The state of the p53 and retinoblastoma genes in human cervical carcinoma cell lines

High resolution profiling of cell cycle-dependent protein and phosphorylation abundance changes in non-transformed cells

The cell cycle governs a precise series of molecular events, regulated by coordinated changes in protein and phosphorylation abundance, that culminates in the generation of two daughter cells. Here, we present a proteomic and phosphoproteomic analysis of the human cell cycle in hTERT-RPE-1 cells using deep quantitative mass spectrometry by isobaric labelling. By analysing non-transformed cells and improving the temporal resolution and coverage of key cell cycle regulators, we present a dataset of cell cycle-dependent protein and phosphorylation site oscillation that offers a foundational reference for investigating cell cycle regulation. These data reveal regulatory intricacies including proteins and phosphorylation sites exhibiting cell cycle-dependent oscillation, and proteins targeted for degradation during mitotic exit. Integrated with complementary resources, our data link cycle-dependent abundance dynamics to functional changes and are accessible through the Cell Cycle database (CCdb), an interactive web-based resource for the cell cycle community.

Ozone-Oxygen Therapy to Prevent HPV-Related Cancers of the Lower Gynecological Tract in Infected Patients: The Rationale for Further Developments

BACKGROUND

O3-O2 therapy is an alternative medical treatment that introduces a mixture of O3-O2 into the body for therapeutic purposes. The objective of this study is to evaluate its margins of applicability in the eradication of HPV infection from the lower gynecological tract by means of vaginal insufflation.

METHODS

An in-depth review of the international literature on this topic is carried out; in addition, O3-O2 therapy is compared with other treatments currently available in terms of its advantages, disadvantages, and exploited technologies.

RESULTS

The possible benefits and limitations of O3-O2 vaginal insufflation are explained in detail; overall, it appears to be an interesting tool as part of complex management to prevent HPV-related cancers of the lower gynecological tract in infected patients.

CONCLUSIONS

The rationale and guidelines of this innovative procedure have been successfully illustrated, providing the technical specifications for further developments.

Adenosinergic Signalling in Cervical Cancer Microenvironment

Despite the emergence of the first human papillomavirus vaccine, the incidence of cervical cancer is still responsible for more than 350,000 deaths yearly. Over the past decade, ecto-5'-nucleotidase (CD73/5'-NT) and extracellular adenosine (ADO) signalling has been the subject of many investigations to target cancer progression. In general, the adenosinergic axis has been linked to tumourigenic effects. However, CD73 can play contradictory effects, probably dependent on the tumour type, tumour microenvironment and tumour stage, thus being in some circumstances, inversely related to tumour progression. We herein reviewed the pathophysiological function of CD73 in cervical cancer and performed in silico analysis of the main components of the adenosinergic signalling in human tissues of cervical cancer compared to non-tumour cervix tissue. Our data showed that the NT5E gene, that encoded CD73, is hypermethylated, leading to a decreased CD73 expression in cervical cancer cells compared to normal cells. Consequently, the high availability of ADO cytoplasmatic/extracellular leads to its conversion to AMP by ADK, culminating in global hypermethylation. Therefore, epigenetic modulation may reveal a new role for CD73 in cervical cancer.

Sustainable Carbon Dots Loaded into Carboxymethylcellulose Based Hydrogels for Uterine Cancer Bioimaging

Background/Objectives: The development of innovative materials for disease diagnostics and therapeutics is a fast-growing area of scientific research. In this work, we report the development of innovative hydrogels incorporating carbon dots (Cdots) for bioimaging purposes. Methods: The Cdots were prepared using a sustainable and low-cost process, starting with an underused fiber from the Brazilian semiarid region. Spectroscopy analysis (Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV-visible spectroscopy), X-ray diffraction, photoluminescence, zeta potential, scanning electron microscopy, and transmission electron microscopy were used to characterize these hydrogels. In addition, biocompatibility using the resazurin assay and cellular uptake by confocal microscopy were evaluated. Results: Our results showed that the Cdots changed the structure and crystallinity of hydrogels, mainly due to heat treatment. In addition, hydrogels' chemical groups suffer red and blue shifts following the Cdots incorporation. Moreover, the Cdots were homogeneously incorporated into the hydrogel matrix. Importantly, the cytotoxicity levels were maintained above 90% (p < 0.01), and cellular uptake studies using HeLa cells demonstrated intracellular fluorescence of both the Cdots and hydrogels after incubation. Additionally, the concentration of Cdots within hydrogels significantly affected fluorescence intensity, even compared with pure Cdots. Conclusions: These results showcase the potential for these hydrogels to be further developed as biomarkers and therapeutic biomaterials for women's health.

What are the essential determinants of human papillomavirus carcinogenesis?

Human papillomavirus (HPV) infection is the leading viral cause of cancer. Over the past several decades, research on HPVs has provided remarkable insight into human cell biology and into the pathology of viral and non-viral cancers. The HPV E6 and E7 proteins engage host cellular proteins to establish an environment in infected cells that is conducive to virus replication. They rewire host cell signaling pathways to promote proliferation, inhibit differentiation, and limit cell death. The activity of the "high-risk" HPV E6 and E7 proteins is so potent that their dysregulated expression is sufficient to drive the initiation and maintenance of HPV-associated cancers. Consequently, intensive research efforts have aimed to identify the host cell targets of E6 and E7, in part with the idea that some or all of the virus-host interactions would be essential cancer drivers. These efforts have identified a large number of potential binding partners of each oncoprotein. However, over the same time period, parallel research has revealed that a relatively small number of genetic mutations drive carcinogenesis in most non-viral cancers. We therefore propose that a high-priority goal is to identify which of the many targets of E6 and E7 are critical drivers of HPV carcinogenesis. By identifying the cancer-driving targets of E6 and E7, it should be possible to better understand the distinct roles of other targets, perhaps in the viral life cycle, and to focus efforts to develop anti-cancer therapies on the subset of virus-host interactions for which therapeutic intervention would have the greatest impact.

Alterations of UHRF family Expression and was regulated by High Risk Type HPV16 in Uterine Cervical Cancer

The altered protein expression of inverted CCAAT box-binding protein of 90 kDa/ubiquitin-like with PHD and RING finger domains 1 (ICBP90/UHRF1), and Np95-like ring finger protein (NIRF)/UHRF2, which belong to the ubiquitin-like with PHD and RING finger domains (UHRF) family, is linked to tumor malignancy and the progression of various cancers. In this study, we analyzed the UHRF family expression in cervical cancers, and it's regulation by human papillomavirus (HPV). Western blotting was performed to analyze protein expression in cervical cancer cell lines. Immunohistochemical analysis were used to investigate the expression of UHRF family and MIB-1 in cervical cancer tissues. Transfection were done for analyze the relationship between UHRF family and HPVs. We showed that NIRF expression was decreased and ICBP90 expression was increased in cervical cancers compared to normal counterparts. Western blotting also showed that NIRF expression was quite low levels, but ICBP90 was high in human cervical cancer cell lines. Interestingly, ICBP90 was up regulated by high risk type HPV16 E6 and E7, but not low-risk type HPV11. On the other hand, NIRF was down regulated by high risk type HPV16 E6 but not by E7. Low risk type HPV11 E6 did not affect the NIRF expression at all. We propose that ICBP90 overexpression, and reduced NIRF expression, found in cervical cancers, is an important event of a cervical carcinogenesis, and especially ICBP90 may offer a proliferating marker and therapeutic target for treating uterine cervical cancers.

Insights into the mechanisms and structure of breakage-fusion-bridge cycles in cervical cancer using long-read sequencing

Cervical cancer is caused by human papillomavirus (HPV) infection, has few approved targeted therapeutics, and is the most common cause of cancer death in low-resource countries. We characterized 19 cervical and four head and neck cancer cell lines using long-read DNA and RNA sequencing and identified the HPV types, HPV integration sites, chromosomal alterations, and cancer driver mutations. Structural variation analysis revealed telomeric deletions associated with DNA inversions resulting from breakage-fusion-bridge (BFB) cycles. BFB is a common mechanism of chromosomal alterations in cancer, and our study applies long-read sequencing to this important chromosomal rearrangement type. Analysis of the inversion sites revealed staggered ends consistent with exonuclease digestion of the DNA after breakage. Some BFB events are complex, involving inter- or intra-chromosomal insertions or rearrangements. None of the BFB breakpoints had telomere sequences added to resolve the dicentric chromosomes, and only one BFB breakpoint showed chromothripsis. Five cell lines have a chromosomal region 11q BFB event, with YAP1-BIRC3-BIRC2 amplification. Indeed, YAP1 amplification is associated with a 10-year-earlier age of diagnosis of cervical cancer and is three times more common in African American women. This suggests that individuals with cervical cancer and YAP1-BIRC3-BIRC2 amplification, especially those of African ancestry, might benefit from targeted therapy. In summary, we uncovered valuable insights into the mechanisms and consequences of BFB cycles in cervical cancer using long-read sequencing.

Fragment-based design and MD simulations of human papilloma virus-16 E6 protein inhibitors

The main objective of this study is to screen potential small molecule inhibitors against HPV (Human Papilloma Virus)-16 E6 protein (HPV16 E6P) using a fragment-based approach. Twenty-six natural HPV inhibitors were selected based on the review of the literature. Among them, Luteolin was selected as the reference compound. These 26 compounds were used to generate novel inhibitors against HPV16 E6P. Fragment script and BREED of Schrodinger software were used to build novel inhibitor molecules. The result in 817 novel molecules was docked into the active binding site of HPV E6 protein and the top ten compounds were screened based on binding affinity compared to Luteolin for further study. Compounds Cpd5, Cpd7, and Cpd10 were the most potent inhibitors of HPV16 E6P and these were non-toxic and showed high Gastrointestinal (GI) absorption and positive drug-likeness score. Complexes of these compounds were stable in the 200 ns Molecular Dynamics (MD) simulation. These 3 HPV16 E6P inhibitors could be the lead molecules as new drugs for HPV-related diseases.Communicated by Ramaswamy H. Sarma.

SIRT1 is an actionable target to restore p53 function in HPV-associated cancer therapy

BACKGROUND

Our aim was to evaluate the efficacy and anti-cancer action of a precision medicine approach involving a novel SIRT1-dependent pathway that, when disrupted, leads to the restoration of a functional p53 in human papillomavirus (HPV)-transformed cells.

METHODS

The anticancer potential of inhibiting SIRT1 was evaluated by examining the effects of the specific SIRT1 inhibitor EX527 (also known as Selisistat) or genetic silencing, either individually or in conjunction with standard chemotherapeutic agents, on a range of HPV+ cancer cells and a preclinical mouse model of HPV16-induced cancer.

RESULTS

We show that SIRT1 inhibition restores a transcriptionally active K382-acetylated p53 in HPV+ but not HPV- cell lines, which in turn promotes G0/G1 cell cycle arrest and inhibits clonogenicity specifically in HPV+ cells. Additionally, EX527 treatment increases the sensitivity of HPV+ cells to sublethal doses of standard genotoxic agents. The enhanced sensitivity to cisplatin as well as p53 restoration were also observed in an in vivo tumorigenicity assay using syngeneic C3.43 cells harbouring an integrated HPV16 genome, injected subcutaneously into C57BL/6J mice.

CONCLUSIONS

Our findings uncover an essential role of SIRT1 in HPV-driven oncogenesis, which may have direct translational implications for the treatment of this type of cancer.

Nona-Arginine Mediated Anti-E6 ShRNA Delivery Suppresses the Growth of Hela Cells in vitro

Background

The E6 oncoprotein of HPV plays a crucial role in promoting cell proliferation and inhibiting apoptosis, leading to tumor growth. Non-viral vectors such as nona-arginine (R9) peptides have shown to be potential as carriers for therapeutic molecules. This study aimed to investigate the efficacy of nona-arginine in delivering E6 shRNA and suppressing the E6 gene of HeLa cells in vitro.

Methods

HeLa cells carrying E6 gene were treated with a complex of nona-arginine and E6 shRNA. The complex was evaluated using gel retardation assay and FESEM microscopy. The optimal N/P ratio for R9 peptide to transfect HeLa cells with luciferase gene was determined. Relative real-time PCR was used to evaluate the efficiency of mRNA suppression efficiency for E6 shRNA, while the effect of E6 shRNA on cell viability was measured using an MTT assay.

Results

The results indicated that R9 efficiently binds to shRNA and effectively transfects E6 shRNA complexes at N/P ratios greater than 30. Transfection with R9 and PEI complexes resulted in a significant toxicity compared to the scrambled plasmid, indicating selective toxicity for HeLa cells. Real-time PCR confirmed the reduction of E6 mRNA expression levels in the cells transfected with anti-E6 shRNA.

Conclusion

The study suggests that R9 is a promising non-viral gene carrier for transfecting E6 shRNA in vitro, with significant transfection efficiency and minimal toxicity.

Insights into the Mechanisms and Structure of Breakage-Fusion-Bridge Cycles in Cervical Cancer using Long-Read Sequencing

Cervical cancer is caused by human papillomavirus (HPV) infection, has few approved targeted therapeutics, and is the most common cause of cancer death in low-resource countries. We characterized 19 cervical and four head and neck cell lines using long-read DNA and RNA sequencing and identified the HPV types, HPV integration sites, chromosomal alterations, and cancer driver mutations. Structural variation analysis revealed telomeric deletions associated with DNA inversions resulting from breakage-fusion-bridge (BFB) cycles. BFB is a common mechanism of chromosomal alterations in cancer, and this is one of the first analyses of these events using long-read sequencing. Analysis of the inversion sites revealed staggered ends consistent with exonuclease digestion of the DNA after breakage. Some BFB events are complex, involving inter- or intra-chromosomal insertions or rearrangements. None of the BFB breakpoints had telomere sequences added to resolve the dicentric chromosomes and only one BFB breakpoint showed chromothripsis. Five cell lines have a Chr11q BFB event, with YAP1/BIRC2/BIRC3 gene amplification. Indeed, YAP1 amplification is associated with a 10-year earlier age of diagnosis of cervical cancer and is three times more common in African American women. This suggests that cervical cancer patients with YAP1/BIRC2/BIRC3-amplification, especially those of African American ancestry, might benefit from targeted therapy. In summary, we uncovered new insights into the mechanisms and consequences of BFB cycles in cervical cancer using long-read sequencing.

Curcumin inhibits human cancer cell growth and migration through downregulation of SVCT2

Curcumin is a natural polyphenol that is extracted from the rhizomes of the turmeric plant (Curcuma longa), a member of the ginger family. It has been used for centuries in traditional Indian and Chinese medicine for its medicinal properties, including anti-inflammatory, antioxidant and antitumor effects. SVCT2 (Solute Carrier Family 23 Member 2, also known as SLC23A2) is a protein that plays a role in the transport of Vitamin C (Ascorbic Acid) into cells. SVCT2 plays an important role in tumor progression and metastasis, however, the molecular mechanisms of curcumin on SVCT2 have not been studied to date. Curcumin treatment inhibited proliferation and migration of cancer cells in a dose dependent manner. We found that curcumin reduced the expression of SVCT2 in cancer cells with a wild type p53, but not in those with a mutant type of p53. SVCT2 downregulation also reduced the MMP2 activity. Taken together, our results indicate that curcumin inhibited human cancer cell growth and migration by regulating SVCT2 through a downregulating p53. These findings provide new insights into the molecular mechanisms of curcumin's anticancer effects and potential therapeutic strategies for the treatment of metastatic migration.

Characterization of DoTc2 4510-Identifying HPV16 Presence in a Cervical Carcinoma Cell Line Previously Considered to Be HPV-Negative

Cervical cancer is the fourth leading cause of cancer deaths in women, with over 340,000 women dying from this disease in 2020. Almost all cases have an underlying persistent infection with an oncogenic high-risk type of human papillomavirus (HPV), mainly HPV16. While cervical squamous cell carcinoma is hardly ever HPV-negative, a small subset of adenocarcinoma exhibits absence of HPV, even after disproval of false-negative testing results due to low viral load. This proportion is evident in many cervical cancer studies and is reflected in the repertoire of model cell lines commonly used in research. As the viral origin of cervical cancer makes it a disease preventable and potentially treatable by immunotherapeutic approaches, it is the focus of many studies. For pertinent research, both a broad set of HPV-infected cervical carcinoma models are required, as well as stringent negative controls. A ubiquitously used HPV-negative cervical adenocarcinoma cell line is C-33A. Another cervical cancer cell line is available for purchase from the American Type Culture Collection (ATCC), namely DoTc2 4510, described to be HPV-negative and thus as a model for a rare gynecological malignancy. Here, we present findings proving that DoTc2 4510 is, in fact, an HPV16-positive cell line. This we assessed using a highly sensitive nested multiplex PCR protocol adapted for the identification of 12 carcinogenic HPV types and a second PCR targeting the HPV16 oncogenes E6 and E7. Subsequently, the protein expression of E6 and E7 was examined, as well as the expression of their target proteins p53, p21, and p16INK4a, to assess E6/E7 functionality. Finally, to attest to the survival dependence of DoTc2 4510 cells on HPV16, we performed an HPV16 E6/E7-targeted siRNA knock-down, which indeed led to senescence induction. Together, these findings demonstrate that DoTc2 4510 is an HPV16-transformed cell line.

Interaction between Human Papillomavirus-Encoded E6 Protein and AurB Induces Cell Immortalization and Proliferation-A Potential Target of Intervention

The human papillomavirus E6 and E7 oncoproteins interact with a different subset of host proteins, leading to dysregulation of the apoptotic, cell cycle, and signaling pathways. In this study, we identified, for the first time, that Aurora kinase B (AurB) is a bona fide interacting partner of E6. We systematically characterized the AurB-E6 complex formation and its consequences in carcinogenesis using a series of in vitro and cell-based assays. We also assessed the efficacy of Aurora kinase inhibitors in halting HPV-mediated carcinogenesis using in vitro and in vivo models. We showed that AurB activity was elevated in HPV-positive cells, and this correlated positively with the E6 protein level. E6 interacted directly with AurB in the nucleus or mitotic cells. A previously unidentified region of E6, located upstream of C-terminal E6-PBM, was important for AurB-E6 complex formation. AurB-E6 complex led to reduced AurB kinase activity. However, the AurB-E6 complex increased the hTERT protein level and its telomerase activity. On the other hand, AurB inhibition led to the inhibition of telomerase activity, cell proliferation, and tumor formation, even though this may occur in an HPV-independent manner. In summary, this study dissected the molecular mechanism of how E6 recruits AurB to induce cell immortalization and proliferation, leading to the eventual cancer development. Our findings revealed that the treatment of AZD1152 exerted a non-specific anti-tumor effect. Hence, a continuous effort to seek a specific and selective inhibitor that can halt HPV-mediated carcinogenesis should be warranted.

Novel canonical and non-canonical viral antigens extend current targets for immunotherapy of HPV-driven cervical cancer

Current immunotherapeutic approaches for human papillomavirus (HPV)-driven cervical cancer target the viral oncogenes E6 and E7. We report viral canonical and alternative reading frame (ARF)-derived sequences presented on cervical tumor cells, including antigens encoded by the conserved viral gene E1. We confirm immunogenicity of the identified viral peptides in HPV-positive women, and women with cervical intraepithelial neoplasia. We observe consistent transcription of the E1, E6, and E7 genes in 10 primary cervical tumor resections from the four most common high-risk HPV subtypes (HPV16, 18, 31, and 45), suggesting the suitability of E1 as therapeutic target. We finally confirm HLA presentation of canonical peptides derived from E6 and E7, and ARF-derived viral peptides from a reverse-strand transcript spanning the HPV E1 and E2 genes in primary human cervical tumor tissue. Our results extend currently known viral immunotherapeutic targets in cervical cancer and highlight E1 as an important cervical cancer antigen.

Adaptogenic activity of withaferin A on human cervical carcinoma cells using high-definition vibrational spectroscopic imaging

Despite invaluable advances in cervical cancer therapy, treatment regimens for recurrent or persistent cancers and low-toxicity alternative treatment options are scarce. In recent years, substances classified as adaptogens have been identified as promising drug sources for preventing and treating cancer-based diseases on their ability to attack multiple molecular targets. This paper establishes the effectiveness of inhibition of the neoplastic process by a withaferin A (WFA), an adaptogenic substance, based on an in vitro model of cervical cancer. This study explores for the first time the potential of high-definition vibrational spectroscopy methods, i.e. Fourier-transform infrared (FT-IR) and Raman spectroscopic (RS) imaging at the single-cell level to evaluate the efficacy of the adaptogenic drug. HeLa cervical cancer cells were incubated with various concentrations of WFA at different incubation times. The multimodal spectroscopic approach combined with partial least squares (PLS) regression allowed the identification of molecular changes (e.g., lipids, protein secondary structures, or nucleic acids) induced by WFA at the cellular level. The results clearly illustrate the enormous potential of WFA in inhibiting the proliferation of cervical cancer cells. WFA inhibited the growth of the studied cancer cell line in a dose-dependent manner. Such studies provide comprehensive information on the sensitivity of cells to adaptogenic drugs. This is a fundamental step towards determining the rate and nature of adaptogen-induced changes in cancer cells.

Mechanistic Contributions of lncRNAs to Cellular Signaling Pathways Crucial to the Lifecycle of Human Papillomaviruses

Papillomaviruses are ubiquitous epitheliotropic viruses with double-stranded circular DNA genomes of approximately 8000 base pairs. The viral life cycle is somewhat unusual in that these viruses can establish persistent infections in the mitotically active basal epithelial cells that they initially infect. High-level viral genome replication ("genome amplification"), the expression of capsid proteins, and the formation of infectious progeny are restricted to terminally differentiated cells where genomes are synthesized at replication factories at sites of double-strand DNA breaks. To establish persistent infections, papillomaviruses need to retain the basal cell identity of the initially infected cells and restrain and delay their epithelial differentiation program. To enable high-level viral genome replication, papillomaviruses also need to hold the inherently growth-arrested terminally differentiated cells in a replication-competent state. To provide ample sites for viral genome synthesis, they target the DNA damage and repair machinery. Studies focusing on delineating cellular factors that are targeted by papillomaviruses may aid the development of antivirals. Whilst most of the current research efforts focus on protein targets, the majority of the human transcriptome consists of noncoding RNAs. This review focuses on one specific class of noncoding RNAs, long noncoding RNAs (lncRNAs), and summarizes work on lncRNAs that may regulate the cellular processes that are subverted by papillomavirus to enable persistent infections and progeny synthesis.

HPV-Related Cervical Cancer and Extracellular Vesicles

Cervical cancer is the fourth most common type of cancer in females worldwide. Infection with a human papillomavirus is crucial to the etiopathogenesis of cervical cancer. The natural trajectory of HPV infection comprises HPV acquisition, HPV persistence versus clearance, and progression to precancer and invasive cancer. The majority of HPV infections are cleared and controlled by the immune system within 2 years, but some infections may become quiescent or undetectable. The persistence of high-risk HPV infection for a longer period of time enhances the risk of malignant transformation of infected cells; however, the mechanisms responsible for the persistence of infection are not yet well-understood. It is estimated that 10-15% of infections do persist, and the local microenvironment is now recognized as an important cofactor promoting infection maintenance. Extracellular vesicles (EVs) are small membrane vesicles derived from both normal cells and cancer cells. EVs contain various proteins, such as cytoskeletal proteins, adhesion molecules, heat shock proteins, major histocompatibility complex, and membrane fusion proteins. EVs derived from HPV-infected cells also contain viral proteins and nucleic acids. These biologically active molecules are transferred via EVs to target cells, constituting a kind of cell-to-cell communication. The viral components incorporated into EVs are transmitted independently of the production of infectious virions. This mode of transfer makes EVs a perfect vector for viruses and their components. EVs participate in both physiological and pathological conditions; they have also been identified as one of the mediators involved in cancer metastasis. This review discusses the potential role of EVs in remodeling the cervical cancer microenvironment which may be crucial to tumor development and the acquisition of metastatic potential. EVs are promising as potential biomarkers in cervical cancer.

FOXP4 inhibits squamous differentiation of atypical cells in cervical intraepithelial neoplasia via an ELF3-dependent pathway

Although the human papillomavirus (HPV) vaccine is effective for preventing cervical cancers, this vaccine does not eliminate pre‐existing infections, and alternative strategies have been warranted. Here, we report that FOXP4 is a new target molecule for differentiation therapy of cervical intraepithelial neoplasia (CIN). An immunohistochemical study showed that FOXP4 was expressed in columnar epithelial, reserve, and immature squamous cells, but not in mature squamous cells of the normal uterine cervix. In contrast with normal mature squamous cells, FOXP4 was expressed in atypical squamous cells in CIN and squamous cell carcinoma lesions. The FOXP4‐positive areas significantly increased according to the CIN stages from CIN1 to CIN3. In monolayer cultures, downregulation of FOXP4 attenuated proliferation and induced squamous differentiation in CIN1‐derived HPV 16‐positive W12 cells via an ELF3‐dependent pathway. In organotypic raft cultures, FOXP4‐downregulated W12 cells showed mature squamous phenotypes of CIN lesions. In human keratinocyte‐derived HaCaT cells, FOXP4 downregulation also induced squamous differentiation via an ELF3‐dependent pathway. These findings suggest that downregulation of FOXP4 inhibits cell proliferation and promotes the differentiation of atypical cells in CIN lesions. Based on these results, we propose that FOXP4 is a novel target molecule for nonsurgical CIN treatment that inhibits CIN progression by inducing squamous differentiation.

Adequacy in Endocervical Curettage

OBJECTIVES

Specimen adequacy is an important quality assurance component of a cervical Papanicolaou test. Although consensus exists on minimal acceptable cellularity for cervical Papanicolaou tests, no such criteria exist for endocervical curettage (ECC) specimens. We sought to identify minimum acceptable cellularity for accurate diagnosis of high-grade dysplasia (HGD) on ECC.

METHODS

All patients with HGD diagnosed in a loop electrosurgical excision procedure (LEEP) from May 8, 2018, to December 18, 2019, and an ECC in the preceding 6 months at our institution were included (n = 51). All ECCs performed before the LEEP were evaluated for cellularity of squamous cells using Aperio eSlide Manager (Leica Biosystems). Biopsy results concurrent with the ECC were noted. We compared the number of squamous cells in positive and negative ECC specimens using a t-test. The proportion of ECC specimens and concurrent biopsies undergoing immunohistochemical (IHC) staining for p16 were compared using the χ2 test. P < .05 was considered significant.

RESULTS

Endocervical curettage specimens positive for HGD have increased cellularity compared with negative ECC specimens (mean cellularity, 10,165 vs 1,055; P < .05). Further, IHC staining for p16 was more likely to be performed on an ECC specimen positive for HGD than on a negative ECC specimen (50% vs 3%; P < .05). Biopsies performed concurrently with a negative ECC finding were more likely to undergo p16 IHC than biopsies performed concurrently with a positive ECC finding (51% vs 7%; P < .05). Finally, we observed no difference in the proportion of biopsies undergoing IHC staining for p16 when comparing biopsies positive for HGD with negative biopsies (37% vs 46%; P = .33).

CONCLUSIONS

We find cellularity of approximately 10,000 cells adequate to diagnose HGD in an ECC specimen and cellularity of approximately 1,000 cells to be inadequate. Further, we find p16 IHC commonly used as a "rule-in" test on ECC specimens at our institution. Biopsies accompanying an ECC specimen negative for HGD are more likely to undergo p16 IHC than those accompanying an ECC specimen positive for HGD, but there is no difference in the proportion of biopsies undergoing p16 IHC when comparing positive and negative results in the biopsies themselves. These findings further support the need for adequate cellularity for diagnosis in ECC, especially when a biopsy is technically difficult. Further areas for exploration include investigating laboratory procedures to maximize the cellularity of ECC specimens.

Phytoconstituents of traditional Himalayan Herbs as potential inhibitors of Human Papillomavirus (HPV-18) for cervical cancer treatment: An In silico Approach

Human papillomavirus (HPV) induced cervical cancer is becoming a major cause of mortality in women. The present research aimed to identify the natural inhibitors of HPV-18 E1 protein (1R9W) from Himalayan herbs with lesser toxicity and higher potency. In this study, one hundred nineteen phytoconstituents of twenty important traditional medicinal plants of Northwest Himalayas were selected for molecular docking with the target protein 1R9W of HPV-18 E1 Molecular docking was performed by AutoDock vina software. ADME/T screening of the bioactive phytoconstituents was done by SwissADME, admetSAR, and Protox II. A couple of best protein-ligand complexes were selected for 100 ns MD simulation. Molecular docking results revealed that among all the selected phytoconstituents only thirty-five phytoconstituents showed the binding affinity similar or more than the standard anti-cancer drugs viz. imiquimod (-6.1 kJ/mol) and podofilox (-6.9 kJ/mol). Among all the selected thirty-five phytoconstituents, eriodictyol-7-glucuronide, stigmasterol, clicoemodin and thalirugidine showed the best interactions with a docking score of -9.1, -8.7, -8.4, and -8.4 kJ/mol. Based on the ADME screening, only two phytoconstituents namely stigmasterol and clicoemodin selected as the best inhibitor of HPV protein. MD simulation study also revealed that stigmasterol and clicoemodin were stable inside the binding pocket of 1R9W, Stigmasterol and clicoemodin can be used as a potential investigational drug to cure HPV infections.

HPV16 E6 gene polymorphisms and the functions of the mutation site in cervical cancer among Uygur ethnic and Han nationality women in Xinjiang, China

BACKGROUND

To investigate the genotype distribution of human papillomavirus (HPV) in infected Uygur and Han women in Xinjiang, China; analyze the HPV16 E6 gene polymorphism site and relationship with the development of cervical cancer.

METHODS

The HPV16 E6 sequence was analyzed using the European standard prototype to perform an evolutionary tree. HPV16 E6-T295/T350, G295/G350, and T295/G350 GV230 vectors were stably transfected into cervical cancer C33A cells to analyze the cell proliferation, migration and invasion, apoptosis by CCK8 and clonogenic assays, transwell and cell scratch assays, FACS experiments.

RESULTS

The total HPV infection rate was 26.390% (760/2879), whereas the Uygur 22.87% (196/857) and the Han was 27.89% (564/2022) (P < 0.05). Among 110 mutations, 65 cases of E6 genes were mutated at nucleotide 350 (T350G) with the leucine changing to valine (L83V). Moreover, there were 7 cases of E6 gene mutated at nucleotide 295 (T295G) with aspartic changing to glutamic (D64E). When E6 vector(s) of mutations sites were transfected into C33A cells, they were found to promote cellular proliferation, migration, invasion, and inhibit apoptosis. T295/G350-E6 was significantly stronger than G295/G350 and T295/T350, G295/G350 was significantly stronger than T295/T350 (P < 0.05). The T295/G350 had the strongest effect on C33A cells and G295/G350 was significantly stronger than T295/T350 (P < 0.05).

CONCLUSIONS

The positive HPV infection rates differed between the Uygur and Han in Xinjiang, China, and the genotype distribution of infection was different. After transfecting C33A cells with different eukaryotic expression vectors, the T295/G350 mutation site promoted the proliferation, migration, and invasion of C33A cells to a greater extent than G295/G350; however, G295/G350 had a stronger effect than T295/T350.

Co-Delivery of p53 Restored and E7 Targeted Nucleic Acids by Poly (Beta-Amino Ester) Complex Nanoparticles for the Treatment of HPV Related Cervical Lesions

The p53 gene has the highest mutation frequency in tumors, and its inactivation can lead to malignant transformation, such as cell cycle arrest and apoptotic inhibition. Persistent high-risk human papillomavirus (HR-HPV) infection is the leading cause of cervical cancer. P53 was inactivated by HPV oncoprotein E6, promoting abnormal cell proliferation and carcinogenesis. To study the treatment of cervical intraepithelial neoplasia (CIN) and cervical cancer by restoring p53 expression and inactivating HPV oncoprotein, and to verify the effectiveness of nano drugs based on nucleic acid delivery in cancer treatment, we developed poly (beta-amino ester)537, to form biocompatible and degradable nanoparticles with plasmids (expressing p53 and targeting E7). In vitro and in vivo experiments show that nanoparticles have low toxicity and high transfection efficiency. Nanoparticles inhibited the growth of xenograft tumors and successfully reversed HPV transgenic mice’s cervical intraepithelial neoplasia. Our work suggests that the restoration of p53 expression and the inactivation of HPV16 E7 are essential for blocking the development of cervical cancer. This study provides new insights into the precise treatment of HPV-related cervical lesions.

Antiproliferative and apoptotic potential of Glycyrrhizin against HPV16+ Caski cervical cancer cells: A plausible association with downreguation of HPV E6 and E7 oncogenes and Notch signaling pathway

Cervical cancer (CCa) is the second most frequent carcinoma in females and human papilloma virus (HPV) oncoproteins are regarded as one of the critical etiological agent. Despite recent advances in screening and management of CCa, still it remains the deadliest carcinoma as advanced and metastatic stages are mostly incurable. This urges for the development of newer therapeutic interventions. The current was aimed to investigate the antiproliferative and apoptotic potential of glycyrrhizin (Gly) against HPV16⁺ CaSki CCa cells. Our findings substantiated that Gly exerted antiproliferative effects on the CaSki cells by obstructing their proliferation rate. Gly substantially enhanced apoptosis in Caski cells in a dose-dependent manner via augmenting the generation of ROS, DNA fragmentation and disruption of the mitochondrial membrane potential. Gly mediated apoptosis in CaSki cells was found to be due to activation of caspase-8 and capsase-9 along with the modulation of pro-and anti-apoptotic gene expression. Moreover, Gly halts the progression of CaSki cells at G₀/G₁ phase which was found to be due to reduced expression of cyclin D1 and cyclin-dependent kinase 4 (CDK4) along with the enhanced expression of CDK inhibitor p21^Cip1. Further, Gly downregulates the expression of HPV oncoproteins (E6 & E7) along with the inhibition of Notch signaling pathway. Taken together, Gly represents as a potential therapeutic modality for CCa which could rapidly be translated for clinical studies.

The degradation of Rap1GAP via E6AP-mediated ubiquitin-proteasome pathway is associated with HPV16/18-infection in cervical cancer cells

BACKGROUND

Cervical cancers are closely associated with persistent high-risk human papillomaviruses (HR HPV) infection. The main mechanism involves the targeting of tumor suppressors, such as p53 and pRB, for degradation by HR HPV-encoded oncoproteins, thereby leading to tumorigenesis. Rap1GAP, a tumor suppressor gene, is down-regulated in many cancers. Previous studies have revealed that down-regulation of Rap1GAP is correlated with HPV16/18 infection in cervical cancer. However, the molecular mechanism remains unclear. In this study, we aimed to address the degradation pathway of Rap1GAP in HPV-positive cervical cancer cells.

METHODS

HPV-positive (HeLa and SiHa) and negative (C33A) cervical cancer cells were used to analyze the pathways of Rap1GAP degradation. MG132 (carbobenzoxy-leucyl-leucyl-leucine) was used to inhibit protein degradation by proteasome. Co-immunoprecipitation (co-IP) was used to detect the interaction between Rap1GAP and E6AP. siRNA for E6AP was used to silence the expression of E6AP. Rapamycin was used to induce cell autophagy. Western blotting was used to check the levels of proteins.

RESULTS

Following treatment with MG132, the levels of Rap1GAP were increased in the HR HPV-positive HeLa and SiHa cells, but not in the HPV-negative C33A cells. Co-immunoprecipitation assay revealed ubiquitinated Rap1GAP protein in HeLa and SiHa cells, but not in C33A cells. E6-associated protein (E6AP) mediated the ubiquitination of Rap1GAP by binding to it in HeLa and SiHa cells, but not in C33A cells. However, the levels of Rap1GAP were decreased in HeLa and SiHa cells after knocking down E6AP by siRNA. Silencing of E6AP did not affect the levels of Rap1GAP in C33A cells. Autophagy marker p62 was decreased and LC3 II/LC3 I was increased after knocking down E6AP in HeLa cells, but not in C33A cells. The levels of Rap1GAP were decreased after treating the cells with rapamycin to induce cell autophagy in HeLa and C33A cells.

CONCLUSION

Rap1GAP may be degraded by autophagy in cervical cancer cells, but HPV infection can switch the degradation pathway from autophagy to E6AP-mediated ubiquitin-proteasome degradation. E6AP may be a key component of the switch.

Identification of microRNAs that stabilize p53 in HPV-positive cancer cells

Etiologically, 5% of all cancers worldwide are caused by the high-risk human papillomaviruses (hrHPVs). These viruses encode two oncoproteins (E6 and E7) whose expression is required for cancer initiation and maintenance. Among their cellular targets are the p53 and the retinoblastoma tumor suppressor proteins. Inhibition of the hrHPV E6-mediated ubiquitylation of p53 through the E6AP ubiquitin ligase results in the stabilization of p53, leading to cellular apoptosis. We utilized a live cell high throughput screen to determine whether exogenous microRNA (miRNA) transfection had the ability to stabilize p53 in hrHPV-positive cervical cancer cells expressing a p53-fluorescent protein as an in vivo reporter of p53 stability. Among the miRNAs whose transfection resulted in the greatest p53 stabilization was 375-3p that has previously been reported to stabilize p53 in HeLa cells, providing validation of the screen. The top 32 miRNAs in addition to 375-3p were further assessed using a second cell-based p53 stability reporter system as well as in non-reporter HeLa cells to examine their effects on endogenous p53 protein levels, resulting in the identification of 23 miRNAs whose transfection increased p53 levels in HeLa cells. While a few miRNAs that stabilized p53 led to decreases in E6AP protein levels, all targeted HPV oncoprotein expression. We further examined subsets of these miRNAs for their abilities to induce apoptosis and determined whether it was p53-mediated. The introduction of specific miRNAs revealed surprisingly heterogeneous responses in different cell lines. Nonetheless, some of the miRNAs described here have potential as therapeutics for treating HPV-positive cancers. Importance Human papillomaviruses cause approximately 5% of all cancers worldwide and encode genes that contribute to both the initiation and maintenance of these cancers. The viral oncoprotein E6 is expressed in all HPV-positive cancers and functions by targeting the degradation of p53 through the engagement of the cellular ubiquitin ligase E6AP. Inhibiting the degradation of p53 leads to apoptosis in HPV-positive cancer cells. Using a high throughput live cell assay we identified several miRNAs whose transfection stabilize p53 in HPV-positive cells. These miRNAs have the potential to be used in the treatment of HPV-positive cancers.

Potent, Selective CARs as Potential T-Cell Therapeutics for HPV-positive Cancers

Next-generation T-cell therapies will likely continue to utilize T-cell receptors (TCRs) and chimeric antigen receptors (CARs) because each receptor type has advantages. TCRs often possess exceptional properties even when tested unmodified from patients' T cells. CARs are generally less sensitive, possibly because their ligand-binding domains are grafted from antibodies selected for binding affinity or avidity and not broadly optimized for a functional response. Because of the disconnect between binding and function among these receptor types, the ultimate potential of CARs optimized for sensitivity and selectivity is not clear. Here, we focus on a thoroughly studied immuno-oncology target, the HLA-A*02/HPV-E629-38 complex, and show that CARs can be optimized by a combination of high-throughput binding screens and low-throughput functional assays to have comparable activity to clinical TCRs in acute assays in vitro. These results provide a case study for the challenges and opportunities of optimizing high-performing CARs, especially in the context of targets utilized naturally by TCRs.

Epstein-Barr virus: Current questions and challenges

Epstein-Barr virus (EBV) infects most people worldwide and persists for life due to complicated interplay between lytic infection and multiple types of latent infections. While usually asymptomatic, EBV is a causative agent in several types of cancer and has a strong association with multiple sclerosis. Exactly how EBV promotes these diseases and why they are rare consequences of infection are incompletely understood. Here I will discuss current ideas on disease induction by EBV, including the importance of lytic protein expression in the context of latent infection as well as the possible importance of specific EBV variants in disease induction.

Mutational analysis of p53 gene in cervical cancer and useful polymorphic variants in exons 3 and 4

Background

Factors contributing to the pathogenesis and progression of cervical cancer include poor attitude to screening and health intervention, late presentation, among others. Mutations in p53 gene have been attributed to several cancer cases. The present study was designed to find relationships between the mutation patterns in p53 gene and cervical carcinoma staging. Such knowledge could contribute to early diagnosis of cervical cancer.

Results

From the sequence analysis of p53 gene fragment isolated by polymerase chain reactions (PCR), nineteen (19) polymorphic variants were identified. Missense mutations occurred in 47% of the samples, 32% were silent mutations, 16% were frameshift mutations and 5% nonsense mutations. Socio-biological characteristics of the study participants revealed that 60% have husbands with multiple sexual partners and that only 23.3% of the participants have ever had the Papanicolaou (Pap) smear test prior to diagnosis, whilst 20% were unaware of the screening test.

Conclusions

Increased severity of cervical carcinoma staging as revealed from the histopathological analysis was found to be associated with accumulation of higher levels of mutations in the p53 gene. Molecular analysis of p53 gene mutations may prove useful as a screening biomarker for cervical cancer.

Nkx2.5 Functions as a Conditional Tumor Suppressor Gene in Colorectal Cancer Cells via Acting as a Transcriptional Coactivator in p53-Mediated p21 Expression

NK2 homeobox 5 (Nkx2.5), a homeobox-containing transcription factor, is associated with a spectrum of congenital heart diseases. Recently, Nkx2.5 was also found to be differentially expressed in several kinds of tumors. In colorectal cancer (CRC) tissue and cells, hypermethylation of Nkx2.5 was observed. However, the roles of Nkx2.5 in CRC cells have not been fully elucidated. In the present study, we assessed the relationship between Nkx2.5 and CRC by analyzing the expression pattern of Nkx2.5 in CRC samples and the adjacent normal colonic mucosa (NCM) samples, as well as in CRC cell lines. We found higher expression of Nkx2.5 in CRC compared with NCM samples. CRC cell lines with poorer differentiation also had higher expression of Nkx2.5. Although this expression pattern makes Nkx2.5 seem like an oncogene, in vitro and in vivo tumor suppressive effects of Nkx2.5 were detected in HCT116 cells by establishing Nkx2.5-overexpressed CRC cells. However, Nkx2.5 overexpression was incapacitated in SW480 cells. To further assess the mechanism, different expression levels and mutational status of p53 were observed in HCT116 and SW480 cells. The expression of p21WAF1/CIP1, a downstream antitumor effector of p53, in CRC cells depends on both expression level and mutational status of p53. Overexpressed Nkx2.5 could elevate the expression of p21WAF1/CIP1 only in CRC cells with wild-type p53 (HCT116), rather than in CRC cells with mutated p53 (SW480). Mechanistically, Nkx2.5 could interact with p53 and increase the transcription of p21WAF1/CIP1 without affecting the expression of p53. In conclusion, our findings demonstrate that Nkx2.5 could act as a conditional tumor suppressor gene in CRC cells with respect to the mutational status of p53. The tumor suppressive effect of Nkx2.5 could be mediated by its role as a transcriptional coactivator in wild-type p53-mediated p21WAF1/CIP1 expression.

Involvement of p53-dependent apoptosis signal in antitumor effect of Colchicine on human papilloma virus (HPV)-positive human cervical cancer cells

Colchicine, a plant-derived alkaloid with relatively low toxicity on normal human epidermal keratinocytes (HEKn), has selective inhibitory effect on the growth of CaSki (HPV16-positive) and HeLa (HPV18-positive) human cervical cancer cell lines via the induction of apoptosis. Colchicine (2.5, 5.0 and 10.0 ng/ml) significantly reduced the expression of human papilloma virus (HPV) 16 E6/E7 mRNA and protein in CaSki and HeLa cells. Moreover, reduced expression of E6 and E7 induced by Colchicine resulted in the up-regulation of tumor suppressor proteins, p53 and Rb, as well as down-regulation of phospho Rb (pRb) protein. In addition, Bax, cytosolic cytochrome c and cleaved caspase-3 protein were increased while Bcl-2 protein was decreased significantly by 48 h of Colchicine treatment. These results implied that Colchicine could be explored as a potent candidate agent for the treatment and prevention of HPV-associated cervical cancer without deleterious effects.

Non-Metabolic Functions of PKM2 Contribute to Cervical Cancer Cell Proliferation Induced by the HPV16 E7 Oncoprotein

Pyruvate kinase M2 (PKM2) mainly catalyzes glycolysis, but it also exerts non-glycolytic functions in several cancers. While it has been shown to interact with the human papillomavirus 16 (HPV16) E7 oncoprotein, the functional significance of PKM2 in HPV-associated cervical cancer has been elusive. Here, we show that HPV16 E7 increased the expression of PKM2 in cervical cancer cells. TCGA data analyses revealed a higher level of PKM2 in HPV+ than HPV- cervical cancers and a worse prognosis for patients with high PKM2 expression. Functionally, we demonstrate that shRNA-mediated PKM2 knockdown decreased the proliferation of HPV+ SiHa cervical cancer cells. PKM2 knockdown also inhibited the E7-induced proliferation of cervical cancer cells. ML265 activating the pyruvate kinase function of PKM2 inhibited cell cycle progression and colony formation. ML265 treatments decreased phosphorylation of PKM2 at the Y105 position that has been associated with non-glycolytic functions. On the contrary, HPV16 E7 increased the PKM2 phosphorylation. Our results indicate that E7 increases PKM2 expression and activates a non-glycolytic function of PKM2 to promote cervical cancer cell proliferation.

Leaf Extract of Nerium oleander L. Inhibits Cell Proliferation, Migration and Arrest of Cell Cycle at G2/M Phase in HeLa Cervical Cancer Cell

BACKGROUND

Cervical cancer is one of the most common gynaecological malignant tumors reported in women. Although a number of early screening and treatment options are available, mortality due to cervical cancer remains high. Nerium oleander L. is a potential medicinal plant that possesses a wide spectrum of pharmacological and physiological activities including anticancer activities.

OBJECTIVE

This study aims to evaluate the antiproliferative activity, inhibition of cell migration and cell cycle arrest by the chloroform extract of leaves of Nerium Oleander L. in HeLa cervical cancer cells. The chloroform extract of Catharanthus roseus which contains anti-cancer compounds, Vinblastin and Vincristin, was used as a positive control for this study.

METHODS

The chloroform extracts of Nerium oleander L. and Catharanthus roseus were prepared using the standard protocol. The cytotoxic effects were studied by MTT assay. Cell migration was studied by in vitro scratch assay. Analysis of the cell cycle was carried out by Propidium iodide staining and Flow Cytometry. The expression level of various proteins was evaluated by immunocytochemistry.

RESULTS

In this study, we showed that the leaf extract of Nerium oleander inhibited the growth of HeLa cervical cancer cells in culture and inhibited cell migration. Besides, it arrested the cell cycle at the G2/M phase. The Epidermal Growth Factor Receptor (EGFR) expression and phosphorylated p-Rb (Ser 780) level were significantly downregulated by leaf extract of Nerium oleander.

CONCLUSION

The extract of Nerium oleander L. contains potential bioactive compounds that inhibit HeLa cell proliferation, cell migration and arrest cell cycle at the G₂/M phase.

Oncolytic Adenovirus H101 Synergizes with Radiation in Cervical Cancer Cells

BACKGROUND

A major challenge in cervical cancer radiotherapy is tailoring the radiation doses efficiently to eliminate malignant cells and reduce the side effects in normal tissues. Oncolytic adenovirus drug H101 was recently tested and approved as a topical adjuvant treatment for several malignancies.

OBJECTIVE

This study aimed to evaluate the potential neoadjuvant radiotherapy benefits of H101 by testing the inhibitory function of H101 in combination with radiation in different cervical cancer cells.

METHODS

Human cervical cancer cell lines C33a, SiHa, CaSki, and HeLa were treated with varying concentrations of H101 alone or in combination with radiation (2 Gy or 4 Gy). Cell viability and apoptosis were measured at the indicated time intervals. HPV16 E6 and cellular p53 mRNA expression alteration was measured by qRT-PCR. In situ RNA scope was used to determine HPV E6 status. P53 protein alterations were detected by Western blot.

RESULTS

Cell viability and apoptosis assays revealed that the combination of a high dose of H101 (MOI=1000, 10000) with radiation yielded a synergistic anticancer effect in all tested cervical cancer cell lines (P<0.05), with the greatest effect achieved in HPV-negative C33a cells (P<0.05). Low-HPV16-viral-load SiHa cells were more sensitive to the combination therapy than high-HPV16- viral-load CaSki cells (P<0.05). The combined treatment reduced HPV16 E6 expression and increased cellular P53 levels compared to those observed with radiation alone in SiHa and CaSki cells (P<0.05).

CONCLUSION

Oncolytic adenovirus H101 effectively enhances the antitumor efficacy of radiation in cervical cancer cells and may serve as a novel combination therapy for cervical cancer.

Viral load and interaction of HPV oncoprotein E6 and E7 with host cellular markers in the progression of cervical cancer

<abstract> <p>Cervical cancer is the sequel of a multi-factorial, long-term unresolved disease that includes genetic, epigenetic, and viral components responsible for its development and progression. It is the second most common cancer of females in India. Human papillomavirus (HPV) is considered the primary causative agent of pre-neoplastic and cancerous lesions and 90% of all cervical carcinomas are linked to high-risk HPV type 16 and type 18. Although most HR-HPV infections are asymptomatic, transient, and self-limiting, the persistent infection with a high risk (HR-HPV) may cause precancerous lesions that can progress to cervical cancer. HPV type 16 is the most common HPV in India associated with more than 75% of cervical cancer, followed by HPV type 18 and other high-risk types. Infection with HPV alone is not sufficient for the development of cervical cancer but there is the involvement of some host genetic factors also that are responsible for the development and progression of cervical cancer. This article briefly reviews molecular pathogenesis, viral load, and the interaction of HPV oncoprotein E6 and E7 with host cellular markers in the progression of cervical cancer.</p> </abstract>

Biological and clinical aspects of HPV-related cancers

Cancer-related diseases represent the second overall cause of death worldwide. Human papilloma virus (HPV) is an infectious agent which is mainly sexually transmitted and may lead to HPV-associated cancers in both men and women. Almost all cervical cancers are HPV-associated, however, an increasing number of head and neck cancers (HNCs), especially oropharyngeal cancer, can be linked to HPV infection. Moreover, anogenital cancers, including vaginal, vulvar, penial, and anal cancers, represent a subset of HPV-related cancers. Whereas testing and prevention of cervical cancer have significantly improved over past decades, anogenital cancers remain more difficult to confirm. Current clinical trials including patients with HPV-related cancers focus on finding proper testing for all HPV-associated cancers as well as improve the currently applied treatments. The HPV viral oncoproteins, E6 and E7, lead to degradation of, respectively, p53 and pRb resulting in entering the S phase without G1 arrest. These high-risk HPV viral oncogenes alter numerous cellular processes, including DNA repair, angiogenesis, and/or apoptosis, which eventually result in carcinogenesis. Additionally, a comprehensive analysis of gene expression and alteration among a panel of DNA double strand breaks (DSB) repair genes in HPV-negative and HPV-positive HNC cancers reveals differences pointing to HPV-dependent modifications of DNA repair processes in these cancers. In this review, we discuss the current knowledge regarding HPV-related cancers, current screening, and treatment options as well as DNA damage response-related biological aspects of the HPV infection and clinical trials.

Synchronization of human retinal pigment epithelial-1 cells in mitosis

Human retinal pigment epithelial-1 (RPE-1) cells are increasingly being used as a model to study mitosis because they represent a non-transformed alternative to cancer cell lines, such as HeLa cervical adenocarcinoma cells. However, the lack of an efficient method to synchronize RPE-1 cells in mitosis precludes their application for large-scale biochemical and proteomics assays. Here, we report a protocol to synchronize RPE-1 cells based on sequential treatments with the Cdk4 and Cdk6 inhibitor PD 0332991 (palbociclib) and the microtubule-depolymerizing drug nocodazole. With this method, the vast majority (80-90%) of RPE-1 cells arrested at prometaphase and exited mitosis synchronously after release from nocodazole. Moreover, the cells fully recovered and re-entered the cell cycle after the palbociclib-nocodazole block. Finally, we show that this protocol could be successfully employed for the characterization of the protein-protein interaction network of the kinetochore protein Ndc80 by immunoprecipitation coupled with mass spectrometry. This synchronization method significantly expands the versatility and applicability of RPE-1 cells to the study of cell division and might be applied to other cell lines that do not respond to treatments with DNA synthesis inhibitors.

Expression of the Long Noncoding RNA DINO in Human Papillomavirus-Positive Cervical Cancer Cells Reactivates the Dormant TP53 Tumor Suppressor through ATM/CHK2 Signaling

Functional restoration of the TP53 tumor suppressor holds great promise for anticancer therapy. Current strategies are focused on modulating TP53 regulatory proteins. Long noncoding RNAs (lncRNAs) have emerged as important regulators of TP53 as well as modulators of downstream tumor-suppressive transcriptional responses. Unlike many other cancer types, human papillomavirus (HPV)-positive cancer cells retain wild-type TP53 that is rendered dysfunctional by the viral E6 protein. We show that acute expression of the damage-induced long noncoding RNA, DINO, a known TP53 transcriptional target and functional modulator, causes TP53 reactivation in HPV-positive cervical cancer cells. This causes increased vulnerability to standard chemotherapeutics as well as biguanide compounds that cause metabolic stress. Hence, strategies that target DINO may be useful for restoring TP53 tumor suppressor activity in HPV-positive cancers and other tumor types that retain wild-type TP53.

Tumor cells overcome the cytostatic and cytotoxic restraints of TP53 tumor suppressor signaling through a variety of mechanisms. High-risk human papillomavirus (HPV)-positive tumor cells retain wild-type TP53 because the HPV E6/UBE3A ubiquitin ligase complex targets TP53 for proteasomal degradation. While restoration of TP53 in tumor cells holds great promise for cancer therapy, attempts to functionally restore the dormant TP53 tumor suppressor in HPV-positive cancer cells by inhibiting the HPV E6/UBE3A ubiquitin ligase complex have not yet been successful. The damage-induced long noncoding RNA, DINO (DINOL), is a TP53 transcriptional target that has been reported to bind to and stabilize TP53, thereby amplifying TP53 signaling. We show that HPV-positive cervical carcinoma cells contain low levels of DINO because of HPV E6/UBE3A-mediated TP53 degradation. Acute DINO expression overrides HPV16 E6/UBE3A-mediated TP53 degradation, causing TP53 stabilization and increased expression of TP53 transcriptional target genes. This causes a marked sensitization to chemotherapy agents and renders cells vulnerable to metabolic stress. Acute DINO expression in HPV-positive cervical cancer cells induces hallmarks of DNA damage response signaling, and TP53 activation involves ATM/CHK2 signaling. DINO upregulation in response to DNA damage is independent of ATM/CHK2 and can occur in cancer cells that express mutant TP53.

In Vitro Organotypic Systems to Model Tumor Microenvironment in Human Papillomavirus (HPV)-Related Cancers

Despite the well-known role of chronic human papillomavirus (HPV) infections in causing tumors (i.e., all cervical cancers and other human malignancies from the mucosal squamous epithelia, including anogenital and oropharyngeal cavity), its persistence is not sufficient for cancer development. Other co-factors contribute to the carcinogenesis process. Recently, the critical role of the underlying stroma during the HPV life cycle and HPV-induced disease have been investigated. The tumor stroma is a key component of the tumor microenvironment (TME), which is a specialized entity. The TME is dynamic, interactive, and constantly changing-able to trigger, support, and drive tumor initiation, progression, and metastasis. In previous years, in vitro organotypic raft cultures and in vivo genetically engineered mouse models have provided researchers with important information on the interactions between HPVs and the epithelium. Further development for an in-depth understanding of the interaction between HPV-infected tissue and the surrounding microenvironment is strongly required. In this review, we critically describe the HPV-related cancers modeled in vitro from the simplified 'raft culture' to complex three-dimensional (3D) organotypic models, focusing on HPV-associated cervical cancer disease platforms. In addition, we review the latest knowledge in the field of in vitro culture systems of HPV-associated malignancies of other mucosal squamous epithelia (anogenital and oropharynx), as well as rare cutaneous non-melanoma associated cancer.

The Role of Long Noncoding RNAs in Human Papillomavirus-associated Pathogenesis

Infections with high-risk human papillomaviruses cause ~5% of all human cancers. E6 and E7 are the only viral genes that are consistently expressed in cancers, and they are necessary for tumor initiation, progression, and maintenance. E6 and E7 encode small proteins that lack intrinsic enzymatic activities and they function by binding to cellular regulatory molecules, thereby subverting normal cellular homeostasis. Much effort has focused on identifying protein targets of the E6 and E7 proteins, but it has been estimated that ~98% of the human transcriptome does not encode proteins. There is a growing interest in studying noncoding RNAs as biochemical targets and biological mediators of human papillomavirus (HPV) E6/E7 oncogenic activities. This review focuses on HPV E6/E7 targeting cellular long noncoding RNAs, a class of biologically versatile molecules that regulate almost every known biological process and how this may contribute to viral oncogenesis.

MiR-23b-3p reduces the proliferation, migration and invasion of cervical cancer cell lines via the reduction of c-Met expression

Malignant transformation and progression in cancer is associated with the altered expression of multiple miRNAs, which are considered as post-transcriptional regulators of genes participating in various cellular processes. Although, it has been proposed that miR-23b-3p acts as a tumor suppressor in cervical cancer (CC), not all the pathways through which it alters the cellular processes have been described. The present study examines whether miR-23b-3p directly represses the c-Met expression and that consequently modifies the proliferation, migration and invasion of C33A and CaSki cells. c-Met has five microRNA response elements (MREs) for miR-23b-3p in the 3′-UTR region. The ectopic overexpression of miR-23b-3p significantly reduces c-Met expression in C33A and CaSki cells. The overexpression of miR-23b-3p reduces proliferation, migration and invasion of CaSki cells and the proliferation and invasion in C33A cells. In CaSki cells, the activation of Gab1 and Fak, downstream of c-Met, is reduced in response to the overexpression of miR-23b-3p. Together, the results in the present study indicate that miR-23b-3p is a tumor suppressor that modulates the progression of CC via post-transcriptional regulation of the c-Met oncogene.

Curcumin stabilizes p53 by interaction with NAD(P)H:quinone oxidoreductase 1 in tumor-derived cell lines

Curcumin is a natural phytochemical with potent anti-neoplastic properties including modulation of p53. Targeting p53 activity has been suggested as an important strategy in cancer therapy. The purpose of this study was to describe a mechanism by which curcumin restores p53 levels in human cancer cell lines. HeLa, SiHa, CaSki and MDA-MB-231 cells were exposed to curcumin and a pulse and chase and immunoprecipitation assays were performed. Here we showed that curcumin increases the half-life of p53 by a physical interaction between p53-NQO1 (p53 - NAD(P)H:quinone oxidoreductase 1) proteins after treatment with curcumin. Interestingly, the cell viability assay after treatment with curcumin showed that the cytotoxic activity was selectively higher in cervical cancer cells contained wild type p53 but not in breast cancer cells contained mutated p53. The cytotoxic effect of curcumin in cervical cancer cells was related to the complex p53-NQO1 that avoids the interaction between p53 and its negative regulator ubiquitin ligase E6-associated protein (E6AP). Finally, we demonstrated that in pancreatic epithelioid carcinoma cells (PANC1) that are knockout for NQO1, the reestablishment of NQO1 expression can stabilize p53 in presence of curcumin. Collectively, our findings showed that curcumin is necessary to promote the protein interaction of NQO1 with p53, therefore, it increases the half-life of p53, and permits the cytotoxic effect of curcumin in cancer cells containing wild type p53. Our findings suggest that the use of curcumin may reactivate the p53 pathway in cancer cells with p53 wild-type.

Human papillomavirus type 18 oncoproteins exert their oncogenicity in esophageal and tongue squamous cell carcinoma cell lines distinctly

Background

Increasing evidence indicates an etiological role of human papillomavirus (HPV) in head and neck cancers, particularly oropharyngeal squamous cell carcinoma (OPSCC). However, the association between HPV and other cancers, including esophageal and tongue remains unclear. This study delineated the molecular characteristics of HPV18 E6 and E7 in esophageal (EC109 and EC9706) and tongue (Tca83) cancer cell lines with reference to cervical cancer (HeLa).

Methods

We analysed the HPV transcription profiles of esophageal and tongue cancer cells through Next-generation RNA sequencing, and the role of HPV18 E6 and E7 in these cells was assessed via siRNA approach, Western blotting and immunofluorescence assays.

Results

Overall, the HPV transcription profiles of esophageal and tongue cancer cells mimicked that of cervical cancer cells, with notable disruption of E2, and expression of E6, spliced E6 (E6^*), E7, E1 and L1 transcripts. As with cervical cancer cells, p53 and its downstream transactivation target, p21, were found to be the major targets of E6 in esophageal and tongue cancer cell lines. Intriguingly, E7 preferentially targeted p130 in the two esophageal cancer cell lines, instead of pRb as in cervical cancer. Tca83 exhibited an E7 to E6 transcript ratio comparable to HeLa (cervix), targeted the ERK1/2 and MMP2 pathways, and was dependent on E6 and E7 to survive and proliferate. In contrast, both the esophageal cancer cell lines were distinct from HeLa in these aspects.

Conclusions

This is the first study that delineates transcript expression and protein interaction of HPV18 E6 and E7 in esophageal and tongue cancer cell lines, suggesting that HPV plays a role in inducing these cancers, albeit via distinct pathways than those observed in cervical cancer.

VERU-111 suppresses tumor growth and metastatic phenotypes of cervical cancer cells through the activation of p53 signaling pathway

In this study, we investigated the therapeutic efficacy of VERU-111 in vitro and in vivo model systems of cervical cancer. VERU-111 treatment inhibited cell proliferation and, clonogenic potential, induce accumulation of p53 and down regulated the expression of HPV E6/E7 expression in cervical cancer cells. In addition, VERU-111 treatment also decreased the phosphorylation of Jak2^{(Tyr1007/1008)} and STAT3 at Tyr705 and Ser727. VERU-111 treatment arrested cell cycle in the G2/M phase and modulated cell cycle regulatory proteins (cyclin B1, p21, p34^cdc2 and pcdk1). Moreover, VERU-111 treatment induced apoptosis and modulated the expression of Bid, Bcl-xl, Survivin, Bax, Bcl2 and cleavage in PARP. In functional assays, VERU-111 markedly reduced the migratory and invasive potential of cervical cancer cells via modulations of MMPs. VERU-111 treatment also showed significant (P < 0.05) inhibition of orthotopic xenograft tumor growth in athymic nude mice. Taken together, our results demonstrate the potent anti-cancer efficacy of VERU-111 in experimental cervical cancer models.Thus, VERU-111 can be explored as a promising therapeutic agent for the treatment of cervical cancer.

A DHX9-lncRNA-MDM2 interaction regulates cell invasion and angiogenesis of cervical cancer

Cervical cancer (CC) is the third most common carcinoma and the fourth leading cause of cancer-associated mortality in women. Here, we report that MDM2-DHX9 interaction mediates CC motility and angiogenesis in a long noncoding RNA-dependent fashion. A long noncoding RNA, named lnc-CCDST, is significantly downregulated in CC tissues, and binds to pro-oncogenic DHX9. DHX9 is upregulated in CC tissue, and promotes CC cell motility and angiogenesis. The lnc-CCDST and DHX9 interaction promotes DHX9 degradation through the ubiquitin proteasome pathway. Furthermore, DHX9 bound to E3 ubiquitin ligase MDM2, and this interaction is enhanced by lnc-CCDST. Thus, lnc-CCDST promotes DHX9 degradation by serving as a scaffold to facilitate the formation of MDM2 and DHX9 complexes. Moreover, HPV oncogenes E6 and E7 abolish the expression of lnc-CCDST resulting in the increase of DHX9. Our results have revealed a novel mechanism by which high-risk HPVs promote motility and angiogenesis of CC by inhibiting expression of lnc-CCDST to disrupt MDM2 and DHX9 interaction, and DHX9 degradation, and identified a potential therapeutic target for CC.

A triphenylethylene nonsteroidal SERM attenuates cervical cancer growth

Selective estrogen receptor modulator drug molecules of triphenylethylene family have gained considerable attention as anti-cancer agents. Despite recent advances in screening and development of HPV vaccines, cervical cancer remains one of the deadliest malignancies as advanced stage metastatic disease is mostly untreatable, thus warrants newer therapeutic strategies. Ormeloxifene (ORM) is a well-known SERM of triphenylethylene family that has been approved for human use, thus represents an ideal molecule for repurposing. In this study, we for the first time have demonstrated the anti-cancerous properties of ormeloxifene in cervical cancer. Ormeloxifene efficiently attenuated tumorigenic and metastatic properties of cervical cancer cells via arresting cell cycle at G1-S transition, inducing apoptosis, decreasing PI3K and Akt phosphorylation, mitochondrial membrane potential, and modulating G1-S transition related proteins (p21, cyclin E and Cdk2). Moreover, ORM repressed the expression of HPV E6/ E7 oncoproteins and restored the expression of their downstream target tumor suppressor proteins (p53, Rb and PTPN 13). As a result, ormeloxifene induces radio-sensitization in cervical cancer cells and caused potent tumor growth inhibition in orthotopic mouse model. Taken together, ormeloxifene represents an alternative therapeutic modality for cervical cancer which may have rapid clinical translation as it is already proven safe for human use.

A combined ANXA2-NDRG1-STAT1 gene signature predicts response to chemoradiotherapy in cervical cancer

BACKGROUND

A better understanding of locally advanced cervical cancer (LACC) is mandatory for further improving the rates of disease control, since a significant proportion of patients still fail to respond or undergo relapse after concurrent chemoradiation treatment (CRT), and survival for these patients has generally remained poor.

METHODS

To identify specific markers of CRT response, we compared pretreatment biopsies from LACC patients with pathological complete response (sensitive) with those from patients showing macroscopic residual tumor (resistant) after neoadjuvant CRT, using a proteomic approach integrated with gene expression profiling. The study of the underpinning mechanisms of chemoradiation response was carried out through in vitro models of cervical cancer.

RESULTS

We identified annexin A2 (ANXA2), N-myc downstream regulated gene 1 (NDRG1) and signal transducer and activator of transcription 1 (STAT1) as biomarkers of LACC patients' responsiveness to CRT. The dataset collected through qPCR on these genes was used as training dataset to implement a Random Forest algorithm able to predict the response of new patients to this treatment. Mechanistic investigations demonstrated the key role of the identified genes in the balance between death and survival of tumor cells.

CONCLUSIONS

Our results define a predictive gene signature that can help in cervical cancer patient stratification, thus providing a useful tool towards more personalized treatment modalities.

Metformin Modulates Cyclin D1 and P53 Expression to Inhibit Cell Proliferation and to Induce Apoptosis in Cervical Cancer Cell Lines

Background:

Cervical cancer is one of the most prevalent gynecological cancers worldwide and contributes in high mortality of Indonesian women. The efficacy of chemotherapy as a standart therapy for cervical cancer decreases because it frequenly rises adverse effects. Recent studies have found that metformin has a potential anticancer effect mostly through reduction of cyclin expression and activation of Activated Adenosine Monophosphate Kinase (AMPK). This study aimed to investigate the effect of metfomin on expression of cyclin D1 and p53 and apoptosis in HeLa cancer cell line.

Methods:

HeLa cells were treated with various doses of metformin and doxorubicin as a positive control. Cytotoxic effect of metformin was determined using the MTT assay. Immunocytochemistry was used to assess cyclin D1 and p53 expression and apoptosis levels of treated HeLa cells were analyzed using flowcytometry. Data of cyclin D1 expression was statistically analyzed using the Kruskal-Wallis test followed by the Tamhane test, whilst ANOVA and Tukey post Hoc tests were used to analyze data of p53 and apoptosis level. The significant value was p< 0.05.

Results:

Metformin was able to inhibit proliferation of HeLa cells with IC50 60 mM. HeLa cells treated with 60 and 120 mM metformin had lower cyclin D1 expression than HeLa cells treated without metformin and reached a significant difference (p= 0.001). Moreover, 30 mM or higher doses of metformin increase significantly p53 expression (p< 0.001). Induction of apoptosis was observed in HeLa cells treated with all doses of metformin and reached statistically difference (p= 0.04 and p < 0.001).

Conclusion:

Metformin can modulate cyclin D1 and p53 expression in HeLa cancer cell line, leading to inhibition of cell proliferation and induction of apoptosis. Other cyclin family members, CDK inhibitors and AMPK signaling should be further investigated in order to know mechanism of metformin action.

G1/S cell cycle regulators mediate effects of circadian dysregulation on tumor growth and provide targets for timed anticancer treatment

Circadian disruption has multiple pathological consequences, but the underlying mechanisms are largely unknown. To address such mechanisms, we subjected transformed cultured cells to chronic circadian desynchrony (CCD), mimicking a chronic jet-lag scheme, and assayed a range of cellular functions. The results indicated a specific circadian clock–dependent increase in cell proliferation. Transcriptome analysis revealed up-regulation of G1/S phase transition genes (myelocytomatosis oncogene cellular homolog [Myc], cyclin D1/3, chromatin licensing and DNA replication factor 1 [Cdt1]), concomitant with increased phosphorylation of the retinoblastoma (RB) protein by cyclin-dependent kinase (CDK) 4/6 and increased G1-S progression. Phospho-RB (Ser807/811) was found to oscillate in a circadian fashion and exhibit phase-shifted rhythms in circadian desynchronized cells. Consistent with circadian regulation, a CDK4/6 inhibitor approved for cancer treatment reduced growth of cultured cells and mouse tumors in a time-of-day–specific manner. Our study identifies a mechanism that underlies effects of circadian disruption on tumor growth and underscores the use of treatment timed to endogenous circadian rhythms.

A study of “jet-lagged” cells reveals a specific molecular mechanism regulating cell proliferation that it impacted by circadian disruption, underscoring the importance of administering anti-cancer treatment at a specific time of day.

Circadian misalignment caused by altered sleep–wake cycles, shift work, or frequent jet lag increases susceptibility to several disorders, including cancer. However, the mechanisms by which circadian disruption contributes to disease are not well understood, and so we addressed this issue by investigating the molecular, cellular, and biochemical consequences of chronic circadian desynchronization. Our studies using cancer cell or tumor tissue models show that chronic circadian desynchronization induces multiple oncogenic pathways to promote cell proliferation. In particular, chronic circadian desynchronization promotes phosphorylation of the retinoblastoma (RB) protein, thereby favoring G1/S phase cell cycle progression. Consistent with these findings, the antiproliferative activity of a selective inhibitor of the enzyme that phosphorylates RB has time-of-day–specific effects on cancer cells and mouse tumors, but this time dependence is abrogated by chronic jet-lag conditions. These data suggest a circadian regulation of G1/S cell cycle progression and provide an important molecular rationale for time-of-day–specific treatment of cancer patients, also known as chronotherapy.