Melanoma is the most prevalent type of
skin cancer with high mortality rates. This study demonstrates the in vitro and in vivo anticancer properties of
chalcone flavokawain B (FKB) induced ROS-mediated apoptosis and autophagy in human
melanoma (human epithelial
melanoma cell line A375 and/or human skin lymph node derived
melanoma cell line A2058) cells. Cell viability was calculated by
3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the expression patterns of various apoptosis, autophagy-associated
proteins were determined by Western blot methods.
Annexin V was detected by flow cytometry, whereas acidic vesicular organelles (AVOs) and intracellular ROS levels were measured by fluorescence microscopy. The in vivo anticancer properties of FKB were evaluated by
xenografting the A375 cells into nude mice. The results convey that FKB inhibited cell viability, B-Raf proto-oncogene,
serine/threonine kinase (BRAF)/
extracellular signal-regulated kinase (ERK) expression in human
melanoma cells.
Caspase-3 activation,
poly (ADP-ribose) polymerase (PARP) cleavage pathway, and Bcl2 associated X (Bax)/
B-cell lymphoma 2 (Bcl-2) dysregulation were involved in the execution of apoptosis. Moreover, FKB-induced autophagy was observed through increased
microtubule-associated protein 1A/1B-light chain 3B (LC3-II) accumulation and AVOs formation, which was also associated with an increase in sequestosome 1 (SQSTM1/p62), decreased
protein kinase B (AKT)/
mammalian target of rapamycin (mTOR) expressions, and dysregulated
Beclin-1/Bcl-2 levels. Autophagy inhibitors [3-methyladenine (3-MA)/
chloroquine (CQ)] and LC3 silencing suppressed FKB-induced apoptosis by decreasing
caspase-3 in
melanoma cells. The
antioxidant N-acetylcysteine (NAC) diminished FKB-induced apoptotic and autophagic cell death. However, the inhibition of apoptosis decreased FKB-induced autophagy (LC3-I/II). The in vivo study confirmed that FKB inhibited
melanoma growth in A375-xenografted nude mice. This study concluded that FKB is critically associated with the execution and generation of ROS-modulated apoptotic and autophagic cell death of
melanoma cells. FKB also repressed
tumor growth in xenografted nude mice. Therefore,
flavokawain B might be a potential anti-
tumor agent in human
melanoma treatment.