The role of HPV16 regulatory region methylation in viral oncogenes E6 and E7 eхpression in primary cervical cancer lesions

Background. Overexpression of the human papillomavirus oncogenes E6 and E7 is a major factor in initiation and progression of HPV-induced tumors. Inactivation of negative regulatory function of E2 protein – the main viral transcription and replication regulator – is considered to be an important mec...

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Main Authors: P. M. Abramov, A. N. Katargin, M. D. Fedorova, N. P. Kisseljova, L. S. Pavlova, S. V. Vinokurova
Format: Article
Language:Russian
Published: ABV-press 2019-01-01
Series:Успехи молекулярной онкологии
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Online Access:https://umo.abvpress.ru/jour/article/view/180
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author P. M. Abramov
A. N. Katargin
M. D. Fedorova
N. P. Kisseljova
L. S. Pavlova
S. V. Vinokurova
author_facet P. M. Abramov
A. N. Katargin
M. D. Fedorova
N. P. Kisseljova
L. S. Pavlova
S. V. Vinokurova
author_sort P. M. Abramov
collection DOAJ
description Background. Overexpression of the human papillomavirus oncogenes E6 and E7 is a major factor in initiation and progression of HPV-induced tumors. Inactivation of negative regulatory function of E2 protein – the main viral transcription and replication regulator – is considered to be an important mechanism leading to the viral oncogenes overexpression. It is known that the loss of E2 functions occurs due to disruption of E2 open reading frame during the viral DNA integration into a cell genome in a part of HPV-positive tumors. An alternative mechanism of E2 function blocking in tumors retained its expression can be methylation of the HPV regulatory region, since it is known that E2 is incapable to bind its methylated binding sites.The study objective is to analyze methylation of the HPV16 regulatory region and expression of the viral E6 and E7 oncogenes in E2 expressing or non-expressing clinical samples of cervical cancer.Results. It has been demonstrated that the level of the HPV16 URR methylation in E2-expressing lesions is significantly higher than that in non-expressing cervical cancer lesions. Demethylation of the HPV16 promoter in cervical cell line Caski is followed by decrease of the viral E6 и E7 oncogenes mRNA levels, supporting the hypothesis that methylation is necessary for effective E6 and E7 transcription and indicates on restitution of E2 regulatory function in E2-expressing cervical cancer cells.Conclusion. These data suggest that methylation of E2 binding sites in HPV16 regulatory region blocking E2 protein binding represents an important mechanism ensuring high level of the viral E6 and E7 oncogenes expression.
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spelling doaj-art-79b0d6d69836474f924899a6dd0c8f4d2025-08-20T03:22:00ZrusABV-pressУспехи молекулярной онкологии2313-805X2413-37872019-01-015411011610.17650/2313-805X-2018-5-4-110-116144The role of HPV16 regulatory region methylation in viral oncogenes E6 and E7 eхpression in primary cervical cancer lesionsP. M. Abramov0A. N. Katargin1M. D. Fedorova2N. P. Kisseljova3L. S. Pavlova4S. V. Vinokurova5N.N. Blokhin National Medical Research Center of Oncology, Ministry of Health of RussiaN.N. Blokhin National Medical Research Center of Oncology, Ministry of Health of RussiaN.N. Blokhin National Medical Research Center of Oncology, Ministry of Health of RussiaN.N. Blokhin National Medical Research Center of Oncology, Ministry of Health of RussiaN.N. Blokhin National Medical Research Center of Oncology, Ministry of Health of RussiaN.N. Blokhin National Medical Research Center of Oncology, Ministry of Health of RussiaBackground. Overexpression of the human papillomavirus oncogenes E6 and E7 is a major factor in initiation and progression of HPV-induced tumors. Inactivation of negative regulatory function of E2 protein – the main viral transcription and replication regulator – is considered to be an important mechanism leading to the viral oncogenes overexpression. It is known that the loss of E2 functions occurs due to disruption of E2 open reading frame during the viral DNA integration into a cell genome in a part of HPV-positive tumors. An alternative mechanism of E2 function blocking in tumors retained its expression can be methylation of the HPV regulatory region, since it is known that E2 is incapable to bind its methylated binding sites.The study objective is to analyze methylation of the HPV16 regulatory region and expression of the viral E6 and E7 oncogenes in E2 expressing or non-expressing clinical samples of cervical cancer.Results. It has been demonstrated that the level of the HPV16 URR methylation in E2-expressing lesions is significantly higher than that in non-expressing cervical cancer lesions. Demethylation of the HPV16 promoter in cervical cell line Caski is followed by decrease of the viral E6 и E7 oncogenes mRNA levels, supporting the hypothesis that methylation is necessary for effective E6 and E7 transcription and indicates on restitution of E2 regulatory function in E2-expressing cervical cancer cells.Conclusion. These data suggest that methylation of E2 binding sites in HPV16 regulatory region blocking E2 protein binding represents an important mechanism ensuring high level of the viral E6 and E7 oncogenes expression.https://umo.abvpress.ru/jour/article/view/180human papillomaviruscervical cancermethylationregulation of expressionviral oncogene e6viral oncogenes e7
spellingShingle P. M. Abramov
A. N. Katargin
M. D. Fedorova
N. P. Kisseljova
L. S. Pavlova
S. V. Vinokurova
The role of HPV16 regulatory region methylation in viral oncogenes E6 and E7 eхpression in primary cervical cancer lesions
Успехи молекулярной онкологии
human papillomavirus
cervical cancer
methylation
regulation of expression
viral oncogene e6
viral oncogenes e7
title The role of HPV16 regulatory region methylation in viral oncogenes E6 and E7 eхpression in primary cervical cancer lesions
title_full The role of HPV16 regulatory region methylation in viral oncogenes E6 and E7 eхpression in primary cervical cancer lesions
title_fullStr The role of HPV16 regulatory region methylation in viral oncogenes E6 and E7 eхpression in primary cervical cancer lesions
title_full_unstemmed The role of HPV16 regulatory region methylation in viral oncogenes E6 and E7 eхpression in primary cervical cancer lesions
title_short The role of HPV16 regulatory region methylation in viral oncogenes E6 and E7 eхpression in primary cervical cancer lesions
title_sort role of hpv16 regulatory region methylation in viral oncogenes e6 and e7 eхpression in primary cervical cancer lesions
topic human papillomavirus
cervical cancer
methylation
regulation of expression
viral oncogene e6
viral oncogenes e7
url https://umo.abvpress.ru/jour/article/view/180
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