Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world and the third leading cause of cancer-related death. Critical roles for long non-coding RNAs (lncRNAs) have recently been demonstrated for a variety of cancers, including hepatocellular carcinoma. However, the effect and mechanism of lncRNAs in HCC tumorigenesis and chemoresistance have not been extensively characterized.
In the current study, Jinan University researchers have identified a HCC-expressed lncRNA termed as HANR (HCC associated long non-coding RNA). They identified HANR by microarray analysis and validated its up-regulated expression by quantitative PCR. RNA pull-down and pathway analyses were conducted to evaluate physical and functional interactions with HANR. In vivo experiments were performed to assess tumorigenesis and increase of chemoresistance. In addition, the HANR expression in HCC specimens was detected by FISH. Xenograft and orthotopic mice model was constructed to observe the effect of HANR on tumorigenesis and chemoresistance in vivo.
HANR was demonstrated to be up-regulated in HCC patients and HCC cell lines. Increased HANR expression in HCC predicted short survival of patients. Knock-down of HANR markedly retarded cell proliferation, suppressed HCC xenograft/orthotopic tumor growth, induced apoptosis and enhanced chemosensitivity to doxorubicin, while over-expression of HANR showed the opposite effects. It was found that HANR bind to GSKIP for regulating the phosphorylation of GSK3β in HCC.
Up-regulated HANR expression in HCC
(A) Microarray analysis was performed in HCC and corresponding peri-tumor (non-cancer) tissue. The genomic location and genetic map of HANR are indicated. (B) Quantitative PCR analysis of the expression of HANR in non-cancer and HCC samples. (C) Quantitative PCR analysis of the basal expression of HANR in normal LO-2 hepatocytes and two hepatoma cell lines. (D) Representative HANR fluorescent in situ hybridization results for clinical specimens (bar = 50 µM). (E) Corresponding quantification of HANR fluorescent staining. (F) Kaplan-Meier analysis of overall survival for HCC patients with HANR high (cancer/non-cancer ratio > 5.83-fold) or low (cancer/non-cancer ratio < 5.83-fold) expression. Data are presented as means ± SEM. *, P<0.05, **, P<0.01, ***, P<0.001.
These results demonstrate that HANR contributes to the development of HCC and is a promising therapeutic target for chemosensitization of HCC cells to doxorubicin, which may represent a promising therapeutic target in the future.