title: Roles of PI3K/Akt and c-Jun signaling pathways in human papillomavirus type 16 oncoprotein-induced HIF-1α, VEGF, and IL-8 expression and in vitro angiogenesis in non-small cell lung cancer cells.
abstract: OBJECTIVE
  Human papillomavirus (HPV)-16 infection may be related to non-smoking associated lung cancer. Our previous studies have found that HPV-16 oncoproteins promoted angiogenesis via enhancing hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), and interleukin-8 (IL-8) expression in non-small cell lung cancer (NSCLC) cells. In this study, we further investigated the roles of PI3K/Akt and c-Jun signaling pathways in it.
  
  
  METHODS
  Human NSCLC cell lines, A549 and NCI-H460, were stably transfected with pEGFP-16 E6 or E7 plasmids. Western blotting was performed to analyze the expression of HIF-1α, p-Akt, p-P70S6K, p-P85S6K, p-mTOR, p-JNK, and p-c-Jun proteins. VEGF and IL-8 protein secretion and mRNA levels were determined by ELISA and Real-time PCR, respectively. The in vitro angiogenesis was observed by human umbilical vein endothelial cells (HUVECs) tube formation assay. Co-immunoprecipitation was performed to analyze the interaction between c-Jun and HIF-1α.
  
  
  RESULTS
  HPV-16 E6 and E7 oncoproteins promoted the activation of Akt, P70S6K, P85S6K, mTOR, JNK, and c-Jun. LY294002, a PI3K inhibitor, inhibited HPV-16 oncoprotein-induced activation of Akt, P70S6K, and P85S6K, expression of HIF-1α, VEGF, and IL-8, and in vitro angiogenesis. c-Jun knockdown by specific siRNA abolished HPV-16 oncoprotein-induced HIF-1α, VEGF, and IL-8 expression and in vitro angiogenesis. Additionally, HPV-16 oncoproteins promoted HIF-1α protein stability via blocking proteasome degradation pathway, but c-Jun knockdown abrogated this effect. Furthermore, HPV-16 oncoproteins increased the quantity of c-Jun binding to HIF-1α.
  
  
  CONCLUSIONS
  PI3K/Akt signaling pathway and c-Jun are involved in HPV-16 oncoprotein-induced HIF-1α, VEGF, and IL-8 expression and in vitro angiogenesis. Moreover, HPV-16 oncoproteins promoted HIF-1α protein stability possibly through enhancing the interaction between c-Jun and HIF-1α, thus making a contribution to angiogenesis in NSCLC cells.
authors: Institute of Biochemistry and Molecular Biology, Guangdong Medical College, Zhanjiang, Guangdong, China; Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical College, Zhanjiang, Guangdong, China.
authors: Erying
authors: E
authors: Zhang
authors: Institute of Biochemistry and Molecular Biology, Guangdong Medical College, Zhanjiang, Guangdong, China; Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical College, Zhanjiang, Guangdong, China.
authors: Xiaowei
authors: X
authors: Feng
authors: Institute of Biochemistry and Molecular Biology, Guangdong Medical College, Zhanjiang, Guangdong, China; Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical College, Zhanjiang, Guangdong, China.
authors: Fei
authors: F
authors: Liu
authors: Institute of Plastic Surgery, Affiliated Hospital of Guangdong Medical College, Zhanjiang, Guangdong, China.
authors: Peihua
authors: P
authors: Zhang
authors: Institute of Plastic Surgery, Affiliated Hospital of Guangdong Medical College, Zhanjiang, Guangdong, China.
authors: Jie
authors: J
authors: Liang
authors: Institute of Biochemistry and Molecular Biology, Guangdong Medical College, Zhanjiang, Guangdong, China; Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Guangdong Medical College, Zhanjiang, Guangdong, China.
authors: Xudong
authors: X
authors: Tang
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000098:blood supply / Q000378:metabolism / Q000821:virology; D045744:Cell Line, Tumor; D002867:Chromones / Q000494:pharmacology; D016758:Genes, jun / Q000187:drug effects; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D066298:In Vitro Techniques; D016209:Interleukin-8 / Q000378:metabolism; D008175:Lung Neoplasms / Q000098:blood supply / Q000378:metabolism / Q000821:virology*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D009025:Morpholines / Q000494:pharmacology; D009389:Neovascularization, Pathologic / Q000378:metabolism* / Q000821:virology; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000378:metabolism*; D050725:Papillomavirus E7 Proteins / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A
chemical_list: D002867:Chromones; C068651:E6 protein, Human papillomavirus type 16; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D016209:Interleukin-8; C549075:LY 290042; D009025:Morpholines; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D012097:Repressor Proteins; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C059731:oncogene protein E7, Human papillomavirus type 16