Roles of E6 and E7 Human Papillomavirus Proteins in Molecular Pathogenesis of Cervical Cancer

2019 ◽  
Vol 20 (9) ◽  
pp. 926-934 ◽  
Author(s):  
Eskandar Taghizadeh ◽  
Sepideh Jahangiri ◽  
Daryoush Rostami ◽  
Forough Taheri ◽  
Pedram Ghorbani Renani ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Human Papillomavirus ◽  
Cancer Cells ◽  
Cellular Response ◽  
Therapeutic Strategies ◽  
Cellular Communication ◽  
Mtor Signaling Pathway ◽  
Health Concerns ◽  
E6 And E7 ◽  
E7 Proteins

Human papillomavirus (HPV) cancers are expected to be major global health concerns in the upcoming decades. The growth of HPV-positive cancer cells depends on the consistent expression of oncoprotein which has been poorly taken into account in the cellular communication. Among them, E6/E7 oncoproteins are attractive therapeutic targets as their inhibition rapidly leads to the onset of aging in HPV-positive cancer cells. This cellular response is associated with the regeneration of p53, pRb anti-proliferative proteins as well as the mTOR signaling pathway; hence, the identification of involved and application of E6/E7 inhibitors can lead to new therapeutic strategies. In the present review, we focused on the pathogenicity of E6/E7 Proteins of human papillomavirus and their roles associated with the cervical cancer.

scholarly journals Endogenous Human Papillomavirus E6 and E7 Proteins Differentially Regulate Proliferation, Senescence, and Apoptosis in HeLa Cervical Carcinoma Cells

2003 ◽  
Vol 77 (2) ◽  
pp. 1551-1563 ◽  
Author(s):  
Rosa Anna DeFilippis ◽  
Edward C. Goodwin ◽  
Lingling Wu ◽  
Daniel DiMaio
Keyword(s):  
Cervical Cancer ◽  
Human Papillomavirus ◽  
Cancer Cells ◽  
Cervical Carcinoma ◽  
Carcinoma Cells ◽  
Rb Pathway ◽  
Cervical Cancer Cells ◽  
E6 And E7 ◽  
E7 Proteins ◽  
E6 Protein

ABSTRACT Cervical cancer cells express high-risk human papillomavirus (HPV) E6 and E7 proteins, and repression of HPV gene expression causes the cells to cease proliferation and undergo senescence. However, it is not known whether both HPV proteins are required to maintain the proliferative state of cervical cancer cells, or whether mutations that accumulate during carcinogenesis eliminate the need for one or the other of them. To address these questions, we used the bovine papillomavirus E2 protein to repress the expression of either the E6 protein or the E7 protein encoded by integrated HPV18 DNA in HeLa cervical carcinoma cells. Repression of the E7 protein activated the Rb pathway but not the p53 pathway and triggered senescence, whereas repression of the E6 protein activated the p53 pathway but not the Rb pathway and triggered both senescence and apoptosis. Telomerase activity, cyclin-dependent kinase activity, and expression of c-myc were markedly inhibited by repression of either E6 or E7. These results demonstrate that continuous expression of both the E6 and the E7 protein is required for optimal proliferation of cervical carcinoma cells and that the two viral proteins exert distinct effects on cell survival and proliferation. Therefore, strategies that inhibit the expression or activity of either viral protein are likely to inhibit the growth of HPV-associated cancers.

scholarly journals Leukemia Inhibitory Factor Downregulates Human Papillomavirus-16 Oncogene Expression and Inhibits the Proliferation of Cervical Carcinoma Cells

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Joseph M. Bay ◽  
Bruce K. Patterson ◽  
Nelson N. H. Teng
Keyword(s):  
Cervical Cancer ◽  
Human Papillomavirus ◽  
Cancer Cells ◽  
Leukemia Inhibitory Factor ◽  
Inhibitory Factor ◽  
Human Papillomavirus 16 ◽  
Oncogene Expression ◽  
Hpv E6 ◽  
Cervical Cancer Cells ◽  
E6 And E7

The constitutive proliferation and resistance to differentiation and apoptosis of neoplastic cervical cells depend on sustained expression of human papillomavirus oncogenes. Inhibition of these oncogenes is a goal for the prevention of progression of HPV-induced neoplasias to cervical cancer. SiHa cervical cancer cells were transfected with an HPV-16 promoter reporter construct and treated with leukemia inhibitory factor (LIF), a human cytokine of the interleukin 6 superfamily. SiHa and CaSki cervical cancer cells were also assessed for proliferation by MTT precipitation, programmed cell death by flow cytometry, and HPV E6 and E7 expression by real-time PCR. LIF-treated cervical cancer cells showed significantly reduced HPV LCR activation, reduced levels of E6 and E7 mRNA, and reduced proliferation. We report the novel use of LIF to inhibit viral oncogene expression in cervical cancer cells, with concomitant reduction in proliferation suggesting re-engagement of cell-cycle regulation.

scholarly journals Human Papillomavirus E6/E7 and Long Noncoding RNA TMPOP2 Mutually Upregulated Gene Expression in Cervical Cancer Cells

2019 ◽  
Vol 93 (8) ◽  
Author(s):  
Hongpeng He ◽  
Xiang Liu ◽  
Yue Liu ◽  
Mengmeng Zhang ◽  
Yongwei Lai ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Cervical Cancer ◽  
Human Papillomavirus ◽  
Cancer Cells ◽  
Long Noncoding Rna ◽  
Noncoding Rna ◽  
Human Papillomaviruses ◽  
Cervical Cancer Cells ◽  
E6 And E7

ABSTRACT TMPOP2 was previously suggested to be an oncogenic long noncoding RNA which is excessively expressed in cervical cancer cells and inhibits E-cadherin gene expression by recruiting transcription repressor EZH2 to the gene promoter. So far, the function and regulation of TMPOP2 in cervical cancer remain largely unknown. Herein, we found that TMPOP2 expression was correlated with human papillomavirus 16/18 (HPV16/18) E6 and E7 in cervical cancer cell lines CaSki and HeLa. Tumor suppressor p53, which is targeted for degradation by HPV16/18, was demonstrated to associate with two p53 response elements in the TMPOP2 promoter to repress the transcription of the TMPOP2 gene. Reciprocally, ectopic expression of TMPOP2 was demonstrated to sequester tumor repressor microRNAs (miRNAs) miR-375 and miR-139 which target HPV16/18 E6/E7 mRNA and resulted in an upregulation of HPV16/18 E6/E7 genes. Thereby, HPV16/18 E6/E7 and the long noncoding RNA (lncRNA) TMPOP2 form a positive feedback loop to mutually derepress gene expression in cervical cancer cells. Moreover, results of RNA sequencing and cell cycle analysis showed that knockdown of TMPOP2 impaired the expression of cell cycle genes, induced cell cycle arrest, and inhibited HeLa cell proliferation. Together, our results indicate that TMPOP2 and HPV16/18 E6/E7 mutually strengthen their expression in cervical cancer cells to enhance tumorigenic activities. IMPORTANCE Human papillomaviruses 16 and 18 (HPV16/18) are the main causative agents of cervical cancer. Viral proteins HPV16/18 E6 and E7 are constitutively expressed in cancer cells to maintain oncogenic phenotypes. Accumulating evidences suggest that HPVs are correlated with the deregulation of long noncoding RNAs (lncRNAs) in cervical cancer, although the mechanism was unexplored in most cases. TMPOP2 is a newly identified lncRNA excessively expressed in cervical cancer. However, the mechanism for the upregulation of TMPOP2 in cervical cancer cells remains largely unknown and its relationship with HPVs is still elusive. The significance of our research is in revealing the mutual upregulation of HPV16/18 E6/E7 and TMPOP2 with the molecular mechanisms explored. This study will expand our understandings of the oncogenic activities of human papillomaviruses and lncRNAs.

A recombinant vaccinia virus encoding human papillomavirus types 16 and 18, E6 and E7 proteins as immunotherapy for cervical cancer

The Lancet ◽  
1996 ◽  
Vol 347 (9014) ◽  
pp. 1523-1527 ◽  
Author(s):  
L.K Borysiewicz ◽  
A Fiander ◽  
M Nimako ◽  
S Man ◽  
G.W.G Wilkinson ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Human Papillomavirus ◽  
Vaccinia Virus ◽  
Recombinant Vaccinia Virus ◽  
Recombinant Vaccinia ◽  
E6 And E7 ◽  
E7 Proteins

scholarly journals Selection of Indonesian Medicinal Plant Active Compounds as Inhibitor Candidates of Oncoproteins E6 and E7 Human Papillomavirus Type 16 by Molecular Docking

2021 ◽  
Vol 3 (1) ◽  
pp. 9-17
Author(s):  
Riyanti Weni Syafitri ◽  
Azzania Fibriani ◽  
Reza Aditama
Keyword(s):  
Cervical Cancer ◽  
Molecular Docking ◽  
Human Papillomavirus ◽  
Medicinal Plant ◽  
Binding Site ◽  
Active Compounds ◽  
Hpv 16 ◽  
E6 And E7 ◽  
E7 Proteins

Cervical cancer cases caused by infection with Human Papillomavirus (HPV), especially HPV 16 (60.5% of cases) continue to increase every year with a high mortality rate. The current anti-cancer drugs were not only specifically targeting cancer cells, but healthy cells and can cause serious side effects. Therefore, it is necessary to find safer alternative therapies, e.g., using active compounds from natural products. The purpose of this study was to find the active compounds of Indonesian medicinal plants potentially as an inhibitor of oncoprotein E6 and E7 HPV 16, the main protein causing cervical cancer by in silico method. In this study, 711 active compounds from 187 medicinal plant species were selected based on molecular weight, solubility, gastrointestinal absorption index, and drug-likeness. Compounds that meet the criteria were tested for their affinity and interaction profile with E6 and E7 proteins through the molecular docking method. The results of this study showed 164 compounds that met the criteria. The molecular docking analysis showed nine of the most potent compounds as E6 inhibitors on the E6AP binding site and six compounds on the p53 binding site. Besides that, there were eleven most potent compounds as E7 inhibitors.  The results of this study indicate that there are natural compounds that can inhibit E6 and E7 proteins and have further potential to be used as anti-HPV drugs. However, further research is needed to test these compounds in vitro and in vivo.

scholarly journals Multiple ASF/SF2 Sites in the Human Papillomavirus Type 16 (HPV-16) E4-Coding Region Promote Splicing to the Most Commonly Used 3′-Splice Site on the HPV-16 Genome

2010 ◽  
Vol 84 (16) ◽  
pp. 8219-8230 ◽  
Author(s):  
Monika Somberg ◽  
Stefan Schwartz
Keyword(s):  
Cervical Cancer ◽  
Human Papillomavirus ◽  
Splice Site ◽  
Binding Sites ◽  
Mrna Levels ◽  
Coding Region ◽  
Cervical Lesions ◽  
Hpv 16 ◽  
Human Papillomavirus Type 16 ◽  
E6 And E7

ABSTRACT Our results presented here demonstrate that the most abundant human papillomavirus type 16 (HPV-16) mRNAs expressing the viral oncogenes E6 and E7 are regulated by cellular ASF/SF2, itself defined as a proto-oncogene and overexpressed in cervical cancer cells. We show that the most frequently used 3′-splice site on the HPV-16 genome, site SA3358, which is used to produce primarily E4, E6, and E7 mRNAs, is regulated by ASF/SF2. Splice site SA3358 is immediately followed by 15 potential binding sites for the splicing factor ASF/SF2. Recombinant ASF/SF2 binds to the cluster of ASF/SF2 sites. Mutational inactivation of all 15 sites abolished splicing to SA3358 and redirected splicing to the downstream-located, late 3′-splice site SA5639. Overexpression of a mutant ASF/SF2 protein that lacks the RS domain, also totally inhibited the usage of SA3358 and redirected splicing to the late 3′-splice site SA5639. The 15 ASF/SF2 binding sites could be replaced by an ASF/SF2-dependent, HIV-1-derived splicing enhancer named GAR. This enhancer was also inhibited by the mutant ASF/SF2 protein that lacks the RS domain. Finally, silencer RNA (siRNA)-mediated knockdown of ASF/SF2 caused a reduction in spliced HPV-16 mRNA levels. Taken together, our results demonstrate that the major HPV-16 3′-splice site SA3358 is dependent on ASF/SF2. SA3358 is used by the most abundantly expressed HPV-16 mRNAs, including those encoding E6 and E7. High levels of ASF/SF2 may therefore be a requirement for progression to cervical cancer. This is supported by our earlier findings that ASF/SF2 is overexpressed in high-grade cervical lesions and cervical cancer.

Human papillomavirus oncoproteins differentially modulate epithelial-mesenchymal transition in 5-FU-resistant cervical cancer cells

Tumor Biology ◽  
2016 ◽  
Vol 37 (10) ◽  
pp. 13137-13154 ◽  
Author(s):  
Kanchan Vishnoi ◽  
Sutapa Mahata ◽  
Abhishek Tyagi ◽  
Arvind Pandey ◽  
Gaurav Verma ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Human Papillomavirus ◽  
Cancer Cells ◽  
Epithelial Mesenchymal Transition ◽  
Mesenchymal Transition ◽  
Cervical Cancer Cells
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