Autophagy induction by xanthoangelol exhibits anti-metastatic activities in hepatocellular carcinoma.

Xanthoangelol (XAG), a prenylated chalcone isolated from the Japanese herb Angelica keiskei Koidzumi, has been reported to exhibit antineoplastic properties. However, the specific anti-tumor activity of XAG in human hepatocellular carcinoma (HCC), and the relevant mechanisms are not known. Herein, we evaluated the effect of XAG against HCC in vitro and in vivo. Although XAG treatment did not significantly reduce the viability of the Hep3B and Huh7 cell lines, it suppressed cell migration, invasion, and EMT. This anti-metastatic effect of XAG was due to induction of autophagy, because treatment with the autophagy inhibitor 3-methyadenine (3-MA) or knockdown of the pro-autophagy Beclin-1 effectively abrogated the XAG-induced suppression of metastasis. Mechanistically, XAG induced autophagy via activation of the AMPK/mTOR signaling pathway, and XAG treatment dramatically increased the expression of p-AMPK while decreasing p-mTOR expression. In addition, blocking AMPK/mTOR axis with compound C abrogated the autophagy-mediated inhibition of metastasis. The murine model of HCC metastasis also showed that XAG effectively reduced the number of metastatic pulmonary nodules. Taken together, our results revealed that autophagy via the activation of AMPK/mTOR pathway is essential for the anti-metastatic effect of XAG against HCC. These findings not only contribute to our understanding of the anti-tumor activity of XAG but also provide a basis for its clinical application in HCC. Before this study, evidence of XAG on HCC was purely anecdotal; present study provides the first comprehensive assessments of XAG on HCC metastasis and investigates its underlying mechanism. Results suggest that XAG exerts anti-metastatic properties against HCC through inducing autophagy which is mediated by the activation of AMPK/mTOR signaling pathway. This research extends our knowledge about the antineoplastic properties of XAG and suggests that induction autophagy may represent future treatment strategies for metastatic HCC.

Retraction Note: Endoplasmic reticulum stress triggers Xanthoangelol-induced protective autophagy via activation of JNK/c-Jun Axis in hepatocellular carcinoma.

An amendment to this paper has been published and can be accessed via the original article.

Endoplasmic reticulum stress triggers Xanthoangelol-induced protective autophagy via activation of JNK/c-Jun Axis in hepatocellular carcinoma.

BACKGROUND: Xanthoangelol (XAG) was reported to exhibit antitumor properties in several cancer. However, the specific anti-tumor activity of XAG in human hepatocellular carcinoma (HCC) and the relevant mechanisms are not known. METHODS: The effects of XAG on HCC cell proliferation and apoptosis were respectively examined by CCK-8 assay and Annexin V-FITC/PI apoptosis kit. Western blotting was conducted to detect the expression of proteins. The effect of XAG on the development of acidic vesicle organelles was assessed using acridine orange staining. mRFP-GFP-LC3 adenovirus was used to transfect HCC cells and the formation of autolysosome was detected using a confocal microscope. RESULTS: Mechanistically, XAG promotes HCC cell death through triggering intrinsic apoptosis pathway, not extrinsic apoptotic pathway. Furthermore, XAG treatment induced autophagy in Bel 7402 and SMMC 7721 cells, as evidenced by an increase in autophagy-associated proteins, including LC3B-II, Beclin-1, and Atg5. Interestingly, inhibition of autophagy with 3-MA, Bafilomycin A1 (Baf A1), or siRNA targeting Atg5 effectively enhanced the apoptotic cell ratio in XAG-treated cells, indicating that protective effect of autophagy induced by XAG in HCC. Moreover, autophagy induced by XAG was mediated by activating endoplasmic reticulum stress (ERS), along with administration of XAG, the expression levels of ERS-associated proteins, including CHOP, GRP78, ATF6, p-eIF2α, IRE1α, and cleaved caspase-12 were significantly increased in HCC cells. Meanwhile, suppressing ERS with chemical chaperones (TUDCA) or CHOP shRNA could effectively abrogate the autophagy-inducing effect of XAG, and increase the apoptotic cell death. Further mechanistic studies showed that ERS-induced autophagy in XAG-treated cells was mediated by activation of JNK/c-jun pathway. XAG treatment resulted in the increase of p-JNK and p-c-jun, while suppressing ERS with TUDCA or CHOP shRNA could effectively reverse it. Meanwhile, SP600125, a JNK inhibitor, effectively reversed XAG-induced protective autophagy and enhanced cell apoptosis in XAG-treated HCC cells. In vivo results demonstrated that XAG exerts potent antitumor properties with low toxicity. CONCLUSIONS: Collectively, these results suggested that XAG could be served as a promising candidate for the treatment and prevention of HCC.