title: Individual and Complementary Effects of Human Papillomavirus Oncogenes on Epithelial Cell Proliferation and Differentiation.
abstract: Previous studies on human papillomavirus (HPV) type 16 protein functions have established the oncogenic nature of three viral proteins: E5, E6 and E7. Here we have studied the functions of these proteins by functional deletion of the individual E5, E6 or E7, or both E6 and E7 oncogenes in the context of the whole viral genome. These mutants, or the intact wild-type genome, were expressed from the natural viral promoters along with differentiation of epithelial HaCaT cells in three-dimensional collagen raft cultures. High episomal viral copy numbers were obtained using a transfection-based loxp-HPV16-eGFP-N1 vector system. All epithelial equivalents carrying the different HPV type 16 genomes showed pronounced hyperplastic and dysplastic morphology. Particularly the E7 oncogene, with contribution of E6, was shown to enhance cell proliferation. Specifically, the crucial role of E7 in HPV-associated hyperproliferation was clearly manifested. Based on morphological characteristics, immunohistochemical staining for differentiation and proliferation markers, and low expression of E1^E4, we propose that our raft culture models produce cervical intraepithelial neoplasia (CIN)1 and CIN2-like tissue. Our experimental setting provides an alternative tool to study concerted functions of HPV proteins in the development of epithelial dysplasia.
authors.affiliation: Research Program in Infection and Cancer, Deutsches Krebsforschungszentrum, Heidelberg, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Bergner
authors.forename: Gordana
authors.initials: G
authors.lastname: Halec
authors.forename: Markus
authors.initials: M
authors.lastname: Schmitt
authors.forename: François
authors.initials: F
authors.lastname: Aubin
authors.forename: Angel
authors.initials: A
authors.lastname: Alonso
authors.forename: Eeva
authors.initials: E
authors.lastname: Auvinen
mesh_terms: D018929:Cell Culture Techniques; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism / Q000473:pathology* / Q000821:virology*; D016679:Genome, Viral; D052162:Human papillomavirus 16 / Q000235:genetics*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics; D009154:Mutation; D009856:Oncogene Proteins, Viral / Q000235:genetics*; D050725:Papillomavirus E7 Proteins / Q000235:genetics; D030361:Papillomavirus Infections / Q000235:genetics* / Q000473:pathology*; D012097:Repressor Proteins / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000235:genetics; D000086082:Viroporin Proteins
chemical_list: D008565:Membrane Proteins; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D012097:Repressor Proteins; D016159:Tumor Suppressor Protein p53; C081876:CKAP4 protein, human; C068651:E6 protein, Human papillomavirus type 16; C054859:oncogene protein E5, Human papillomavirus type 16; D000086082:Viroporin Proteins