EFNA4 promotes cell proliferation and tumor metastasis in hepatocellular carcinoma through a PIK3R2/GSK3β/β-catenin positive feedback loop

Junhao Lin,Chunting Zeng,Jiakang Zhang,Zhenghui Song,Na Qi,Xinhui Liu,Ziyan Zhang,Aimin Li,Fengsheng Chen

doi:10.1016/j.omtn.2021.06.002

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 (GSK3β)/β-catenin signaling pathway. Moreover, overexpression of β-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/GSK3β/β-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.

Highlights

Liver cancer is one of the most common types of malignant tumors, ranking fourth in mortality rate and second in cancer-related mortality of males in 2018 worldwide.[1]
For TCGA database analysis, the results indicated that EFNA4 was significantly overexpressed in patients with liver cancer, and this overexpression was linked to a worse clinical prognosis
We found that the expression of EFNA4 was positively correlated with TNM staging, and high EFNA4 expression was a significant indicator of poor overall survival (OS) and progress-free survival (PFS; OS: hazard ratio [HR] = 1.96, 95% confidence interval [CI]: 1.37–2.81, p = 0.00018; PFS: HR = 1.61, 95% CI: 1.16–2.22, p = 0.0036) (Figures 1A–1C)

Summary

Introduction

Liver cancer is one of the most common types of malignant tumors, ranking fourth in mortality rate and second in cancer-related mortality of males in 2018 worldwide.[1]. The EPH/ephrin (EPH/EFN) system is widely expressed in various cells by binding to the cell membrane. It plays crucial roles in development, cell proliferation, and differentiation by cell-cell contact, regulation of cell signals and transfer into the nucleus, and stimulation of downstream signaling pathways, which are closely related to the appearance of tumors. EFNA ligands bind to the corresponding EPH receptor, activate the tyrosine kinase in the cytoplasm of the receptor by changing the conformation of EPH, and result in phosphorylation of the corresponding receptor and activation of downstream signaling.[3] In addition, EFNA ligands activate the relevant surface receptors of their host cells, such as the p75NT receptor (p75NTR).[3,4]

Objectives

Methods

Results

Conclusion