Plumbagin restrains hepatocellular carcinoma angiogenesis by suppressing the migration and invasion of tumor-derived vascular endothelial cells.

Yanfei Wei,Qi Yang,Yuan Zhang,Tiejian Zhao,Junxuan Li,Jing Ma,Xuemei Liu,Yongxin Chen,Chuan Zhao,Jing Zhong

doi:10.18632/oncotarget.14774

Abstract

Tumor occurrence and development are very complicated processes. In addition to the roles of exogenous carcinogenic factors, the body's internal factors also play important roles. These factors include the host response to the tumor and the tumor effect on the host. In particular, the proliferation, migration and activation of endothelial cells are involved in tumor angiogenesis. Angiogenesis is one of the hallmarks of cancer. In this study, we investigate whether plumbagin can abrogate angiogenesis-mediated tumor growth in hepatocellular carcinoma (HCC) and, if so, through which molecular mechanisms. We observed that in co-cultures of the human endothelial cell line EA.hy926 and the human hepatoma cell line SMMC-7721 and Hep3B, the hepatoma cells induced migration, invasion, tube formation and viability of the EA.hy926 cells in vitro, and these processes were inhibited by plumbagin. Real-Time PCR, Western Blot and Immunofluorescence staining showed that plumbagin treatment suppressed expression of angiogenesis pathways (PI3K-Akt, VEGF/KDR and Angiopoietins/Tie2) and angiogenic factors (VEGF, CTGF, ET-1, bFGF),which is associated with tumor angiogenesis in cancer cells and xenograft tumor tissues. Furthermore, plumbagin was also found to significantly reduce tumor growth in an orthotopic HCC mouse model and to inhibit tumor-induced angiogenesis in HCC patient xenografts. Taken together, our findings strongly suggest that plumbagin might be a promising anti-angiogenic drug with significant antitumor activity in HCC.

Highlights

Angiogenesis is essential for solid tumors metastasis formation and growth [1]. experimental and clinical data have proved that angiogenic factors vascular endothelial growth factor (VEGF), basic fibroblast growth factor, connective tissue growth factor (CTGF), endothelia (ET-1) and angiopoietins(Ang1/Ang2) stimulates normal vessel excessive growth contribute to cancer progression [2]. cancer cells stimulate angiogenesis in an effort to maintain and allow tumor progression [3]
To assess the in vitro anti-angiogenic property of plumbagin, we examined its effects on the chemotactic motility of endothelial cells using transwell migration and invasion assays
We further noticed that plumbagin treatment inhibit the expression of phospho-PI3K and AKT Figure 7, We demonstrate for the first time the potential of plumbagin to inhibit tumor-induced angiogenesis in hepatocellular carcinoma (HCC) patient xenografts implanted in BALB/c mice

Summary

Introduction

Angiogenesis is essential for solid tumors metastasis formation and growth [1]. experimental and clinical data have proved that angiogenic factors vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), connective tissue growth factor (CTGF), endothelia (ET-1) and angiopoietins(Ang1/Ang2) stimulates normal vessel excessive growth contribute to cancer progression [2]. cancer cells stimulate angiogenesis in an effort to maintain and allow tumor progression [3]. Angiogenesis is essential for solid tumors metastasis formation and growth [1]. Experimental and clinical data have proved that angiogenic factors vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), connective tissue growth factor (CTGF), endothelia (ET-1) and angiopoietins(Ang1/Ang2) stimulates normal vessel excessive growth contribute to cancer progression [2]. Cancer cells stimulate angiogenesis in an effort to maintain and allow tumor progression [3]. Cancer cells by secreting growth factors connect with endothelial cells [4]. Growth factor bind to receptors on endothelial cells to initiate basement membrane degradation.as the result, endothelial cell proliferation and migration, capillary tubule formation and an increase in vessel permeability [5]. Endothelial cells were activated by pro-angiogenic factors, receptor tyrosine kinases (PI3K/Akt and RAF/MEK/ERK) signaling pathways [7]. Our study was designed to determine whether plumbagin regulates the migration and invasion of endothelial cells, inhibiting the tumor vasculature

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