Para-Phenylenediamine Induces Apoptotic Death of Melanoma Cells and Reduces Melanoma Tumour Growth in Mice

Figure 5

p-PD activates extrinsic apoptotic pathways earlier than the intrinsic ones in human melanoma cells. (a) A375 cells were treated with p-PD as indicated. Cells treated for 6 and 24 hours were lysed with protein loading buffer (Materials and Methods). 30 μg of total protein lysate (same as described in Figure 3(a)) was loaded in each lane and subjected to western blot and probed for activated caspase 3, activated caspase 8, activated caspase 9, and Bid as indicated. Arrow and “⧫” indicate the cleaved fragments of caspase 8 and caspase 9, respectively. Cells that were not treated with p-PD (0) but with 0.1% DMSO served as controls. (b) Cells treated for 48 hours were lysed and analysed by western blot as mentioned above by probing with antibodies against active caspase 9 and Bid. “⧫” indicates both cleaved fragments of caspase 9. β-actin is used as a loading control for both panels. These blots are representative of three independent analyses.

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