HCC (Hepatocellular Carcinoma) is a critical health issue worldwide. Our previous animal experiment has confirmed that blueberry malvidin-3-galactoside (M3G) can regulate the progression of HCC. In this study, feces samples from the same batch of mice were collected to explore the regulatory mechanism of M3G on intestinal microbiota and microbial TCA cycle metabolism KEGG pathway in HCC mice based on 16S rRNA sequencing and metagenomics. Our results showed that blueberry M3G increased the microbial diversity and regulated the structure of intestinal microbiota in mice, such as increasing the abundance of Clostridia (butyric acid-producing bacteria), Oscillospira and Ruminococcus, and reducing the abundance of pathogenic Erysipelotrichi. Compared with the group of liver cancer and 5-fluorouracil, blueberry M3G significantly regulated microbial TCA cycle KEGG pathway via improving the expression of key proteins (porA, DLAT, aceE, PC and OGDH). Additionally, we found which the abundance of Muribaculum intestinale increased by blueberry M3G may be an important factor affecting the microbial TCA cycle KEGG pathway via the pearson correlation (R) analysis of protein and microbiota. Taken together, these results demonstrate that the blueberry M3G has the potential to be an intestinal microbiota regulator and an adjuvant to HCC therapy.

Malvidin-3-galactoside (Mv-3-gal) is the major anthocyanin monomer in blueberry anthocyanins. The compound is well-characterized by its anti-oncogenesis function in multiple organs including liver. In the current study, the mechanism driving the anti-hepatocellular carcinoma (HCC) function of Mv-3-gal was further explored by focusing on apoptosis and metastases pathways. HCC cell line Huh-7 was firstly administrated with Mv-3-gal of different concentrations and the effect of Mv-3-gal on cell proliferation, apoptosis, colony formation ability, metastasis potential as well as the activity of Akt/PTEN and MAPK pathways was assessed. The results showed that Mv-3-gal inhibited the cell proliferation and colony formation ability, induced cell cycle arrest and apoptosis in a dose-dependent manner. Regarding the metastasis potential, Mv-3-gal suppressed the migration and invasion potential of Huh-7 cells by regulating MMPs expression. Taken together, the findings highlighted the anti-HCC potent of Mv-3-gal, which was associated with the inhibition of Akt/PTEN, MAPK and MMP pathways.