BAX and cancer: Specifically, justicidin B exerts its cytotoxic effect by acting on specific mechanisms in different cancer cell lines, targeting definite key proteins involved in apoptosis regulation; for example, it increases the Bax/Bcl-2 ratio by enhancing Bax expression in human melanoma A375 cells, and it causes downregulation of Bcl-2, caspase-3 and PARP-1 in the HeLa cell line [13,14,15].