title: Human papillomavirus 16 oncoprotein regulates the translocation of β-catenin via the activation of epidermal growth factor receptor.
abstract: BACKGROUND
  To understand the mechanism of frequent and early lymph node metastasis in high-risk human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC), this study investigated whether β-catenin is regulated by the HPV oncoprotein and contributes to OPSCC metastasis.
  
  
  METHODS
  Expression levels of p16, β-catenin, and epidermal growth factor receptor (EGFR) were examined in OPSCC samples (n = 208) by immunohistochemistry. The expression and subcellular localization of β-catenin and EGFR activation were also studied in HPV-positive and HPV-negative head and neck squamous cell carcinoma cell lines with western blot analysis. HPV16 E6 small interfering RNA was used to elucidate the effect of the HPV oncoprotein on β-catenin translocation. The involvement of EGFR in β-catenin translocation was confirmed by treatment with erlotinib. Moreover, the invasive capacity was evaluated after HPV16 E6/E7 repression.
  
  
  RESULTS
  The results showed that the membrane weighted index of β-catenin was inversely correlated with p16 positivity (P < .001) and lymph node metastasis (P = .026), whereas nuclear staining of β-catenin was associated with p16-positive OPSCC (P < .001). A low level of membrane β-catenin expression was significantly associated with disease-free and overall survival (P < .0001 in both cases). Furthermore, the membrane weighted index of EGFR was inversely correlated with p16 positivity (P < .001) and positively correlated with membrane β-catenin (P < .001). The in vitro study showed that HPV16 E6 repression led to reductions of phospho-EGFR and nuclear β-catenin, which were also observed after erlotinib treatment, and inhibition of invasion.
  
  
  CONCLUSIONS
  The findings suggest that HPV16 E6 mediates the translocation of β-catenin to the nucleus, which may be regulated by activated EGFR.
authors.affiliation: Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, Georgia; Department of Pathology, Xiangya Hospital, Central South University, Changsha, China; Department of Pathology, Xiangya Medical School, Central South University, Changsha, China.
authors.forename: Zhongliang
authors.initials: Z
authors.lastname: Hu
authors.forename: Susan
authors.initials: S
authors.lastname: Müller
authors.forename: Guoqing
authors.initials: G
authors.lastname: Qian
authors.forename: Jing
authors.initials: J
authors.lastname: Xu
authors.forename: Sungjin
authors.initials: S
authors.lastname: Kim
authors.forename: Zhengjia
authors.initials: Z
authors.lastname: Chen
authors.forename: Ning
authors.initials: N
authors.lastname: Jiang
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Wang
authors.forename: Hongzheng
authors.initials: H
authors.lastname: Zhang
authors.forename: Nabil F
authors.initials: NF
authors.lastname: Saba
authors.forename: Dong M
authors.initials: DM
authors.lastname: Shin
authors.forename: Zhuo Georgia
authors.initials: ZG
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000378:metabolism; D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D045744:Cell Line, Tumor; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000069347:Erlotinib Hydrochloride; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis / Q000235:genetics / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009856:Oncogene Proteins, Viral / Q000378:metabolism*; D009959:Oropharyngeal Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D050725:Papillomavirus E7 Proteins / Q000378:metabolism*; D011237:Predictive Value of Tests; D011379:Prognosis; D011799:Quinazolines / Q000627:therapeutic use; D034741:RNA, Small Interfering / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014178:Translocation, Genetic; D051176:beta Catenin / Q000032:analysis / Q000235:genetics* / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; C068651:E6 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D011799:Quinazolines; D034741:RNA, Small Interfering; D012097:Repressor Proteins; D051176:beta Catenin; C059731:oncogene protein E7, Human papillomavirus type 16; D000069347:Erlotinib Hydrochloride; D066246:ErbB Receptors
keywords: epidermal growth factor receptor (EGFR); human papillomavirus 16 (HPV); lymph node metastasis; oropharyngeal squamous cell carcinoma; β-catenin