AN N-terminal Smac peptide sensitizes human prostate carcinoma cells to methyl jasmonate-induced apoptosis

Although the anti-cancer agent methyl jasmonate (MJ) has been shown to selectively target malignant cells while sparing normal ones, hormone-refractory prostate cancer cells are relatively resistant to MJ than other cancer cells. In the present study, we investigated the effect of cell permeable seven-residue peptide of Smac (SmacN7), an antagonist of the inhibitor of apoptosis proteins (IAPs), on MJ-induced apoptosis. SmacN7 significantly enhanced the growth inhibition effect of MJ in human prostate cancer cells, but not in proximal tubular epithelial cells. Moreover, SmacN7 sensitizes MJ-induced apoptosis through both caspase-9-dependent and -independent pathways. Thus, blockade of the over-expressed IAPs in cancer cells could yield a potential therapeutic benefit in jasmonates-based chemotherapy.