Apoptotic effect of cyclosporin a and dexamethasone in malignant cells of patients with B-chronic lymphocytic leukemia.

B-chronic lymphocytic leukemia (B-CLL) is a malignant disorder characterized by the accumulation of the leukemic cells in the G0-G1 phase of the cell cycle and expressing high levels of the anti-apoptotic protein Bcl-2. Since we observed that the treatment of autoimmune complications with Cyclosporine A (CsA) determined in some CLL patients an improvement not only of the autoimmune phenomena, but also of the leukemic process, we evaluated the in vitro cytotoxicity of CsA as compared to Dexamethasone (Dex) on leukemic cells. Leukemic cells obtained from 32 B-CLL patients showed a heterogeneous pattern of spontaneous apoptosis at 24 h interval and this pattern permitted to identify: Group 1 (14/32) with high (>20%) apoptotic rate and Group 2 (18/32) with low cell death. CsA and Dex increased cell death in both groups with a different timing by an apoptotic mechanism that does not involve Bcl-2. Furthermore, in Group 2, CsA-induced apoptosis was significant higher than that observed with Dex both at 4 and 24 h. We suggest that, in B-CLL, CsA has a significant pro-apoptotic activity manifested also in patients with low spontaneous apoptosis. Our observations might be taken into account to consider new therapeutic strategies in B-CLL.

Telomerase expression in B-cell chronic lymphocytic leukemia predicts survival and delineates subgroups of patients with the same igVH mutation status and different outcome.

Activation of telomerase reverse transcriptase (hTERT) is essential for unlimited cell growth and plays a critical role in tumorigenesis. We investigated hTERT gene expression in 134 B-cell chronic lymphocytic leukemia (B-CLL) cases and evaluated its prognostic value with other prognostic markers (IgVH mutation status, CD38 and ZAP-70 expression). Real-time PCR assays to quantify either all hTERT transcripts (AT) or only the full length (FL) transcript encoding the functional protein were developed. hTERT-AT levels strongly correlated with hTERT-FT levels (r=0.743, P<0.0001); both inversely correlated with the percentage of IgVH mutation (P<0.005) and were significantly higher in unmutated than in mutated cases (P=0.004 and P=0.001, respectively). The hTERT values which best discriminated between the unmutated and mutated IgVH cases were 150 and 40 copies for hTERT-AT and hTERT-FL, respectively. Using these cut-off values, there was a significant difference in the survival of patients with high or low hTERT levels (P<0.0001). Unmutated cases with low hTERT levels had an overall survival close to mutated cases with high hTERT levels. Thus, this work identifies hTERT-RNA level as a new prognostic marker in B-CLL, and may be used to identify previously unrecognized patient groups with the same IgVH mutation status and different disease outcomes.