNA levels with P-glycoprotein l evels viability.