Molecular transitions from papillomavirus infection to cervical precancer and cancer: Role of stromal estrogen receptor signaling

Genome-Wide Transcriptome Analysis of Human Papillomavirus 16-Infected Primary Keratinocytes Reveals Subtle Perturbations Mostly due to E7 Protein Expression

It is established that the host cell transcriptomes of natural lesions, organotypic rafts, and human papillomavirus (HPV)-immortalized keratinocytes are altered in the presence of HPV genomes. However, the establishment of HPV-harboring cell lines requires selection and immortalization, which makes it impossible to distinguish between alterations directly induced by HPV or indirectly by the need for immortalization or selection. To address direct effects of HPV infection on the host cell transcriptome, we have used our recently established infection model that allows efficient infection of primary keratinocytes with HPV16 virions. We observed only a small set of genes to be deregulated at the transcriptional level at 7 days postinfection (dpi), most of which fall into the category regulated by pocket proteins pRb, p107, and p130. Furthermore, cell cycle genes were not deregulated in cells infected with a virus lacking E7 despite the presence of episomal genome and viral transcripts. These findings imply that the majority of transcriptional changes are due to the E7 protein impairing pocket protein function. Additional pathways, such as the Fanconi anemia-BRCA pathway, became perturbed only after long-term culturing of infected cells. When grown as organotypic raft cultures, keratinocytes infected with wild-type but not E7 mutant virus had perturbed transcriptional regulation of pathways previously identified in natural lesions and in rafts derived from immortalized keratinocytes. We conclude that the HPV infection model provides a valuable tool to distinguish immediate transcriptional alterations from those induced by persistent infection and the need for selection and immortalization.IMPORTANCE To establish infection and complete the viral life cycle, human papillomavirus (HPV) needs to alter the transcriptional program of host cells. Until recently, studies were restricted to keratinocyte-derived cell lines immortalized by HPV due to the lack of experimental systems to efficiently infect primary keratinocytes. Need for selection and immortalization made it impossible to distinguish between alterations induced by HPV and secondary adaptation due to selection and immortalization. With our recent establishment of an extracellular matrix (ECM)-to-cell transfer system allowing efficient infection of primary keratinocytes, we were able to identify transcriptional changes attributable to HPV16 infection. Most perturbed genes fall into the class of S-phase genes, which are regulated by pocket proteins. Indeed, infection with viruses lacking E7 abrogated most transcriptional changes. It is important to note that many transcriptional alterations thought to be important for the HPV life cycle are actually late events that may reflect immortalization and, possibly, disease progression.

T Cells in Viral Infections: The Myriad Flavours of Antiviral Immunity

Viral diseases are a major cause of morbidity and mortality and result in a significant public health burden. T lymphocytes first identified in the chordate lineage and constitute a highly sophisticated branch of adaptive immune system. Apart from B cells, it is the only cell type that exhibits antigenic specificities; achieved by gene rearrangement. T cells are unique with respect to diversity of their subsets, which have distinct effector specificities, proliferative abilities, memory generation, and life span. T cells are impactful in viral infections by virtue of their capability to combat intracellular pathogens. The effector functions of T cells are mediated through cytokines/chemokines and by direct cytotoxicity of infected cells. T cell response can be beneficial or detrimental to host; prognosis depending on qualitative and quantitative differences in the response. Persistent viral infections are associated with functionally suboptimal, exhausted T cell responses, which are unable to clear virus. Specific subsets such as regulatory T cells (Tregs) dampen antiviral responses; thereby favouring viral persistence. However, Tregs protect the host from immunopathology by limiting perpetual inflammation. Certain other subsets such as Th17 cells may contribute to autoimmune component of viral infections. The importance of T cells is highlighted by the fact that modern vaccination and therapeutic approaches focus on modulating T cell frequencies and effector functions. This chapter emphasises the understanding how T cells influence outcomes of viral infections, modern vaccination and therapeutic strategies with thrust on T cell biology.

Carcinogenesis Associated with Human Papillomavirus Infection. Mechanisms and Potential for Immunotherapy

Human papillomavirus (HPV) infection is responsible for approximately 5% of all cancers and is associated with 30% of all pathogen-related cancers. Cervical cancer is the third most common cancer in women worldwide; about 70% of cervical cancer cases are caused by the high-risk HPVs (HR HPVs) of genotypes 16 and 18. HPV infection occurs mainly through sexual contact; however, viral transmission via horizontal and vertical pathways is also possible. After HPV infection of basal keratinocytes or ecto-endocervical transition zone cells, viral DNA persists in the episomal form. In most cases, infected cells are eliminated by the immune system. Occasionally, elimination fails, and HPV infection becomes chronic. Replication of HPVs in dividing epithelial cells is accompanied by increased expression of the E6 and E7 oncoproteins. These oncoproteins are responsible for genomic instability, disruption of the cell cycle, cell proliferation, immortalization, and malignant transformation of HPV-infected cells. Besides, E6 and E7 oncoproteins induce immunosuppression, preventing the detection of HPV-infected and transformed cells by the immune system. HPV integration into the genome of the host cell leads to the upregulation of E6 and E7 expression and contributes to HPV-associated malignization. Prophylactic HPV vaccines can prevent over 80% of HPV-associated anogenital cancers. The vaccine elicits immune response that prevents initial infection with a given HPV type but does not eliminate persistent virus once infection has occurred and does not prevent development of the HPV-associated neoplasias, which necessitates the development of therapeutic vaccines to treat chronic HPV infections and HPV-associated malignancies.

Estrogen signaling and estrogen receptors as prognostic indicators in laryngeal cancer

Laryngeal squamous cell carcinoma (LSCC) has been shown to respond to 17β-estradiol. However, the presence and characterization of estrogen receptors (ER) and other sex hormone receptors in LSCC are still being determined. Sex hormone receptors and the way sex hormones impact LSCC tumors are important for understanding which patients would benefit from hormone therapies, such as anti-estrogen therapies. This information also has prognostic value, as there may be a correlation between ER profiles and LSCC aggression. Recent work by our team and others has shown that the canonical ER, estrogen receptor α (ERα), and its splice variant ERα36, are important modulators of estrogen signaling in LSCC. This review describes some common 17β-estradiol signaling pathways, and explains how these signaling pathways might control LSCC tumor growth. We also show that loss of ERα, but not ERα36, imbues LSCC with enhanced aggression, a pattern which has previously only been observed in breast cancer. We make a case for using ERα as a tumorigenic modulator and pathogenic marker in LSCC on par with the use of ERα as a prognostic marker in breast cancer.

Medroxyprogesterone Acetate Prevention of Cervical Cancer through Progesterone Receptor in a Human Papillomavirus Transgenic Mouse Model

Cervical dysplastic lesions called cervical intraepithelial neoplasias (CINs) need be treated to prevent cervical cancer. Currently available surgical procedures are effective, but the development of noninvasive treatment is warranted. In human papillomavirus transgenic mice engineered to express human papillomavirus type 16 E6 and E7, short-term treatment with 17β-estradiol induces CINs that progress to cervical cancer if the treatment is continued. In the present study, this mouse model was used to determine whether medroxyprogesterone acetate (MPA), a progestin drug, is chemopreventive. Human papillomavirus transgenic mice bearing CIN lesions were treated with MPA plus 17β-estradiol. Unlike control mice treated with 17β-estradiol alone, cervical cancer was absent in the MPA-treated mice. This observation suggests that MPA prevented CIN from progressing to invasive cancer. MPA was associated with inhibited cell proliferation and the promotion of apoptosis in CIN lesions. Confirming the role of the progesterone receptor, the preventive effect of MPA was absent in human papillomavirus transgenic mice in which the expression of progesterone receptor was genetically ablated. These results suggest that MPA is efficient in treating progesterone receptor–positive CIN lesions. These findings provide the basis for a biomarker-driven clinical trial of the secondary prevention of cervical cancer.

Hsps responsible for apoptosis induction failure in cervical cancer cells upon osthole and tamoxifen treatment

Aim: The aim of the present study was to investigate the efficacy of osthole (7-metoxy-8-isopenthenocoumarin) alone and combined with tamoxifen (TAM) in the elimination of human cervical cancer cells via programmed death. The involvement of heat shock proteins, i.e. well-known molecular chaperones, will be investigated. Material/Methods: Three human cervical cancer cell lines, infected with human papilloma virus (HPV), i.e. HeLa (HPV 18), SiHa (HPV 16), and CaSki (HPV 16 and 18), were used in the experiments. After osthole and TAM treatment, cells stained with fluorochromes were analyzed microscopically according to apoptotic, autophagic, and necrotic morphology. Hsp27, Hsp72, and Hsp90 levels were analyzed by immunoblotting. Transfection with specific siRNA was used for blocking of Hsp expression. Results: In the HeLa, CaSki, and SiHa cell lines, osthole and TAM applied alone had no significant effect on cell death induction. This was correlated with an overexpression of heat shock proteins 27, 72, and 90. In the case of a combination of both drugs, the level of apoptosis was elevated only in SiHa cells. Preincubation with osthole followed by TAM addition as well as simultaneous incubation with both drugs was the most effective. This was correlated with the inhibition of Hsp27, Hsp72, and Hsp90 expression. Blocking of Hsp expression with specific siRNA increased the sensitivity of the studied cell lines to the induction of apoptosis, but not to autophagy or necrosis. Conclusions: Our results indicated that the elimination of heat shock proteins from cervical cancer cells sensitized them to initiation of apoptosis after osthole and tamoxifen treatment.

Soluble guanylyl cyclase α1 subunit is a key mediator of proliferation, survival, and migration in ECC-1 and HeLa cell lines

Soluble guanylyl cyclase (sGC) is a heterodimeric enzyme constituted by two subunits, α1 and β1. Previously we have shown that 17β-estradiol (E2) exerts opposite effects on these subunits by increasing α1 and decreasing both β1 expression and enzymatic activity. To date, the physiological relevance of E2-induced sGC subunits' imbalance has not been addressed. Also, increased levels strongly correlate with E2-induced proliferation in E2-dependent tissues. The aim of the present study was to investigate the role of sGCα1 in proliferation, survival, and migration in two E2-responsive and non-responsive tumour cell lines. Here we showed that E2 stimulated sGCα1 expression in ECC-1 endometrial cancer cells. sGCα1 knock-down significantly reduced E2-dependent cell proliferation. Moreover, sGCα1 silencing caused G1 arrest together with an increase in cell death and dramatically inhibited cell migration. Surprisingly, disruption of sGCα1 expression caused a similar effect even in absence of E2. Confirming this effect, sGCα1 knock-down also augmented cell death and decreased proliferation and migration in E2-unresponsive HeLa cervical cancer cells. Our results show that sGCα1 mediated cell proliferation, survival, and migration in ECC-1 and HeLa cells and suggest that sGCα1 can not only mediate E2-tumour promoting effects but can also be involved in hormone-independent tumour progression.

Differences in gene expression between high-grade dysplasia and invasive HPV+ and HPV- tonsillar and base of tongue cancer

BACKGROUND

Human papillomavirus (HPV) is a causative agent for tonsillar and base of tongue squamous cell carcinoma (TSCC/BOTSCC), as well as for cervical cancer. Premalignant stages in cervical cancer have been studied extensively, while little is known about premalignant stages in TSCC/BOTSCC and the role of HPV. Here we analyzed differences in gene and protein expression between high-grade dysplasia and invasive cancer in both HPV-positive (HPV+ ) and HPV-negative (HPV- ) TSCC/BOTSCC.

METHODS

High-grade dysplasia and invasive carcinoma were laser microdissected from HPV+ and HPV- TSCC/BOTSCC tumor sections. Differential gene expression was studied utilizing nanoString RNA-panels and genes of interest were validated on the protein level by immunohistochemistry.

RESULTS

Forty genes in the HPV+ tumors showed significantly different expression between high-grade dysplasia and invasive cancer and 33 genes in the HPV- tumors. Five out of the nine most significant pathways showed similar increased activity in invasive cancer as compared to high-grade dysplasia in both HPV+ and HPV- tumors. Lastly, significant differences in protein expression was confirmed for SPARC, psoriasin, type I collagen and galectin-1 in both HPV+ and HPV- tumors.

CONCLUSIONS

This is to our knowledge the first study disclosing differences and similarities in gene expression between dysplastic and invasive HPV+ and HPV- TSCC/BOTSCC.

Suppression of Stromal Interferon Signaling by Human Papillomavirus 16

Human papillomaviruses (HPVs) infect squamous epithelia and cause several important cancers. Immune evasion is critical for viral persistence. Fibroblasts in the stromal microenvironment provide growth signals and cytokines that are required for proper epithelial differentiation, maintenance, and immune responses and are critical in the development of many cancers. In this study, we examined the role of epithelial-stromal interactions in the HPV16 life cycle using organotypic (raft) cultures as a model. Rafts were created using uninfected human foreskin keratinocytes (HFKs) and HFKs containing either wild-type HPV16 or HPV16 with a stop mutation to prevent the expression of the viral oncogene E5. Microarray analysis revealed significant changes in gene expression patterns in the stroma in response to HPV16, some of which were E5 dependent. Interferon (IFN)-stimulated genes (ISGs) and extracellular matrix remodeling genes were suppressed, the most prominent pathways affected. STAT1, IFNAR1, IRF3, and IRF7 were knocked down in stromal fibroblasts using lentiviral short hairpin RNA (shRNA) transduction. HPV late gene expression and viral copy number in the epithelium were increased when the stromal IFN pathway was disrupted, indicating that the stroma helps control the late phase of the HPV life cycle in the epithelium. Increased late gene expression correlated with increased late keratinocyte differentiation but not decreased IFN signaling in the epithelium. These studies show HPV16 has a paracrine effect on stromal innate immunity, reveal a new role for E5 as a stromal innate immune suppressor, and suggest that stromal IFN signaling may influence keratinocyte differentiation.IMPORTANCE The persistence of high-risk human papillomavirus (HPV) infections is the key risk factor for developing HPV-associated cancers. The ability of HPV to evade host immunity is a critical component of its ability to persist. The environment surrounding a tumor is increasingly understood to be critical in cancer development, including immune evasion. Our studies show that HPV can suppress the expression of immune-related genes in neighboring fibroblasts in a three-dimensional (3D) model of human epithelium. This finding is significant, because it indicates that HPV can control innate immunity not only in the infected cell but also in the microenvironment. In addition, the ability of HPV to regulate stromal gene expression depends in part on the viral oncogene E5, revealing a new function for this protein as an immune evasion factor.

Association of Estrogen Receptor Alpha Expression With Survival in Oropharyngeal Cancer Following Chemoradiation Therapy

BACKGROUND

Oropharyngeal squamous carcinoma (OPSC) continues to increase in incidence secondary to human papillomavirus (HPV) infection. Despite the good overall prognosis for these patients, treatment with chemoradiation is associated with morbidity and treatment failure. Better predictors for disease outcome are needed to guide de-intensification regimens. We hypothesized that estrogen receptor α (ERα), a prognostic biomarker in oncology with therapeutic implications, might have similar utility in OPSC.

METHODS

To investigate associations among ERα and demographics, HPV status, and survival, we analyzed ERα mRNA expression of head and neck squamous carcinomas (HNSC) from The Cancer Genome Atlas (TCGA) and immunohistochemistry (IHC) of pretreatment biopsy specimens from an independent group of 215 OPSC patients subsequently treated with primary chemoradiation (OPSC-CR). Associations among variables were evaluated with Fisher exact tests and logistic regression; associations with survival were evaluated with log-rank tests and Cox proportional hazards regression.

RESULTS

Among 515 patients in TCGA, ERα mRNA expression was highest in HPV-positive OPSC. High ERα mRNA expression was associated with improved survival among those receiving chemoradiation (hazard ratio adjusted for HPV status = 0.44, 95% confidence interval = 0.21 to 0.92). In OPSC-CR, ERα was positive by IHC in 51.6% of tumors and was associated with improved overall, disease-specific, progression-free, and relapse-free survival (log-rank tests: P < .001, P < .001, P = .002, P = .003, respectively); statistically significant associations of ERα positivity with improved survival were maintained after adjusting for clinical risk factors including HPV status.

CONCLUSION

In two independent cohorts, ERα is a potential biomarker for improved survival that also may represent a therapeutic target in OPSC.

Estrogen receptor 1 mutations in 260 cervical cancer samples from Chinese patients

Cervical cancer is one of the leading causes of cancer-associated mortality among females; however, the underlying molecular mechanisms of its carcinogenesis remain largely unclear. Previous comprehensive genomic studies have revealed prevalent estrogen receptor 1 (ESR1) mutations in breast cancer, which are rare in certain other types of cancer. To the best of our knowledge, it is unknown whether ESR1 mutations also exist in cervical cancer. Considering the evidence that cervical cancer shares certain genetic aberrations with breast cancer, and that the progression of both breast and cervical cancers can be affected by estrogen, it is possible that cervical cancer may also harbor ESR1 mutations. In the present study, a total of 260 Chinese cervical cancer samples with distinct subtypes were tested for the presence of ESR1 mutations. A total of three heterozygous missense ESR1 mutations, p.K303R (c.908A>G), p.T311M (c.932C>T) and p.Y537C (c.1610A>G), were identified in 3/207 (1.4%) cervical squamous cell carcinoma samples, which were absent in 27 adenosquamous carcinomas and 26 adenocarcinomas samples. Of the three individuals with an ESR1mutation, 1 patient was also diagnosed with ovarian endometriosis and the other 2 patients were diagnosed with a uterine fibroid. A bioinformatics analysis suggested that these ESR1 mutations may be pathogenic by promoting the development of cervical cancer. Furthermore, a previous comprehensive study confirmed that individuals with cervical squamous cell carcinoma possessed ESR1 mutations. These combined studies indicate that ESR1 mutations may participate in the carcinogenesis of cervical squamous cell carcinoma, albeit at a low frequency. In conclusion, the present study identified three potentially pathogenic ESR1 mutations in Chinese cervical squamous cell carcinoma samples, but not in other subtypes.

Altered microRNA processing proteins in HPV-induced cancers

High-risk human papilloma virus (hrHPV) infections are associated with the development of anogenital cancers, in particular cervical cancer, and a subset of head and neck cancers. Previous studies have shown that microRNAs (miRNAs) contribute to the development and progression of HPV-induced malignancies. miRNAs are small non-coding RNAs that exist as multiple length and sequence variants, termed isomiRs. Efficient processing of miRNAs and generation of isomiRs is accomplished by several processing proteins. Deregulation of Drosha, AGO2, and TENT2, among others, has been observed in HPV-induced cancers and was even found at the precancerous stage. This suggests that miRNA processing proteins may be involved during early cancer development and that the generated isomiRs could provide promising biomarkers for early cancer diagnosis.

Long non‑coding RNA plasmacytoma variant translocation 1 gene promotes the development of cervical cancer via the NF‑κB pathway

The long noncoding RNA plasmacytoma variant translocation 1 gene (LncRNA PVT1) has an important role in tumor occurrence and development, yet the role and underlying molecular mechanisms of this RNA in cervical cancer have not yet been elucidated. In the present study, three cervical cancer cell lines (HeLa, Ca Ski and SiHa) were used to verify how LncRNA PVT1 mediates cervical cancer development, and the H8 cell line was used as a control. A LncRNA PVT1 overexpression vector or small interfering RNAs targeting LncRNA PVT1 were transfected into cervical cancer cells to generate LncRNA PVT1 overexpression and silencing in these cells. LncRNA PVT1 overexpression accelerated the growth of cervical cancer cells by advancing the cell cycle and inhibiting cellular apoptosis; increases in Cyclin D1 (CCND1) mRNA and activated Bcl‑2 protein expression levels also supported this finding. Furthermore, NF‑κB activation and expression was increased by LncRNA PVT1 overexpression. In addition, NF‑κB activation or inhibition induced changes in cell viability, accompanied by changes in CCND1 and Bcl‑2 expression. Increases or decreases in microRNA‑16 (miR‑16) expression (using miR mimics and inhibitors) also corresponded to changes in LncRNA PVT1 expression, in vitro. miR‑16 mimics and inhibitor had opposite effects to those of NF‑κB activity, and miR‑16 was demonstrated to directly interact with the NF‑κB gene as measured using the dual‑luciferase assay. In summary, LncRNA PVT1 inhibits the effect of miR‑16, promoting the cell cycle and inhibiting cellular apoptosis of cervical cancer cells, potentially via the NF‑κB pathway. The data from the present study will contribute to the current knowledge surrounding the theoretical basis of cervical cancer and provide a new perspective for the treatment of cervical cancer.

Expression of estrogen receptor alpha is associated with pathogenesis and prognosis of human papillomavirus-positive oropharyngeal cancer

Human papillomavirus (HPV) has been identified as a causative agent of cervical cancer and oropharyngeal cancer (OPC). Intriguingly, estrogen and HPV were shown to play synergistic roles in cervical carcinogenesis. We recently demonstrated that the apolipoprotein B mRNA-editing catalytic polypeptide 3 (APOBEC3, A3) family, which is inducible by estrogen, could lead to HPV DNA hypermutation and cause viral DNA integration. In the present study, we examined the relationships between estrogen-estrogen receptor α (ERα) and A3s in HPV-positive OPC. ERα expression was associated with HPV positivity in OPC biopsy samples using immunohistochemical analysis and reverse-transcription quantitative polymerase chain reaction. In addition, ERα was significantly associated with improved overall survival in HPV-positive OPC (hazard ratio, 0.26; p = 0.029). APOBEC3A (A3A) mRNA was induced by estrogen in HPV and ERα-positive OPC cells. Furthermore, A3A mRNA and protein expression were significantly higher in ERα-positive cases than in ERα-negative ones, among HPV-positive biopsy samples (p = 0.037 and 0.047). These findings suggest that A3A is associated with a good prognosis in ERα-positive OPC, and indicate the prognostic significance of ERα in HPV-positive OPC. This is the first study to demonstrate the prognostic role of ERα in HPV-positive OPC.

Identification of candidate biomarkers correlated with the diagnosis and prognosis of cervical cancer via integrated bioinformatics analysis

Background: Cervical carcinoma is one of the most common malignant gynecological tumors and is associated with high rates of morbidity and mortality. Early diagnosis and early treatment can reduce the mortality rate of cervical cancer. However, there is still no specific biomarkers for the diagnosis and detection of cervical cancer prognosis. Therefore, it is greatly urgent in searching biomarkers correlated with the diagnosis and prognosis of cervical cancer.

Results: The mRNA and microRNA expression profile datasets (GSE7803, GSE9750, GSE63514, and GSE30656) were downloaded from the Gene Expression Omnibus database (GEO). The three microarray datasets were integrated to one via integrated bioinformatics. Differentially expressed genes (DEGs) and microRNAs (DEMs) were obtained by R software. The protein–protein interaction (PPI) networks of the DEGs were performed from the STRING database and further visualized by Cytoscape software. A total of 83 DEGs and 14 DEMs were screened from the microarray expression profile datasets. The miRNAs validated to be associated with cervical cancer were obtained using HMDD online website and the target genes of DEMs were identified using the miRWalk2.0 online database. ESR1, PPP1R3C, NSG1, and TMPRSS11D were the gene targets of hsa-miR-21; the targets of hsa-miR-16 were GYS2, ENDOU, and KLF4. These targets were all downregulated in cervical cancer. Finally, we verified the expression of those targets in cervical tissues from TCGA and GTEx databases and analyzed their relationship with survival of cervical cancer patients. In the end, the expression of key genes in cervical cancer tissues was verified via experiment method, we found KLF4 and ESR1 were downregulated in tumor tissues.

Conclusion: This study indicates that KLF4 and ESR1 are downregulated by the upregulated miR21 and miRNA16 in cervical cancer, respectively, using bioinformatics analysis, and the lower expression of KLF4 and ESR1 is closely related to the poor prognosis. They might be of clinical significance for the diagnosis and prognosis of cervical cancer, and provide effective targets for the treatment of cervical cancer.

Novel Genomic Biomarker Candidates for Cervical Cancer As Identified by Differential Co-Expression Network Analysis

Cervical cancer is the second most common malignancy and the third reason for mortality among women in developing countries. Although infection by the oncogenic human papilloma viruses is a major cause, genomic contributors are still largely unknown. Network analyses, compared with candidate gene studies, offer greater promise to map the interactions among genomic loci contributing to cervical cancer risk. We report here a differential co-expression network analysis in five gene expression datasets (GSE7803, GSE9750, GSE39001, GSE52903, and GSE63514, from the Gene Expression Omnibus) in patients with cervical cancer and healthy controls. Kaplan-Meier Survival and principle component analyses were employed to evaluate prognostic and diagnostic performances of biomarker candidates, respectively. As a result, seven distinct co-expressed gene modules were identified. Among these, five modules (with sizes of 9-45 genes) presented high prognostic and diagnostic capabilities with hazard ratios of 2.28-11.3, and diagnostic odds ratios of 85.2-548.8. Moreover, these modules were associated with several key biological processes such as cell cycle regulation, keratinization, neutrophil degranulation, and the phospholipase D signaling pathway. In addition, transcription factors ETS1 and GATA2 were noted as common regulatory elements. These genomic biomarker candidates identified by differential co-expression network analysis offer new prospects for translational cancer research, not to mention personalized medicine to forecast cervical cancer susceptibility and prognosis. Looking into the future, we also suggest that the search for a molecular basis of common complex diseases should be complemented by differential co-expression analyses to obtain a systems-level understanding of disease phenotype variability.

Comparative RNA sequencing reveals that HPV16 E6 abrogates the effect of E6*I on ROS metabolism

High-risk Human Papillomavirus infections are responsible for anogenital and oropharyngeal cancers. Alternative splicing is an important mechanism controlling HPV16 gene expression. Modulation in the splice pattern leads to polycistronic HPV16 early transcripts encoding a full length E6 oncoprotein or truncated E6 proteins, commonly named E6*. Spliced E6*I transcripts are the most abundant RNAs produced in HPV-related cancers. To date, the biological function of the E6*I isoform remains controversial. In this study, we identified, by RNA sequencing, cellular targets deregulated by E6*I, among which genes related to ROS metabolism. Concomitantly, E6*I-overexpressing cells display high levels of ROS. However, co-overexpression of both E6 and E6*I has no effect on ROS production. In HPV16-infected cells expressing different E6/E6*I levels, we show that the newly identified targets CCL2 and RAC2 are increased by E6*I but decreased by E6 expression, suggesting that E6 abrogates the effect of E6*I. Taken together, these data support the idea that E6*I acts independently of E6 to increase ROS production and that E6 has the ability to counteract the effects of E6*I. This asks the question of how E6*I can be considered separately of E6 in the natural history of HPV16 infection.

Estrogen stimulates female cancer progression by inducing myeloid-derived suppressive cells: investigations on pregnant and non-pregnant experimental models

Objective

To investigate the clinical implications of 17β-estradiol (E2) in estrogen receptor α (ERα)-negative female cancer progression as well as the underlying biological mechanisms.

Methods

Clinical data from 306 locally-advanced cervical cancer (stage IIB-IVA) patients were analyzed in order to investigate the relationships between age, serum E2 levels, and treatment outcomes. Clinical samples, ERα-negative cervical and breast cancer cell lines, and mouse xenograft models of cervical and breast cancers were employed in order to elucidate the mechanisms responsible for the E2- and pregnancy-mediated progression of cervical and breast cancers, with a focus on the role of myeloid-derived suppressor cells (MDSC).

Results

Younger patients with elevated E2 levels showed significantly shorter progression-free survival (P = 0.040) and overall survival (P = 0.039). The exogenous E2 treatment stimulated the mobilization of MDSC from bone marrow and directly augmented their suppressive activities, leading to the progression of ERα-negative cervical and breast cancers. The co-administration of an anti-Gr-1 neutralizing antibody with E2 prevented the E2-mediated induction of MDSC, and attenuated E2-mediated tumor growth in cervical and breast cancer xenografts. Significantly increased MDSC numbers and enhanced tumor growth were observed during pregnancy in mice with cervical or breast cancer. Significantly increased MDSC numbers were also observed during pregnancy in cervical cancer patients.

Conclusions

E2 facilitates the progression of ERα-negative cervical or breast cancer under non-pregnant and pregnant conditions by inducing MDSC. MDSC inhibition therapy may have therapeutic efficacy in premenopausal or pregnant female cancer patients.

A Novel In Vivo Infection Model To Study Papillomavirus-Mediated Disease of the Female Reproductive Tract

Papillomaviruses exhibit species-specific tropism, thereby limiting understanding and research of several aspects of HPV infection and carcinogenesis. The discovery of a murine papillomavirus (MmuPV1) provides the opportunity to study papillomavirus infections in a tractable, in vivo laboratory model. MmuPV1 infects and causes disease in the cutaneous epithelium, as well as the mucosal epithelia of the oral cavity and anogenital tract. In this report, we describe a murine model of MmuPV1 infection and neoplastic disease in the female reproductive tracts of wild-type immunocompetent FVB mice. Low-grade dysplastic lesions developed in reproductive tracts of FVB mice infected with MmuPV1 for 4 months, and mice infected for 6 months developed significantly worse disease, including squamous cell carcinoma (SCC). We also tested the contribution of estrogen and/or UV radiation (UVR), two cofactors we previously identified as being involved in papillomavirus-mediated disease, to cervicovaginal disease. Similar to HPV16 transgenic mice, exogenous estrogen treatment induced high-grade precancerous lesions in the reproductive tracts of MmuPV1-infected mice by 4 months and together with MmuPV1 efficiently induced SCC by 6 months. UV radiation and exogenous estrogen cooperated to promote carcinogenesis in MmuPV1-infected mice. This murine infection model represents the first instance of de novo papillomavirus-mediated carcinogenesis in the female reproductive tract of wild-type mice resulting from active virus infection and is also the first report of the female hormone estrogen contributing to this process. This model will provide an additional platform for fundamental studies on papillomavirus infection, cervicovaginal disease, and the role of cellular cofactors during papillomavirus-induced carcinogenesis.IMPORTANCE Tractable and efficient models of papillomavirus-induced pathogenesis are limited due to the strict species-specific and tissue-specific tropism of these viruses. Here, we report a novel preclinical murine model of papillomavirus-induced cervicovaginal disease in wild-type, immunocompetent mice using the recently discovered murine papillomavirus, MmuPV1. In this model, MmuPV1 establishes persistent viral infections in the mucosal epithelia of the female reproductive tract, a necessary component needed to accurately mimic HPV-mediated neoplastic disease in humans. Persistent MmuPV1 infections were able to induce progressive neoplastic disease and carcinogenesis, either alone or in combination with previously identified cofactors of papillomavirus-induced disease. This new model will provide a much-needed platform for basic and translational studies on both papillomavirus infection and associated disease in immunocompetent mice.

Association of estradiol and HPV/HPV16 infection with the occurrence of cervical squamous cell carcinoma

The associations between human papillomavirus (HPV) infection or hormonal exposure and cervical cancer risk are well established. However, to the best of our knowledge, the association between high endogenous estradiol levels in conjunction with HPV/HPV16 infection and the risk of cervical squamous cell carcinoma remains unknown. To investigate this, the current study conducted a matched case-control study in Shanxi Province, China, in which clinical samples were obtained from 74 females with newly diagnosed uterine cervix squamous cell carcinoma and 74 matched healthy females who were selected from 582 healthy females according to age, place of residence, marital status and menopausal status. From all participants, DNA was extracted from cells obtained from a cervical smear and serum was separated from venous blood withdrawn during days 5-8 of the menstrual cycle. HPV/HPV16 DNA and estradiol expression levels in the serum were measured by general polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Significant differences were identified in the positive HPV and HPV16 DNA expression rates between patients and controls, with odds ratios (95% confidence interval) of 3.74 (1.84-7.59) and 4.04 (1.97-8.28), respectively. Expression levels of estradiol in patients were significantly higher compared with the controls (P<0.001), however, this was only identified when the HPV16 E2 or E6 oncogene status was negative. Considering 40 ng/ml as the cut-off estradiol level, 78.38% of patients exhibited high estradiol levels, which was significantly higher than the percentage of controls (P<0.001). An additive interaction pattern was revealed between estradiol expression levels and HPV/HPV16 infection. The results suggest that among the various types of HPV, HPV16 may be most likely to cause uterine cervix squamous cell carcinoma and an abnormally high level of endogenous estradiol may further increase this risk. Therefore, estradiol therapy may represent a new treatment strategy for cases of cervical cancer associated with HPV infection.

E2F7, EREG, miR-451a and miR-106b-5p are associated with the cervical cancer development

PURPOSE

We aimed to seek the crucial genes or microRNAs (miRNA) correlated with the cervical cancer development.

METHODS

The miRNA profiling GSE30656 and gene expression profiling GSE63514 were obtained from Gene Expression Omnibus database. Differentially expressed microRNAs (DEMiRs) and differentially expressed genes (DEGs) were screened. Then target genes of DEMiRs were obtained and matched with DEGs to obtain interaction pairs between DEMiRs and DEGs. Gene Ontology-biological process and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted for DEGs and DEMiRs in the DEMiRs-DEGs pairs. The DEMiRs-DEGs regulatory network, protein-protein interaction network and transcription factor (TF)-target regulatory network were constructed. Ultimately, long non-coding RNAs (lncRNAs) associated with DEMiRs were obtained, and then lncRNA-miRNA-target ceRNA network was established.

RESULTS

Total 18 DEMiRs and 620 DEGs were identified. DEMiRs were enriched in 35 KEGG pathways, such as PI3K-Akt signaling pathway (involving miR-451a). DEGs were enriched in various functions, such as DNA replication (involving E2F7) and angiogenesis (involving EREG). There were 120 nodes and 216 interaction pairs in the DEMIR-DEG regulatory network, and miR-106b-5p has the greatest degree. EREG and E2F7 were regulated by miR-451a and miR-148a-3p, respectively. Besides, E2F7 was identified in the TF-target regulatory network, regulating CDC6. There were 15 lncRNAs, 11 miRNAs and 90 DEGs in the ceRNA network. Specially, miR-148a-3p was interacted with lncRNA HOTAIR in the ceRNA network.

CONCLUSION

E2F7, EREG, miR-451a and miR-106b-5p were likely to be related to the cervical cancer development.

Discovery of microarray-identified genes associated with the progression of cervical intraepithelial neoplasia

OBJECTIVE

To identify genes potentially associated with cervical intraepithelial neoplasia (CIN) progression through bioinformatic approaches and clinicopathological verification.

METHODS

mRNA expression microarray data related to CIN progression were screened from the Gene Expression Omnibus (GEO) database and re-analyzed using bioinformatics approaches. Tissue microarray immunohistochemistry was conducted to assess the significant identified genes in CIN, cervical cancer, and normal tissues.

RESULTS

Biological annotation and text mining showed that 14 differentially expressed genes were directly or indirectly related to CIN progression. The expression of 5 up-regulated differentially expressed genes, namely, CCND2, TGFBR2, PRKCB, SH3KBP1 and WNT2B, was examined by tissue microarray immunohistochemistry, with the known CIN progression genes P16 and Ki-67 as the internal reference. Expression of TGFBR2, SH3KBP1, and WNT2B were not detected in CIN and cervical carcinoma, whereas no significant difference in the expression rate of PRKCB was detected (P > 0.05). CCND2, P16, and Ki-67 expression showed a gradual increasing trend in normal, CIN, and cervical cancer.

CONCLUSIONS

14 differentially expressed genes were associated with CIN progression, as indicated by the microarray data analysis results. CCND2 may be a new marker for the prediction of CIN progression in addition to P16 and Ki-67.

Identification of key candidate genes and small molecule drugs in cervical cancer by bioinformatics strategy

Purpose

Cervical cancer (CC) is one of the most common malignant tumors among women. The present study aimed at integrating two expression profile datasets to identify critical genes and potential drugs in CC.

Materials and methods

Expression profiles, GSE7803 and GSE9750, were integrated using bioinformatics methods, including differentially expressed genes analysis, Kyoto Encyclopedia of Genes and Genomes pathway analysis, and protein–protein interaction (PPI) network construction. Subsequently, survival analysis was performed among the key genes using Gene Expression Profiling Interactive Analysis websites. Connectivity Map (CMap) was used to query potential drugs for CC.

Results

A total of 145 upregulated genes and 135 downregulated genes in CC were identified. The functional changes of these differentially expressed genes related to CC were mainly associated with cell cycle, DNA replication, p53 signaling pathway, and oocyte meiosis. A PPI network was identified by STRING with 220 nodes and 2,111 edges. Thirteen key genes were identified as the intersecting genes of the enrichment pathways and the top 20 nodes in PPI network. Survival analysis revealed that high mRNA expression of MCM2, PCNA, and RFC4 was significantly associated with longer overall survival, and the survival was significantly better in the low-expression RRM2 group. Moreover, CMap predicted nine small molecules as possible adjuvant drugs to treat CC.

Conclusion

Our study found key dysregulated genes involved in CC and potential drugs to combat it, which might provide insights into CC pathogenesis and might shed light on potential CC treatments.

An interaction network driven approach for identifying biomarkers for progressing cervical intraepithelial neoplasia

Overlapping genes across high-grade squamous intraepithelial lesions (CIN2 and 3) and cancer may serve as potential biomarkers for this progressive disease. Differentially expressed genes (DEGs) of dysplastic (CIN2 and CIN3) and cancer cells were identified by microarray data analysis. Gene interaction network was constructed using the 98 common DEGs among the dysplastic and cancer cells and analysed for the identification of common modules, hubs and significant motifs. Two significant modules and 10 hubs of the common gene interaction network, with 125 nodes and 201 edges were found. DEGs namely NDC80, ZWINT, CDC7, MCM4, MCM2 and MCM6 were found to be common in both the significant modules as well as the hubs. Of these, ZWINT, CDC7, MCM4, MCM2 and MCM6 were further identified to be part of most significant motifs. This overlapping relationship provides a list of common disease related genes among pre-cancerous and cancer stages which could help in targeting the proliferating cancerous cells during onset. Capitalizing upon and targeting Minichromosome maintenance protein complex - specifically the MCM2, MCM4 and MCM6 subunits, ZWINT and CDC7 for experimental validation, may provide valuable insights in understanding and detection of progressing cervical neoplasia to cervical cancer at an early stage.

Meta-Analysis of Polymorphic Variants Conferring Genetic Risk to Cervical Cancer in Indian Women Supports CYP1A1 as an Important Associated Locus

Objective: Association of multiple polymorphic variants with cervical cancer has been elucidated by several candidate gene based as well as genome-wide association studies. However, contradictory outcomes of those studies have failed to estimate the true effect of the polymorphic variants on cervical cancer. Methods: Literature mining of the PubMed database was done to gather all the publications related to genetic association with cervical cancer in India. Out of 98 PubMed hits only 29 genetic association studies were selected for meta-analysis based on specific inclusion criteria. A fixed-effect meta-analysis was performed to evaluate the overall association of the genetic polymorphisms with cervical cancer. Cochran’s Q test was performed to assess between study heterogeneity. Publication bias was also estimated by funnel plots and Egger’s regression test. Further, sub-group analysis was conducted by fixed-effect meta-regression to assess the impact of polymorphisms on cervical cancer in the presence of Human Papilloma Virus (HPV). Result: Following a fixed-effect model, meta-analysis was conducted that revealed 2 polymorphic variants viz. ‘deletion polymorphism (Del2) (OR=1.79, 95% CI= 1.08-2.95, P=0.023) in GSTM1’ and ‘rs1048943 (OR = 2.34, 95% CI=1.37-3.99, P=0.0018) in CYP1A1’ to be associated with cervical cancer. However, multiple testing correction showed only rs1048943 of CYP1A1 to be significantly associated (P-value=0.029) with cervical cancer with significant publication bias (P-value=0.0113) as estimated by Egger’s regression test. The polymorphic variants ‘rs1801131’, ‘rs1801133’, ‘rs2430561’, ‘rs1799782’, ‘rs25486’ and ‘rs25487’ showed significant (p<0.05) evidence of heterogeneity between studies by Cochran’s Q test and also by heterogeneity index (I2) calculation. Conclusion: Therefore, our study revealed significant association of rs1048943 in CYP1A1, but a nominal association of deletion polymorphism (Del2) in GSTM1 with cervical cancer, which provides a comprehensive insight on the true effect of the polymorphisms, reported in various case-control studies, on the risk of the development of cervical cancer in Indian women.

Human papillomavirus type 16 antagonizes IRF6 regulation of IL-1β

Human papillomavirus type 16 (HPV16) and other oncoviruses have been shown to block innate immune responses and to persist in the host. However, to avoid viral persistence, the immune response attempts to clear the infection. IL-1β is a powerful cytokine produced when viral motifs are sensed by innate receptors that are members of the inflammasome family. Whether oncoviruses such as HPV16 can activate the inflammasome pathway remains unknown. Here, we show that infection of human keratinocytes with HPV16 induced the secretion of IL-1β. Yet, upon expression of the viral early genes, IL-1β transcription was blocked. We went on to show that expression of the viral oncoprotein E6 in human keratinocytes inhibited IRF6 transcription which we revealed regulated IL-1β promoter activity. Preventing E6 expression using siRNA, or using E6 mutants that prevented degradation of p53, showed that p53 regulated IRF6 transcription. HPV16 abrogation of p53 binding to the IRF6 promoter was shown by ChIP in tissues from patients with cervical cancer. Thus E6 inhibition of IRF6 is an escape strategy used by HPV16 to block the production IL-1β. Our findings reveal a struggle between oncoviral persistence and host immunity; which is centered on IL-1β regulation.

Integrative machine learning analysis of multiple gene expression profiles in cervical cancer

Although most of the cervical cancer cases are reported to be closely related to the Human Papillomavirus (HPV) infection, there is a need to study genes that stand up differentially in the final actualization of cervical cancers following HPV infection. In this study, we proposed an integrative machine learning approach to analyse multiple gene expression profiles in cervical cancer in order to identify a set of genetic markers that are associated with and may eventually aid in the diagnosis or prognosis of cervical cancers. The proposed integrative analysis is composed of three steps: namely, (i) gene expression analysis of individual dataset; (ii) meta-analysis of multiple datasets; and (iii) feature selection and machine learning analysis. As a result, 21 gene expressions were identified through the integrative machine learning analysis which including seven supervised and one unsupervised methods. A functional analysis with GSEA (Gene Set Enrichment Analysis) was performed on the selected 21-gene expression set and showed significant enrichment in a nine-potential gene expression signature, namely PEG3, SPON1, BTD and RPLP2 (upregulated genes) and PRDX3, COPB2, LSM3, SLC5A3 and AS1B (downregulated genes).

Potential biomarkers and therapeutic targets in cervical cancer: Insights from the meta-analysis of transcriptomics data within network biomedicine perspective

The malignant neoplasm of the cervix, cervical cancer, has effects on the reproductive tract. Although infection with oncogenic human papillomavirus is essential for cervical cancer development, it alone is insufficient to explain the development of cervical cancer. Therefore, other risk factors such as host genetic factors should be identified, and their importance in cervical cancer induction should be determined. Although gene expression profiling studies in the last decade have made significant molecular findings about cervical cancer, adequate screening and effective treatment strategies have yet to be achieved. In the current study, meta-analysis was performed on cervical cancer-associated transcriptome data and reporter biomolecules were identified at RNA (mRNA, miRNA), protein (receptor, transcription factor, etc.), and metabolite levels by the integration of gene expression profiles with genome-scale biomolecular networks. This approach revealed already-known biomarkers, tumor suppressors and oncogenes in cervical cancer as well as various receptors (e.g. ephrin receptors EPHA4, EPHA5, and EPHB2; endothelin receptors EDNRA and EDNRB; nuclear receptors NCOA3, NR2C1, and NR2C2), miRNAs (e.g., miR-192-5p, miR-193b-3p, and miR-215-5p), transcription factors (particularly E2F4, ETS1, and CUTL1), other proteins (e.g., KAT2B, PARP1, CDK1, GSK3B, WNK1, and CRYAB), and metabolites (particularly, arachidonic acids) as novel biomarker candidates and potential therapeutic targets. The differential expression profiles of all reporter biomolecules were cross-validated in independent RNA-Seq and miRNA-Seq datasets, and the prognostic power of several reporter biomolecules, including KAT2B, PCNA, CD86, miR-192-5p and miR-215-5p was also demonstrated. In this study, we reported valuable data for further experimental and clinical efforts, because the proposed biomolecules have significant potential as systems biomarkers for screening or therapeutic purposes in cervical carcinoma.

Early synergistic interactions between the HPV16‑E7 oncoprotein and 17β-oestradiol for repressing the expression of Granzyme B in a cervical cancer model

Although high-risk human papillomavirus (HR‑HPV) infection has a prominent role in the aetiology of cervical cancer (CC), sex steroid hormones may also be involved in this process; however, the cooperation between oestrogen and HR‑HPV in the early stages of cervical carcinogenesis is poorly understood. Since 17β-oestradiol (E2) and the HPV type 16‑E7 oncoprotein induce CC in transgenic mice, a microarray analysis was performed in the present study to generate global gene expression profiles from 2‑month‑old FVB (non‑transgenic) and K14E7 (transgenic) mice who were left untreated or were treated for 1 month with E2. Upregulation of cancer-related genes that have not been previously reported in the context of CC, including glycerophosphodiester phosphodiesterase domain containing 3, interleukin 1 receptor type II, natriuretic peptide type C, MGAT4 family member C, lecithin-retinol acyltransferase (phosphatidylcholine-retinol-O-acyltransferase) and glucoside xylosyltransferase 2, was observed. Notably, upregulation of the serine (or cysteine) peptidase inhibitor clade B member 9 gene and downregulation of the Granzyme gene family were observed; the repression of the Granzyme B pathway may be a novel mechanism of immune evasion by cancer cells. The present results provide the basis for further studies on early biomarkers of CC risk and synergistic interactions between HR‑HPV and oestrogen.

Murine HPV16 E7-expressing transgenic skin effectively emulates the cellular and molecular features of human high-grade squamous intraepithelial lesions

Currently available vaccines prevent HPV infection and development of HPV-associated malignancies, but do not cure existing HPV infections and dysplastic lesions. Persistence of infection(s) in immunocompetent patients may reflect induction of local immunosuppressive mechanisms by HPV, providing a target for therapeutic intervention. We have proposed that a mouse, expressing HPV16 E7 oncoprotein under a Keratin 14 promoter (K14E7 mice), and which develops epithelial hyperplasia, may assist with understanding local immune suppression mechanisms that support persistence of HPV oncogene-induced epithelial hyperplasia. K14E7 skin grafts recruit immune cells from immunocompetent hosts, but consistently fail to be rejected. Here, we review the literature on HPV-associated local immunoregulation, and compare the findings with published observations on the K14E7 transgenic murine model, including comparison of the transcriptome of human HPV-infected pre-malignancies with that of murine K14E7 transgenic skin. We argue from the similarity of i) the literature findings and ii) the transcriptome profiles that murine K14E7 transgenic skin recapitulates the cellular and secreted protein profiles of high-grade HPV-associated lesions in human subjects. We propose that the K14E7 mouse may be an appropriate model to further study the immunoregulatory effects of HPV E7 expression, and can facilitate development and testing of therapeutic vaccines.

The effect of aberrant expression and genetic polymorphisms of Rad21 on cervical cancer biology

The therapeutic challenge of advanced, recurrent, and refractory cervical cancer (CC) needs to develop new molecularly targeted drugs. Rad21 is an important regulatory gene that maintains the correct dissociation of sister chromatids during cell mitosis. The aim of this study was to investigate the effect of Rad21 on CC. Rad21 expression in CC and cervical intraepithelial neoplasia III was significantly increased. Women with the rs2289937 C genotype (CC+CT) of rs4570 and rs4579555 genotypes and haplotype 1 (TTTCAGGCGC) were significantly associated with CC risk, while women with low frequencies of haplotype 6 (TTTTAGGCGC) also increased the risk of CC.Rad21‐specific shRNA decreased cancerous cell proliferation, migration, and invasion and increased the proportion of cells in G2/M phase as well as sensitivity to radiation. The Rad21 influenced the expression of XPO1, CyclinB1, CDK1, P21, P27, and P53 through up‐and downregulating the Rad21 expression. The TCGA database of CC also showed that Rad21 expression was associated with poor disease survival and XPO1 expression. Moreover, the KEGG pathway indicated that Rad21 is broadly involved in the cell cycle and RNA transportation via XPO1. This suggests that Rad21 involves the development of cervical cancer possibly by participating in the regulation of cell cycle and the nuclear output of the tumor suppressor gene via XPO1.

Bioinformatics and in vitro experimental analyses identify the selective therapeutic potential of interferon gamma and apigenin against cervical squamous cell carcinoma and adenocarcinoma

The clinical management and treatment of cervical cancer, one of the most commonly diagnosed cancers and a leading cause of cancer-related female death, remains a huge challenge for researchers and health professionals. Cervical cancer can be categorized into two major subtypes: common squamous cell carcinoma (SCC) and adenocarcinoma (AC). Although it is a relatively rare histological subtype of cervical cancer, there has been a steady increase in the incidences of AC. Therefore, new strategies to treat cervical cancer are urgently needed. In this study, the potential uses of IFNγ-based therapy for cervical cancer were evaluated using bioinformatics approaches. Gene expression profiling identified that cell cycle dysregulation was a major hallmark of cervical cancer including SCC and AC subtypes, and was associated with poor clinical outcomes for cervical cancer patients. In silico and in vitro experimental analyses demonstrated that IFNγ treatment could reverse the cervical cancer hallmark and induce cell cycle arrest and apoptosis. Furthermore, we demonstrated that apigenin could enhance the anticancer activity of IFNγ in a HeLa cervical AC cell line by targeting cyclin-dependent kinase 1. Taken together, the present study suggests the selective therapeutic potential of IFNγ alone or in combination with apigenin for managing cervical SCC and AC.

Exploration of the molecular mechanisms of cervical cancer based on mRNA expression profiles and predicted microRNA interactions

The molecular mechanisms of cervical cancer have been minimally explored with multi-omics data. In the present study, mRNA expression profiles were analyzed and combined with predicted miRNA interactions to contribute to the characterization of the underlying regulatory mechanisms of cervical cancer. A total of 92 significantly differentially expressed genes (DEGs) were identified in 33 tumor samples by comparison with 29 normal samples. mRNA-miRNA interaction network analysis revealed that 16 out of the 92 DEGs, including checkpoint kinase 1 (CHEK1), SRY-box 17 (SOX17), centrosomal protein 55, cyclin dependent kinase inhibitor 2A (CDKN2A), and inhibitor of DNA binding 4, were the targets of 4 miRNAs which were previously reported to be involved in the regulation of cervical cancer. Tumor and normal samples could be distinctly classified into two groups based on the expression of the 16 DEGs. Furthermore, survival analysis using the SurvExpress database indicated that the 16 DEGs could individually significantly differentiate low- and high-risk cervical cancer groups. Overall, multiple biological processes are likely to participate in the progression of cervical cancer based on the pathway and function enrichment identified for the DEGs. The dysregulation of SOX17 is associated with the regulation of embryonic development, the determination of cell fate and likely promotes cancer cell transformation. The dysregulation of CHEK1 and CDKN2A further promote cancer cell proliferation by affecting the cell cycle checkpoint in response to DNA damage. The identification of critical genes and biological processes associated with cervical cancer may be beneficial for the exploration of the molecular mechanisms.

Epithelial oestrogen receptor α is dispensable for the development of oestrogen-induced cervical neoplastic diseases

Human papillomavirus (HPV) is required but not sufficient for cervical carcinoma (CxCa) development. Oestradiol (E₂ ) promotes CxCa development in K14E7 transgenic mice expressing the HPV16 E7 oncoprotein under the control of the keratin (K14) promoter. E₂ mainly functions through oestrogen receptor α (ERα). However, the role of ERα in human CxCa has been underappreciated largely because it is not expressed in carcinoma cells. We have shown that deletion of Esr1 (the ERα-coding gene) in the cervical stroma of K14E7 mice promotes regression of cervical intraepithelial neoplasia (CIN), the precursor lesion of CxCa. Here, we deleted Esr1 in the cervical epithelium but not in the stroma. We found that E₂ induced cervical epithelial cell proliferation in epithelial ERα-deficient mice. We also found that E₂ promoted the development of CIN and CxCa in epithelial ERα-deficient K14E7 mice and that all neoplastic epithelial cells were negative for ERα. In addition, proliferation indices were similar between ERα^- and ERα⁺ CxCa. These results indicate that epithelial ERα is not necessary for E₂ -induced CIN and CxCa. Taking these findings together, we conclude that stromal ERα rather than epithelial ERα mediates oncogenic E₂ signalling in CxCa. Our results support stromal ERα signalling as a therapeutic target for the disease. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Human papillomavirus type 16 E5-mediated upregulation of Met in human keratinocytes

Human papillomaviruses (HPVs) cause benign lesions that can lead to malignancy. How cellular changes induced by viral oncogenes contribute to the progeny virion production is not always clear. Stromally-derived growth factors and their receptors are critical for development of malignancy, but their impact on the pre-malignant HPV life cycle is unknown. We show that HPV16 increases levels of Met, a growth factor receptor critical for tumor cell invasion, motility, and cancer metastasis. The viral oncogene E5 is primarily responsible for Met upregulation, with E6 playing a minor role. Met induction by E5 requires the epidermal growth factor receptor, which is also increased by E5 at the mRNA level. E5-induced Met contributes motility of HPV-containing cells. Finally, Met signaling is necessary for viral gene expression, particularly in the differentiation-dependent phase of the viral life cycle. These studies show a new role for E5 in epithelial-stromal interactions, with implications for cancer development.

Integrated analysis of HPV-mediated immune alterations in cervical cancer

OBJECTIVE

Human papillomavirus (HPV) infection is the primary cause of cervical cancer. HPV-mediated immune alterations are known to play crucial roles in determining viral persistence and host cell transformation. We sought to thoroughly understand HPV-directed immune alterations in cervical cancer by exploring publically available datasets.

METHODS

130 HPV positive and 7 HPV negative cervical cancer cases from The Cancer Genome Atlas were compared for differences in gene expression levels and functional enrichment. Analyses for copy number variation (CNV) and genetic mutation were conducted for differentially expressed immune genes. Kaplan-Meier analysis was performed to assess survival and relapse differences across cases with or without alterations of the identified immune signature genes.

RESULTS

Genes up-regulated in HPV positive cervical cancer were enriched for various gene ontology terms of immune processes (P=1.05E-14~1.00E-05). Integrated analysis of the differentially expressed immune genes identified 9 genes that displayed either CNV, genetic mutation and/or gene expression changes in at least 10% of the cases of HPV positive cervical cancer. Genomic amplification may cause elevated levels of these genes in some HPV positive cases. Finally, patients with alterations in at least one of the nine signature genes overall had earlier relapse compared to those without any alterations. The altered expression of either TFRC or MMP13 may indicate poor survival for a subset of cervical cancer patients (P=1.07E-07).

CONCLUSIONS

We identified a novel immune gene signature for HPV positive cervical cancer that is potentially associated with early relapse of cervical cancer.

Lon Peptidase 2, Peroxisomal (LONP2) Contributes to Cervical Carcinogenesis via Oxidative Stress

Background

Lon protease is responsible for degrading proteins injured by oxidation, and has 2 isoforms, located in mitochondria and peroxisomes. Recent research showed that Lon protease was upregulated in different types of human cancer, but the role of Lon peptidase 2, peroxisomal (LONP2) in cancer is not well understood. It is known, however, that in cancer biology, reduction-oxidation is one of the molecular mechanisms involved in tumorigenesis.

Material/Methods

Oncomine databases and tissue microarrays, initially using immunohistochemistry, were used to analyze LONP2 expression in cervical cancer. In order to uncover the biologic functions and mechanism(s) underlying LONP2 in cervical tumorigenesis, we downregulated the expression of LONP2 using 2 siRNAs transduced in HeLa and SiHa cells. CCK8 assays were performed to evaluate cell viability. Cell cycle and apoptosis assays were used to determine cell growth. Cell migration and invasion assays were used to study changes in cell migration and invasion capacity. Immunofluorescence and flow cytometry were performed to analyze the changes in ROS production.

Results

We found that the expression of LONP2 was significantly upregulated in cervical cancer, and there was a significant association with pathology type, pathology grade, and clinical stage, but not with age or lymph node metastasis. Moreover, we demonstrated that knocking down LONP2 in HeLa and SiHa cells reduced cell proliferation, cell cycle, apoptosis, migration, invasion, and oxidative stress levels.

Conclusions

Our findings suggest that LONP2 promotes cervical tumorigenesis via oxidative stress and may be a potential biomarker and therapeutic target in cervical cancer.

DNA Tumor Virus Regulation of Host DNA Methylation and Its Implications for Immune Evasion and Oncogenesis

Viruses have evolved various mechanisms to evade host immunity and ensure efficient viral replication and persistence. Several DNA tumor viruses modulate host DNA methyltransferases for epigenetic dysregulation of immune-related gene expression in host cells. The host immune responses suppressed by virus-induced aberrant DNA methylation are also frequently involved in antitumor immune responses. Here, we describe viral mechanisms and virus–host interactions by which DNA tumor viruses regulate host DNA methylation to evade antiviral immunity, which may contribute to the generation of an immunosuppressive microenvironment during cancer development. Recent trials of immunotherapies have shown promising results to treat multiple cancers; however, a significant number of non-responders necessitate identifying additional targets for cancer immunotherapies. Thus, understanding immune evasion mechanisms of cancer-causing viruses may provide great insights for reversing immune suppression to prevent and treat associated cancers.

Expression of Estrogen and Progesterone Receptor in Tumor Stroma Predicts Favorable Prognosis of Cervical Squamous Cell Carcinoma

OBJECTIVES

The aim of this study was to investigate the expression of estrogen receptor α (ERα) and progesterone receptor B (PRB) in the stroma and carcinoma tissues of cervical cancer and their relationship to clinical characteristics and the status of human papillomavirus (HPV) infection.

METHODS

Expressional levels of ERα and PRB in tissue blocks of 95 cervical carcinomas were independently scored by 2 pathologists. Human papillomavirus DNA, viral load, and genotypes were determined by polymerase chain reaction. Clinical characteristics were reviewed from chart and cancer registry.

RESULTS

Estrogen receptor α and PRB were mainly expressed in the stroma but not in the carcinoma tissues of the cervical cancer, and their expressions were highly correlated. More stromal ERαs were found in early-stage tumors than in advanced-stage tumors. Greater stromal expressions of ERα and PRB were associated with a more favorable prognosis (P = 0.018 and P = 0.004, respectively). The expressions were not related to the differentiation of cancer, the status of HPV infection, the HPV load, or the genotype. In multivariate analysis, stromal ERα and PRB expressions were independently associated with a lower risk of mortality. The adjusted hazard ratios of mortality for low and high expressions of ERα were 0.19 (95% confidential interval [95% CI], 0.04-0.87) and 0.15 (95% CI, 0.03-0.81), respectively, whereas for low and high expressions of PRB hazard ratios were 0.46 (95% CI, 0.19-1.16) and 0.24 (95% CI, 0.06-0.96), respectively.

CONCLUSIONS

This study showed that stromal ERα and PRB expressions are independent prognostic indicators of cervical squamous cell carcinoma.

Application of deep learning to the classification of images from colposcopy

The objective of the present study was to investigate whether deep learning could be applied successfully to the classification of images from colposcopy. For this purpose, a total of 158 patients who underwent conization were enrolled, and medical records and data from the gynecological oncology database were retrospectively reviewed. Deep learning was performed with the Keras neural network and TensorFlow libraries. Using preoperative images from colposcopy as the input data and deep learning technology, the patients were classified into three groups [severe dysplasia, carcinoma in situ (CIS) and invasive cancer (IC)]. A total of 485 images were obtained for the analysis, of which 142 images were of severe dysplasia (2.9 images/patient), 257 were of CIS (3.3 images/patient), and 86 were of IC (4.1 images/patient). Of these, 233 images were captured with a green filter, and the remaining 252 were captured without a green filter. Following the application of L2 regularization, L1 regularization, dropout and data augmentation, the accuracy of the validation dataset was ~50%. Although the present study is preliminary, the results indicated that deep learning may be applied to classify colposcopy images.

Human Papilloma Viruses and Their Genotype Distribution in Women with High Socioeconomic Status in Central Anatolia, Turkey: A Pilot Study

Background

In the present study we retrospectively evaluated the results of outpatients who had an HPV analysis, and present objective evidence for the administration of preventive inoculation in our area.

Material/Methods

We retrospectively reviewed 532 outpatients who visited a single center between 2012 and 2016 and had an HPV infection analysis. The criteria for inclusion of patients with unhealthy cervix in the study were: erosion, chronic cervicitis, healed lacerations, hypertrophied cervix, and abnormal discharges from the cervix.

Results

We found that 122 out of 532 patients were infected with HPV, and the rate of multiple infections was 59.0% (72/122). HR-HPV (group 1 carcinogens HPV-16 (18.9%, 23/122), HPV-18 (13.1%, 16/122), HPV- 31 (4.9%, 6/122), HPV-33 (3.3%, 4/122), HPV-35 (7.4.9%/122), HPV-39 (5.7%, 7/122), HPV-45 (5.7%, 7/122), HPV-51 (11.5%, 15/122); Group 3 LR-HPV; HPV-6 (31.1%, 38/122), HPV-11 (26.2%, 32/122), HPV-42 (9.0%, 11/122) and HPV-43 (4.9%, 6/122). In terms of linear-by-linear association test, no significant statistical difference was identified between years. The P value for HPV infection rate on year basis was P>0.05.

Conclusions

In this hospital-based retrospective analysis, HPV types were found to be similar to HPV types reported in developed countries. We firmly suggest that patients should be informed about the risk of HPV infection at early ages.

Systematic assessment of cervical cancer initiation and progression uncovers genetic panels for deep learning-based early diagnosis and proposes novel diagnostic and prognostic biomarkers

Although many outstanding achievements in the management of cervical cancer (CxCa) have obtained, it still imposes a major burden which has prompted scientists to discover and validate new CxCa biomarkers to improve the diagnostic and prognostic assessment of CxCa. In this study, eight different gene expression data sets containing 202 cancer, 115 cervical intraepithelial neoplasia (CIN), and 105 normal samples were utilized for an integrative systems biology assessment in a multi-stage carcinogenesis manner. Deep learning-based diagnostic models were established based on the genetic panels of intrinsic genes of cervical carcinogenesis as well as on the unbiased variable selection approach. Survival analysis was also conducted to explore the potential biomarker candidates for prognostic assessment. Our results showed that cell cycle, RNA transport, mRNA surveillance, and one carbon pool by folate were the key regulatory mechanisms involved in the initiation, progression, and metastasis of CxCa. Various genetic panels combined with machine learning algorithms successfully differentiated CxCa from CIN and normalcy in cross-study normalized data sets. In particular, the 168-gene deep learning model for the differentiation of cancer from normalcy achieved an externally validated accuracy of 97.96% (99.01% sensitivity and 95.65% specificity). Survival analysis revealed that ZNF281 and EPHB6 were the two most promising prognostic genetic markers for CxCa among others. Our findings open new opportunities to enhance current understanding of the characteristics of CxCa pathobiology. In addition, the combination of transcriptomics-based signatures and deep learning classification may become an important approach to improve CxCa diagnosis and management in clinical practice.

Oestrogen Receptor-α binds the FOXP3 promoter and modulates regulatory T-cell function in human cervical cancer

Oestrogen controls Foxp3 expression in regulatory T cells (Treg cells) via a mechanism thought to involve oestrogen receptor alpha (ERα), but the molecular basis and functional impact of ERα signalling in Treg cells remain unclear. We report that ERα ligand oestradiol (E2) is significantly increased in human cervical cancer (CxCa) tissues and tumour-infiltrating Treg cells (CD4+CD25hiCD127low), whereas blocking ERα with the antagonist ICI 182,780 abolishes FOXP3 expression and impairs the function of CxCa infiltrating Treg cells. Using a novel approach of co-immunoprecipitation with antibodies to E2 for capture, we identified binding of E2:ERα complexes to FOXP3 protein in CxCa-derived Treg cells. Chromatin immunoprecipitation analyses of male blood Treg cells revealed ERα occupancy at the FOXP3 promoter and conserved non-coding DNA elements 2 and 3. Accordingly, computational analyses of the enriched regions uncovered eight putative oestrogen response elements predicted to form a loop that can activate the FOXP3 promoter. Together, these data suggest that E2-mediated ERα signalling is critical for the sustenance of FOXP3 expression and Treg cell function in human CxCa via direct interaction of ERα with FOXP3 promoter. Overall, our work gives a molecular insight into ERα signalling and highlights a fundamental role of E2 in controlling human Treg cell physiology.

Transgenic Mouse Models of Tumor Virus Action

Genetically engineered mice (GEMs) have provided valuable insights into the carcinogenic properties of various human tumor viruses, which, in aggregate, are etiologically associated with over 15% of all human cancers. This review provides an overview of seminal discoveries made through the use of GEM models for human DNA tumor viruses. Emphasis is placed on the discoveries made in the study of human papillomaviruses, Merkel cell carcinoma-associated polyomavirus, Epstein-Barr virus, and Kaposi's sarcoma-associated herpesvirus, because GEMs have contributed extensively to our understanding of how these DNA tumor viruses directly contribute to human cancers.