DEVELOPMENT OF A HAMMERHEAD RIBOZYME AGAINST BCL-2 .2. RIBOZYME TREATMENT SENSITIZES HORMONE-RESISTANT PROSTATE-CANCER CELLS TO APOPTOTIC AGENTS

Background: Several lines of evidence strongly implicate a crucial rol e for the apoptosis suppressing bcl-2 oncogene in the genesis of hormo ne-refractory human prostate cancer. By efficiently destroying the int racellular bcl-2 mRNA, one might be able to make the prostate cancer c ell responsive again to conventional apoptotic stimuli such as androge n withdrawal. To achieve this end we have devised a catalytic antisens e RNA strategy (Ribozyme) for bcl-2 and evaluated its gene therapeutic potential Methods and Results: Bcl-2 overexpressing LNCaP prostatic c arcinoma cells (LNCaP/bcl-2) were transfected with the anti-bcl-2 ribo zyme RNA using a polyamine-based transfection reagent and the reductio n in the intracellular bcl-2 mRNA levels was followed by a ribonucleas e protection assay. Using a cell viability assay, prior ribozyme trans fection and subsequent application of apoptotic stimuli such as serum starvation or phorbol ester treatment caused a 30% increase in cell de ath by apoptosis than with these apoptotic stimuli alone. Conclusions: The results obtained strongly support the ability of a potential anti -bcl-2 ribozyme therapy to synergize with other agents in inducing apo ptosis of hormone-resistant human prostate cancer cells.