Short hairpin RNA (shRNA) constructs targeting high mobility group box-1 (HMGB1) expression leads to inhibition of prostate cancer cell survival and apoptosis

High mobility group box protein I (HMGB1), transcriptional activity regulatory protein is associated with most cancers including prostate cancer. To investigate the effects of down-regulation of HMGB1 expression, we have transfected LNCaP cells with four short hairpin RNA (shRNA) targeting HMGB I plasmid vectors. Transfection with the four shRNAs efficiently and specifically reduced the HMGB1 expression in LNCaP cells. The gene silencing effects on HMGB1 expression were subsequently confirmed by RT-PCR and immunoblotting analyses. Down-regulation of HMGB1 expression resulted in the inhibition of cell growth in LNCaP prostate cancer cells and the decreased cell number was due to transfected cells undergoing apoptosis via caspase-3-dependent pathways. These findings suggest that HMGB I is critical for the survival of prostate cancer cells and targeted knockdown of HMGB1 mRNA can be used as a strategy to kill prostate cancer cells. Our findings may have some potential therapeutic relevance for treating prostate cancer.