ABSTRACT
The incidence and mortality of hepatocellular carcinoma (HCC) are gradually increasing during the past years. Recently, some studies have reported that malic enzyme (ME) plays an important role in cancer development, while the involvement of ME2 in HCC remains still undetermined. Here, we demonstrated that ME2 played an oncogenic role in HCC. ME2 was overexpressed in HCC tissues. TCGA database showed that the ME2 transcript level was inversely associated with the survival of HCC patients. Loss-of-function and gain-of-function assays showed that ME2 promoted HCC cell growth and migration. Furthermore, the xenografted tumorigenesis of MHCC97H cells was retarded by ME2 knockdown. ME2 silencing also suppressed the cell cycle process and induced apoptosis. Mechanistically, ME2 potentiated triglyceride synthesis, inhibition of which suppressed the proliferation and migration. We propose that ME2 promotes HCC progression by increasing triglyceride production.
Subject(s)
Carcinoma, Hepatocellular/physiopathology , Liver Neoplasms/physiopathology , Malate Dehydrogenase/adverse effects , Triglycerides/adverse effects , Animals , Carcinogenesis , Carcinoma, Hepatocellular/mortality , Cell Line, Tumor , Cell Proliferation , Disease Progression , Female , Humans , Liver Neoplasms/mortality , Male , Mice , Mice, Nude , Survival AnalysisABSTRACT
Circular RNA (circRNAs) functions vital in the pathogenesis and progression of hepatocellular carcinoma (HCC). However, the expressions and functions of certain circRNAs on metastasis and proliferation of that cancer is still unclear. Bioinformation analysis and qRT-PCR indicated that CircC16orf62 was prominent upregulated in HCC of which the expression level was positively associated to cancer's malignant progression. Gain or loss-of-function studies indicated that the reduction of CircC16orf62 expression promotes the proliferation, invasion, and glycolysis of HCC in vitro and in vivo. The bioinformatic analysis found that miR-138-5p and PTK2 were the downstream target of CircC16or62. Then, the FISH(Fluorescence immunoin situ hybridization) and cell nucleoplasmic separation determined that CircC16orf62 located in the cell cytoplasm. Plasmid vectors or siRNAs were used to change the expression of CircC16orf62, miR-138-5p, and PTK2 in PC cell lines. CircC16orf62 functioned as a molecular sponge for miR-138-5p, and a competitive endogenous RNA for PTK2, promoting AKT/mTOR pathway activation. Our observations lead us to conclude that CircC16orf62 functions as an oncogene in HCC progression, behaving as a competitive endogenous RNA for miR-138-5p binding, thus activating the AKT/mTOR pathway. In conclusion, CircC16orf62 is an oncogene through the miR-138-5p/PTK2/Akt axis in HCC cells, indicating CircC16orf62 can be a therapeutic target with potentiality for liver cancer and a predictive marker for people with HCC.
