transforming-growth-factor-alpha and Papillomavirus-Infections

Human papillomaviruses (HPV) are causative agents of various tumours such as cervical cancer. HPV binding to the cell surface of keratinocytes leads to virus endocytosis at tetraspanin enriched microdomains. Complex interactions of the capsid proteins with host proteins as well as ADAM17-dependent ERK1/2 signal transduction enable the entry platform assembly of the oncogenic HPV type 16. Here, we studied the importance of tetraspanin CD9, also known as TSPAN29, in HPV16 infection of different epithelial cells. We found that both overexpression and loss of the tetraspanin decreased infection rates in cells with low endogenous CD9 levels, while reduction of CD9 expression in keratinocytes that exhibit high-CD9 protein amounts, led to an increase of infection. Therefore, we concluded that low-CD9 supports infection. Moreover, we found that changes in CD9 amounts affect the shedding of the ADAM17 substrate transforming growth factor alpha (TGFα) and the downstream phosphorylation of ERK. These effects correlate with those on infection rates suggesting that a specific CD9 optimum promotes ADAM17 activity, ERK signalling and virus infection. Together, our findings implicate that CD9 regulates HPV16 infection through the modulation of ADAM17 sheddase activity.

Topics: ADAM17 Protein; Endocytosis; Gene Expression Regulation; Gene Knockdown Techniques; HaCaT Cells; HeLa Cells; Human papillomavirus 16; Humans; Keratinocytes; MAP Kinase Signaling System; Papillomavirus Infections; Tetraspanin 29; Transforming Growth Factor alpha; Virus Internalization

Human papillomavirus (HPV)-positive and HPV-negative oropharyngeal squamous cell carcinomas (OSCCs) are two distinct entities. We defined the molecular profiles of druggable receptor tyrosine kinases (RTKs) in both groups.. E5 expression and RTK alterations were studied in 17 HPV-positive and 59 HPV-negative formalin-fixed OSCCs. RTK activation was explored in further 12 frozen OSCCs.. The HPV-positive OSCCs showed E5 expression and 33.3% expressed low level of HER2. The HPV-negative OSCCs showed HER2 expression (31.2%), increased HER2 gene copy number (46.51%, P = 0.045) and HER2 activation through HER2/EGFR heterodimerisation; HER3 (51.06%, P = 0.008) and neuregulin (65.63%; P = 0.03) expression, HER3 activation and HER3/EGFR heterodimerisation; and increased IGF-1R copy number (40.50%, P = 0.021), high IGF-1R cDNA values (P = 0.002), IGF-1R activation and expression of IGF1/2 and amphiregulin. PI3KCA mutations/expression/increased gene copy number and PTEN mutations were found in both groups, whereas PTEN gene loss was only observed in the HPV-positive cases.. Human papillomavirus-positive and HPV-negative OSCC showed different RTK profiles. In HPV-positive cases, it would be interesting to study the expression of E5, which may modulate EGFR turnover and activate VEGF and PDGFRβ. In HPV-negative cases, HER3 may be a promising druggable biomarker that deserves further investigation. PI3KCA and PTEN alterations encourage the promising clinical evaluation of PI3K/mTOR inhibitor activity in OSCC, particularly in HPV-positive/PI3KCA-mutated OSCCs because they may be driven by PI3KCA mutation alone.

Topics: Amphiregulin; Biomarkers, Tumor; Carcinoma, Squamous Cell; Humans; Mouth Neoplasms; Mutation; Oropharyngeal Neoplasms; Papillomaviridae; Papillomavirus Infections; Peptide Fragments; Phosphatidylinositol 3-Kinases; PTEN Phosphohydrolase; Real-Time Polymerase Chain Reaction; Receptor Protein-Tyrosine Kinases; Receptor, ErbB-2; Transforming Growth Factor alpha

Epithelial growth factor receptor (EGFR) sends signals to the proliferation signal transduction system, receiving two ligands: epithelial growth factor (EGF) and transforming growth factor-alpha (TGF-alpha). This immunohistochemical study examined the roles of EGFR and its ligands in the proliferation of normal and neoplastic vulvar squamous cells in 25 patients with vulvar squamous cell carcinoma (VSCC), 10 patients with vulvar condyloma acuminata (VCA), 15 patients with vulvar intra-epithelial neoplasm I-II or III (VIN I-II or III), and 5 subjects with vulvar normal squamous cells (VNSC). EGFR was detected in a few basal cells in 40% of the VNSC, in highly dysplastic cells in 40% of the VIN III, in many neoplastic cells in 80% of the VCA, and in some malignant cells in 64% of the VSCC. EGF was seen in the cytoplasm in 20% of the VIN I-II, 100% of the VIN III, 100% of the VCA, and 100% of the VSCC. Diffuse TGF-alpha was weakly expressed in the cytoplasm in 100% of the VNSC, more intensely in 100% of the VIN and 100% of the VCA, and intensely in 100% of the VSCC. These findings led to the suggestion that the TGF-alpha-EGFR system maintains the growth of normal squamous cells and, in part, maintains the growth of dysplastic and neoplastic squamous cells in the vulva. EGF expression was an early sign of neoplasia. The expression of EGFR with overexpression of its two ligands contributed to the proliferation of dysplastic and neoplastic squamous cells in VIN III and VCA. EGFR expression appeared to contribute to essential neoplastic abnormalities in 64% of the VSCC.

Topics: Carcinoma in Situ; Carcinoma, Squamous Cell; Condylomata Acuminata; DNA, Viral; Epidermal Growth Factor; ErbB Receptors; Female; Humans; Immunohistochemistry; Ligands; Papillomaviridae; Papillomavirus Infections; Transforming Growth Factor alpha; Tumor Virus Infections; Vulva; Vulvar Neoplasms

Like other types of pre-malignant lesions and carcinoma, angiogenesis is associated with high-grade cervical dysplasia and with invasive squamous carcinoma of the cervix. Vascular endothelial cell growth factor (VEGF) is known to be one of the most important inducers of angiogenesis and is upregulated in carcinoma of the cervix. Human Papilloma Virus 16 (HPV-16) has been etiologically linked to human cervical cancer, and the major oncogenic proteins encoded by the viral genome, E6 and E7, are involved in the immortalization of target cells. Because several oncogenes including mutant ras, EGF receptor, ErbB2/Her2, c-myc and v-src upregulate VEGF expression, we asked whether HVP-16 E6 oncoprotein could act in a similar fashion. We found that HPV-16 E6-positive cells generally express high levels of VEGF message. Furthermore, co-expression of the VEGF promoter-Luc (luciferase) reporter gene with E6 in both human keratinocytes and mouse fibroblast showed that E6 oncoprotein upregulates VEGF promoter activity, and does so in a p53 independent manner. An E6 responsive region which comprises four Sp-1 sites, between -194 and -50 bp of the VEGF promoter, is also necessary for constitutive VEGF transcription. Taken together, our results suggest the possibility that the HPV oncoprotein E6 may contribute to tumor angiogenesis by direct stimulation of the VEGF gene.

Topics: Autocrine Communication; Carcinoma, Squamous Cell; Endothelial Growth Factors; ErbB Receptors; Female; Genes, p53; HeLa Cells; Humans; Keratinocytes; Lymphokines; Neoplasm Proteins; Neovascularization, Pathologic; Oncogene Proteins, Viral; Papillomaviridae; Papillomavirus Infections; Promoter Regions, Genetic; Recombinant Fusion Proteins; Repressor Proteins; Transcription, Genetic; Transcriptional Activation; Transforming Growth Factor alpha; Tumor Cells, Cultured; Tumor Suppressor Protein p53; Tumor Virus Infections; Uterine Cervical Neoplasms; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors; Vulvar Neoplasms