Oviductus Ranae (OR) is a valuable Chinese crude drug and has been reported to have a range of biological activities. Protein hydrolysate extracted from OR (ORPH) was previously found to have immune regulatory effect and anti-glioma activity. This study was aimed to investigate the effects of ORPH on hepatocellular carcinoma (HCC) progression.

MTT, BrdU, colony formation and transwell assays were used to determine proliferation and mobility of HCC cells in vitro. Glucose consumption and lactate production assays were carried out to measure the glycolysis of HCC cells. The subcutaneous tumor model and lung metastasis model in nude mice were established to detect tumor growth and metastasis of HCC in vivo. The direct binding of miR-491-5p to 3’UTR of pyruvate kinase M2 (PKM2) was confirmed by luciferase reporter assay.

In vitro experiments showed that ORPH significantly inhibited proliferation, migration, invasion, epithelial-to-mesenchymal transition (EMT) and glycolysis of HCC cells. Moreover, ORPH treatment prominently suppressed HCC growth and metastasis in mice. We demonstrated that ORPH effectively decreased the expression of PKM2 in HCC cells. Forced expression of PKM2 abrogated the inhibitory effects of ORPH on HCC cells. Mechanically, ORPH reduced PKM2 expression in a post-transcriptional manner by up-regulating miR-491-5p. miR-491-5p exhibited a similar tumor suppressive effects with ORPH in HCC cells. Moreover, ORPH exerted its inhibitory effects on HCC cells through regulating miR-491-5p/PKM2 axis. Lastly, decreased miR-491-5p level and increased PKM2 expression were correlated with unfavorable clinical features and poor prognosis of HCC patients.

In all, this study reveals that ORPH inhibits the growth, metastasis and glycolysis of HCC cells by targeting miR-491-5p/PKM2 axis. ORPH may be a potential effective anti-tumor agent for HCC.