Antitumor activity of CDA-â ¡, a urinary preparation, on human multiple myeloma cell lines via the mitochondrial pathway.

Cell differentiation agent II (CDA­II) is a DNA methyltransferase inhibitor isolated from healthy human urine. In the present study, the antitumor activity of CDA­II on human multiple myeloma (MM) cell lines via the mitochondrial pathway was first revealed. The human MM cell lines were exposed to CDA­II. Cytotoxicity, caspase activation, apoptosis and the effects on the mitochondrial pathway were assessed. CDA­â…¡ was capable of decreasing the depolarized mitochondrial membranes and activating caspase­3 and ­9 and poly (ADP­ribose) polymerase in MM cells treated with CDA­II. CDA­II induced caspase­dependent cell death accompanied by a significant decrease in X-linked inhibitor of apoptosis protein (XIAP), survivin and Mcl­1 levels. The caspase­3 inhibitor, Z­DEVD­FMK, inhibited CDA­II­induced apoptosis. CDA­II potently increased the Bax levels, decreased the Bcl­2/Bax ratio and decreased the expression of the downstream targets of NF­κB. In conclusion, the results of the present study demonstrated that CDA­II treatment leads to the inhibition of p65 nuclear localization and potently induces caspase­dependent apoptosis in MM cells mediated through the mitochondrial pathway at low nanomolar concentrations. These results indicate that CDA­II is a novel inhibitor of NF­κB activity, with notable antimyeloma efficacy. This study provides a rationale for the clinical investigation of CDA­â…¡ in human MM.