title: (-)-Epigallocatechin-3-gallate inhibits human papillomavirus (HPV)-16 oncoprotein-induced angiogenesis in non-small cell lung cancer cells by targeting HIF-1α.
abstract: OBJECTIVE
  To investigate the effects of (-)-epigallocatechin-3-gallate (EGCG) on human papillomavirus (HPV)-16 oncoprotein-induced angiogenesis in non-small cell lung cancer (NSCLC) cells and the underlying mechanisms.
  
  
  METHODS
  NSCLC cells (A549 and NCI-H460) transfected with EGFP plasmids containing HPV-16 E6 or E7 oncogene were treated with different concentrations of EGCG for 16 h. The effects of EGCG on angiogenesis in vitro and in vivo were observed. The expression of HIF-1α, p-Akt, and p-ERK1/2 proteins in NSCLC cells was analyzed by Western blot. The levels of HIF-1α mRNA in NSCLC cells were detected by real-time RT-PCR. The concentration of VEGF and IL-8 in the conditioned media was determined by ELISA. HIF-1α, VEGF, and CD31 expression in A549 xenografted tumors of nude mice was analyzed by immunohistochemistry.
  
  
  RESULTS
  HPV-16 E6 and E7 oncoproteins HIF-1α-dependently promoted angiogenesis in vitro and in vivo, which was inhibited by EGCG. Mechanistically, EGCG inhibited HPV-16 oncoprotein-induced HIF-1α protein expression but had no effect on HIF-1α mRNA expression in NSCLC cells. Additionally, 50 and 100 μmol/L of EGCG significantly reduced the secretion of VEGF and IL-8 proteins induced by HPV-16 E7 oncoprotein in NSCLC A549 cells. Meanwhile, HPV-16 E6 and E7 oncoproteins HIF-1α-dependently enhanced Akt activation in A549 cells, which was suppressed by EGCG. Furthermore, EGCG inhibited HPV-16 oncoprotein-induced HIF-1α and HIF-1α-dependent VEGF and CD31 expression in A549 xenografted tumors.
  
  
  CONCLUSIONS
  EGCG inhibited HPV-16 oncoprotein-induced angiogenesis conferred by NSCLC through the inhibition of HIF-1α protein expression and HIF-1α-dependent expression of VEGF, IL-8, and CD31 as well as activation of Akt, suggesting that HIF-1α may be a potential target of EGCG against HPV-related NSCLC angiogenesis.
authors.affiliation: Institute of Biochemistry and Molecular Biology, Guangdong Medical College, 2 Wenming Donglu, Xiashan, Zhanjiang 524023, Guangdong, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: He
authors.forename: Erying
authors.initials: E
authors.lastname: Zhang
authors.forename: Jingli
authors.initials: J
authors.lastname: Shi
authors.forename: Xiangyong
authors.initials: X
authors.lastname: Li
authors.forename: Keyuan
authors.initials: K
authors.lastname: Zhou
authors.forename: Qunzhou
authors.initials: Q
authors.lastname: Zhang
authors.forename: Anh D
authors.initials: AD
authors.lastname: Le
authors.forename: Xudong
authors.initials: X
authors.lastname: Tang
mesh_terms: D020533:Angiogenesis Inhibitors; D000818:Animals; D015153:Blotting, Western; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy* / Q000473:pathology; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D045744:Cell Line, Tumor; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression / Q000187:drug effects; D052162:Human papillomavirus 16 / Q000187:drug effects*; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000096:biosynthesis / Q000187:drug effects*; D016209:Interleukin-8 / Q000096:biosynthesis; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009389:Neovascularization, Pathologic / Q000139:chemically induced* / Q000517:prevention & control*; D015513:Oncogene Proteins / Q000187:drug effects*; D009856:Oncogene Proteins, Viral / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D050725:Papillomavirus E7 Proteins / Q000037:antagonists & inhibitors*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000096:biosynthesis; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012097:Repressor Proteins / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis
chemical_list: D020533:Angiogenesis Inhibitors; C068651:E6 protein, Human papillomavirus type 16; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D016209:Interleukin-8; D015513:Oncogene Proteins; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D012097:Repressor Proteins; D042461:Vascular Endothelial Growth Factor A; C059731:oncogene protein E7, Human papillomavirus type 16; D002392:Catechin; C045651:epigallocatechin gallate; D051057:Proto-Oncogene Proteins c-akt