Background: Circular RNAs (circRNAs) play a critical regulatory role in cancer progression. However, the underlying mechanisms of circRNAs in hepatocellular carcinoma (HCC) metastasis remain mostly unknown. Methods: Has_circ_0003998 (circ0003998) was identified by RNAs sequencing in HCC patients with /without portal vein tumor thrombus (PVTT) metastasis. The expression level of circ0003998 was further detected by in situ hybridization on tissues microarray (ISH-TMA) and qRT-PCR in 25 HCC patients with PVTT metastasis. Moreover, the 25 HCC patients with PVTT metastasis and 50 HCC patients without PVTT metastasis were recruited together to analyze the correlation between circ0003998 expression and HCC clinical characteristics. Transwell, migration and CCK8 assays, as well as nude mice model of lung or liver metastasis were used to evaluate the role of circ0003998 in epithelial to mesenchymal transition (EMT) in HCC. The regulatory mechanisms of circ0003998 in miR-143-3p and PCBP1 were determined by dual-luciferase reporter assay, nuclear-cytoplasmic fractionation, fluorescent in situ hybridization, RNA pull- down, microRNA sequence, western blot and RNA immunoprecipitation. Results: Compared with adjacent normal liver tissues (ANL), circ0003998 expression was significantly upregulated in PVTT tissues and HCC tissues, and its expression correlates with the aggressive characteristics of HCC patients. Further assays suggested that circ0003998 promoted EMT of HCC both in vitro and in vivo. Mechanistically, our data indicated that circ0003998 may act as a ceRNA (competing endogenous RNA) of microRNA-143-3p to relieve the repressive effect on EMT-related stimulator, FOSL2; meanwhile, circ0003998 could bind with PCBP1-poly(rC) binding protein 1 (PCBP1) to increase the expression level of EMT-related genes, CD44v6. Conclusion: Circ0003998 promotes EMT of HCC by circ0003998/miR-143-3p/FOSL2 axis and circ0003998 /PCBP1/CD44v6 axis.

Recent studies have shown that the occurrence and progression of nonalcoholic fatty liver disease (NAFLD) can be aggravated by dysregulation of intestinal flora. We previously found that phytosterol esters (PSEs) could effectively prevent the progression of NAFLD. Here, we further investigated the regulatory effect that PSEs have on gut flora and faecal metabolites in rats with NAFLD. Adult SD (Sprague Dawley) rats were randomized into four groups: the normal chow diet (NC), high-fat diet (HFD), low-dose PSE (0.05 g per 100 g BW, PSEL) and high-dose PSE (0.10 g per 100 g BW, PSEH) groups. PSEs were intragastrically administered once a day for 12 consecutive weeks. Our work indicated that high-dose PSE treatment effectively inhibited the increase in liver and abdominal fat indexes (P < 0.01) and hepatic lipids (P < 0.01); a high dose PSE treatment effectively corrected the HFD-induced intestinal flora imbalance by changing the diversity. The relative abundances of the four phyla (Firmicutes, Proteobacteria, Actinobacteria and Verrucomicrobia) and partial bacteria at the genus level (Faecalibacterium, Akkermansia, etc.) in the PSEH group were closer to those in the NC group. High-dose PSE intervention significantly increased the relative abundance of Bacteroidetes and Anaerostipes. Compared with the HFD, PSEH treatment significantly decreased the ionic strengths of bile acid metabolism products (P < 0.05), which were positively correlated with hepatic steatosis. In conclusion, PSE treatment exerts a beneficial effect on NAFLD that is associated with its regulatory action on intestinal flora and faecal metabolites, which might present a new opportunity to develop effective and safe preventive strategies against NAFLD.

The aim of this study was to investigate the combined effect of n-3 fatty acids (EPA and DHA, at an EPA:DHA ratio of 150:500) and phytosterol esters (PS) on non-alcoholic fatty liver disease (NAFLD) patients. We conducted a randomised, double-blind, placebo-controlled trial. Ninety-six NAFLD subjects were randomly assigned to the following groups: the PS group (receiving 3·3 g/d PS); the FO group (receiving 450 mg EPA + 1500 mg DHA/d); the PS + FO combination group (receiving 3·3 g/d PS and 450 mg EPA + 1500 mg DHA/d) and the PO group (a placebo group). The baseline clinical characteristics of the four groups were similar. The primary outcome was liver:spleen attenuation ratio (L:S ratio). The percentage increase in liver–spleen attenuation (≤1) in the PS + FO group was 36 % (P = 0·083), higher than those in the other three groups (PS group, 11 %, P = 0·519; FO group, 18 %, P = 0·071; PO group, 15 %, P = 0·436). Compared with baseline, transforming growth factor-β (TGF-β) was significantly decreased in the three study groups at the end of the trial (PS, P = 0·000; FO, P = 0·002; PS + FO, P = 0·001) and TNF-α was significantly decreased in the FO group (P = 0·036), PS + FO group (P = 0·005) and PO group (P = 0·032) at the end of the intervention. Notably, TGF-β was reduced significantly more in the PS + FO group than in the PO group (P = 0·032). The TAG and total cholesterol levels of the PS + FO group were reduced by 11·57 and 9·55 %, respectively. In conclusion, co-supplementation of PS and EPA + DHA could increase the effectiveness of treatment for hepatic steatosis.