Isoamylamine Induces B16-F1 Melanoma Cell Autophagy by Upregulating the 5' Adenosine Monophosphate-Activated Protein Pathway.

Isoamylamine (IA) is an aliphatic monoamine molecule present in cheese, eggs, and wine. It belongs to the family of polyamines and also can be synthesized endogenously. It has been known that regulation of polyamines in cells is related to cell cycle and tumor formation. Malignant melanoma is difficult to treat and easily resistant to chemotherapy/radiotherapy through autophagy. In this study, we aim to clarify whether IA has a growth control effect on melanoma tumor cells and the regulatory mechanism. We treated B16-F1 melanoma cells with IA at concentrations of 0, 200, 400, and 600 ppm for 24 h. The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay was checked for cell viability and results showed that IA has an inhibitory effect on B16-F1 melanoma cells. The signaling molecules, which included Raf/MEK/ERK, were activated, while MSK1 and protein kinase B (AKT) were suppressed. Autophagy was also confirmed to be induced by IA. The acridine orange stain-positive cells were increased and BECN-1/LC3 upregulated. The data also showed that the autophagy regulatory molecule, 5'-adenosine monophosphate-activated protein kinase (AMPK), was induced after IA treatment, so we used dorsomorphin to inhibit AMPK and found that it could suppress autophagy. In conclusion, IA has an effect of inducing autophagy in B16-F1 cells and it is regulated through AMPK.