Dataset Information

Human papillomavirus (HPV)-18 E6 oncoprotein interferes with the epithelial cell polarity Par3 protein.

ABSTRACT: High-risk human papillomavirus (HPV) infection is the principal risk factor for the development of cervical cancer. The HPV E6 oncoprotein has the ability to target and interfere with several PSD-95/DLG/ZO-1 (PDZ) domain-containing proteins that are involved in the control of cell polarity. This function can be significant for E6 oncogenic activity because a deficiency in cell polarisation is a marker of tumour progression. The establishment and control of polarity in epithelial cells depend on the correct asymmetrical distribution of proteins and lipids at the cell borders and on specialised cell junctions. In this report, we have investigated the effects of HPV E6 protein on the polarity machinery, with a focus on the PDZ partitioning defective 3 (Par3) protein, which is a key component of tight junctions (TJ) and the polarity network. We demonstrate that E6 is able to bind and induce the mislocalisation of Par3 protein in a PDZ-dependent manner without significant reduction in Par3 protein levels. In addition, the high-risk HPV-18 E6 protein promotes a delay in TJ formation when analysed by calcium switch assays. Taken together, the data presented in this study contribute to our understanding of the molecular mechanism by which HPVs induce the loss of cell polarity, with potential implications for the development and progression of HPV-associated tumours.

SUBMITTER: Facciuto F

PROVIDER: S-EPMC5528639 | biostudies-literature | 2014 May

REPOSITORIES: biostudies-literature

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Human papillomavirus (HPV)-18 E6 oncoprotein interferes with the epithelial cell polarity Par3 protein.

Facciuto Florencia F Bugnon Valdano Marina M Marziali Federico F Massimi Paola P Banks Lawrence L Cavatorta Ana Laura AL Gardiol Daniela D

Molecular oncology 20140114 3

High-risk human papillomavirus (HPV) infection is the principal risk factor for the development of cervical cancer. The HPV E6 oncoprotein has the ability to target and interfere with several PSD-95/DLG/ZO-1 (PDZ) domain-containing proteins that are involved in the control of cell polarity. This function can be significant for E6 oncogenic activity because a deficiency in cell polarisation is a marker of tumour progression. The establishment and control of polarity in epithelial cells depend on ...[more]

PMID: 24462519

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Project description:BackgroundPersistent infection with high-risk Human Papillomavirus (HPVs) is associated with the development of cervical cancer. The transforming capacity of these viruses relies on the cooperative action of the E6 and E7 viral oncoproteins. Among the oncogenic activities of E6, the interaction and interference with cell polarity PDZ proteins have been well established. One of the most characterized PDZ targets of HPV E6 is human Disc large 1 (DLG1), a scaffolding protein involved in the control of cell polarity and proliferation. Interestingly, in cervical squamous intraepithelial lesions, alterations in DLG1 expression were observed in association to tumour progression. Moreover, the expression of both HPV E6 and E7 proteins may be responsible for the changes in DLG1 abundance and cell localization observed in the HPV-associated lesions.MethodsDue to the relevance of DLG1 deregulation in tumour development, we have performed an in-depth investigation of the expression of DLG1 in the presence of the HPV oncoproteins in epithelial cultured cells. The effects of HPV E6 and E7 proteins on DLG1 abundance and subcellular localization were assessed by western blot and confocal fluorescence microscopy, respectively.ResultsWe demonstrated that the relative abundance of HPV-18 E6 and DLG1 is a key factor that contributes to defining the expression abundance of both proteins. We also show here that a high expression level of DLG1 may negatively affect HPV-18 E6 nuclear expression. Moreover, the co-expression of HPV-18 E6 and E7 produces a striking effect on DLG1 subcellular localization and a co-distribution in the cytoplasmic region. Interestingly, HPV-18 E7 is also able to increase DLG1 levels, likely by rescuing it from the E6-mediated proteasomal degradation.ConclusionsIn general, the data suggest that HPV-18 E6 and E7 may have opposing activities in regards to the regulation of DLG1 levels and may cooperatively contribute to its subcellular redistribution in the HPV context. These findings constitute a step forward in understanding the differential expression of DLG1 during tumour progression in an HPV-associated model.

Project description:Cervical cancer is a significant public health problem, especially in low- and middle-income countries, where women have little access to cervical cancer screening; consequently 80% of cervical cancer related mortality occurs in these regions. The development of screening methods that need less infrastructure thus represents an urgent medical need. The study aims to compare the detection rates of high-risk human papillomavirus 16 and 18 E6 oncoprotein in urine, vaginal self-collected, and cervical scrapes of women using the OncoE6™ Cervical Test and compare the HPV16 and/or HPV18 E6 detection rates with the HPV DNA testing. Paired urine, vaginal self-collected and cervical specimens were collected from 124 women who participated in cervical cancer screening or treatment in this proof-of-concept study and underwent to HPV16/18-E6 testing and high-risk HPV DNA testing prior to treatment of cervical neoplasia or cancer. Concordance between urinary, vaginal and cervical HPV16/18-E6 and HPV-DNA testing was evaluated for patients classified as negative group (<CIN2) and histological positive group (CIN2, CIN3 and invasive carcinoma). Overall, HPV16/18-E6 oncoprotein was detected in 30.6% of cervical samples, 20.3% of self-collected vaginal samples and 21% of urine samples. Regarding the clinical sensitivity, the HPV16/18-E6 oncoprotein was not detected in CIN2 cases, and was detected at low rates in CIN3 cases. The clinical sensitivity of the HPV16/18-E6 oncoprotein for detecting invasive cervical cancer was 70% for cervical scrapes, 55% for self-collected vaginal samples and 52% for urine samples. This study reports the urinary detection of E6 oncoprotein in vivo for the first time and our results suggest that this detection is only for invasive/microinvasive lesions. Then, further protocol development and standardization to achieve a clinical sensitivity for CIN2/3 detection close to what can be achieved for invasive lesions using the physician collected cervical is needed.

Dataset Information

Human papillomavirus (HPV)-18 E6 oncoprotein interferes with the epithelial cell polarity Par3 protein.

Publications

Human papillomavirus (HPV)-18 E6 oncoprotein interferes with the epithelial cell polarity Par3 protein.

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