title: Transcriptional gene silencing of HPV16 E6/E7 induces growth inhibition via apoptosis in vitro and in vivo.
abstract: OBJECTIVE
  Transcriptional silencing of HPV oncogenes using short interfering RNA (siRNA) blocks E6/E7 expression. Our objective was to estimate the effective value of E6/E7 specific siRNA-induced transcriptional gene silencing as a potential therapeutic strategy for cervical cancer.
  
  
  METHODS
  In vitro studies were performed by employing two categories of siRNA targeting promoter of E6/E7 gene and E7 transcript, respectively, and inhibitory effect of both siRNAs was further observed in vitro and on xenograft in BALB/c mice that were inoculated with siRNA transfected SiHa cells and parental SiHa cells followed by siRNA intratumoral injection in vivo. Tumor volume and growth curves were assessed. Furthermore, cellular proliferation and apoptosis of inoculated tumors were determined by immunohistochemistry staining and TUNEL assay.
  
  
  RESULTS
  The two most active siRNA sequences specifically knockdown E6/E7 expressions at mRNA level in HPV16 positive Siha cells, increased p53 and decreased p16 expressions at protein level, inhibited cell proliferation, and induced cell apoptosis in vitro. Furthermore, both siRNAs effectively inhibited tumor formation and growth no matter in mice with siRNA transfected cells in vitro or with siRNA intratumoral injection in vivo. TUNEL staining and FCM assay consistently showed that tumor retardation was through induction of cellular apoptosis.
  
  
  CONCLUSIONS
  RNAi targeting the promoter of HPV16 E6/E7 acts effectively in vitro and in vivo, especially through intratumoral delivery, and may be a candidate therapeutic strategy for cervical cancer.
authors: Women's Reproductive Health Laboratory of Zhejiang Province, China.
authors: Jiansong
authors: J
authors: Zhou
authors: Chanjuan
authors: C
authors: Peng
authors: Baohua
authors: B
authors: Li
authors: Fenfen
authors: F
authors: Wang
authors: Caiyun
authors: C
authors: Zhou
authors: Die
authors: D
authors: Hong
authors: Feng
authors: F
authors: Ye
authors: Xiaodong
authors: X
authors: Cheng
authors: Weiguo
authors: W
authors: Lü
authors: Xing
authors: X
authors: Xie
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000473:pathology / Q000628:therapy / Q000821:virology; D045744:Cell Line, Tumor; D019941:Cyclin-Dependent Kinase Inhibitor p16; D005260:Female; D055785:Gene Knockdown Techniques; D020868:Gene Silencing; D052162:Human papillomavirus 16 / Q000235:genetics; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics; D009856:Oncogene Proteins, Viral / Q000096:biosynthesis / Q000235:genetics*; D050725:Papillomavirus E7 Proteins / Q000096:biosynthesis / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics*; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000235:genetics; D002583:Uterine Cervical Neoplasms / Q000235:genetics* / Q000473:pathology / Q000628:therapy / Q000821:virology; D023041:Xenograft Model Antitumor Assays
chemical_list: C000614131:CDKN2A protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16; C068651:E6 protein, Human papillomavirus type 16; D009363:Neoplasm Proteins; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D012097:Repressor Proteins; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C059731:oncogene protein E7, Human papillomavirus type 16