Targeting Bcl-2 in CLL.

Chronic lymphocytic leukemia (CLL) is a common adult leukemia in the Western world with an incidence of 4.2/100,000/year. The clinical course of disease is highly heterogenous; it affects people over 65-70 years of age. This hematologic cancer is characterized by the resistance to apoptosis stimuli predominantly associated with overexpression of antiapoptotic Bcl-2 family members. Therapeutic options for advanced CLL patients are limited. Thus there is an urgent need to discover a novel, less toxic, and much more effective agent(s) or drug combinations for CLL patients. Among chemotherapeutic(s) and immunotherapeutics currently in use, several enzyme inhibitors were tested to gain better results in CLL treatment. Here, we review the main achievements made on targeting of prosurvival Bcl-2 proteins through the use of different approaches, i.e. anti-sense methodology, small molecules that mimic the action of BH3 domain and microRNAs (mainly miRNA-15a and miRNA-16-1).

Enzyme-linked immunosorbent assay in screening of leukemia-associated nuclear proteins.

Our previous data revealed some diversities in electrophoretic characteristics of nuclear fraction proteins isolated from peripheral blood mononuclear cells of B-cell chronic lymphocytic leukemia (B-CLL) patients and healthy donors. Two electrophoretically-specific nuclear non-histones in the molecular mass zone of 38/39 and 44/46 kDa of leukemic mononuclear cells were used as immunogens to produce rabbit antisera. The Western blot analysis indicated that both nuclear components are expressed only in mononuclear cells isolated from peripheral blood of B-CLL patients, but not in those isolated from the blood of healthy donors. For further investigations of nuclear fraction from normal and B-CLL mononuclear cells, an enzyme-linked immunosorbent assay (ELISA) was used. The results obtained by ELISA with the antisera raised against both electrophoretically-specific B-CLL nuclear polypeptides revealed a different extend of cross-reactivity of nuclear fraction preparations isolated from normal cells and those isolated from leukemic ones. We noticed that nuclear fraction preparations which originated from leukemic mononuclear cells are much more reactive than normal ones with both antisera (at a broad range of antisera dilutions).

Two-dimensional gel electrophoresis of nuclear proteins of different stages of B-chronic lymphocytic leukaemia.

Two-dimensional polyacrylamide gel electrophoresis was used to compare the composition of nuclear proteins from normal and B-chronic lymphocytic leukaemia (B-CLL) mononuclear cells. Some differences in the electrophoretic behaviour of these proteins from normal and transformed cells, especially with molecular weights/pI of 14-16 kD/5.9-7.4; 28-32 kD/4.9-5.5; 38-39 kD/5.4-6.1; 44-46 kD/5.1-5.6; 47-52 kD/5.0-5.6; 64-69 kD/5.1-5.7, and 95-105 kD/5.2-5.5, were observed. The comparative analysis of nuclear proteins, obtained from mononuclear cells of patients with B-CLL at different stages of development, indicated that the expression of some protein components might be correlated with the progression of this disease.

Altered expression of nuclear non-histone protein (p44/46) in different stages of B-chronic lymphocytic leukemia.

Our previous data have shown some differences in electrophoretic characteristics of proteins from cellular fractions (nuclear, mitochondrial, microsomal and cytosolic) isolated from peripheral blood mononuclear cells of B-cell chronic lymphocytic leukemia (B-CLL), acute lymphoblastic leukemia (ALL) patients and healthy donors. The main differences were found in electrophoretic patterns of nuclear proteins from normal and leukemia cells, especially in the nuclear mass regions of 36-52, 58-85, and 120-180 kDa. Electrophoretically-specific nuclear non-histone protein in the molecular mass zone 44/46 kDa of cells obtained from the peripheral blood of a B-CLL patient was used to produce rabbit polyclonal antiserum. SDS-polyacrylamide gel electrophoresis as well as immunological techniques (Western blot and immunocytochemistry) indicate that the nuclear protein with a molecular mass of 44/46 kDa is specifically expressed in mononuclear cells from B-CLL patients. The expression of this particular nuclear protein seems to correlate with the progression of the leukemia.