CASP9 and melanoma: Moreover, we found that treatment with the PERK inhibitor GSK2606414 alone or in combination with BRAF inhibitor PLX4032 increased the protein level of cleaved PARP, cleaved caspase-7, cleaved caspase-3, and cleaved caspase-9 in BRAFi-resistant melanoma cells (Fig. 5 and Supplementary Fig. 5), suggesting that the inhibition of PERK by a small molecular inhibitor could promote tumor cell apoptosis.