Coenzyme Q0 (CoQ0, 2,3-dimethoxy-5-methyl-1,4-benzoquinone), a novel quinone derivative, has been shown to modulate cellular redox balance. However, effect of this compound on melanoma remains unclear. This study examined the in vitro or in vivo anti-tumor, apoptosis, and anti-metastasis activities of CoQ0 (0-20 μM) through inhibition of Wnt/β-catenin signaling pathway. CoQ0 exhibits a significant cytotoxic effect on melanoma cell lines (B16F10, B16F1, and A2058), while causing little toxicity toward normal (HaCaT) cells. The suppression of β-catenin was seen with CoQ0 administration accompanied by a decrease in the expression of Wnt/β-catenin transcriptional target c-myc, cyclin D1, and survivin through GSK3β-independent pathway. We found that CoQ0 treatment caused G1 cell-cycle arrest by reducing the levels of cyclin E and CDK4. Furthermore, CoQ0 treatment induced apoptosis through caspase-9/-3 activation, PARP degradation, Bcl-2/Bax dysregulation, and p53 expression. Notably, non- or sub-cytotoxic concentrations of CoQ0 markedly inhibited migration and invasion, accompanied by the down-regulation of MMP-2 and -9, and up-regulation of TIMP-1 and -2 expressions in highly metastatic B16F10 cells. Furthermore, the in vivo study results revealed that CoQ0 treatment inhibited the tumor growth in B16F10 xenografted nude mice. Histological analysis and western blotting confirmed that CoQ0 significantly decreased the xenografted tumor progression as demonstrated by induction of apoptosis, suppression of β-catenin, and inhibition of cell cycle-, apoptotic-, and metastatic-regulatory proteins. The data suggest that CoQ0 unveils a novel mechanism by down-regulating Wnt/β-catenin pathways and could be used as a potential lead compound for melanoma chemotherapy.

Antrodia camphorata (AC) is well known in Taiwan as a traditional Chinese medicine. The aim of this study was to investigate whether a fermented culture broth of AC could inhibit melanoma proliferation and progression via suppression of the Wnt/β-catenin signaling pathway. In this study, we observed that AC treatment resulted in decreased cell viability and disturbed Wnt/β-catenin cascade in B16F10 and/or B16F1 melanoma cells. This result was accompanied by a decrease in the expression of Wnt/β-catenin transcriptional targets, including c-Myc and survivin. Furthermore, treatment of melanoma cells with AC resulted in a significant increase in apoptosis, which was associated with DNA fragmentation, cytochrome c release, caspase-9 and -3 activation, PARP degradation, Bcl-2/Bax dysregulation, and p53 expression. We also observed that AC caused G1 phase arrest mediated by a downregulation of cyclin D1 and CDK4 and increased p21 and p27 expression. In addition, we demonstrated that non- and subcytotoxic concentrations of AC markedly inhibited migration and invasion of highly metastatic B16F10 cells. The antimetastatic effect of AC was further confirmed by reductions in the levels of MMP-2, MMP-9, and VEGF expression. These results suggest that Antrodia camphorata may exert antitumor activity by downregulating the Wnt/β-catenin pathways.

Antrodia camphorata is well known in Taiwan as a nutritional food. The objective of our study was to determine if fermented culture broth of Antrodia camphorata (AC‐10; 40–120 μg/mL) could modulate the key elements of Wnt pathway in murine melanoma cell (B16F10); an efficacy for chemoprevention of this malignancy. The suppression of β‐catenin, a key mediator of Wnt signaling pathway, was seen in B16F10 cell with AC‐10 administration. The transcriptional targets of c‐myc and cyclin D1 were also dramatically downregulated. We also observed that AC‐10 caused the G1 arrest that was mediated through reductions in the levels of cyclinD1 and CDK4, and increases in p27 and p21 levels in B16F10 cell. In addition, treatment B16F10 with AC‐10 resulted in a significant dose‐dependent increase in apoptosis, which was associated with DNA fragmentation, sub‐G1 phase accumulation. Gelatin zymography and western blotting showed that reduced cell invasion with AC‐10 treatment correlated with MMP‐9 and MMP‐2 expression. These results suggested that AC‐10 may exert anti‐tumor activity by modulating Wnt/β‐catenin pathway.The source of research support: American Society for Nutrition (ASN)