B. Schutte et al., THE EFFECT OF THE CYCLIN-DEPENDENT KINASE INHIBITOR OLOMOUCINE ON CELL-CYCLE KINETICS, Experimental cell research, 236(1), 1997, pp. 4-15
The effect of the cyclin-dependent (CDK) inhibitors olomoucine and ros
covitine on cell kinetics was studied. To this end, nonsmall cell lung
cancer (NSCLC) cell line MR65 and neuroblastoma cell line CHP-212 wer
e pulse labeled with bromodeoxyuridine (BrdUrd) and chased in culture
medium, to which various concentrations of olomoucine or roscovitine w
ere added. A dose-dependent inhibition of the G(1)/S-phase and G(2)/M-
/G(1) transitions was observed. Furthermore, S-phase progression was a
lso inhibited in a dose-dependent manner. Similarly, roscovitine, anot
her CDK inhibitor with a 10-fold higher efficiency for both CDK1 and C
DK2 as compared to olomoucine, showed the same effects at a 10-fold lo
wer concentration. At the highest tested doses both olomoucine (200 mu
M) and roscovitine (40 mu M) induced a complete cell cycle block in b
oth cell lines, paralleled by the appearance of apoptotic figures. In
these cultures a decrease in CDK1 protein level was found as shown by
Western blotting. Bivariate CDK1/DNA analysis confirmed these observat
ions and showed that a subpopulation of cells with characteristics of
apoptosis became CDK1 negative. The presented data suggest that cyclin
s and CDKs are involved at an important nodal point shared by pathways
regulating cellular proliferation and apoptosis. (C) 1997 Academic Pr
ess.