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Department of Experimental Pathology and Oncology, University of Florence, Florence, Italy (L.P., E.W., M.D., M.L., E.B., A.T., A.L., N.S., S.C.); Program in Biomolecular Research, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia (K.A.K.); and Department of Pharmacology, University of Milan, Italy (A.M.B, A.N.)
We have identified previously a destabilizing adenine- and uracil-rich element (ARE) in the 3'-UTR of bcl-2 mRNA that interacted with ARE-binding proteins to down-regulate bcl-2 gene expression in response to apoptotic stimuli. We have also described three contiguous 2'-O-methyl oligoribonucleotides (ORNs) in both sense and antisense orientation with respect to the bcl-2 ARE that are able to regulate the bcl-2 mRNA half-life and Bcl-2 protein level in two different cell lines. Here we show that treatment of neuronal cell line (SHSY-5Y) with antisense ORNs targeting the bcl-2 ARE (bcl-2 ARE asORNs) prevents bcl-2 down-regulation in response to apoptotic stimuli with glucose/growth factor starvation (Locke medium) or oxygen deprivation and enhances the apoptotic threshold as evaluated by time-lapse videomicroscopy, fluorescence-activated cell sorting analysis, and caspase-3 activation. Additional effects of bcl-2 ARE asORNs included inhibition of cell cycle entry and a marked increase of cellular neurite number and length, a hallmark of neuronal differentiation resulting from bcl-2 up-regulation. The ability of bcl-2 ARE asORNs to enhance the apoptotic threshold and to induce neuronal differentiation implies their potential application as a novel informational tool to protect cells from ischemic damage and to prevent neuronal degeneration.
Address correspondence to: Dr. Nicola Schiavone, Department of Experimental Pathology and Oncology, University of Florence, Viale G.B. Morgagni 50, 50134 Florence, Italy. E-mail: nicola{at}unifi.it