scholarly journals Human Papillomavirus Type 16 E6 Induces Self-Ubiquitination of the E6AP Ubiquitin-Protein Ligase

2000 ◽  
Vol 74 (14) ◽  
pp. 6408-6417 ◽  
Author(s):  
Wynn H. Kao ◽  
Sylvie L. Beaudenon ◽  
Andrea L. Talis ◽  
Jon M. Huibregtse ◽  
Peter M. Howley
Keyword(s):  
Cervical Cancer ◽  
Cancer Cells ◽  
Half Life ◽  
Mammalian Cells ◽  
Human Papillomaviruses ◽  
26S Proteasome ◽  
Hpv16 E6 ◽  
Ubiquitin Protein Ligase ◽  
Cervical Cancer Cells

ABSTRACT The E6 protein of the high-risk human papillomaviruses (HPVs) and the cellular ubiquitin-protein ligase E6AP form a complex which causes the ubiquitination and degradation of p53. We show here that HPV16 E6 promotes the ubiquitination and degradation of E6AP itself. The half-life of E6AP is shorter in HPV-positive cervical cancer cells than in HPV-negative cervical cancer cells, and E6AP is stabilized in HPV-positive cancer cells when expression of the viral oncoproteins is repressed. Expression of HPV16 E6 in cells results in a threefold decrease in the half-life of transfected E6AP. E6-mediated degradation of E6AP requires (i) the binding of E6 to E6AP, (ii) the catalytic activity of E6AP, and (iii) activity of the 26S proteasome, suggesting that E6-E6AP interaction results in E6AP self-ubiquitination and degradation. In addition, both in vitro and in vivo experiments indicate that E6AP self-ubiquitination results primarily from an intramolecular transfer of ubiquitin from the active-site cysteine to one or more lysine residues; however, intermolecular transfer can also occur in the context of an E6-mediated E6AP multimer. Finally, we demonstrate that an E6 mutant that is able to immortalize human mammary epithelial cells but is unable to degrade p53 retains its ability to bind and degrade E6AP, raising the possibility that E6-mediated degradation of E6AP contributes to its ability to transform mammalian cells.

scholarly journals Disruption of repressive p130–DREAM complexes by human papillomavirus 16 E6/E7 oncoproteins is required for cell-cycle progression in cervical cancer cells

2011 ◽  
Vol 92 (11) ◽  
pp. 2620-2627 ◽  
Author(s):  
Nurshamimi Nor Rashid ◽  
Rohana Yusof ◽  
Roger J. Watson
Keyword(s):  
Cell Cycle ◽  
Cervical Cancer ◽  
Cancer Cells ◽  
Cell Cycle Progression ◽  
Human Papillomaviruses ◽  
G1 Arrest ◽  
Cycle Progression ◽  
Hpv16 E6 ◽  
Cervical Cancer Cells ◽  
E6 And E7

Human papillomaviruses (HPVs) with tropism for mucosal epithelia are the major aetiological factors in cervical cancer. Most cancers are associated with so-called high-risk HPV types, in particular HPV16, and constitutive expression of the HPV16 E6 and E7 oncoproteins is critical for malignant transformation in infected keratinocytes. E6 and E7 bind to and inactivate the cellular tumour suppressors p53 and Rb, respectively, thus delaying differentiation and inducing proliferation in suprabasal keratinocytes to enable HPV replication. One member of the Rb family, p130, appears to be a particularly important target for E7 in promoting S-phase entry. Recent evidence indicates that p130 regulates cell-cycle progression as part of a large protein complex termed DREAM. The composition of DREAM is cell cycle-regulated, associating with E2F4 and p130 in G0/G1 and with the B-myb transcription factor in S/G2. In this study, we addressed whether p130–DREAM is disrupted in HPV16-transformed cervical cancer cells and whether this is a critical function for E6/E7. We found that p130–DREAM was greatly diminished in HPV16-transformed cervical carcinoma cells (CaSki and SiHa) compared with control cell lines; however, when E6/E7 expression was targeted by specific small hairpin RNAs, p130–DREAM was reformed and the cell cycle was arrested. We further demonstrated that the profound G1 arrest in E7-depleted CaSki cells was dependent on p130–DREAM reformation by also targeting the expression of the DREAM component Lin-54 and p130. The results show that continued HPV16 E6/E7 expression is necessary in cervical cancer cells to prevent cell-cycle arrest by a repressive p130–DREAM complex.

scholarly journals Adenoviral Vectors Armed with PAPILLOMAVIRUs Oncogene Specific CRISPR/Cas9 Kill Human-Papillomavirus-Induced Cervical Cancer Cells

Cancers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1934 ◽  
Author(s):  
Eric Ehrke-Schulz ◽  
Sonja Heinemann ◽  
Lukas Schulte ◽  
Maren Schiwon ◽  
Anja Ehrhardt
Keyword(s):  
Cervical Cancer ◽  
Cancer Cells ◽  
Cell Lines ◽  
Cancer Cell ◽  
Cancer Cell Lines ◽  
Adenoviral Vectors ◽  
Human Papillomaviruses ◽  
Cervical Cancer Cell ◽  
Adenoviral Delivery ◽  
Cervical Cancer Cells

Human papillomaviruses (HPV) cause malignant epithelial cancers including cervical carcinoma, non-melanoma skin and head and neck cancer. They drive tumor development through the expression of their oncoproteins E6 and E7. Designer nucleases were shown to be efficient to specifically destroy HPV16 and HPV18 oncogenes to induce cell cycle arrest and apoptosis. Here, we used high-capacity adenoviral vectors (HCAdVs) expressing the complete CRISPR/Cas9 machinery specific for HPV18-E6 or HPV16-E6. Cervical cancer cell lines SiHa and CaSki containing HPV16 and HeLa cells containing HPV18 genomes integrated into the cellular genome, as well as HPV-negative cancer cells were transduced with HPV-type-specific CRISPR-HCAdV. Upon adenoviral delivery, the expression of HPV-type-specific CRISPR/Cas9 resulted in decreased cell viability of HPV-positive cervical cancer cell lines, whereas HPV-negative cells were unaffected. Transduced cervical cancer cells showed increased apoptosis induction and decreased proliferation compared to untreated or HPV negative control cells. This suggests that HCAdV can serve as HPV-specific cancer gene therapeutic agents when armed with HPV-type-specific CRISPR/Cas9. Based on the versatility of the CRISPR/Cas9 system, we anticipate that our approach can contribute to personalized treatment options specific for the respective HPV type present in each individual tumor.

The Potential Oncogenic and MLN4924-Resistant Effects of CSN5 on Cervical Cancer Cells

2021 ◽  
Author(s):  
Huilin Zhang ◽  
Ping He ◽  
Qing Zhou ◽  
Yan Lu ◽  
Bingjian Lu
Keyword(s):  
Cell Cycle ◽  
Cervical Cancer ◽  
Cell Proliferation ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Cervical Cancer Cell ◽  
Cervical Cancers ◽  
Cervical Cancer Cells

Abstract BackgroundsCSN5, a member of Cop9 signalosome, is essential for protein neddylation. It has been supposed to serve as an oncogene in some cancers. However, the role of CSN5 has not been investigated in cervical cancer yet.MethodsData from TCGA cohorts and GEO dataset was analyzed to examine the expression profile of CSN5 in cervical cancers. The role of CSN5 on cervical cancer cell proliferation was investigated in cervical cancer cell lines, Siha and Hela, through CSN5 knockdown via CRISPR-CAS9. Western blot was used to detect the effect of CSN5 knockdown and overexpression. CCK8, clone formation assay and cell cycle assay were also employed. Besides, the role CSN5 knockdown in vivo was evaluated by xenograft tumor model. Moreover, MLN4924 was applied in Siha and Hela with CSN5 overexpression.ResultsWe found that downregulation of CSN5 in Siha and Hela cells inhibited cell proliferation in vitro and in vivo, and the inhibitory effects were largely rescued by CSN5 overexpression. Moreover, deletion of CSN5 caused cell cycle arrest rather than inducing apoptosis. Importantly, CSN5 overexpression confers resistance to the anti-cancer effects of MLN4924 (pevonedistat) in cervical cancer cells.ConclusionsOur findings demonstrated that CSN5 functions as an oncogene in cervical cancers and may serve as a potential indicator for predicting the effects of MLN4924 treatment in the future.

Quantification of DNA double-strand break induced by radiation in cervix cancer cells: in vitro study

2018 ◽  
Vol 18 (1) ◽  
pp. 52-54
Author(s):  
Sothing Vashum ◽  
Rabi Raja Singh I ◽  
Saikat Das ◽  
Mohammed Azharuddin KO ◽  
Prabhakaran Vasudevan
Keyword(s):  
Cervical Cancer ◽  
Cancer Cells ◽  
Strand Break ◽  
Double Strand Break ◽  
Ionising Radiation ◽  
Dependent Manner ◽  
Survival Fraction ◽  
Dna Double Strand Break ◽  
Cervical Cancer Cells

AbstractAimDNA double-strand break (DSB) results in the phosphorylation of the protein, H.2AX histone. In this study, the effect of radiotherapy and chemotherapy on DNA DSB in cervical cancer cells is analysed by the phosphorylation of the protein.MethodsThe cervical cancer cells (HeLa cells) were cultured and exposed to ionising radiation. Radiation sensitivity was measured by clonogenic survival fraction after exposing to ionising radiation. Since the phosphorylation of H.2AX declines with time, the DNA damage was quantified at different time points: 1 hour, 3 hours and 1 week after exposed to the radiation. The analysis of γ-H.2AX was done by Western-blot technique. The protein expression was observed at different dose of radiation and combination of both radiation and paclitaxel.ResultsLow-dose hypersensitivity was observed. By 1 week after radiation at 0·5, 0·8 and 2 Gy, there was no expression of phosphorylated H.2AX. Previous experiments on the expression of phosphorylated H.2AX (γ-H.2AX) in terms of foci analysis was found to peak at 1 hour and subsequently decline with time. In cells treated with the DNA damaging agents, the expression of phosphorylated H.2AX decreases in a dose-dependent manner when treated with radiation alone. However, when combined with paclitaxel, at 0·5 Gy, the expression peaked and reduces at 0·8 Gy and slightly elevated at 2 Gy.FindingsIn this study, the peak phosphorylation was observed at 3 hour post irradiation indicating that DSBs are still left unrepaired.

scholarly journals Radiation enhancing effects of sanazole and gemcitabine in hypoxic breast and cervical cancer cells in vitro

2015 ◽  
Vol 3 ◽  
pp. 236-240
Author(s):  
Yue-Can Zeng ◽  
Rong Wu ◽  
Yu-Ping Xiao ◽  
Yan Xin ◽  
Feng Chi ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Cancer Cells ◽  
Breast And Cervical Cancer ◽  
Cervical Cancer Cells

Growth Inhibition of Human Cervical Cancer Cells with the Recombinant Adenovirusp53 in Vitro

1996 ◽  
Vol 60 (3) ◽  
pp. 373-379 ◽  
Author(s):  
Katsuyuki Hamada ◽  
Wei-Wei Zhang ◽  
Ramon Alemany ◽  
Judith Wolf ◽  
Jack A. Roth ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Growth Inhibition ◽  
Cancer Cells ◽  
Cervical Cancer Cells ◽  
Human Cervical Cancer Cells ◽  
Human Cervical Cancer

scholarly journals Upregulation of Long Non-Coding RNA Small Nucleolar RNA Host Gene 12 Contributes to Cell Growth and Invasion in Cervical Cancer by Acting as a Sponge for MiR-424-5p

2018 ◽  
Vol 45 (5) ◽  
pp. 2086-2094 ◽  
Author(s):  
Jing Dong ◽  
Qing Wang ◽  
Li Li ◽  
Zhang Xiao-jin
Keyword(s):  
Cervical Cancer ◽  
Tumor Growth ◽  
Cancer Cells ◽  
Host Gene ◽  
Migration And Invasion ◽  
Small Nucleolar Rna ◽  
Cervical Cancer Cells ◽  
Cancer Tissues ◽  
Nucleolar Rna

Background/Aims: Cervical cancer, which is one of the most aggressive cancers affecting females, has high rates of recurrence and mortality. Small nucleolar RNA host gene 12 (SNHG12) is known to promote the progression of several cancers; however, its exact effects and molecular mechanisms in cervical cancer remain unknown. Methods: Real-time quantitative PCR was used to determine the expression level of SNHG12 in cervical cancer tissues and cell lines. Loss-of-function assays were performed to examine the effect of SNHG12 on the proliferation, apoptosis, migration and invasion of cervical cancer cells in vitro and tumor growth in vivo. Luciferase experiments were employed to explore the interactions between SNHG12 and miR-424-5p. Results: SNHG12 was found to be abnormally elevated in human cervical cancer tissues compared with paired adjacent normal tissues. Moreover, high SNHG12 expression in tumor tissues was significantly correlated with vascular involvement, lymph node metastasis, advanced FIGO stage and poor prognosis. Furthermore, the knockdown of SNHG12 was found to inhibit proliferation, migration and invasion of cervical cancer cells in vitro, and silencing SNHG12 was shown to suppress tumor growth in a nude mouse model. Mechanistic studies showed that SNHG12 functioned as an endogenous sponge for miR-424-5p, thereby downregulating the expression of miR-424-5p in cervical cancer. Furthermore, the inhibition of miR-424-5p in SNHG12-depleted cells partially reversed the effects on cervical cancer cell apoptosis, adhesion and invasion. Conclusion: In summary, our findings suggest that the tumor-promoting role of SNHG12 is to function as a molecular sponge, which negatively regulates miR-424-5p. These findings may provide a potent therapeutic target for cervical cancer.

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