title: Molecular genetic characterization of p53 mutated oropharyngeal squamous cell carcinoma cells transformed with human papillomavirus E6 and E7 oncogenes.
abstract: Patients with HPV-positive oropharyngeal cancer show better tumor response to radiation or chemotherapy than patients with HPV-negative cancer. HPV oncoprotein E6 binds and degrades a typically wild-type p53 protein product. However, HPV16 infection and p53 mutation infrequently coexist in a subset of HNSCCs. The purpose of this study was to investigate the mechanisms through which tumor biology and molecular genetic mechanisms change when two HPV-negative, p53-mutated oropharyngeal cell lines (YD8, non-disruptive p53 mutation; YD10B, disruptive p53 mutation) derived from patients with a history of heavy smoking are transfected with HPV E6 and E7 oncogenes in vitro. Transfection with HPV E6 and E7 oncogenes in YD8, reduced the abundance of proteins encoded by tumor suppressor genes, such as p-p53 and p-Rb. Cell proliferative activity was increased in the cells transfected with E6E7 compared to cells transfected with vector alone (P=0.09), whereas the invasiveness of E6E7-transfected cells was significantly reduced (P=0.02). cDNA microarray of the transfected cells with E6E7 showed significant changes in mRNA expression in several signaling pathways, including focal adhesion, JAK-STAT signaling pathway, cell cycle and p53 signaling pathway. Regarding the qPCR array for the p53 signaling pathway, the mRNA expression of STAT1 was remarkably upregulated by 6.47-fold (P<0.05); in contrast, IGF-1R was significantly downregulated by 2.40-fold in the YD8-vector compared toYD8-E6E7 (P<0.01). Finally, data collected from these two array experiments enabled us to select two genes, STAT1 and IGF-1R, for further study. In immunohistochemical study, nuclear STAT1 expression was slightly higher in HPV-positive compared to HPV-negative oropharyngeal tumors (P=0.18); however, cytoplasmic STAT1 was significantly lower in HPV-positive cases (P=0.03). IGF-1R expression levels were remarkably lower in HPV-positive compared to HPV-negative cases (P=0.01). Our data suggest that upregulated STAT1 and interferon signals by HPV16 E6 and E7 genes may play a major role in the relatively favorable prognosis for HPV-positive oropharyngeal squamous cell carcinoma cases with non-disruptive p53 mutations.
authors.affiliation: Laboratory of Medical Oncology, Research Institutes of Medical Science, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Ji-Eun
authors.initials: JE
authors.lastname: Oh
authors.forename: Jeong-Oh
authors.initials: JO
authors.lastname: Kim
authors.forename: Jung-Young
authors.initials: JY
authors.lastname: Shin
authors.forename: Xiang-Hua
authors.initials: XH
authors.lastname: Zhang
authors.forename: Hye-Sung
authors.initials: HS
authors.lastname: Won
authors.forename: Sang-Hoon
authors.initials: SH
authors.lastname: Chun
authors.forename: Chan-Kwon
authors.initials: CK
authors.lastname: Jung
authors.forename: Won-Sang
authors.initials: WS
authors.lastname: Park
authors.forename: Suk-Woo
authors.initials: SW
authors.lastname: Nam
authors.forename: Jung-Woo
authors.initials: JW
authors.lastname: Eun
authors.forename: Jin-Hyoung
authors.initials: JH
authors.lastname: Kang
mesh_terms: D017209:Apoptosis; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000378:metabolism / Q000821:virology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002472:Cell Transformation, Viral / Q000235:genetics*; D022001:Focal Adhesions / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D052162:Human papillomavirus 16 / Q000235:genetics; D006801:Humans; D053612:Janus Kinases / Q000378:metabolism; D009361:Neoplasm Invasiveness; D009856:Oncogene Proteins, Viral / Q000235:genetics*; D009959:Oropharyngeal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000821:virology; D050725:Papillomavirus E7 Proteins / Q000235:genetics*; D030361:Papillomavirus Infections / Q000235:genetics / Q000821:virology; D012333:RNA, Messenger / Q000096:biosynthesis; D017526:Receptor, IGF Type 1 / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics*; D050794:STAT1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*
chemical_list: C068651:E6 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D016159:Tumor Suppressor Protein p53; D017526:Receptor, IGF Type 1; D053612:Janus Kinases