No abstract

Rapid tumor progression, metastasis, and diagnosis in advanced stages of disease are the main reasons for the short survival time and high mortality rate of patients with hepatocellular carcinoma (HCC). Ephrin A4 (EFNA4), the ligand of the EPH family, participates in the development of blood vessels and epithelium by regulating cell migration and rejection. In our study, based on bioinformatics analyses, we found that EFNA4 was highly expressed and led to poor prognosis in patients with HCC. We demonstrated that overexpression of EFNA4 significantly promoted HCC cell proliferation and migration in vivo or in vitro. In addition, knockdown of EFNA4 inhibited the proliferation and migration of HCC cells. Furthermore, EFNA4 was found to directly interact with EPHA2 and promote its phosphorylation at Ser897, followed by recruitment of phosphoinositide-3-kinase regulatory subunit 2 (PIK3R2) and activation of the glycogen synthase kinase-3beta (GSK3b)/b-catenin signaling pathway. Moreover, overexpression of b-catenin further promoted the expression of PIK3R2, which formed a positive feedback loop. The results revealed that abnormal expression of EFNA4 is the main switch of the PIK3R2/GSK3b/b-catenin loop that influenced the proliferation and migration of HCC cells and suggest that EFNA4 is a potential prognostic marker and a prospective therapeutic target in patients with HCC.

Long noncoding RNAs have been proved in regulating tumourigenesis, including hepatocellular carcinoma (HCC). However, up to date, the role of PCAT6 in HCC is rare to be reported. In current study, bioinformatics analysis and quantitative realtime PCR were applied to examine the expression of PCAT6 in HCC. The role of PCAT6 in cell proliferation, cell cycle arrest, apoptosis, and metastasis were detected in both gain-and loss-of-function studies by cell biological assays. Bioinformatics analysis was employed to investigate the PCAT6-related genes and pathways in HCC. And we found that PCAT6 was significantly upregulated in HCC tissues and correlated with poor overall survival and disease-free survival in HCC patients. Furthermore, elevated PCAT6 promoted cell proliferation, inhibited cell cycle arrest and cell apoptosis while deficiency of PCAT6 impaired cell proliferation, caused cell cycle arrest and induced cell apoptosis of HCC. Moreover, as for bioinformatics analysis, a total of 389 PCAT6-related genes were found in both HCC tissue and cell lines, and these promising target genes were highly enriched in various key pathways, such as Wnt, HIF-1 signalling pathway, and metabolic pathways. Additionally, among these genes, DCAF13, SNRPB2, RPS8, and FKBP1A were revealed to be overexpressed in HCC and predicted poor prognosis. Taken together, our findings illustrate that PCAT6 contributes to HCC progression and might be a potential target for HCC therapy. Bioinformatics analysis may present a new way for assessing the underlying mechanism of PCAT6 in HCC. Significance of the Study: Hepatocellular carcinoma (HCC) is one of the most common and malignant tumours all over the world. In this study, we observed that PCAT6 was upregulated in HCC and correlated with poor prognosis of HCC patients. PCAT6 could promote cell proliferation, inhibit cell cycle arrest and cell apoptosis of HCC, suggesting PCAT6 exerts tumorigenic role in HCC. Moreover, bioinformatics analysis revealed a total of 389 PCAT6-related genes in both HCC tissue and cell lines, and these promising target genes were highly enriched in various key pathways, such as Yue Luo and Junhao Lin contributed equally to this work.