title: RNA interference of human papillomavirus type 16 E7 increases HLA class I antigen expression in HaCaT-E7 cells.
abstract: BACKGROUND
  High-risk human papillomaviruses (HPVs) are the major causative agents of cervical cancer. The E7 protein of high-risk HPV disturbs cell cycle control and down-regulates components of the antigen presentation pathway, suggesting an ideal target for development of the immunotherapy in HPV-positive cervical cancers. We previously reported that HPV16 E7 could down-regulate cell-surface HLA class I antigen accompanying decreased expression of transporter associated with antigen processing 1 (TAP-1). The purpose of this study was to determine whether knockdown of HPV16 E7 could up-regulate surface HLA class I antigen expression in HPV16 E7 expressing HaCaT cells (HaCaT-E7).
  
  
  METHODS
  An E7-specific small interfering RNA (siRNA) was transfected into the HaCaT-E7 cells, and the expression of HPV16 E7 was measured by real-time reverse transcriptase polymerase chain reaction and Western blot. With the use of flow cytometry analysis, the levels of cell surface HLA class I antigen and intracellular TAP-1 expression were detected.
  
  
  RESULTS
  It was found that transfection of HPV16 E7-siRNA reduced HPV16 E7 expression as measured on messenger RNA and protein levels. The flow cytometry analysis showed that, compared with mock transfection, a statistically significant increase of approximately 75% in surface HLA class I levels was observed in HaCaT-E7 cells at 72 hours after transfection of E7 siRNA. Moreover, he knockdown of E7 in HaCaT-E7 cells could result in an increase of intracellular TAP-1 expression, which is essential for the expression of HLA class I at cell surface.
  
  
  CONCLUSIONS
  Our study showed that the knockdown of HPV16 E7 could increase cell surface HLA class I antigen expression in HaCaT-E7 cells. In addition, for HPV-positive human cervical cancer, our observations indicate that the HPV E7 gene is a target of choice.
authors.affiliation: Department of Clinical Laboratory, Qilu Hospital, Shandong University, Jinan, China.
authors.forename: Xiao-Mei
authors.initials: XM
authors.lastname: Deng
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhang
authors.forename: Chuan-Xin
authors.initials: CX
authors.lastname: Wang
authors.forename: Zhao-Gang
authors.initials: ZG
authors.lastname: Dong
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Gui-Xi
authors.initials: GX
authors.lastname: Zheng
authors.forename: Xu-Hua
authors.initials: XH
authors.lastname: Zhang
authors.forename: Ni
authors.initials: N
authors.lastname: Zheng
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Wang
authors.forename: Lu-Tao
authors.initials: LT
authors.lastname: Du
authors.forename: Shun
authors.initials: S
authors.lastname: Wang
mesh_terms: D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D045744:Cell Line, Tumor; D055785:Gene Knockdown Techniques; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000378:metabolism*; D052162:Human papillomavirus 16 / Q000235:genetics*; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism*; D050725:Papillomavirus E7 Proteins / Q000235:genetics* / Q000378:metabolism*; D030361:Papillomavirus Infections / Q000235:genetics*; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000493:pharmacokinetics*; D014162:Transfection; D015854:Up-Regulation
chemical_list: D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters; D000199:Actins; D015395:Histocompatibility Antigens Class I; D050725:Papillomavirus E7 Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C073119:TAP1 protein, human; C059731:oncogene protein E7, Human papillomavirus type 16