title: Intracellular autocrine VEGF signaling promotes EBDC cell proliferation, which can be inhibited by Apatinib.
abstract: Tumor cells produce vascular endothelial growth factor (VEGF) which can interact with membrane or cytoplasmic VEGF receptors (VEGFRs) to promote cell growth. We aimed to investigate the role of extracellular/intracellular autocrine VEGF signaling and Apatinib, a highly selective VEGFR2 inhibitor, in extrahepatic bile duct cancer (EBDC). We found conditioned medium or recombinant human VEGF treatment promoted EBDC cell proliferation through a phospholipase C-γ1-dependent pathway. This pro-proliferative effect was diminished by VEGF, VEGFR1 or VEGFR2 neutralizing antibodies, but more significantly suppressed by intracellular VEGFR inhibitor. The rhVEGF induced intracellular VEGF signaling by promoting nuclear accumulation of pVEGFR1/2 and enhancing VEGF promoter activity, mRNA and protein expression. Internal VEGFR2 inhibitor Apatinib significantly inhibited intracellular VEGF signaling, suppressed cell proliferation in vitro and delayed xenograft tumor growth in vivo, while anti-VEGF antibody Bevacizumab showed no effect. Clinically, overexpression of pVEGFR1 and pVEGFR2 was significantly correlated with poorer overall survival (P = .007 and P = .020, respectively). In conclusion, the intracellular autocrine VEGF loop plays a predominant role in VEGF-induced cell proliferation. Apatinib is an effective intracellular VEGF pathway blocker that presents a great therapeutic potential in EBDC.
authors.affiliation: Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Sui
authors.initials: S
authors.lastname: Peng
authors.affiliation: Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Hepatobiliary Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Peng
authors.affiliation: Department of Pathology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Zunfu
authors.initials: Z
authors.lastname: Ke
authors.affiliation: Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Lixia
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Tianhong
authors.initials: T
authors.lastname: Su
authors.affiliation: Department of Surgery, University of Pittsburgh, Dallas, TX, USA.
authors.forename: Allan
authors.initials: A
authors.lastname: Tsung
authors.affiliation: Department of Surgery, University of Pittsburgh, Dallas, TX, USA.
authors.forename: Samer
authors.initials: S
authors.lastname: Tohme
authors.affiliation: Department of Surgery, University of Pittsburgh, Dallas, TX, USA.
authors.forename: Hai
authors.initials: H
authors.lastname: Huang
authors.affiliation: University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Qiuyang
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Division of Vascular Interventional Radiology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, USA.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Lencioni
authors.affiliation: Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Zhirong
authors.initials: Z
authors.lastname: Zeng
authors.affiliation: Department of Hepatobiliary Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Baogang
authors.initials: B
authors.lastname: Peng
authors.affiliation: Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China. Electronic address: chenminhu@vip.163.com.
authors.forename: Minhu
authors.initials: M
authors.lastname: Chen
authors.affiliation: Department of Hepatobiliary Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China; Division of Interventional Ultrasound, Department of Medical Ultrasound, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China. Electronic address: kuangminda@hotmail.com.
authors.forename: Ming
authors.initials: M
authors.lastname: Kuang
mesh_terms: D000818:Animals; D000068258:Bevacizumab / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D001651:Cholestasis, Extrahepatic / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D020935:MAP Kinase Signaling System / Q000502:physiology; D051379:Mice; D011725:Pyridines / Q000494:pharmacology*; D040262:Receptors, Vascular Endothelial Growth Factor / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology*
chemical_list: D011725:Pyridines; D042461:Vascular Endothelial Growth Factor A; D000068258:Bevacizumab; C553458:apatinib; D040262:Receptors, Vascular Endothelial Growth Factor
keywords: Apatinib; Extrahepatic bile duct cancer; Proliferation; Targeted therapy; VEGFR