Determination of the in vivo effects of cladribine alone and its combination with cyclophosphamide or cyclophosphamide and mitoxantrone on Bax and Bcl-2 protein expression in B-CLL cells.

The present study investigated a correlation between expression of Bcl-2 family members, Bax and Bcl-2 (the Bax/Bcl-2 ratio values) in B-CLL cells in vivo and the response of these cells to chemotherapy. Western blot technique combined with videodensitometry was used for Bax and Bcl-2 determination in homogenate, nuclear and postnuclear fractions of mononuclear cells isolated from peripheral blood of B-CLL patients treated with cladribine alone (C), and in combination with cyclophosphamide (CC) or mitoxantrone and cyclophosphamide (CMC). The Bax/Bcl-2 ratio values were changed in B-CLL cells originated from blood samples of patients treated by the three therapy protocols, and was the most elevated in the case of CMC treatment. High degree of B-CLL cell apoptosis induction with cladribine combined with mitoxantrone and cyclophosphamide was confirmed by DNA fragmentation and an appearance of apoptotic morphology among leukemic cells from the blood of patients treated with this form of combined therapy.