CASP3 and melanoma: Therefore, we treated the three BRAFV600E-mutated melanoma cell lines A375-P, UACC-62 and WM-266-4 either with α-amanitin alone or in combination with PLX4720 for 72 hours and assessed POLR2A protein levels as well as PARP and Caspase-3 cleavage by western blot (Fig. 3A–C).