title: Activities of E6 Protein of Human Papillomavirus 16 Asian Variant on miR-21 Up-regulation and Expression of Human Immune Response Genes.
abstract: BACKGROUND
  Variants of human papillomavirus (HPV) show more oncogenicity than do prototypes. The HPV16 Asian variant (HPV16As) plays a major role in cervical cancer of Asian populations. Some amino acid changes in the E6 protein of HPV16 variants affect E6 functions such as p53 interaction and host immune surveillance. This study aimed to investigate activities of HPV16As E6 protein on modulation of expression of miRNA-21 as well as interferon regulatory factors (IRFs) 1, 3, 7 and c-fos.
  
  
  METHODS
  Vectors expressing E6 protein of HPV16As (E6D25E) or HPV16 prototype (E6Pro) were constructed and transfected into C33A cells. HCK1T cells expressing E6D25E or E6Pro were established by transducing retrovirus-containing E6D25E or 16E6Pro. The E6AP-binding activity of E6 and proliferation of the transfected C33A cells were determined. MiR-21 and mRNA of interesting genes were detected in the transfected C33A cells and/or the HCK1T cells, with or without treatment by culture medium from HeLa cells (HeLa-CM).
  
  
  RESULTS
  E6D25E showed binding activity with E6AP similar to that of E6Pro. Interestingly, E6D25E showed a higher activity of miR-21 induction than did E6Pro in C33A cells expressing E6 protein. This result was similar to the HCK1T cells expressing E6 protein, with HeLa-CM treatment. The miR-21 up-regulation significantly corresponded to its target expression. Different levels of expression of IRFs were also observed in the HCK1T cells expressing E6 protein. Interestingly, when treated with HeLa-CM, IRFs 1, 3 and 7 as well as c-fos were significantly suppressed in the HCK1T cells expressing E6D25E, whereas those in the HCK1T cells expressing E6Pro were induced. A similar situation was seen for IFN-α and IFN-β.
  
  
  CONCLUSIONS
  E6D25E of the HPV16As variant differed from the E6 prototype in its activities on epigenetic modulation and immune surveillance and this might be a key factor for the important role of this variant in cervical cancer progression.
authors.affiliation: Department of Microbiology, Faculty of Medicine, 3HPV and EBV and Carcinogenesis Research Group, Khon Kaen University, Khon Kaen, Thailand E-mail : tipeka@kku.ac.th.
authors.forename: Peechanika
authors.initials: P
authors.lastname: Chopjitt
authors.forename: Chamsai
authors.initials: C
authors.lastname: Pientong
authors.forename: Sureewan
authors.initials: S
authors.lastname: Bumrungthai
authors.forename: Bunkerd
authors.initials: B
authors.lastname: Kongyingyoes
authors.forename: Tipaya
authors.initials: T
authors.lastname: Ekalaksananan
mesh_terms: D015153:Blotting, Western; D002453:Cell Cycle; D049109:Cell Proliferation; D005260:Female; D006367:HeLa Cells; D006801:Humans; D050856:Interferon Regulatory Factor-1 / Q000235:genetics / Q000378:metabolism*; D050838:Interferon Regulatory Factor-3 / Q000235:genetics / Q000378:metabolism*; D050839:Interferon Regulatory Factor-7 / Q000235:genetics / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics*; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D015854:Up-Regulation; D002583:Uterine Cervical Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
chemical_list: C068651:E6 protein, Human papillomavirus type 16; C494232:IRF3 protein, human; D050856:Interferon Regulatory Factor-1; D050838:Interferon Regulatory Factor-3; D050839:Interferon Regulatory Factor-7; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D009856:Oncogene Proteins, Viral; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D012097:Repressor Proteins