Human Papillomavirus 16 E7 Promotes EGFR/PI3K/AKT1/NRF2 Signaling Pathway Contributing to PIR/NF-κB Activation in Oral Cancer Cells.

A subset of oral carcinomas is etiologically related to high-risk human papillomavirus (HR-HPV) infection, with HPV16 being the most frequent HR-HPV type found in these carcinomas. The oncogenic role of HR-HPV is strongly dependent on the overexpression of E6 and E7 oncoproteins, which, in turn, induce p53 and pRb degradation, respectively. Additionally, it has been suggested that HR-HPV oncoproteins are involved in the regulation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), inducing cancer progression and metastasis. Previously, we reported that HPV16 E7 oncoprotein promotes Pirin upregulation resulting in increased epithelial-mesenchymal transition (EMT) and cell migration, with Pirin being an oxidative stress sensor and activator of NF-κB. In this study, we demonstrate the mechanism by which HPV16 E7-mediated Pirin overexpression occurs by promoting EGFR/PI3K/AKT1/NRF2 signaling, thus causing PIR/NF-κB activation in oral tumor cells. Our results demonstrate a new mechanism by which E7 contributes to oral cancer progression, proposing PIR as a potential new therapeutic target.

HPV-Mediated Resistance to TNF and TRAIL Is Characterized by Global Alterations in Apoptosis Regulatory Factors, Dysregulation of Death Receptors, and Induction of ROS/RNS.

Persistent infection with high-risk human papilloma virus (HR-HPV) is the main risk factor for the development of invasive cervical cancer although is not sufficient to cause cervical cancer. Several host and environmental factors play a key role in cancer initiation/progression, including cytokines and other immune-response mediators. Here, we characterized the response to the individual and combined action of the pro-inflammatory cytokines tumor necrosis factor (TNF) and TNF-related apoptosis-inducing ligand (TRAIL) on HPV-transformed cells and human keratinocytes ectopically expressing E6 and E7 early proteins from different HPV types. We showed that keratinocytes expressing HPV early proteins exhibited global alterations in the expression of proteins involved in apoptosis regulation/execution, including TNF and TRAIL receptors. Besides, we provided evidence that TNF receptor 1 (TNFR1) was down-regulated and may be retained in the cytoplasm of keratinocytes expressing HPV16 oncoproteins. Finally, fluorescence analysis demonstrated that cytokine treatment induced the production and release of reactive oxygen and nitrogen species (ROS/RNS) in cells expressing HPV oncogenes. Alterations in ROS/RNS production and apoptosis regulatory factors expression in response to inflammatory mediators may favor the accumulation of genetic alterations in HPV-infected cells. Altogether, our results suggested that these events may contribute to lesion progression and cancer onset.

Co-infection of sexually transmitted pathogens and Human Papillomavirus in cervical samples of women of Brazil.

BACKGROUND: Some sexually transmitted infectious agents, such as Chlamydia trachomatis and Herpes simplex, cause local inflammation, and could contribute to Human Papillomavirus (HPV) and cervical lesion progression. Thus, the aim of this study was to determine any association between the presence of microorganisms of gynecological importance, sexual behavior, clinical and demographical variables to the development and progress of cervical lesions. METHODS: One hundred and thirty-two women between 14 and 78 years and living at Vitória da Conquista, Bahia, Brazil, were included (62 individuals with cervical lesions and 70 without lesions). They answered a questionnaire to provide data for a socioeconomic and sexual activity profile. Samples of cervical swabs were collected and analyzed by PCR to detect genital microorganisms and HPV. Quantitative PCR was used to detect and quantify Ureaplasma urealyticum and Ureaplasma parvum. Univariate and multiple logistic regression were performed to measure the association with the cervical lesions, and an odds ratio (OR) with 95% confidence intervals (95%CI) were calculated. The Mann-Whitney U test was also used to compare the microorganism load in the case and control groups. The significance level was 5% in all hypotheses tested. RESULTS: Cervical lesions were associated with: women in a stable sexual relationship (OR = 14.21, 95%CI = 3.67-55.018), positive PCR for HPV (OR = 16.81, 95%CI = 4.19-67.42), Trichomonas vaginalis (OR = 8.566, 95%CI = 2.04-35.94) and Gardnerella vaginalis (OR = 6.13, 95%CI = 1.53-24.61), adjusted by age and qPCR for U. parvum. U. parvum load showed a statistical difference between the case and control groups (p-value = 0.002). CONCLUSION: Variables such as stable relationship, HPV, T. vaginalis, G. vaginalis were associated with cervical lesions in epidemiological studies. U. parvum load was higher in woman with cervical lesions compared with women without lesions. Additional studies are needed to better understand the role of these factors in cervical lesion development.