Original Article
Copyright ©2014 Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 21, 2014; 20(47): 17894-17904
Published online Dec 21, 2014. doi: 10.3748/wjg.v20.i47.17894
HIF-1α induces VE-cadherin expression and modulates vasculogenic mimicry in esophageal carcinoma cells
Na-Na Tang, Hong Zhu, Hong-Jie Zhang, Wei-Feng Zhang, Hai-Lin Jin, Lu Wang, Pin Wang, Gui-Jun He, Bo Hao, Rui-Hua Shi
Na-Na Tang, Hong Zhu, Hong-Jie Zhang, Wei-Feng Zhang, Hai-Lin Jin, Lu Wang, Pin Wang, Gui-Jun He, Bo Hao, Rui-Hua Shi, Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu Province, China
Author contributions: Tang NN, Wang L and Jin HL performed the majority of experiments; Zhang WF, Hao B and Wang P provided vital reagents and analytical tools; He GJ collected all the human materials; Shi RH designed the study; Tang NN wrote the manuscript; Zhang HJ and Zhu H revised the manuscript.
Supported by National Natural Science Foundation of China, No. 30770991 and No. 30800511; and Esophageal Carcinoma Innovative Research Program of Jiangsu Provincial Hospitals
Correspondence to: Rui-Hua Shi, PhD, Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, Jiangsu Province, China. ruihuashi@126.com
Telephone: +86-25-83718836 Fax: +86-25-83674636
Received: January 19, 2014
Revised: April 3, 2014
Accepted: May 29, 2014
Published online: December 21, 2014
Abstract

AIM: To investigate whether hypoxia inducible factor (HIF)-1α modulates vasculogenic mimicry (VM) by upregulating VE-cadherin expression in esophageal squamous cell carcinoma (ESCC).

METHODS: Esophageal squamous cancer cell lines Eca109 and TE13 were transfected with plasmids harboring small interfering RNAs targeting HIF-1α or VE-cadherin. The proliferation and invasion of esophageal carcinoma cells were detected by MTT and Transwell migration assays. The formation of tubular networks of cells was analyzed by 3D culture in vitro. BALB/c nude mice were used to observe xenograft tumor formation. The relationship between the expression of HIF-1α and VE-cadherin, ephrinA2 (EphA2) and laminin5γ2 (LN5γ2) was measured by Western blot and real-time polymerase chain reaction.

RESULTS: Knockdown of HIF-1α inhibited cell proliferation (32.3% ± 6.1% for Eca109 cells and 38.6% ± 6.8% for TE13 cells, P < 0.05). Both Eca109 and TE13 cells formed typical tubular networks. The number of tubular networks markedly decreased when HIF-1α or VE-cadherin was knocked down. Expression of VE-cadherin, EphA2 and LN5γ2 was dramatically inhibited, but the expression of matrix metalloproteinase 2 had no obvious change in HIF-1α-silenced cells. Knockdown of VE-cadherin significantly decreased expression of both EphA2 and LN5γ2 (P < 0.05), while HIF-1α expression was unchanged. The time for xenograft tumor formation was 6 ± 1.2 d for Eca109 cells and Eca109 cells transfected with HIF-1α Neo control short hairpin RNA (shRNA) vector, and 8.4 ± 2.1 d for Eca109 cells transfected with an shRNA against HIF-1α. Knockdown of HIF-1α inhibited vasculogenic mimicry (VM) and tumorigenicity in vivo.

CONCLUSION: HIF-1α may modulate VM in ESCC by regulating VE-cadherin expression, which affects VM formation through EphA2 and LN5γ2.

Keywords: Esophageal squamous cell carcinoma, Hypoxia-inducible factor-1α, VE-cadherin, RNA interference, Vasculogenic mimicry

Core tip: Hypoxia-inducible factor (HIF) is a key factor in regulating and promoting tumor progression. Angiogenesis and vasculogenic mimicry (VM) may play an important role in tumor acquisition of increased blood supply. We investigated the role of HIF-1α in the formation of VM in esophageal squamous cell carcinoma (ESCC). We showed that HIF-1α may upregulate the expression of VE-cadherin to modulate VM in ESCC, which may be related to changes in ephrin A2 and laminin 5γ2 protein expression. These results may have implications for the treatment of malignant tumor diseases.