Human papilloma virus, DNA methylation and microRNA expression in cervical cancer (Review)

Molecular Insights into HPV-Driven Cervical Cancer: Oncoproteins, Immune Evasion, and Epigenetic Modifications

Cervical cancer ranks third in mortality and fourth in incidence among women worldwide as one of the leading causes of death from cancer in females. The main reason behind cervical carcinogenesis is long-term infection with high-risk human papillomavirus (HPV) genotypes, particularly HPV16 and HPV18. This review investigates HPV distribution across the world, along with cervical cancer molecular development mechanisms and current treatment strategies. Epidemiological data show that disease patterns vary significantly between different geographic regions because underdeveloped nations bear a higher disease burden. The molecular mechanisms of oncogenes E6 and E7 disrupt tumor suppressor pathways, while epigenetic modifications through DNA methylation and miRNA dysregulation promote malignant cell transformation. The reduction in HPV infection through prophylactic vaccination has shown promise, yet barriers related to accessibility and coverage still exist. The therapeutic technologies of gene expression inhibitors together with immunotherapies and epigenetic targeting agents show promise but require optimization to achieve specific targeting while minimizing off-target effects. A combined approach that integrates HPV vaccination with early diagnosis and molecular-specific therapies represents the most effective method to manage cervical cancer impact. The future care of patients will require increased translational research along with better immunization programs to drive prevention and therapeutic outcomes.

Oncogenic HPV-induced high expression of ESM1 predicts poor prognosis and regulates aerobic glycolysis in cervical cancer

The impact of endothelial cell-specific molecule 1 (ESM1) on the initiation and progression of diverse cancers has been extensively studied, yet its regulatory mechanisms in relation to cervical cancer remain insufficiently understood. Through bioinformatics analysis, we revealed that ESM1 was highly expressed in cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) and correlated with dismal clinicopathological features. The activation of ESM1 is facilitated by the presence of oncogenic HPV E6 and E7. HPV E6 and E7 enhance the expression of ESM1 by diminishing the levels of miR-205-5p, which specifically targets the 3' untranslated region of ESM1 mRNA. In addition, we demonstrated that ESM1 facilitates aerobic glycolysis of cervical cancer cells via the Akt/mTOR pathway. Suppression of ESM1 led to a reduction in the expression of HIF-1α and multiple glycolytic enzymes. Taken together, our findings provide insights into the mechanisms by which HPV infections regulate oncogenes, thereby contributing to cervical carcinogenesis.

Host DNA Demethylation Induced by DNMT1 Inhibition Up-Regulates Antiviral OASL Protein during Influenza a Virus Infection

Influenza A virus (IAV) is a leading cause of human respiratory infections and poses a major public health concern. IAV replication can affect the expression of DNA methyltransferases (DNMTs), and the subsequent changes in DNA methylation regulate gene expression and may lead to abnormal gene transcription and translation, yet the underlying mechanisms of virus-induced epigenetic changes from DNA methylation and its role in virus-host interactions remain elusive. Here in this paper, we showed that DNMT1 expression could be suppressed following the inhibition of miR-142-5p or the PI3K/AKT signaling pathway during IAV infection, resulting in demethylation of the promotor region of the 2'-5'-oligoadenylate synthetase-like (OASL) protein and promotion of its expression in A549 cells. OASL expression enhanced RIG-I-mediated interferon induction and then suppressed replication of IAV. Our study elucidated an innate immunity mechanism by which up-regulation of OASL contributes to host antiviral responses via epigenetic modifications in IAV infection, which could provide important insights into the understanding of viral pathogenesis and host antiviral defense.

The HPV16 E6, E7/miR-23b-3p/ICAT signaling axis promotes proliferation, migration, invasion and EMT of cervical cancer cells

Cervical cancer (CC) remains one of the most common female malignancies, with higher incidence and mortality rates. more than 99% of CCs are associated with persistent infection with high-risk human papillomavirus. In view of the growing evidence that HPV 16 E6 and E7, two key oncoproteins encoded by HPV 16, regulate the expression of many other multifunctional genes and downstream effectors that contribute to the development of CC. Herein, we undertook a comprehensive effort into how HPV16 E6, E7 oncogenes affect the progression of CC cells. Previous studies have shown that ICAT expression was significantly increased in CC and had a pro-cancer effect. We observed that knockdown of HPV16 E6, E7 expression in SiHa and CasKi cells resulted in significant inhibition of ICAT expression and upregulation of miR-23b-3p expression. Besides, dual luciferase assays confirmed that ICAT was a target gene of miR-23b-3p, and negatively modulated by miR-23b-3p. Functional experiments showed that the overexpression of miR-23b-3p suppressed malignant behaviors of CC cells, such as migration, invasion and EMT. The overexpression of ICAT counteracted the suppressive effect of miR-23b-3p on HPV16-positive CC cells. Furthermore, after the knockdown of HPV16 E6 and E7, the inhibition of miR-23b-3p could increase the ICAT expression and rescue the siRNA HPV16 E6, E7-mediated suppressive impact on the aggressiveness of SiHa and CaSki cells. Collectively, our findings uncover that HPV16 E6, E7/miR-23b-3p/ ICAT axis plays an important role in HPV16-positive CC pathogenesis, which may serve as a promising therapeutic target for HPV16-associated CC.

High-risk HPV infection-associated hypermethylated genes in oropharyngeal squamous cell carcinomas

Background

HPV-positive oropharyngeal squamous cell carcinomas (OPSCCs) are sensitive to chemo-radiation therapy and have favorable survival outcomes compared with HPV-negative cancers. These tumors are usually not related to tobacco and alcohol exposure. Therefore, diagnosing HPV-positive OPSCCs for the appropriate disease management is crucial, and no suitable markers are available for detecting early malignancies in HPV-infected tissues. In this study, we attempt to find HPV-specific epigenetic biomarkers for OPSCCs.

Methods

A total of 127 surgical samples were analyzed for HPV positivity and promoter methylation of a panel of genes. HPV detection was performed by PCR detection of HPV E6 and E7 viral oncoproteins. In addition, promoter methylation of a total of 8 genes (DAPK, FHIT, RASSF1A, TIMP3, AGTR1, CSGALNACT2, GULP1 and VGF) was analyzed by quantitative-methylation specific PCR (QMSP), and their associations with HPV positivity or RB/p16 expressions were evaluated.

Results

AGTR1 and FHIT were frequently methylated in HPV-positive OPSCC samples with a good area under the curve (AUC over 0.70). In addition, these genes' promoter methylation was significantly associated with p16 positive and RB negative cases, which were the characteristics of OPSCC cases with favorable survival outcomes. Either AGTR1 or FHIT methylated cases were significantly associated with HPV-positive cancers with 92.0% sensitivity (P < 0.001). Also, they had significantly better overall survival (P = 0.047) than both unmethylated cases.

Conclusions

A combination of AGTR1 and FHIT methylation demonstrated a suitable detection marker of OPSCCs derived from the HPV-infected field, familiar with p16-positive and RB-negative phenotypes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10227-w.

Chrysin Modulates Aberrant Epigenetic Variations and Hampers Migratory Behavior of Human Cervical (HeLa) Cells

Purpose: Plant-derived phytochemicals have shown epigenetic modulatory effect in different types of cancer by reversing the pattern of DNA methylation and chromatin modulation, thereby restoring the function of silenced tumor-suppressor genes. In the present study, attempts have been made to explore chrysin-mediated epigenetic alterations in HeLa cells. Methods: Colony formation and migration assays followed by methylation-specific PCR for examining the methylation status of CpG promoters of various tumor-suppressor genes (TSGs) and the expression of these TSGs at the transcript and protein levels were performed. Furthermore, global DNA methylation; biochemical activities of DNA methyltransferases (DNMTs), histone methyl transferases (HMTs), histone deacetylases (HDACs), and histone acetyl transferases (HATs) along with the expression analysis of chromatin-modifying enzymes; and H3 and H4 histone modification marks analyses were performed after chrysin treatment. Results: The experimental analyses revealed that chrysin treatment encourages cytostatic behavior as well as inhibits the migration capacity of HeLa cells in a time- and dose-dependent manner. Chrysin reduces the methylation of various tumor-suppressor genes, leading to their reactivation at mRNA and protein levels. The expression levels of various chromatin-modifying enzymes viz DNMTs, HMTs, HDACs, and HATS were found to be decreased, and H3 and H4 histone modification marks were modulated too. Also, reduced global DNA methylation was observed following the treatment of chrysin. Conclusion: This study concludes that chrysin can be used as a potential epigenetic modifier for cancer treatment and warrants for further experimental validation.

Getting out of crises: Environmental, social-ecological and evolutionary research is needed to avoid future risks of pandemics

The implementation of One Health/EcoHealth/Planetary Health approaches has been identified as key (i) to address the strong interconnections between risk for pandemics, climate change and biodiversity loss and (ii) to develop and implement solutions to these interlinked crises. As a response to the multiple calls from scientists on that subject, we have here proposed seven long-term research questions regarding COVID-19 and emerging infectious diseases (EIDs) that are based on effective integration of environmental, ecological, evolutionary, and social sciences to better anticipate and mitigate EIDs. Research needs cover the social ecology of infectious disease agents, their evolution, the determinants of susceptibility of humans and animals to infections, and the human and ecological factors accelerating infectious disease emergence. For comprehensive investigation, they include the development of nature-based solutions to interlinked global planetary crises, addressing ethical and philosophical questions regarding the relationship of humans to nature and regarding transformative changes to safeguard the environment and human health. In support of this research, we propose the implementation of innovative multidisciplinary facilities embedded in social ecosystems locally: ecological health observatories and living laboratories. This work was carried out in the frame of the European Community project HERA (www.HERAresearchEU.eu), which aims to set priorities for an environment, climate and health research agenda in the European Union by adopting a systemic approach in the face of global environmental change.

Effects of Traditional Chinese Medicine for Vaginal Lavage Combined with Psychological Intervention in Postoperative Patients with Cervical Cancer

Purpose

To explore the effects of traditional Chinese medicine for vaginal lavage combined with psychological intervention on the immune function and clinical efficacy in patients with cervical cancer.

Methods

Patients with cervical cancer treated in our hospital from January 2020 to May 2021 were included in this study. All patients were treated with traditional Chinese medicine for vaginal lavage combined with psychological nursing intervention. The treatment outcomes of the patients were observed, and the quality-of-life scores and depression of the patients before and after treatment were compared. Changes in T-lymphocyte subset-related indicators, changes in blood routine-related indicators, and changes in the detection level of tumor markers were compared with anxiety scores.

Results

After treatment, depression and anxiety were significantly reduced and the patient's quality of life significantly improved. After treatment, the patient's CD3⁺, CD4⁺, and CD4⁺/CD8⁺ proportions were dramatically higher than before treatment (P < 0.05), there was no significant difference in CD8⁺ proportion before and after treatment (P > 0.05), and the white blood cell (WBC), hemoglobin (Hb), platelet (PLT) of patients, and the level of tumor marker (CA125) after treatment were immensely lower than before treatment (P < 0.05).

Conclusions

Treating patients with cervical cancer with traditional Chinese medicine for vaginal lavage combined with psychological nursing can effectively improve the patient's immune function, effectively reduce the level of tumor marker CA125, increase the level of T-lymphocyte subsets, and improve the bone marrow hematopoietic function.

β-Estradiol Induces Mitochondrial Apoptosis in Cervical Cancer Through the Suppression of AKT/NF-κB Signaling Pathway

BACKGROUND

Cervical cancer is the fourth most prevalent gynecological cancer worldwide, which threatens women's health and causes cancer-related mortality. In the search for effective anticervical cancer drugs, we discovered that β-estradiol (E2), a patent drug for estrogen deficiency syndrome treatment, displays the most potent cytotoxicity against HeLa cells.

OBJECTIVE

This study aims to evaluate the growth inhibitory effect of β-estradiol on HeLa cells and explore its underlying mechanisms.

METHODS

CCK-8 assay was used to evaluate the cytotoxicity of 6 compounds against HeLa cells. Flow cytometric analysis and Hoechst 33258 staining assay were performed to detect cell cycle arrest and apoptosis induction. The collapse of the mitochondrial potential was observed by the JC-1 staining assay. The expression levels of proteins were examined by western blotting.

RESULTS

β-Estradiol, at high concentration, displays potent cytotoxicity against HeLa cells with an IC50 value of 18.71 ± 1.57 μM for 72 h treatment. β-Estradiol induces G2/M cell cycle arrest through downregulating Cyclin B1 and p-CDK1. In addition, β-estradiol-induced apoptosis is accompanied by the loss of mitochondrial potential, activation of the Caspase family, and altered Bax/Bcl-2 ratio. β-Estradiol markedly decreased the expression level of p-AKT and p-NF-κB.

CONCLUSION

This study demonstrated that β-estradiol induces mitochondrial apoptosis in cervical cancer through the suppression of the AKT/NF-κB signaling pathway, indicating that β-estradiol may serve as a potential agent for cervical cancer treatment.

Epstein-Barr Virus Infection Alone or Jointly with Human Papillomavirus Associates with Down-Regulation of miR-145 in Oral Squamous-Cell Carcinoma

Down-regulation of tumor-suppressive miR-145 has been reported in various malignancies, including oral squamous-cell carcinoma (OSCC) that is influenced by several factors, including Epstein-Barr virus (EBV) and human papillomavirus (HPV). Oncoviruses can modulate the expression of cellular microRNAs. Therefore, we sought to investigate the association of miR-145 down-regulation in OSCC with EBV and/or HPV infection, which might be a possible mechanism of these viruses in oral carcinogenesis. Herein, prevalence of EBV, HPV, and their co-infection was significantly higher in tumors than normal tissues of OSCC. EBV infection alone or jointly with HPV was significantly associated with down-regulation of miR-145 in tumors compared with normal adjacent tissues. In cell lines infected with EBV or HPV, miR-145 was also down-regulated. Consistently, methylation of miR-145 was significantly greater in tumors, and well correlated with increased expression of DNMT3B, which was influenced by infection with EBV and HPV. In cell lines, only EBV infection was associated with increased expression of DNMT3B. Moreover, the level of EBV-LMP1 mRNA in tumors was negatively correlated with miR-145 and positively correlated with DNMT3B. Therefore, EBV alone or jointly with HPV is associated with down-regulation of miR-145 and may influence on miR-145 promoter methylation through the induction of DNMT3B in OSCC.

Cervical cancer development, chemoresistance, and therapy: a snapshot of involvement of microRNA

Cervical cancer (CC) is one of the leading causes of death in women due to cancer and a major concern in the developing world. Persistent human papilloma virus (HPV) infection is the major causative agent for CC. Besides HPV infection, genetic and epigenetic factors including microRNA (miRNA) also contribute to the malignant transformation. Earlier studies have revealed that miRNAs participate in cell proliferation, invasion and metastasis, angiogenesis, and chemoresistance processes by binding and inversely regulating the target oncogenes or tumor suppressor genes. Based on functions and mechanistic insights, miRNAs have been identified as cellular modulators that have an enormous role in diagnosis, prognosis, and cancer therapy. Signatures of miRNA could be used as diagnostic markers which are necessary for early diagnosis and management of CC. The therapeutic potential of miRNAs has been shown in CC; however, more comprehensive clinical trials are required for the clinical translation of miRNA-based diagnostics and therapeutics. Understanding the molecular mechanism of miRNAs and their target genes has been useful to develop miRNA-based therapeutic strategies for CC and overcome chemoresistance. In this review, we summarize the role of miRNAs in the development, progression, and metastasis of CC as well as chemoresistance. Further, we discuss the diagnostic and therapeutic potential of miRNAs to overcome chemoresistance and treatment of CC.

Role of Virus-Induced Host Cell Epigenetic Changes in Cancer

The tumor viruses human T-lymphotropic virus 1 (HTLV-1), hepatitis C virus (HCV), Merkel cell polyomavirus (MCPyV), high-risk human papillomaviruses (HR-HPVs), Epstein-Barr virus (EBV), Kaposi’s sarcoma-associated herpes virus (KSHV) and hepatitis B virus (HBV) account for approximately 15% of all human cancers. Although the oncoproteins of these tumor viruses display no sequence similarity to one another, they use the same mechanisms to convey cancer hallmarks on the infected cell. Perturbed gene expression is one of the underlying mechanisms to induce cancer hallmarks. Epigenetic processes, including DNA methylation, histone modification and chromatin remodeling, microRNA, long noncoding RNA, and circular RNA affect gene expression without introducing changes in the DNA sequence. Increasing evidence demonstrates that oncoviruses cause epigenetic modifications, which play a pivotal role in carcinogenesis. In this review, recent advances in the role of host cell epigenetic changes in virus-induced cancers are summarized.

Detection of Cervical Lesions and Cancer in Air-Dried Cytologic Smears by Combined Analysis of mRNA and miRNA Expression Levels

Cervical cancer screening is based on cytologic analysis and high-risk human papillomavirus (HR-HPV) testing, each having their drawbacks. Implementation of new biomarker-based methods may improve screening accuracy. Here, the levels of 25 microRNAs (miRNAs, miRs) and 12 mRNAs involved in cervical carcinogenesis in 327 air-dried Papanicolaou-stained cervical smears from patients with cervical precancerous lesions, cancer, or without the disease were estimated by real-time PCR. Using logistic regression analysis, small-scale miRNA-based, mRNA-based, and combined molecular classifiers were built based on paired ratios of miRNA or mRNA concentrations; their ability to detect high-grade cervical lesions and cancer was then compared. Combined mRNA-miRNA classifiers manifested a better combination of sensitivity and specificity than miRNA- and mRNA-based classifiers. The best classifier, combining miR-375, miR-20, miR-96, CDKN2A, TSP4, and ECM1, predicted high-grade lesions with diagnostic sensitivity of 89.0%, specificity of 84.2%, and a receiver-operating characteristic area under the curve of 0.913. Additionally, in a subsample of the same specimens, the levels of MIR124-2 and MAL promoter methylation, HR-HPV genotypes, and viral loads were analyzed. The relative high-grade lesion risk estimated by the classifier correlated with the frequency of MAL and MIR124-2 methylation but not with the HR-HPV genotype or viral load. The results support the feasibility of cellular biomarker-based methods for cervical screening and patient management.

Is There a Carcinogenic Risk Attached to Vitamin B12 Deficient Diets and What Should We Do About It? Reviewing the Facts

The number of individuals partaking in veganism has increased sharply in the last decade. Therefore, it is critical to look at the implications of vegan diets for public health. Although there are multiple health benefits of a vegan diet, studies have also linked the diet with deficiencies in various micronutrients. This study focuses on vitamin B12, because of its critical role in DNA synthesis and methylation. In light of these connections, a critical review of recent scientific literature is conducted to understand the effects of a B12 deficient diet on the genome and epigenome, and whether it can give rise to cancer. It is observed that a B12 deficiency leads to increased uracil misincorporation, leading to impaired DNA synthesis and genomic instability. The deficiency also leads to global hypomethylation of DNA, a hallmark of early carcinogenesis. The findings of this study highlight the need for increased awareness among vegans to ensure adequate B12 intake through supplementation or consumption of fortified products as a preventative measure. Additionally, the biofortification of staple crops and an improved version of fermented products with increased B12 content can be developed when inadequate intake seems otherwise inevitable.

Integrative Analysis of miRNAs Identifies Clinically Relevant Epithelial and Stromal Subtypes of Head and Neck Squamous Cell Carcinoma

PURPOSE

The objective of this study is to characterize the role of miRNAs in the classification of head and neck squamous cell carcinoma (HNSCC).

EXPERIMENTAL DESIGN

Here, we analyzed 562 HNSCC samples, 88 from a novel cohort and 474 from The Cancer Genome Atlas, using miRNA microarray and miRNA sequencing, respectively. Using an integrative correlations method followed by miRNA expression-based hierarchical clustering, we validated miRNA clusters across cohorts. Evaluation of clusters by logistic regression and gene ontology approaches revealed subtype-based clinical and biological characteristics.

RESULTS

We identified two independently validated and statistically significant (P < 0.01) tumor subtypes and named them "epithelial" and "stromal" based on associations with functional target gene ontology relating to differing stages of epithelial cell differentiation. miRNA-based subtypes were correlated with individual gene expression targets based on miRNA seed sequences, as well as with miRNA families and clusters including the miR-17 and miR-200 families. These correlated genes defined pathways relevant to normal squamous cell function and pathophysiology. miRNA clusters statistically associated with differential mutation patterns including higher proportions of TP53 mutations in the stromal class and higher NSD1 and HRAS mutation frequencies in the epithelial class. miRNA classes correlated with previously reported gene expression subtypes, clinical characteristics, and clinical outcomes in a multivariate Cox proportional hazards model with stromal patients demonstrating worse prognoses (HR, 1.5646; P = 0.006).

CONCLUSIONS

We report a reproducible classification of HNSCC based on miRNA that associates with known pathologically altered pathways and mutations of squamous tumors and is clinically relevant.

Upregulation of miR-205 induces CHN1 expression, which is associated with the aggressive behaviour of cervical cancer cells and correlated with lymph node metastasis

BACKGROUND

Cervical cancer is the leading cause of cancer-related death in women worldwide. However, the mechanisms mediating the development and progression of cervical cancer are unclear. In this study, we aimed to elucidate the roles of microRNAs and a1-chimaerin (CHN1) protein in cervical cancer progression.

METHODS

The expression of miR-205 and CHN1 protein was investigated by in situ hybridisation and immunohistochemistry. We predicted the target genes of miR-205 using software prediction and dual luciferase assays. The expression of mRNAs and proteins was tested by qRT-PCR and western blotting respectively. The ability of cell growth, migration and invasion was evaluated by CCK-8 and transwell. Cell apoptosis was analysed by flow cytometry analysis.

RESULTS

We found that miR-205 and CHN1 were highly expressed in human cervical cancer tissue compared with paired normal cervical tissues. The CHN1 gene was shown to be targeted by miR-205 in HeLa cells. Interestingly, transfection with miR-205 mimic upregulated CHN1 mRNA and protein, while miR-205 inhibitor downregulated CHN1 in high-risk and human papilloma virus (HPV)-negative human cervical cancer cells in vitro,. These data suggested that miR-205 positively regulated the expression of CHN1. Furthermore, the miR-205 mimic promoted cell growth, apoptosis, migration, and invasion in high-risk and HPV-negative cervical cancer cells, while the miR-205 inhibitor blocked these biological processes. Knockdown of CHN1 obviously reduced the aggressive cellular behaviours induced by upregulation of miR-205, suggesting that miR-205 positively regulated CHN1 to mediate these cell behaviours during the development of cervical cancer. Furthermore, CHN1 was correlated with lymph node metastasis in clinical specimens.

CONCLUSIONS

Our findings showed that miR-205 positively regulated CHN1 to mediate cell growth, apoptosis, migration, and invasion during cervical cancer development, particularly for high-risk HPV-type cervical cancer. These findings suggested that dysregulation of miR-205 and subsequent abnormalities in CHN1 expression promoted the oncogenic potential of human cervical cancer.

PRINS lncRNA Is a New Biomarker Candidate for HPV Infection and Prognosis of Head and Neck Squamous Cell Carcinomas

Numerous studies have shown that human papillomavirus (HPV) infection is one of the important risk factors for head and neck squamous cell carcinoma (HNSCC) progression and affects the expression of multiple genes, which might serve as new biomarkers. This study examines the effects of HPV infection on long non-coding RNA (lncRNA) expression and the immune system, particularly PRINS (Psoriasis susceptibility-related RNA Gene Induced by Stress). The Cancer Genome Atlas (TCGA) expression data for lncRNA genes and clinical data were analyzed by GraphPad Prism 5/7. The expressions of PRINS, CDKN2B-AS1, TTTY14, TTTY15, MEG3, and H19 were significantly different in HPV-positive and HPV-negative patients. HPV-positive patients with high PRINS expression demonstrated significantly better overall survival (OS) and disease-free survival (DFS). HPV-positive patients with high PRINS expression showed changes in gene expression associated with immune and antiviral responses. A majority of HPV-positive patients with high PRINS expression demonstrated a high number of immune cells within tumors. PRINS expression was significantly associated with HPV-infection HNSCC tumors. Validation of these results using data set from Gene Expression Omnibus (GEO) indicated that PRINS is upregulated in HPV active infections and in “atypical 1 (IR)” HNSCC clusters, negatively influencing patients’ overall survival. Patients with high PRINS expression display different immunological profiles than those with low expression levels. For instance, they have active HPV infection status or are clustered in the “atypical 1 (IR)” subtype of HNSCC which influences both viral infection and patients’ survival. It is likely that PRINS could be used as a potential biomarker for HNSCC patients, but its role is dual. On the one hand, it stimulates patients’ immune response, while on the other it can be favorable in virus replication.

miR-9, miR-21, miR-27b, and miR-34a Expression in HPV16/58/52-Infected Cervical Cancer

The aim of this study was to observe the expression of miR-9, miR-21, miR-27b, and miR-34a related with E6/E7 in HPV16-, HPV52-, and HPV58-infected cervical cancer patients and explore their possible role in cervical cancer with HPV infection. The expression levels of 4 miRNAs were detected in cervical exfoliated cells using qRT-PCR. In the current study, miR-34a expression was significantly upregulated in HPV-positive cervical cancer compared with the HPV-negative healthy population and HPV-positive CIN, but just the expression of miR-34a in HPV16 cervical cancer was statistically significant, and the expression of HPV52 and HPV58 was not statistically significant. The expression of miR-21 increased in HPV-positive cervical cancer compared with HPV-positive CIN, but only HPV16-infected cervical cancer had statistical significance compared with HPV16-infected CIN. By observing the change trend of each subtype group, we can show that the expression of miR-9 in HPV16 CIN was opposite to the other subtypes, and it was upregulated, compared with HPV58 CIN, and significantly increased. The level change of miR-27b in HPV58 cervical cancer and HPV58 CIN was opposite to the other subtypes; unlike the expression of miR-27b which was upregulated in HPV16 and HPV52 infected, it was downregulated compared with Normal. We also found that the expression of miR-34a and miR-9 was contrary to other studies. These findings indicate that the upregulated miR-21 expression may be a biomarker to distinguish between CC and CIN. miR-34a in HPV infection, especially in HPV16 infection, might be related to the occurrence and development of cervical cancer. The infection of different subtypes may play different roles in disease by activating different mechanisms; miRNAs play a very complex role in tumorigenesis and development, and there may be multiple targets in which multiple mechanisms play a role.

An increase of microRNA-16-1 is associated with the high proliferation of squamous intraepithelial lesions in the presence of the integrated state of HR-HPV in liquid cytology samples

Studies of cervical cancer (CC) have reported that microRNA-16-1 (miR-16-1), which is an oncomiR, is increased in the tissues and cell lines of CC. The aim of the present study was to investigate the association of miRNA-16-1 expression level with squamous cell carcinoma (SCC), the presence of squamous intraepithelial lesions (SIL) and the integration of high-risk human papillomavirus (HR-HPV) DNA. The current study analyzed 80 samples obtained from women by liquid-based cytology, which revealed that 20 were negative for SIL (NSIL) and without HPV, 20 were low-grade SIL (LSIL), 20 were high-grade SIL (HSIL), and 20 were diagnosed as SCC with HR-HPV. The genotyping of the viral DNA was conducted via an INNO-LiPA-HPV array, the expression of miR-16-1 was determined by reverse transcription-quantitative PCR, and the physical state of the HR-HPV was ascertained by in situ hybridization with amplification with tyramide. A total of eight HR-HPV genotypes were distinguished; the most frequent of these being HPV16, followed by multiple infection with HR-HPV (including HPV16). The mixed state of the HR-HPV was observed in 60 and 65% of LSIL and HSIL cases, respectively, while an integrated HR-HPV state was identified in 90% of cases with SCC. The expression level of miR-16-1 increased according to the grade of SIL, and cases with HSIL exhibited a significantly higher miR-16-1 expression level compared with women with NSIL (P<0.001; Table II). It can therefore be determined that the expression of miR-16-1 effects cellular proliferation, due to the viral integration of various HR-HPV genotypes in unique infection or in multiple infection. Thus, the overexpression of miR-16-1 could be monitored in women with LSIL, in order to discard a major lesion.

Discovery of 2-(2-aminobenzo[d]thiazol-6-yl) benzo[d]oxazol-5-amine derivatives that regulated HPV relevant cellular pathway and prevented cervical cancer from abnormal proliferation

Human papillomavirus (HPV) is a well-established etiological factor for cervical cancer, and the expression of oncogenic protein E7 is crucial for carcinogenesis. Herein, virtual screening was performed and 2-(2-aminobenzo[d]thiazol-6-yl) benzo[d]oxazol-5-amine derivatives were designed, synthesized as antineoplastic agents, and evaluated for their anti-tumor activities. Among them, the most promising compound H1 showed specific anti-proliferation ability against HeLa cells (IC₅₀ = 380 nM) as well as excellent inhibition of tumor growth in the HeLa xenograft model without inducing obvious side effects. It is interesting that compound H1 displayed significant inhibition against HPV18-positive cervical cell lines (HeLa) but not for HPV16-positive cervical cell lines (SiHa). Further study demonstrated that a low concentration of compound H1 could lead to a cell cycle blockage at the G1 phase and promote cell apoptosis slightly (8.77%). Compound H1 also exhibited transcription repression, especially those associated with the oncoprotein E7 cellular pathway like E7/Rb/E2F-1/DNMT1, which were essential in tumorigenesis. Proteomics analysis revealed that E7 might be degraded through E3 ubiquitin ligases, which aligned with decreasing expression of E7 following the treatment of compound H1. Taken together, it indicated that compound H1 could be a promising potential agent for cervical cancer treatment.

The detection of DNA methylation of tumour suppressor genes in cervical high-grade squamous intraepithelial lesion: A prospective cytological-histological correlation study of 70 cases

BACKGROUND

DNA methylation has been suggested as one of the epigenetic changes promoting carcinogenesis. The aim of this study was to prospectively evaluate the methylation status of CADM 1, MAL and hsa-miR-124 genes in high-grade squamous intraepithelial lesion (HSIL) liquid-based cytology (LBC) samples with a histological correlation.

METHODS

Seventy histologically confirmed cases of HSIL paired with prior screening LBC diagnosis of HSIL within a 3-month interval were selected. Histologically, the lesions were reviewed and assessed including: (a) number of blocks harbouring dysplastic squamous epithelium; (b) number of blocks containing glandular extension of dysplastic epithelium; and (c) the depth of glandular extension (which was assessed semi-quantitatively as graded 1-3). Human papillomavirus (HPV) subtyping was performed from residual LBC materials using the LINEAR ARRAY HPV Genotyping Test and in-house polymerase chain reaction targeting the HPV E1 gene. The detection of methylation silencing of tumour suppressor genes CADM1, MAL and hsa-miR-124 was performed by multiplex methylation-specific real-time polymerase chain reaction.

RESULTS

A positive methylation status was detected in 41 cases (58.6%). The number of blocks with HSIL varied from one to 13. Glandular extension was seen in 44 cases with the number of blocks involved ranging from one to 10. The depth of HSIL glandular extension varied.

CONCLUSION

The DNA methylation test allows HSIL lesions to be divided into two distinct groups of methylated HSIL in significantly older patients and unmethylated HSIL in younger patients. This study was not able to prove that methylation status in cervical HSIL correlates with the size of the lesion (measured by the number of blocks involved) or with HSIL propensity for endocervical glandular extension, nor with HPV type or multi-infection.

Host proteome linked to HPV E7-mediated specific gene hypermethylation in cancer pathways

Background

Human papillomavirus (HPV) infection causes around 90% of cervical cancer cases, and cervical cancer is a leading cause of female mortality worldwide. HPV-derived oncoprotein E7 participates in cervical carcinogenesis by inducing aberrant host DNA methylation. However, the targeting specificity of E7 methylation of host genes is not fully understood but is important in the down-regulation of crucial proteins of the hallmark cancer pathways. In this study, we aim to link E7-driven aberrations in the host proteome to corresponding gene promoter hypermethylation events in the hope of providing novel therapeutic targets and biomarkers to indicate the progression of cervical cancer.

Methods

HEK293 cells were transfected with pcDNA3.1-E7 plasmid and empty vector and subjected to mass spectrometry-based proteomic analysis. Down-regulated proteins (where relative abundance was determined significant by paired T-test) relevant to cancer pathways were selected as gene candidates for mRNA transcript abundance measurement by qPCR and expression compared with that in SiHa cells (HPV type 16 positive). Methylation Specific PCR was used to determine promoter hypermethylation in genes downregulated in both SiHa and transfected HEK293 cell lines. The FunRich and STRING databases were used for identification of potential regulatory transcription factors and the proteins interacting with transcription factor gene candidates, respectively.

Results

Approximately 400 proteins totally were identified in proteomics analysis. The transcripts of six genes involved in the host immune response and cell proliferation (PTMS, C1QBP, BCAP31, CDKN2A, ZMYM6 and HIST1H1D) were down-regulated, corresponding to proteomic results. Methylation assays showed four gene promoters (PTMS, C1QBP, BCAP31 and CDKN2A) were hypermethylated with 61, 55.5, 70 and 78% increased methylation, respectively. Those four genes can be regulated by the GA-binding protein alpha chain, specificity protein 1 and ETS-like protein-1 transcription factors, as identified from FunRich database predictions.

Conclusions

HPV E7 altered the HEK293 proteome, particularly with respect to proteins involved in cell proliferation and host immunity. Down-regulation of these proteins appears to be partly mediated via host DNA methylation. E7 possibly complexes with the transcription factors of its targeting genes and DNMT1, allowing methylation of specific target gene promoters.

Profiling of tRNA Halves and YRNA Fragments in Serum and Tissue From Oral Squamous Cell Carcinoma Patients Identify Key Role of 5' tRNA-Val-CAC-2-1 Half

Oral squamous cell carcinoma (OSCC) is the most common type of head and neck cancer and, as indicated by The Oral Cancer Foundation, kills at an alarming rate of roughly one person per hour. With this study, we aimed at better understanding disease mechanisms and identifying minimally invasive disease biomarkers by profiling novel small non-coding RNAs (specifically, tRNA halves and YRNA fragments) in both serum and tumor tissue from humans. Small RNA-Sequencing identified multiple 5' tRNA halves and 5' YRNA fragments that displayed significant differential expression levels in circulation and/or tumor tissue, as compared to control counterparts. In addition, by implementing a modification of weighted gene coexpression network analysis, we identified an upregulated genetic module comprised of 5' tRNA halves and miRNAs (miRNAs were described in previous study using the same samples) with significant association with the cancer trait. By consequently implementing miRNA-overtargeting network analysis, the biological function of the module (and by "guilt by association," the function of the 5' tRNA-Val-CAC-2-1 half) was found to involve the transcriptional targeting of specific genes involved in the negative regulation of the G1/S transition of the mitotic cell cycle. These findings suggest that 5' tRNA-Val-CAC-2-1 half (reduced in serum of OSCC patients and elevated in the tumor tissue) could potentially serve as an OSCC circulating biomarker and/or target for novel anticancer therapies. To our knowledge, this is the first time that the specific molecular function of a 5'-tRNA half is specifically pinpointed in OSCC.

Role of miR-337-3p and its target Rap1A in modulating proliferation, invasion, migration and apoptosis of cervical cancer cells

OBJECTIVE

To investigate the role of miR-337-3p targeting Rap1A in modulating proliferation, invasion, migration and apoptosis of cervical cancer cells.

METHODS

The expression levels of miR-337-3p and Rap1A in cervical cancer tissues and normal tissues were evaluated through quantitative Real-time PCR (qRT-PCR) and Western blotting; and correlations of miR-337-3p with clinicopathological characteristics and prognosis of patients were also analyzed. Besides, human cervical cancer cell line HeLa cells were randomly divided into five groups (Mock, NC, miR-337-3p mimic, Rap1A, and miR-337-3p mimic + Rap1A groups). CCK-8 assay was utilized to measure cell proliferation, flow cytometry to evaluate cell apoptosis, and wound-healing and Transwell assays to detect cell migration and invasion.

RESULTS

Cervical cancer tissues presented a significant decrease in miR-337-3p and a remarkable increase in Rap1A protein. Besides, the expression levels of miR-337-3p and Rap1A were closely related to the major clinicopathological characteristics of cervical cancer; and patients with high-miR-337-3p-expression had the higher 5-year survival rate (all p< 0.05). When compared to Mock group, cells in miR-337-3p mimic group were suppressed in proliferation, migration, and invasion, but significantly promoted in apoptosis; meanwhile, cells in the Rap1A group showed changes in a completely opposite trend (all p< 0.05). Moreover, Rap1A can reverse the effect of miR-337-3p mimic on cell proliferation, invasion, migration and apoptosis (all p< 0.05).

CONCLUSION

MiR-337-3p was discovered to be decreased in cervical cancer, and miR-337-3p up-regulation may inhibit the proliferation, migration and invasion and promote the apoptosis of cervical cancer cells via down-regulating Rap1A.

Molecular mechanisms in progression of HPV-associated cervical carcinogenesis

Cervical cancer is the fourth most frequent cancer in women worldwide and a major cause of mortality in developing countries. Persistent infection with high-risk human papillomavirus (HPV) is a necessary cause for the development of cervical cancer. In addition, genetic and epigenetic alterations in host cell genes are crucial for progression of cervical precancerous lesions to invasive cancer. Although much progress has been made in understanding the life cycle of HPV and it’s role in the development of cervical cancer, there is still a critical need for accurate surveillance strategies and targeted therapeutic options to eradicate these cancers in patients. Given the widespread nature of HPV infection and the type specificity of currently available HPV vaccines, it is crucial that molecular details of the natural history of HPV infection as well as the biological activities of viral oncoproteins be elucidated. A better understanding of the mechanisms involved in oncogenesis can provide novel insights and opportunities for designing effective therapeutic approaches against HPV-associated malignancies. In this review, we briefly summarize epigenetic alterations and events that cause alterations in host genomes inducing cell cycle deregulation, aberrant proliferation and genomic instability contributing to tumorigenesis.

Optimal subset of signature miRNAs consisting of 7 miRNAs that can serve as a novel diagnostic and prognostic predictor for the progression of cervical cancer

Cervical cancer is the second most commonly diagnosed cancer in women. Novel prognostic biomarkers are required to predict the progression of cervical cancer. Cervical cancer expression data were obtained from The Cancer Genome Atlas (TCGA) database. MicroRNAs (miRNAs) significantly differentially expressed between early- and advanced-stage samples were identified by expression analysis. An optimal subset of signature miRNAs for pathologic stage prediction was delineated using the random forest algorithm and was used for the construction of a cervical cancer-specific support vector machine (SVM) classifier. The roles of signature miRNAs in cervical cancer were analyzed by functional annotation. In total, 44 significantly differentially expressed miRNAs were identified. An optimal subset of 7 signature miRNAs was identified, including hsa-miR-144, hsa-miR-147b, hsa-miR-218-2, hsa-miR-425, hsa-miR-451, hsa-miR-483 and hsa-miR-486. The signature miRNAs were used to construct an SVM classifier and exhibited a good performance in predicting pathologic stages of samples. SVM classification was found to be an independent prognostic factor. Functional enrichment analysis indicated that these signature miRNAs are involved in tumorigenesis. In conclusion, the subset of signature miRNAs could potentially serve as a novel diagnostic and prognostic predictor for cervical cancer.

TET1 promotes 5hmC-dependent stemness, and inhibits a 5hmC-independent epithelial-mesenchymal transition, in cervical precancerous lesions

DNA hypermethylation is a driving force in carcinogenesis. However, the role of active DNA hypomethylation in cancer remains largely unknown. This process, facilitated by ten-eleven translocation methylcytosine dioxygenase 1 (TET1), which oxidizes 5-methylcytosine (5 mC) to 5-hydroxymethylcytosine (5hmC), has never been studied in cervical cancer. Here, we found that TET1 and 5hmC correlative increases from normal cervix to Low-grade squamous intraepithelial lesion (LSIL), maximizing in High-grade squamous intraepithelial lesion (HSIL), and decreasing in invasive cancer. Full-length HPV-immortalized HSIL cells demonstrated higher TET1/5hmC levels, and stemness properties, compared to invasive cancer cells. TET1 silencing promoted the epithelial-mesenchymal transition (EMT), to transform precancerous cells in vivo. TET1 increased 5hmC in the ZEB1 and VIM promoters, surprisingly, silencing both genes. TET1 interaction with the histone modifiers, LSD1 and EZH2, on the ZEB1 promoter, resulted in gene silencing, via loss of histone H3K4 trimethylation, and gain of histone H3K27 trimethylation. Taken together, TET1 promotes stemness properties, and inhibits EMT, in HSIL cells, through 5hmC-dependent and -independent mechanisms.

Deregulation of miR-21 and miR-29a in Cervical Cancer Related to HPV Infection

BACKGROUND

Early diagnosis is an important factor to improve the survival of Invasive Cervical Cancer (ICC) patients. Molecular biomarkers such as micro RNA (miRNA) can be used in the early detection of ICC. The expression of miR-21 and miR-29a are deregulated in many types of human cancers.

OBJECTIVE

The aim of this study was to investigate the differences in miR-21 and miR-29a expression patterns in the Human Papilloma Virus (HPV) infection and various grades of cervical cancer among Iranian women.

METHODS

Small RNAs were extracted from positive for HPV, cervical cancer and healthy samples from 43, 50 and 46 individuals, respectively. Expression levels of miR-21 and miR-29a were analyzed by SYBR Green real-time RT-PCR using specific primers, and 5s rRNA as the internal reference gene.

RESULTS

Results have shown a significant increase in miR-21 and decrease in miR-29 in cancerous samples in comparison with the control groups (P < 0.0001).

CONCLUSION

This study illustrated that miR-21 and miR-29a could be operated as an oncogene and tumor-suppressor in cervical cancer progression. More studies are needed to demonstrate the role of miR-21 and miR-29a as potential biomarkers for the diagnosis of cervical cancer in future investigations.

Epigallocatechin gallate inhibits cell growth and regulates miRNA expression in cervical carcinoma cell lines infected with different high-risk human papillomavirus subtypes

The aim of the present study was to investigate the inhibitory effects of the polyphenol epigallocatechin-3-gallate (EGCG) on the growth of cervical carcinoma cell lines infected with different high-risk human papillomavirus (HPV) subtypes, as well as the associated regulation of microRNA (miR) expression. Cell proliferation was measured using an MTT assay. The effects of 7 different concentrations of EGCG (100, 80, 60, 40, 20, 10 and 0 µg/ml) on HeLa cell proliferation were assessed. HeLa cell growth was significantly inhibited by EGCG in a dose- and time-dependent manner (P<0.05), and the IC₅₀ was 90.74 and 72.74 µg/ml at 24 and 48 h, respectively. The expression of miR-210, miR-29a, miR-203 and miR-125b in HeLa (HPV16/18+), SiHa (HPV16+), CaSki (HPV16+) and C33A (HPV-) cell lines was measured using quantitative polymerase chain reaction analysis. In CA33 cells, miR-203 (all P<0.001) and miR-125b (P<0.01 and <0.0001) were significantly downregulated by EGCG, and miR-210 was significantly upregulated with 40 and 60 µg/ml EGCG (P<0.0001). miR-125b was significantly downregulated (P<0.001 and <0.0001), and miR-210 and miR-29 were significantly upregulated by ≤80 µg/ml EGCG in HeLa cells (all P<0.0001). In CaSki cells, miR-210, miR-29a (all P<0.001) and miR-125b (P<0.01–0.0001) were significantly upregulated by EGCG. In SiHa cells, miR-125b (both P<0.001) and miR-203 (P<0.01 and <0.0001) were significantly upregulated by EGCG. In conclusion, the results of the present study suggest that EGCG suppresses cervical carcinoma cell growth, possibly via regulating the expression of miRs, suggesting their potential as therapeutic targets for the control and prevention of cervical cancer. Additionally, EGCG may be considered a novel anti-cervical cancer drug in the future.

Comprehensive analysis of HPV infection, EGFR exon 20 mutations and LINE1 hypomethylation as risk factors for malignant transformation of sinonasal-inverted papilloma to squamous cell carcinoma

Different risk factors are suspected to be involved in malignant transformation of sinonasal papillomas and include HPV infection, tobacco smoking, occupational exposure, EGFR/KRAS mutations and DNA methylation alterations. In our study, 25 inverted sinonasal papillomas (ISPs), 5 oncocytic sinonasal papillomas (OSP) and 35 squamous cell carcinomas (SCCs) from 54 patients were genotyped for 10 genes involved in EGFR signalling. HPV-DNA detection was performed by in-situ hybridisation and LINE-1 methylation was quantitatively determined by bisulphite-pyrosequencing. High-risk HPV was observed only in 13% of ISP-associated SCC and in 8% of de novo-SCC patients. EGFR mutations occurred in 72% of ISPs, 30% of ISP-associated SCCs and 17% of de novo-SCCs. At 5-year follow-up, SCC arose in only 30% (6/20) of patients with EGFR-mutated ISPs compared to 76% (13/17) of patients with EGFR-wild-type ISP (p = 0.0044). LINE-1 hypomethylation significantly increased from papilloma/early stage SCC to advanced stage SCC (p = 0.03) and was associated with occupational exposure (p = 0.01) and worse prognosis (p = 0.09). In conclusion, our results suggest that a small subset of these tumours could be related to HPV infection; EGFR mutations characterise those ISPs with a lower risk of developing into SCC; LINE-1 hypomethylation is associated with occupational exposure and could identify more aggressive nasal SCC.

Outcomes of Conservative Management of High Grade Squamous Intraepithelial Lesions in Young Women

OBJECTIVE

The aim of the study was to determine regression rates of cervical intraepithelial neoplasia (CIN) 2 and 3 in women younger than 24 years, followed conservatively for up to 24 months.

MATERIALS AND METHODS

This is a retrospective chart review of colposcopy patients in clinic database based on the following: (1) younger than 24 years at first visit; (2) first visit January 1, 2010, to May 31, 2013, and at least 1 follow-up visit after diagnosis; (3) histologic diagnosis of CIN2+; and (4) optimal conservative management (observation for up to 24 months or to 24 years, whichever occurred first). Patient information and clinical/pathologic data were extracted from charts to examine patient characteristics and treatment outcomes, CIN2+ regression rates, median times to regression for CIN2 versus CIN3 (Kaplan-Meier survival analysis), and predictors of regression (multivariate logistic regression analysis).

RESULTS

A total of 154 women met criteria. The most severe histological diagnoses were CIN2 in 99 (64.3%), CIN3 in 51 (33.1%), and adenocarcinoma in situ in 4 (2.6%). Adenocarcinoma in situ was immediately treated. In follow-up, CIN2 regressed to CIN1 or negative in 74 women (74.7%)-median time to regression, 10.8 months. Cervical intraepithelial neoplasia 3 regressed in 11 women (21.6%)-median time to regression not reached (last follow-up censored at 52.7 months). Cervical intraepithelial neoplasia 2 on biopsy, low grade referral Pap, and younger age predicted regression. Overall, 49 women (31.8%) were treated.

CONCLUSIONS

Conservative management should continue to be recommended to young women with CIN2. Rigorous retention mechanisms are required to ensure that these women return for follow-up.

MiR-875 and miR-3144 switch the human papillomavirus 16 E6/E6* mRNA ratio through the EGFR pathway and a direct targeting effect

By employing bioinformatics scanning approaches and luciferase reporter, our previous study showed that two less common human miRNAs, miR-875 and miR-3144, target a conserved site in the genomes of most high-risk human papillomaviruses (HR-HPVs). In this study, we found that the site targeted by miR-875 and miR-3144 overlapped with the 5' alternative splice site of E6E7 transcripts in HPV16. Using HPV16+ SiHa cells, we showed that high levels of miR-875 and miR-3144 reduced the abundance of unspliced E6, while they promoted three E6* spliced transcripts and decreased the expression levels of E6/E7 oncoproteins and epidermal growth factor receptor (EGFR). A potential miR-875 target site was predicted in EGFR. Meanwhile, depletion of EGFR resulted in a failure to promote E6* but maintained the suppression of unspliced E6 driven by miR-875 and miR-3144. The data suggest that these two miRNAs switch the E6/E6* ratio through both the EGFR pathway and direct targeting. Here, we demonstrate for the first time that human miRNAs regulate the HPV splice isoforms. Furthermore, miRNA-875 and miRNA-3144 are only found in vertebrates and Homo sapiens, and the binding site in EGFR is highly conserved in Boreoeutheria. Our findings highlight the tumour-suppressing effect of miRNAs that possibly appeared in the late stage of biological evolution.

ABBREVIATIONS

Assessment of viral methylation levels for high risk HPV types by newly designed consensus primers PCR and pyrosequencing

Background

Measuring viral DNA methylation in human papillomavirus (HPV) infected women showed promise for accurate detection of high-grade cervical lesions and cancer. Methylation status has been widely investigated for HPV16, sporadically for other HPV types.

Methods

Objective of this methodological study was to set up molecular methods to test the methylation levels in the twelve oncogenic HPV types by pyrosequencing, minimizing the number of HPV type-specific PCR protocols. Target CpGs were selected on the HPV L1 (two regions, L1 I and L1 II) and L2 genes.

Study samples included DNA stored at Turin, Italy, purified by cervical cells collected in Standard Transport Medium or PreservCyt from women who participated in two studies (N = 126 and 140) nested within the regional organized screening programme.

PCR consensus primers were designed by PyroMark Assay Design software to be suitable for amplification of many different oncogenic HPV types.

Results

Generation of consensus primers was successful for L1 I and II regions, unsuccessful for L2 region, for which HPV type-specific primers remained necessary. The difference between replicated tests on the same sample was ≤4% in 88%, 77% and 91% of cases when targeting the L1 I, L1 II and L2 regions, respectively. The corresponding intra-class correlation coefficients (ICC) were 0.94, 0.87 and 0.97 respectively. When comparing methylation measures based on consensus and type-specific primers, ICC was 0.97 for the L1 I region and 0.99 the for L1 II region.

Conclusions

The proposed protocols, applying consensus primers suitable to amplify the oncogenic HPV types and minimize the number of PCR reactions, represent a promising tool to quantify viral methylation in women positive for any high risk HPV type.

Impact

Potential application of these methylation protocols in screening settings can be explored to identify women with high probability of progression to high grade lesions.

DNA methylation regulated microRNAs in human cervical cancer

Regulation of miRNA gene expression by DNA promoter methylation may represent a key mechanism to drive cervical cancer progression. In order to understand the impact of DNA promoter methylation on miRNAs at various stages of cervical carcinogenesis, we performed DNA methylation microarray on Normal Cervical Epithelium (NCE), Cervical Intraepithelial Neoplasia (CIN I-III) and Squamous Cell Carcinoma (SCC) tissues to identify differentially methylated miRNAs followed by validation by bisulfite sequencing. Further, expression of miRNAs was analyzed by qRT-PCR in clinical tissues and cervical cancer cell lines. Transcriptional activity was determined by luciferase assay. We identified a total of 69 hypermethylated and hypomethylated miRNA promoters encompassing 78 CpG islands in all except Y chromosome, among the three groups. The candidate DNA promoters of miR-424 were significantly hypermethylated and miR-200b and miR-34c were significantly hypomethylated in SCC compared to NCE (P < 0.05). Expression of miR-424, miR-200b, and miR-34c were inversely correlated with promoter DNA methylation in tissue samples. Treatment of cell lines with 5-aza-2'-deoxycytidine showed differential expression in all three miRNAs. We observed a decrease in miRNA promoter activity following in vitro SssI methylase treatment of miR-424, miR-200b, and miR-34c. Luciferase assay demonstrated that miR-200b and miR-424 functionally interacts with 3'-UTR of HIPK3 and RBBP6 respectively and decreased their activity in presence of miR-200b and miR-424 mimics transfected in SiHa cells. Taken together, we have identified deregulation of miRNAs by aberrant DNA promoter methylation, leading to its transcriptional silencing during cervical carcinogenesis, which can be potential targets for diagnosis and therapy.

DNA methylation regulated microRNAs in HPV-16-induced head and neck squamous cell carcinoma (HNSCC)

INTRODUCTION

Epigenetic modifications have been reported to play an important role in regulating gene expression and these modifications become critical when they have a role in controlling another important layer of epigenetic regulation namely microRNAs. In the present study, we have identified the microRNAs that may be regulated by promoter DNA methylation and histone acetylation in Human papilloma virus-positive head and neck squamous cell carcinoma.

METHODOLOGY

HPV-negative cell line (UPCI:SCC-116) and HPV-16 +ve cell line (UPCI:SCC-090) were treated with methylation inhibitor (5-aza-2'-deoxycytidine, AZA) and acetylation inhibitor (Trichostatin-A, TSA), followed by micro-array analysis. The differentially expressed miRNAs were validated in control (n = 10), HPV-16 +ve (n = 30), and HPV -ve (n = 30) HNC, TCGA (n = 529) tissue samples, and two HPV -ve (SCC116 and Hacat) and two HPV +ve (SCC090 and SiHa) cell lines. Methylation-specific PCR (MSP) and chromatin immunoprecipitation assay (CHIP) were performed to validate their regulation. In silico and in vitro analyses of identified miRNAs were done to study putative pathways they target and their possible role in carcinogenesis.

RESULTS

Among 10 miRNAs specifically up-regulated in microarray analysis of AZA-treated SCC090 cells, we observed significantly decreased expression of hsa-miR-181c-5p, hsa-miR-132-5p, hsa-miR-658 in HPV +ve HNC cohort, TCGA tissue samples, and cell lines as compared to their HPV -ve counterpart, and their promoter region also possesses CpG islands. MSP and analysis of TCGA data (MethHC) revealed increased frequency of methylation at the promoter of hsa-miR-132-5p that is negatively correlated with its expression. In TSA-treated SCC090 cells, out of 7 miRNAs, two namely Hsa-miR-129-2-3p and Hsa-miR-449a were found to be up-regulated as compared to HPV -ve cells. However, the levels of enrichment by anti-acetyl-H3 and anti-acetyl-H4 were significantly low in cell lines compared to respective controls and both were up-regulated in HPV +ve compared to HPV -ve TCGA tissue samples. In silico analysis revealed hsa-miR-132-5p targeted canonical β-catenin/wnt pathway and modulation of down-stream genes of the pathway was observed on over-expression/inhibition of hsa-miR-132-5p.

CONCLUSION

This study suggests the role of epigenetic modifications in regulating expression of miRNAs in HPV +ve HNSCC.

Modulation of DNA methylation by human papillomavirus E6 and E7 oncoproteins in cervical cancer

Human papillomaviruses (HPVs) are double stranded circular DNA viruses that infect cutaneous and mucosal epithelial cells. Almost 99% of cervical cancer has a HPV infection. The early oncoproteins E6 and E7 are important in this cellular transformation process. Epigenetic mechanisms have long been known to result in decisive alterations in DNA, leading to alterations in DNA-protein interactions, alterations in chromatin structure and compaction and significant alterations in gene expression. The enzymes responsible for these epigenetic modifications are DNA methyl transferases (DNMTs), histone acetylases and deacetylases. Epigenetics has an important role in cancer development by modifying the cellular micro environment. In this review, the authors discuss the role of HPV oncoproteins E6 and E7 in modulating the epigenetic mechanisms inside the host cell. The oncoproteins induce the expression of DNMTs which lead to aberrant DNA methylations and disruption of the normal epigenetic processes. The E7 oncoprotein may additionally directly bind and induce methyl transferase activity of the enzyme. These modulations lead to altered gene expression levels, particularly the genes involved in apoptosis, cell cycle and cell adhesion. In addition, the present review discusses how epigenetic mechanisms may be targeted for possible therapeutic interventions for HPV mediated cervical cancer.

Down-regulation of p16 and MGMT promotes the anti-proliferative and pro-apoptotic effects of 5-Aza-dC and radiation on cervical cancer cells

Cervical cancer is one of the most common malignancies of the female reproductive system. Therefore, it is critical to investigate the molecular mechanisms involved in the development and progression of cervical cancer. In this study, we stimulated cervical cancer cells with 5-aza-2'-deoxycytidine (5-Aza-dC) and found that this treatment inhibited cell proliferation and induced apoptosis; additionally, methylation of p16 and O-6-methylguanine-DNA methyltransferase (MGMT) was reversed, although their expression was suppressed. 5-Aza-dC inhibited E6 and E7 expression and up-regulated p53, p21, and Rb expression. Cells transfected with siRNAs targeting p16 and MGMT as well as cells stimulated with 5-Aza-dC were arrested in S phase, and the expression of p53, p21, and Rb was up-regulated more significantly. However, when cells were stimulated with 5-Aza-dC after transfection with siRNAs targeting p16 and MGMT, proliferation decreased significantly, and the percentage of cells in the sub-G1 peak and in S phase was significantly increased, suggesting a marked increase in apoptosis. But E6 and E7 overexpression could rescue the observed effects in proliferation. Furthermore, X-ray radiation caused cells to arrest in G2/M phase, but cells transfected with p16- and MGMT-targeted siRNAs followed by X-ray radiation exhibited a significant decrease in proliferation and were shifted toward the sub-G1 peak, also indicating enhanced apoptosis. In addition, the effects of 5-Aza-dC and X-ray radiation were most pronounced when MGMT expression was down-regulated. Therefore, down-regulation of p16 and MGMT expression enhances the anti-proliferative effects of 5-Aza-dC and X-ray radiation. This discovery may provide novel ideas for the treatment of cervical cancer.

3-(2-Chloropropyl amide)-4-methoxy-N-phenylbenzamide inhibits expression of HPV oncogenes in human cervical cancer cell

BACKGROUND

Human papillomaviruses (HPVs) are the primary causative agents for cervical cancer, and HPV oncoproteins E6 and E7 are known to be the main reason for the onset and maintenance of the malignancies. Therefore, inhibition of viral E6 and E7 oncoproteins expression represents a viable strategy to cervical cancer therapies. This study is to evaluate the antiviral effect of a novel N-Phenylbenzamide derivative, 3-(2-Chloropropyl amide)-4-methoxy-N-phenylbenzamide (L17), against HPV16 in vitro and identify its associated mechanism of action in cervical cancer cells.

METHODS

The cytotoxic effect of L17 was assessed by MTT assay. The mRNA and protein levels of E6 and E7 oncogenes were analyzed by quantitative real-time reverse transcription PCR (qRT-PCR) and Western blot, respectively. p53 and Rb protein levels were also detected by Western blot. The effect of L17 on cell cycle was analyzed by flow cytometry.

RESULTS

The cytotoxic effect of L17 was greater in cervical carcinoma cells than in normal cells. L17 significantly reduced the expression of HPV16 E6 and E7 mRNA and protein, at least partly by enhancing degradation of HPV16 E6 and E7 mRNA. Moreover, reduced expression of E6 and E7 induced by L17 resulted in the up-regulation of p53 and Rb expression, which subsequently induced CaSki cells arrest at G₀/G₁ phase.

CONCLUSIONS

L17 has antiviral activity through suppressing E6 and E7 oncogene expression and could inhibit CaSki cell proliferating by inducing cells arrest at G₀/G₁ phase at nontoxic concentration, implying that L17 might be exploited as a candidate agent for HPV-associated cervical cancer prevention and treatment.

APOBEC-mediated genomic alterations link immunity and viral infection during human papillomavirus-driven cervical carcinogenesis

Cervical cancer is one of the most frequently diagnosed cancers and is a major cause of death from gynecologic cancers worldwide; the cancer burden from cervical cancer is especially heavy in less developed countries. Most cases of cervical cancer are caused by persistent infection with carcinogenic human papillomavirus (HPV) genotypes 16 and 18. Non-resolving inflammation caused by HPV infection provides a microenvironment that facilitates cancer development. Molecular alterations during the process of HPV-induced carcinogenesis are characterized by DNA methylation within the HPV genome, promoter hypermethylation of tumor suppressor genes in the host genome, as well as genomic instability caused by viral DNA integrating into the host genome. Catalytic polypeptide-like apolipoprotein B mRNA editing enzymes (APOBECs) normally function as part of the innate immune system. APOBEC expression is stimulated upon viral infection and plays an important role in HPV-induced cervical cancer. APOBECs catalyze the deamination of cytosine bases in nucleic acids, which leads to a conversion of target cytosine (C) to uracil (U) and consequently a change in the single-stranded DNA/RNA sequence. APOBEC proteins mediate the complex interactions between HPV and the host genome and link immunity and viral infection during HPV-driven carcinogenesis. Understanding the effects of APOBECs in HPV-induced cervical carcinogenesis will enable the development of better tools for HPV infection control and personalized prevention and treatment strategies.

Methylomics of nitroxidative stress on precancerous cells reveals DNA methylation alteration at the transition from in situ to invasive cervical cancer

Epigenetic dysregulation is important in cervical cancer development, but the underlying mechanism is largely unknown. Increasing evidence indicates that DNA methylation is sensitive to changes in microenvironmental factors, such as nitric oxide (NO) in the chronic inflammatory cervix. However, the epigenomic effects of NO in cancer have not been investigated. In this study, we explored the methylomic effects of nitroxidative stress in HPV-immortalized precancerous cells. Chronic NO exposure promoted the acquisition of malignant phenotypes such as cell growth, migration, invasion, and anchorage-independent growth. Epigenetic analysis confirmed hypermethylation of PTPRR. Whole-genome methylation analysis showed BOLA2B, FGF8, HSPA6, LYPD2, and SHE were hypermethylated in cells. The hypermethylation BOLA2B, FGF8, HSPA6, and SHE was confirmed in cervical scrapings from invasive cancer, but not in CIN3/CIS, CIN2 and CIN1 (p=0.019, 0.023, 0.023 and 0.027 respectively), suggesting the role in the transition from in situ to invasive process. Our results reveal that nitroxidative stress causes epigenetic changes in HPV-infected cells. Investigation of these methylation changes in persistent HPV infection may help identify new biomarkers of DNA methylation for cervical cancer screening, especially for precancerous lesions.

Transcript levels of ten-eleven translocation type 1-3 in cervical cancer and non-cancerous cervical tissues

Decreased expression of ten-eleven translocation (TET1, TET2 and TET3) proteins has been reported in various types of cancer. However, the expression levels of TET proteins in cervical cancer (CC) remain to be elucidated. The present study determined the levels of TET1, TET2 and TET3 transcripts in cancerous (n=80) and non-cancerous cervical tissues (n=41). The results revealed a significant reduction in TET1 transcripts (P=0.0000001) in cervical tissue samples from patients with primary CC compared with samples from control patients. Significantly decreased TET1 transcript levels, as compared to non-cancerous cervical tissues, were also observed in tissue samples with the following characteristics: Stage I (P=0.016), II (P<0.0001), III (P=0.00007) and grade of differentiation G1 (P=0.026), G2 (P=0.00006), G3 (P=0.0007) and Gx (P=0.0004) and squamous histological type (P<0.00001). TET1 transcript levels were significantly lower in patients aged 45-60 years (P=0.0002) and patients age >60 years (P=0.003), as compared with non-cancerous cervical tissues. TET2 transcript levels were lower in cervical cancer tissues classified as stage II (P=0.043) and TET3 transcript levels were lower in stage III samples (P=0.010), tissue samples with a grade of differentiation of G3 (P=0.025) and tissue with squamous type histology (P=0.047), all compared with non-cancerous cervical tissues. The present study demonstrated a significantly reduced level of TET1 transcripts in cancerous cervical tissues, as compared with non-cancerous tissues. Furthermore, decreased TET1-3 transcript levels were identified when patients with CC were stratified by clinicopathological variables, as compared with non-cancerous cervical tissues.

Human Papillomavirus and Its Testing Assays, Cervical Cancer Screening, and Vaccination

Human papillomavirus (HPV) was found to be the causative agent for cervical cancer in the 1980s with almost 100% of cervical cancer cases testing positive for HPV. Since then, many studies have been conducted to elucidate the molecular basis of HPV, the mechanisms of carcinogenesis of the virus, and the risk factors for HPV infection. Traditionally, the Papanicolaou test was the primary screening method for cervical cancer. Because of the discovery and evolving understanding of the role of HPV in cervical dysplasia, HPV testing has been recommended as a new method for cervical cancer screening by major professional organizations including the American Cancer Society, American Society for Colposcopy and Cervical Pathology, and the American Society for Clinical Pathology. In order to detect HPV infections, many sensitive and specific HPV assays have been developed and used clinically. Different HPV assays with various principles have shown their unique advantages and limitations. In response to a clear causative relationship between high-risk HPV and cervical cancer, HPV vaccines have been developed which utilize virus-like particles to create an antibody response for the prevention of HPV infection. The vaccines have been shown in long-term follow-up studies to be effective for up to 8 years; however, how this may impact screening for vaccinated women remains uncertain. In this chapter, we will review the molecular basis of HPV, its pathogenesis, and the epidemiology of HPV infection and associated cervical cancer, discuss the methods of currently available HPV testing assays as well as recent guidelines for HPV screening, and introduce HPV vaccines as well as their impact on cervical cancer screening and treatments.

Role of Host miRNA Hsa-miR-139-3p in HPV-16-Induced Carcinomas

Purpose: Human papillomavirus 16 (HPV-16) is an important risk factor in head and neck cancer (HNC). Studies suggest that miRNAs play an important role in cancer; however, their role in HPV-mediated oncogenesis remains largely unknown. We investigated the role of miRNAs with HPV-16 as putative target in HPV-16-mediated cancers.Experimental Design: Using in silico tools, we identified miRNAs with putative binding sequences on HPV-16 miRNAs. Hsa-miR-139-3p was identified as best candidate miRNA by luciferase reporter assay and was found to be significantly downregulated in HPV-16-positive tissues and cell lines. Overexpression/inhibition studies were performed to determine the role of miRNA in regulating oncogenic pathways.Results: Hsa-miR-139-3p was found to target high-risk HPV-16 oncogenic proteins and revive major tumor suppressor proteins (p53, p21, and p16). This resulted in inhibition of cell proliferation and cell migration, cell-cycle arrest at G₂-M phase and increased cell death of HPV-16-positive cells. Analysis of The Cancer Genome Atlas (TCGA) data showed decreased expression of Hsa-miR-139-3p in HPV-16-positive HNC and cervical cancer cases, and its higher expression correlated with better survival outcome in both cases. Increased DNA methylation of Hsa-miR-139-3p harboring gene PDE2A at its promoter/CpG islands was observed in HPV-16-positive tissues and cell lines, which further correlated with Hsa-miR-139-3p expression, suggesting its role in regulating Hsa-miR-139-3p expression. Furthermore, we observed an increased sensitization of Hsa-miR-139-3p overexpressed HPV-16-positive cells to chemotherapeutic drugs (cisplatin and 5-fluorouracil).Conclusions: HPV-16-mediated downregulation of Hsa-miR-139-3p may promote oncogenesis in HNC and cervical cancer. Clin Cancer Res; 23(14); 3884-95. ©2017 AACR.

Ranpirnase eradicates human papillomavirus in cultured cells and heals anogenital warts in a Phase I study

BACKGROUND

Human papillomaviruses (HPV), the causative agents of anogenital warts, are the most prevalent sexually transmitted infectious agents, and wart treatment poses a persistent challenge. We assessed the safety and efficacy of treating HPV with ranpirnase, an endoribonuclease from the northern leopard frog that has been used extensively in Phase III oncology trials.

METHODS

As initial verification of ranpirnase antiviral activity, we assessed its ability to eliminate papillomaviruses in cultured cells. To further assess its feasibility for treating anogenital warts in humans, we performed a Phase I study. Forty-two male volunteers with genital/perianal warts were treated topically with three different formulations of 1 mg/ml ranpirnase. Patients were monitored for 8 weeks or until healing. Four patients with HIV were treated in accordance with the compassionate programme but were not evaluated.

RESULTS

In cultured cells, ranpirnase showed specific activity against HPV-11 with low toxicity (selectivity index >88). The broad applicability of ranpirnase for treating papillomaviruses was verified using the cottontail rabbit papillomavirus. In the clinical study, eight participants were lost-to-follow-up or discontinued due to protocol violation or non-compliance. Among 30 evaluable participants, topical ranpirnase was moderately well-tolerated, with discontinuation by 5 (16.7%) due to adverse reactions. Clinical healing was achieved by 25 participants (83.3%) and 50% improvement by the 5 discontinued participants (16.7%). The median time to clinical healing was 30 days.

CONCLUSIONS

This study provides the first in vitro and clinical evidence of the antiviral efficacy of ranpirnase against HPV and supports assessment of ranpirnase in expanded clinical studies.

Precision medicine in cancer: challenges and recommendations from an EU-funded cervical cancer biobanking study

Background:

Cervical cancer (CC) remains a leading cause of gynaecological cancer-related mortality worldwide. CC pathogenesis is triggered when human papillomavirus (HPV) inserts into the genome, resulting in tumour suppressor gene inactivation and oncogene activation. Collecting tumour and blood samples is critical for identifying these genetic alterations.

Methods:

BIO-RAIDs is the first prospective molecular profiling clinical study to include a substantial biobanking effort that used uniform high-quality standards and control of samples. In this European Union (EU)-funded study, we identified the challenges that were impeding the effective implementation of such a systematic and comprehensive biobanking effort.

Results:

The challenges included a lack of uniform international legal and ethical standards, complexities in clinical and molecular data management, and difficulties in determining the best technical platforms and data analysis techniques. Some difficulties were encountered by all investigators, while others affected only certain institutions, regions, or countries.

Conclusions:

The results of the BIO-RAIDs programme highlight the need to facilitate and standardise regulatory procedures, and we feel that there is also a need for international working groups that make recommendations to regulatory bodies, governmental funding agencies, and academic institutions to achieve a proficient biobanking programme throughout EU countries. This represents the first step in precision medicine.

DNA Methylation of Cellular Retinoic Acid-Binding Proteins in Cervical Cancer

This study determined the methylation status of cellular retinoic acid-binding protein (CRABP) gene promoters and associated them with demographic characteristics, habits, and the presence of human papilloma virus (HPV) in patients with cervical cancer (CC), low and high squamous intraepithelial lesions, and no intraepithelial lesion. Women (n = 158) were selected from the Colposcopy Clinic of Sanitary Jurisdiction II in Ciudad Juarez, Chihuahua, Mexico. Demographic characteristics and habit information were collected. Cervical biopsy and endocervical scraping were used to determine methylation in promoter regions by methylation-specific polymerase chain reaction technique. We found hemi-methylation patterns in the promoter regions of CRABP1 and CRABP2; there was 28.5% hemi-methylation in CRABP1 and 7.0% in that of CRABP2. Methylation in CRABP1 was associated with age (≥35 years, P = 0.002), family history of cancer (P = 0.032), the presence of HPV-16 (P = 0.013), and no alcohol intake (P = 0.035). These epigenetic changes could be involved in the CC process, and CRABP1 has the potential to be a predictive molecular marker of retinoid therapy response.

Mammalian microRNA: an important modulator of host-pathogen interactions in human viral infections

MicroRNAs (miRNAs), which are small non-coding RNAs expressed by almost all metazoans, have key roles in the regulation of cell differentiation, organism development and gene expression. Thousands of miRNAs regulating approximately 60 % of the total human genome have been identified. They regulate genetic expression either by direct cleavage or by translational repression of the target mRNAs recognized through partial complementary base pairing. The active and functional unit of miRNA is its complex with Argonaute proteins known as the microRNA-induced silencing complex (miRISC). De-regulated miRNA expression in the human cell may contribute to a diverse group of disorders including cancer, cardiovascular dysfunctions, liver damage, immunological dysfunction, metabolic syndromes and pathogenic infections. Current day studies have revealed that miRNAs are indeed a pivotal component of host-pathogen interactions and host immune responses toward microorganisms. miRNA is emerging as a tool for genetic study, therapeutic development and diagnosis for human pathogenic infections caused by viruses, bacteria, parasites and fungi. Many pathogens can exploit the host miRNA system for their own benefit such as surviving inside the host cell, replication, pathogenesis and bypassing some host immune barriers, while some express pathogen-encoded miRNA inside the host contributing to their replication, survival and/or latency. In this review, we discuss the role and significance of miRNA in relation to some pathogenic viruses.