title: Influence of physiologic folate deficiency on human papillomavirus type 16 (HPV16)-harboring human keratinocytes in vitro and in vivo.
abstract: Although HPV16 transforms infected epithelial tissues to cancer in the presence of several co-factors, there is insufficient molecular evidence that poor nutrition has any such role. Because physiological folate deficiency led to the intracellular homocysteinylation of heterogeneous nuclear ribonucleoprotein E1 (hnRNP-E1) and activated a nutrition-sensitive (homocysteine-responsive) posttranscriptional RNA operon that included interaction with HPV16 L2 mRNA, we investigated the functional consequences of folate deficiency on HPV16 in immortalized HPV16-harboring human (BC-1-Ep/SL) keratinocytes and HPV16-organotypic rafts. Although homocysteinylated hnRNP-E1 interacted with HPV16 L2 mRNA cis-element, it also specifically bound another HPV16 57-nucleotide poly(U)-rich cis-element in the early polyadenylation element (upstream of L2L1 genes) with greater affinity. Together, these interactions led to a profound reduction of both L1 and L2 mRNA and proteins without effects on HPV16 E6 and E7 in vitro, and in cultured keratinocyte monolayers and HPV16-low folate-organotypic rafts developed in physiological low folate medium. In addition, HPV16-low folate-organotypic rafts contained fewer HPV16 viral particles, a similar HPV16 DNA viral load, and a much greater extent of integration of HPV16 DNA into genomic DNA when compared with HPV16-high folate-organotypic rafts. Subcutaneous implantation of 18-day old HPV16-low folate-organotypic rafts into folate-replete immunodeficient mice transformed this benign keratinocyte-derived raft tissue into an aggressive HPV16-induced cancer within 12 weeks. Collectively, these studies establish a likely molecular linkage between poor folate nutrition and HPV16 and predict that nutritional folate and/or vitamin-B(12) deficiency, which are both common worldwide, will alter the natural history of HPV16 infections and also warrant serious consideration as reversible co-factors in oncogenic transformation of HPV16-infected tissues to cancer.
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202-5254, USA.
authors.forename: Suhong
authors.initials: S
authors.lastname: Xiao
authors.forename: Ying-Sheng
authors.initials: YS
authors.lastname: Tang
authors.forename: Rehana A
authors.initials: RA
authors.lastname: Khan
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Zhang
authors.forename: Praveen
authors.initials: P
authors.lastname: Kusumanchi
authors.forename: Sally P
authors.initials: SP
authors.lastname: Stabler
authors.forename: Hiremagalur N
authors.initials: HN
authors.lastname: Jayaram
authors.forename: Asok C
authors.initials: AC
authors.lastname: Antony
mesh_terms: D000818:Animals; D001483:Base Sequence; D036022:Capsid Proteins / Q000235:genetics / Q000378:metabolism; D002374:Catalase / Q000096:biosynthesis / Q000235:genetics; D018929:Cell Culture Techniques; D049109:Cell Proliferation; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D004268:DNA-Binding Proteins; D005260:Female; D005492:Folic Acid / Q000378:metabolism; D005494:Folic Acid Deficiency; D017930:Genes, Reporter; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006710:Homocysteine / Q000737:chemistry / Q000378:metabolism; D054884:Host-Pathogen Interactions; D052162:Human papillomavirus 16 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism / Q000637:transplantation / Q000821:virology*; D051379:Mice; D008819:Mice, Nude; D008969:Molecular Sequence Data; D009374:Neoplasms, Experimental / Q000473:pathology / Q000821:virology*; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000378:metabolism; D030361:Papillomavirus Infections / Q000821:virology*; D011485:Protein Binding; D059748:Proteolysis; D012333:RNA, Messenger / Q000096:biosynthesis / Q000737:chemistry; D012367:RNA, Viral / Q000737:chemistry / Q000378:metabolism; D016601:RNA-Binding Proteins; D013438:Sulfhydryl Compounds / Q000378:metabolism; D047368:Tumor Burden; D016662:Virus Integration
chemical_list: D036022:Capsid Proteins; D004268:DNA-Binding Proteins; D034441:Heterogeneous-Nuclear Ribonucleoproteins; C063316:L2 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; C094604:PCBP1 protein, human; D012333:RNA, Messenger; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D013438:Sulfhydryl Compounds; D006710:Homocysteine; C063317:L1 protein, Human papillomavirus type 16; D005492:Folic Acid; D002374:Catalase