Effects of HB57-dex on B-CLL cell proliferation and survival. (A) A total of 2 × 105 isolated B cells in triplicate from 17 U-CLL and 17 M-CLL cases were cultured for ∼ 68 hours with culture medium or with HB57-dex. Cultures were pulsed with tritiated thymidine for the last 16 hours and harvested to count incorporated radioactivity. Stimulation ratios were calculated for each case as the ratio of radioactivity incorporated in stimulated cells relative to unstimulated cells. HB57-dex elicited significantly higher proliferation in U-CLL compared with M-CLL clones (P < .001; Mann-Whitney test). Purified B-CLL cells from 20 cases each of the U-CLL and M-CLL subgroups were incubated without or with BCR stimulation or mitogenic stimulation with PMA + ionomycin for a period of 3 days. (B) DNA content indicative of sub G0 (apoptotic peak) measured by propidium iodide staining. (C) Spontaneous apoptosis in B cells from 20 U-CLL and 20 M-CLL cases was significantly higher in U-CLL. (D) HB57-dex mediated rescue from apoptosis. Bar graphs represent mean ± SE values for rescue from apoptosis 20 cases each. Significant rescue from apoptosis is observed only in HB57-dex–treated U-CLL cells. (E) Simultaneous analysis of cell survival and telomerase activity in cell extracts after 3 days in culture. There is an inverse association in representative U-CLL and M-CLL cases.
