Involvement of caspase-8, -9 and -3 in p-phenylenediamine induced apoptosis in murine myeloma p3 cells: regulation by reactive oxygen species

P-phenylenediamine (PPD) is a monocyclic arylamine frequently used as a component in permanent hair dyes, inks and certain tattoos. It has been reported that a number of hair dye constituents including monocyclic PPD have genotoxic properties in experimental systems. In this study, the molecular mechanism of PPD, a suspected carcinogen, induced cell death in murine myeloma cells P3X63Ag8.653 (P3) was investigated. Apoptosis was evaluated by DAPI staining and DNA gel electrophoresis. The activity of caspase-8, -3 and -9 was assessed by spectrophotometry using colorimetric tests. Glutathione (GSH) was used in this study as antioxidant. Results have demonstrated that PPD decreased cell viability in a dose- and a time-dependent manner. In addition, cell death via apoptosis was confirmed by chromatin condensation and enhanced DNA fragmentation. Furthermore, caspase-8, -9 and -3 activities in PPD treated cells were higher than those of untreated cells. Moreover, pre-treatment of P3 cells with glutathione GSH as antioxidant inhibited PPD induced cytotoxicity and DNA damage and decreased the activity of caspases. Based on these results, we suggested that PPD induced apoptosis in murine myeloma P3 cells was mediated by caspase-8, -9 and caspase-3 activation and with the involvement of reactive oxygen species (ROS).