Flavopiridol and UCN-01 induce apoptosis of B-CLL cells in vitro.

B-CLL cells were cultured in the presence or absence of flavopiridol (panels A and B) or UCN-01 (panels C and D) at the concentrations indicated. After 3 days, the percentage of apoptotic cells was determined by fluorescence-activated cell sorter–based TUNEL assay. Panels A and C show representative examples of dose-response data. Panels B and D show compilation of data for B-CLL specimens tested, contrasting the percentage of apoptosis that occurred in vitro during 2 days' culture in the absence or presence of kinase inhibitors (flavopiridol, P < .005; UCN-01, P < .0005).