Human papillomavirus deregulates the response of a cellular network comprising of chemotactic and proinflammatory genes

The cutaneous beta human papillomavirus type 8 E6 protein induces CCL2 through the CEBPα/miR-203/p63 pathway to support an inflammatory microenvironment in epidermodysplasia verruciformis skin lesions

Human papillomavirus type 8 (HPV8), a cutaneous genus beta HPV type, has co-carcinogenic potential at sun-exposed sites in patients suffering from the inherited skin disease epidermodysplasia verruciformis (EV). We had previously shown that Langerhans cells responsible for epithelial immunosurveillance were strongly reduced at infected sites and that the HPV8 E7 protein interferes with the CCAAT/enhancer-binding protein (C/EBP)β to suppress the Langerhans cell chemokine CCL20. At the same time, however, we observed that EV lesions are heavily infiltrated with inflammatory immune cells, which is similar to the situation in HPV8 E6 transgenic mice. To identify critical inflammatory factors, we used a broad multiplex approach and found that the monocyte attracting chemokine CCL2 was significantly and strongly induced by HPV8 E6 but not E7-expressing HaCaT cells, which were used as a model for UV-damaged skin keratinocytes. Conditioned media from HPV8 E6-expressing keratinocytes enhanced CCL2-receptor (CCR2)-dependent monocyte recruitment in vitro, and macrophages predominated in the stroma but were also detected in the epidermal compartment of EV lesions in vivo. CCL2 induction by HPV8 E6 was even stronger than stimulation with the proinflammatory cytokine TNF-α, and both HPV8 E6 and TNF-α resulted in substantial suppression of the transcription factor C/EBPα. Using RNAi-mediated knockdown and overexpression approaches, we demonstrated a mechanistic role of the recently identified C/EBPα/miR-203/p63 pathway for HPV8 E6-mediated CCL2 induction at protein and transcriptional levels. Epithelial co-expression of p63 and CCL2 was confirmed in HPV8 E6-expressing organotypic air-liquid interface cultures and in lesional EV epidermis in vivo. In summary, our data demonstrate that HPV8 oncoproteins actively deregulate epidermal immune homeostasis through modulation of C/EBP factor-dependent pathways. While HPV8 E7 suppresses immunosurveillance required for viral persistence, the present study provides evidence that E6 involves the stemness-promoting factor p63 to support an inflammatory microenvironment that may fuel carcinogenesis in EV lesions.

Unraveling Emerging Anal Cancer Clinical Biomarkers from Current Immuno-Oncogenomics Advances

Anal squamous cell carcinoma (ASCC) is a rare gastrointestinal malignancy associated with high-risk human papillomavirus (HPV) and is currently one of the fastest-growing causes of cancer incidence and mortality in developed countries. Although next-generation sequencing technologies (NGS) have revolutionized cancer and immuno-genomic research in various tumor types, a limited amount of clinical research has been developed to investigate the expression and the functional characterization of genomic data in ASCC. Herein, we comprehensively assess recent advancements in "omics" research, including a systematic analysis of genome-based studies, aiming to identify the most relevant ASCC cancer driver gene expressions and their associated signaling pathways. We also highlight the most significant biomarkers associated with anal cancer progression, gene expression of potential diagnostic biomarkers, expression of therapeutic drug targets, and emerging treatment opportunities. This review stresses the urgent need for developing target-specific therapies in ASCC. By illuminating the molecular characteristics and drug-target expression in ASCC, this study aims to provide insights for the development of precision medicine in anal cancer.

Human Papilloma Virus Positive Oropharyngeal Squamous Cell Carcinoma and the Immune System: Pathogenesis, Immunotherapy and Future Perspectives

Oropharyngeal squamous cell carcinoma (OPSCC), a subset of head and neck squamous cell carcinoma (HNSCC), involves the palatine tonsils, soft palate, base of tongue, and uvula, with the ability to spread to adjacent subsites. Personalized treatment strategies for Human Papillomavirus-associated squamous cell carcinoma of the oropharynx (HPV+OPSCC) are yet to be established. In this article, we summarise our current understanding of the pathogenesis of HPV+OPSCC, the intrinsic role of the immune system, current ICI clinical trials, and the potential role of small molecule immunotherapy in HPV+OPSCC.

Immune Responses in Oral Papillomavirus Clearance in the MmuPV1 Mouse Model

Human papillomavirus (HPV)-induced oropharyngeal cancer now exceeds HPV-induced cervical cancer, with a noticeable sex bias. Although it is well established that women have a more proficient immune system, it remains unclear whether immune control of oral papillomavirus infections differs between sexes. In the current study, we use genetically modified mice to target CCR2 and Stat1 pathways, with the aim of investigating the role of both innate and adaptive immune responses in clearing oral papillomavirus, using our established papillomavirus (MmuPV1) infection model. Persistent oral MmuPV1 infection was detected in Rag1ko mice with T and B cell deficiencies. Meanwhile, other tested mice were susceptible to MmuPV1 infections but were able to clear the virus. We found sex differences in key myeloid cells, including macrophages, neutrophils, and dendritic cells in the infected tongues of wild type and Stat1ko mice but these differences were not observed in CCR2ko mice. Intriguingly, we also observed a sex difference in anti-MmuPV1 E4 antibody levels, especially for two IgG isotypes: IgG2b and IgG3. However, we found comparable numbers of interferon-gamma-producing CD8 T cells stimulated by E6 and E7 in both sexes. These findings suggest that males and females may use different components of innate and adaptive immune responses to control papillomavirus infections in the MmuPV1 mouse model. The observed sex difference in immune responses, especially in myeloid cells including dendritic cell (DC) subsets, may have potential diagnostic and prognostic values for HPV-associated oropharyngeal cancer.

Epidemiology, Molecular Pathogenesis, Immuno-Pathogenesis, Immune Escape Mechanisms and Vaccine Evaluation for HPV-Associated Carcinogenesis

Human papillomavirus (HPV) is implicated in over 90% of cervical cancer cases, with factors like regional variability, HPV genotype, the population studied, HPV vaccination status, and anatomical sample collection location influencing the prevalence and pathology of HPV-induced cancer. HPV-16 and -18 are mainly responsible for the progression of several cancers, including cervix, anus, vagina, penis, vulva, and oropharynx. The oncogenic ability of HPV is not only sufficient for the progression of malignancy, but also for other tumor-generating steps required for the production of invasive cancer, such as coinfection with other viruses, lifestyle factors such as high parity, smoking, tobacco chewing, use of contraceptives for a long time, and immune responses such as stimulation of chronic stromal inflammation and immune deviation in the tumor microenvironment. Viral evasion from immunosurveillance also supports viral persistence, and virus-like particle-based prophylactic vaccines have been licensed, which are effective against high-risk HPV types. In addition, vaccination awareness programs and preventive strategies could help reduce the rate and incidence of HPV infection. In this review, we emphasize HPV infection and its role in cancer progression, molecular and immunopathogenesis, host immune response, immune evasion by HPV, vaccination, and preventive schemes battling HPV infection and HPV-related cancers.

Immune microenvironment of cervical cancer and the role of IL-2 in tumor promotion

The tumor microenvironment (TME) is a heterogeneous mixture of resident and tumor cells that maintain close communication through their secretion products. The composition of the TME is dynamic and complex among the different types of cancer, where the immune cells play a relevant role in the elimination of tumor cells, however, under certain circumstances they contribute to tumor development. In cervical cancer (CC) the human papilloma virus (HPV) shapes the microenvironment in order to mediate persistent infections that favors transformation and tumor development. Interleukin-2 (IL-2) is an important TME cytokine that induces CD8+ effector T cells and NKs to eliminate tumor cells, however, IL-2 can also suppress the immune response through Treg cells. Recent studies have shown that CC cells express the IL-2 receptor (IL-2R), that are induced to proliferate at low concentrations of exogenous IL-2 through alterations in the JAK/STAT pathway. This review provides an overview of the main immune cells that make up the TME in CC, as well as the participation of IL-2 in the tumor promotion. Finally, it is proposed that the low density of IL-2 produced by immunocompetent cells is used by tumor cells through its IL-2R as a mechanism to proliferate simultaneously depleting this molecule in order to evade immune response.

The Prognostic Role of Baseline Eosinophils in HPV-Related Cancers: a Multi-institutional Analysis of Anal SCC and OPC Patients Treated with Radical CT-RT

BACKGROUND AND AIM

Anal squamous cell carcinoma (SCC) and oropharyngeal cancer (OPC) are rare tumors associated with HPV infection. Bioumoral predictors of response to chemoradiation (CT-RT) are lacking in these settings. With the aim to find new biomarkers, we investigated the role of eosinophils in both HPV-positive anal SCC and HPV-related oropharyngeal cancer (OPC).

METHODS

We retrieved clinical and laboratory data of patients with HPV-positive anal SCC treated with CT-RT in 5 institutions, and patients with locally advanced OPC SCC treated with CT-RT in 2 institutions. We examined the association between baseline eosinophil count (the best cutoff has been evaluated by ROC curve analysis: 100 × 10^9/L) and disease-free survival (DFS). Unadjusted and adjusted hazard ratios by baseline characteristics were calculated using the Cox proportional hazards model.

RESULTS

Three hundred four patients with HPV-positive anal SCCs and 168 patients with OPCs (122 HPV-positive, 46 HPV-negative diseases) were analyzed. In anal SCC, low eosinophil count (< 100 × 10^9/L) correlates to a better DFS (HR = 0.59; p = 0.0392); likewise, in HPV-positive OPC, low eosinophil count correlates to a better DFS (HR = 0.50; p = 0.0428). In HPV-negative OPC, low eosinophil count confers worse DFS compared to high eosinophil count (HR = 3.53; p = 0.0098). After adjustment for age and sex, eosinophils were confirmed to be independent prognostic factors for DFS (HR = 4.55; p = 0.0139).

CONCLUSION

Eosinophil count could be used as a prognostic factor in anal HPV-positive SCC. The worse prognosis showed in HPV-positive patients with high eosinophil count is likely to derive from an unfavorable interaction between the HPV-induced immunomodulation and eosinophils, which may hamper the curative effect of RT.

Human papillomavirus in the setting of immunodeficiency: Pathogenesis and the emergence of next-generation therapies to reduce the high associated cancer risk

Human papillomavirus (HPV), a common sexually transmitted virus infecting mucosal or cutaneous stratified epithelia, is implicated in the rising of associated cancers worldwide. While HPV infection can be cleared by an adequate immune response, immunocompromised individuals can develop persistent, treatment-refractory, and progressive disease. Primary immunodeficiencies (PIDs) associated with HPV-related disease include inborn errors of GATA, EVER1/2, and CXCR4 mutations, resulting in defective cellular function. People living with secondary immunodeficiency (e.g. solid-organ transplants recipients of immunosuppression) and acquired immunodeficiency (e.g. concurrent human immunodeficiency virus (HIV) infection) are also at significant risk of HPV-related disease. Immunocompromised people are highly susceptible to the development of cutaneous and mucosal warts, and cervical, anogenital and oropharyngeal carcinomas. The specific mechanisms underlying high-risk HPV-driven cancer development in immunocompromised hosts are not well understood. Current treatments for HPV-related cancers include surgery with adjuvant chemotherapy and/or radiotherapy, with clinical trials underway to investigate the use of anti-PD-1 therapy. In the setting of HIV co-infection, persistent high-grade anal intraepithelial neoplasia can occur despite suppressive antiretroviral therapy, resulting in an ongoing risk for transformation to overt malignancy. Although therapeutic vaccines against HPV are under development, the efficacy of these in the setting of PID, secondary- or acquired- immunodeficiencies remains unclear. RNA-based therapeutic targeting of the HPV genome or mRNA transcript has become a promising next-generation therapeutic avenue. In this review, we summarise the current understanding of HPV pathogenesis, immune evasion, and malignant transformation, with a focus on key PIDs, secondary immunodeficiencies, and HIV infection. Current management and vaccine regimes are outlined in relation to HPV-driven cancer, and specifically, the need for more effective therapeutic strategies for immunocompromised hosts. The recent advances in RNA-based gene targeting including CRISPR and short interfering RNA (siRNA), and the potential application to HPV infection are of great interest. An increased understanding of both the dysregulated immune responses in immunocompromised hosts and of viral persistence is essential for the design of next-generation therapies to eliminate HPV persistence and cancer development in the most at-risk populations.

Human Papillomavirus Cervical Infection: Many Ways to a Single Destination

Human papillomavirus (HPV) infection represents the most diffuse sexually transmitted disease of the lower genital tract, with an estimated risk of infection in the general population of 80% over the course of the lifetime [...].

How Risk Factors Affect Head and Neck Squamous Cell Carcinoma (HNSCC) Tumor Immune Microenvironment (TIME): Their Influence on Immune Escape Mechanisms and Immunotherapy Strategy

Most head and neck squamous cell carcinomas (HNSCCs) are caused by lifestyle, such as cigarette smoking, or by viruses, such as human papillomavirus (HPV) and Epstein–Barr virus (EBV). HNSCC remains a clinical challenge, notwithstanding the improvements observed in the past years, involving surgery, radiotherapy, and chemotherapy. Recurrent/metastatic (R/M) disease represents an unmet clinical need. Immunotherapy has improved the prognosis of a small proportion of these patients, but most still do not benefit. In the last decade, several preclinical and clinical studies have explored the HNSCC tumor immune microenvironment (TIME), identifying important differences between smoking-associated and virus-associated HNSCCs. This review aims to present how different etiologies affect the HNSCC TIME, affecting immune escape mechanisms and sensitivity to immunotherapy.

Comparison of Interleukin-1 Ligand Expression by Human Papilloma Virus Status in HNSCCs

Interleukin-1 alpha (IL-1α) is a cytokine involved in the acute phase immune response and its expression is upregulated in a variety of solid tumors including head and neck squamous cell carcinomas (HNSCCs). Tumor expression of IL-1α is associated with increased tumor aggressiveness in HNSCCs, but this has yet to be studied in the context of human papilloma virus (HPV) status. This study is aimed at determining differences in tumor expression and subcellular localization of IL-1α in HPV-positive (HPV+) and HPV-negative (HPV-) HNSCC tumors. Tissue microarrays (TMAs) containing HPV+ (n = 31) and HPV- (n = 47) primary and metastatic HNSCCs were analyzed for IL-1α expression using immunohistochemical (IHC) staining. HPV status was confirmed using p16 IHC staining and RNA in situ hybridization (RNA ISH). Differences in IL-1α protein expression and secretion in HPV+ and HPV- HNSCC cell lines were determined by western blot and ELISA respectively. Associations between tumor IL1A expression and survival outcomes were assessed in HPV+ and HPV- HNSCC patients from publicly available gene expression datasets. Tumor expression of IL-1α was significantly increased in HPV- tumors and cell lines (as detected by IHC and western blot respectively) compared to HPV+ tumors and cell lines. There was no difference in IL-1α release between HPV+ and HPV- cell lines. IL-1α was expressed in both nuclear and cytoplasmic compartments, with predominant expression in the nucleus. Gene expression of IL1A was significantly increased in HPV-tumors/cell lines compared to HPV+ tumors/cell lines. Lastly, increased IL1A gene expression was significantly associated with worse survival in HPV- tumors but not in HPV+ tumors. Overall IL-1α expression particularly in the nucleus may possess more prognostic significance in HPV- tumors rather than HPV+ tumors. This work warrants further investigation into the role of intracellular IL-1α ligand expression in HNSCCs and may have important implications in IL-1 pathway blockade as therapeutic strategy.

TLR9 in the Human Papilloma Virus Infections: Friend or Foe?

Immune system plays dual roles during human papilloma virus (HPV) infections, from defense against the virus to induction or stimulation of the HPV-related cancers. It appears that various differences within the immune-related genes and the functions of the immunological parameters of the patients are the main factors responsible for the roles played by immune system during HPV infections. Toll-like receptors (TLRs) play key roles in the recognition of viruses and activation of immune responses. The molecules also can alter the target cell intracellular signaling and may participate in the transformation of the infected cells. TLR9 is the unique intracellular member of TLRs that recognize foreign DNA, including viral DNA. Thus, TLR9 may play significant roles in the defense against HPV and its related cancers. This review article discusses TLR9 antiviral and pathological roles during HPV infection.

HPV infection alters vaginal microbiome through down-regulating host mucosal innate peptides used by Lactobacilli as amino acid sources

Despite the high prevalence of both cervico-vaginal human papillomavirus (HPV) infection and bacterial vaginosis (BV) worldwide, their causal relationship remains unclear. While BV has been presumed to be a risk factor for HPV acquisition and related carcinogenesis for a long time, here, supported by both a large retrospective follow-up study (n = 6,085) and extensive in vivo data using the K14-HPV16 transgenic mouse model, we report a novel blueprint in which the opposite association also exists. Mechanistically, by interacting with several core members (NEMO, CK1 and β-TrCP) of both NF-κB and Wnt/β-catenin signaling pathways, we show that HPV E7 oncoprotein greatly inhibits host defense peptide expression. Physiologically secreted by the squamous mucosa lining the lower female genital tract, we demonstrate that some of these latter are fundamental factors governing host-microbial interactions. More specifically, several innate molecules down-regulated in case of HPV infection are hydrolyzed, internalized and used by the predominant Lactobacillus species as amino acid source sustaining their growth/survival. Collectively, this study reveals a new viral immune evasion strategy which, by its persistent/negative impact on lactic acid bacteria, ultimately causes the dysbiosis of vaginal microbiota.

HPV and Recurrent Respiratory Papillomatosis: A Brief Review

Recurrent Respiratory Papillomatosis (RRP) is a rare but severe manifestation of human papillomavirus (HPV). As our knowledge about HPV infections has expanded, it has become possible to understand the course of RRP disease and unravel plausible efficient methods to manage the disease. However, the surge in reports on HPV has not been accompanied by a similar increase in research about RRP specifically. In this paper, we review the clinical manifestation and typical presentation of the illness. In addition, the pathogenesis and progression of the disease are described. On the other hand, we discuss the types of treatments currently available and future treatment strategies. The role of vaccination in both the prevention and treatment of RRP will also be reviewed. We believe this review is essential to update the general knowledge on RRP with the latest information available to date to enhance our understanding of RRP and its management.

Genomic Risk Factors for Cervical Cancer

Cervical cancer is the fourth common cancer amongst women worldwide. Infection by high-risk human papilloma virus is necessary in most cases, but not sufficient to develop invasive cervical cancer. Despite a predicted genetic heritability in the range of other gynaecological cancers, only few genomic susceptibility loci have been identified thus far. Various case-control association studies have found corroborative evidence for several independent risk variants at the 6p21.3 locus (HLA), while many reports of associations with variants outside the HLA region remain to be validated in other cohorts. Here, we review cervical cancer susceptibility variants arising from recent genome-wide association studies and meta-analysis in large cohorts and propose 2q14 (PAX8), 17q12 (GSDMB), and 5p15.33 (CLPTM1L) as consistently replicated non-HLA cervical cancer susceptibility loci. We further discuss the available evidence for these loci, knowledge gaps, future perspectives, and the potential impact of these findings on precision medicine strategies to combat cervical cancer.

Virus-Induced Tumorigenesis and IFN System

Oncogenic viruses favor the development of tumors in mammals by persistent infection and specific cellular pathways modifications by deregulating cell proliferation and inhibiting apoptosis. They counteract the cellular antiviral defense through viral proteins as well as specific cellular effectors involved in virus-induced tumorigenesis. Type I interferons (IFNs) are a family of cytokines critical not only for viral interference but also for their broad range of properties that go beyond the antiviral action. In fact, they can inhibit cell proliferation and modulate differentiation, apoptosis, and migration. However, their principal role is to regulate the development and activity of most effector cells of the innate and adaptive immune responses. Various are the mechanisms by which IFNs exert their effects on immune cells. They can act directly, through IFN receptor triggering, or indirectly by the induction of chemokines, the secretion of further cytokines, or by the stimulation of cells useful for the activation of particular immune cells. All the properties of IFNs are crucial in the host defense against viruses and bacteria, as well as in the immune surveillance against tumors. IFNs may be affected by and, in turn, affect signaling pathways to mediate anti-proliferative and antiviral responses in virus-induced tumorigenic context. New data on cellular and viral microRNAs (miRNAs) machinery, as well as cellular communication and microenvironment modification via classical secretion mechanisms and extracellular vesicles-mediated delivery are reported. Recent research is reviewed on the tumorigenesis induced by specific viruses with RNA or DNA genome, belonging to different families (i.e., HPV, HTLV-1, MCPyV, JCPyV, Herpesviruses, HBV, HCV) and the IFN system involvement.

HPV-related head and neck cancers: Pathology and biology

Discovering the key role HPV plays in head and neck carcinogenesis has revolutionized our approach to cancers such as oropharyngeal carcinomas. As the role of HPV expands beyond the oropharynx, there is a pursued need to understand the oncogenic mechanisms of HPV-driven tumorigenesis and their implications. Optimizing HPV detection methods all while acknowledging their limitations will ensure our ability to diagnose HPV-driven neoplasia wherever clinically relevant.

The interplay between the vaginal microbiome and innate immunity in the focus of predictive, preventive, and personalized medical approach to combat HPV-induced cervical cancer

HPVs representing the most common sexually transmitted disease are a group of carcinogenic viruses with different oncogenic potential. The immune system and the vaginal microbiome represent the modifiable and important risk factors in HPV-induced carcinogenesis. HPV infection significantly increases vaginal microbiome diversity, leading to gradual increases in the abundance of anaerobic bacteria and consequently the severity of cervical dysplasia. Delineation of the exact composition of the vaginal microbiome and immune environment before HPV acquisition, during persistent/progressive infections and after clearance, provides insights into the complex mechanisms of cervical carcinogenesis. It gives hints regarding the prediction of malignant potential. Relative high HPV prevalence in the general population is a challenge for modern and personalized diagnostics and therapeutic guidelines. Identifying the dominant microbial biomarkers of high-grade and low-grade dysplasia could help us to triage the patients with marked chances of lesion regression or progression. Any unnecessary surgical treatment of cervical dysplasia could negatively affect obstetrical outcomes and sexual life. Therefore, understanding the effect and role of microbiome-based therapies is a breaking point in the conservative management of HPV-associated precanceroses. The detailed evaluation of HPV capabilities to evade immune mechanisms from various biofluids (vaginal swabs, cervicovaginal lavage/secretions, or blood) could promote the identification of new immunological targets for novel individualized diagnostics and therapy. Qualitative and quantitative assessment of local immune and microbial environment and associated risk factors constitutes the critical background for preventive, predictive, and personalized medicine that is essential for improving state-of-the-art medical care in patients with cervical precanceroses and cervical cancer. The review article focuses on the influence and potential diagnostic and therapeutic applications of the local innate immune system and the microbial markers in HPV-related cancers in the context of 3P medicine.

SARS-CoV-2 Nonstructural Proteins 1 and 13 Suppress Caspase-1 and the NLRP3 Inflammasome Activation

Viral infection-induced activation of inflammasome complexes has both positive and negative effects on the host. Proper activation of inflammasome complexes induces down-stream effector mechanisms that inhibit viral replication and promote viral clearance, whereas dysregulated activation has detrimental effects on the host. Coronaviruses, including SARS-CoV and MERS-CoV, encode viroporins that activate the NLRP3 inflammasome, and the severity of coronavirus disease is associated with the inflammasome activation. Although the NLRP3 inflammasome activation is implicated in the pathogenesis of coronaviruses, these viruses must evade inflammasome-mediated antiviral immune responses to establish primary replication. Screening of a complementary DNA (cDNA) library encoding 28 SARS-CoV-2 open reading frames (ORFs) showed that two nonstructural proteins (NSPs), NSP1 and NSP13, inhibited caspase-1-mediated IL-1β activation. NSP1 amino acid residues involved in host translation shutoff and NSP13 domains responsible for helicase activity were associated with caspase-1 inhibition. In THP-1 cells, both NSP1 and NSP13 significantly reduced NLRP3-inflammasome-induced caspase-1 activity and IL-1β secretion. These findings indicate that SARS-CoV-2 NSP1 and NSP13 are potent antagonists of the NLRP3 inflammasome.

Human papillomavirus (HPV) deregulation of Toll-like receptor 9

Persistent infection by high-risk human papillomavirus (HPV) is associated with cervical carcinoma. Blocking innate immune responses in the cervix is critical for the establishment of persistent infections. Here, we discuss how HPV-16-encoded factors suppress the activity of Toll-like receptor 9, which plays a major role in innate antiviral immune responses.

Harnessing immunity for therapy in human papillomavirus driven cancers

In persistent high-risk HPV infection, viral gene expression can trigger some important early changes to immune capabilities which act to protect the lesion from immune attack and subsequently promote its growth and ability for sustained immune escape. This includes immune checkpoint-inhibitor ligand expression (e.g. PD-L1) by tumour or associated immune cells that can block any anti-tumour T-cell effectors. While there are encouraging signs of efficacy for cancer immunotherapies including with immune checkpoint inhibitors, therapeutic vaccines and adoptive cell therapies, overall response and survival rates remain relatively low. HPV oncogene vaccination has shown some useful efficacy in treatment of patients with high-grade lesions but was unable to control later stage cancers. To maximally exploit anti-tumour immune responses, the suppressive factors associated with HPV carcinogenesis must be countered. Importantly, a combination of chemotherapy, reducing immunosuppressive myeloid cells, with therapeutic HPV vaccination significantly improves impact on cancer treatment. Many clinical trials are investigating checkpoint inhibitor treatments in HPV associated cancers but response rates are limited; combination with vaccination is being tested. Further investigation of how chemo- and/or radio-therapy can influence the recovery of effective anti-tumour immunity is warranted. Understanding how to optimally deploy and sequence conventional and immunotherapies is the challenge.

Temporal changes in the vaginal microbiota in self-samples and its association with persistent HPV16 infection and CIN2

Background

The vaginal microbiota has been reported to be associated with HPV infection and cervical cancer. This study was performed to compare the vaginal microbiota at two timepoints in women performing self-sampling and had a persistent or transient HPV16 infection. The women were tested for 12 high-risk HPV (hrHPV) types but only women with single type (HPV16) were included to reduce confounding variables.

Methods

In total 96 women were included in this study. Of these, 26 were single positive for HPV16 in the baseline test and HPV negative in the follow-up test and 38 were single positive for HPV16 in both tests and diagnosed with CIN2+ in histology. In addition, 32 women that were negative for all 12 HPV tested were included. The samples of vaginal fluid were analyzed with the Ion 16S™ Metagenomics Kit and Ion 16S™ metagenomics module within the Ion Reporter™ software.

Results

K-means clustering resulted in two Lactobacillus-dominated groups, one with Lactobacillus sp. and the other specifically with Lactobacillus iners. The two remaining clusters were dominated by a mixed non-Lactobacillus microbiota. HPV negative women had lower prevalence (28%) of the non-Lactobacill dominant cluster in the baseline test, as compared to women with HPV16 infection (42%) (p value = 0.0173). Transition between clusters were more frequent in women with persistent HPV16 infection (34%) as compared in women who cleared the HPV16 infection (19%) (p value = 0.036).

Conclusions

The vaginal microbiota showed a higher rate of transitioning between bacterial profiles in women with persistent HPV16 infection as compared to women with transient infection. This indicate an instability in the microenvironment in women with persistent HPV infection and development of CIN2+.

HPV Induces Changes in Innate Immune and Adhesion Molecule Markers in Cervical Mucosa With Potential Impact on HIV Infection

While most HPV infections are asymptomatic and clear spontaneously, persistent infection with high-risk HPVs is associated with cervical cancer and with increased risk of HIV acquisition. Although several hypotheses have been proposed to explain this phenomenon, none has been confirmed. Our aim was to investigate the expression of host factors involved in the susceptibility to HIV infection among HPV-infected women. Cervical samples were collected to characterize the expression levels of HIV susceptibility markers in the mucosa of HPV-infected compared with HPV-uninfected women. No differences in the frequency of CCR5+, integrin α4β7+, activated and memory CD4+ T-cell were detected between the groups. We additionally evaluated the expression levels of genes involved in innate immune responses and in cell adhesion. HPV infected patients expressed higher levels of TLR9 and lower levels of pattern recognition receptors that recognize RNA (TLR3, TLR7, and MDA5/IFIH1). We also detected an impaired IFN pathway, with an increased Type I IFN and a decreased IFNα2 receptor expression. HPV+ samples displayed reduced expression of genes for adherens and tight junctions. Taken together, these results suggest that although HPV infection does not result in the recruitment/activation of susceptible CD4+ T-cell in the female genital tract, it leads to changes in the innate antiviral immune responses and in cell adhesion that are likely to favor HIV infection.

Immunology of HPV-mediated cervical cancer: current understanding

Human papilloma virus (HPV) has emerged as a primary cause of cervical cancer worldwide. HPV is a relatively small (55 nm in diameter) and non-enveloped virus containing approximately 8 kb long double stranded circular DNA genome. To date, 228 genotypes of HPV have been identified. Although all HPV infections do not lead to the development of malignancy of cervix, only persistent infection of high-risk types of HPV (mainly with HPV16 and HPV18) results in the disease. In addition, the immunity of the patients also acts as a key determinant in the carcinogenesis. Since, no HPV type specific medication is available for the patient suffering with cervical cancer, hence, a deep understanding of the disease etiology may be vital for developing an effective strategy for its prevention and management. From the immunological perspectives, the entire mechanisms of disease progression still remain unclear despite continuous efforts. In the present review, the recent developments in immunology of HPV-mediated cervix carcinoma were discussed. At the end, the prevention of disease using HPV type specific recombinant vaccines was also highlighted.

Insights into the toll-like receptors in sexually transmitted infections

Toll-like receptors (TLRs) are like soldiers of an innate immune system, which protects vital biological processes against invading pathogens. TLR signalling pathways help in the removal of pathogens and mediate well-established inflammatory processes. However, these processes may also aid in the development or augmentation of an infection or an autoimmune disease. Recent studies have delineated TLR polymorphism's role in the loss of function, making hosts more resistant or vulnerable to the development of an infection. In this review, we have discussed the association of TLRs with sexually transmitted infections (STIs), especially to the pathogen-specific ligands. We have also assessed the impact on TLR downstream signalling and the maintenance of cellular homeostasis during immune responses. Besides, we have discussed the role of TLRs single nucleotide polymorphisms in various STIs. Since TLRs are known to play a part in defence mechanisms and in aiding infections therefore, a thorough understanding of TLRs structure and molecular mechanisms is required to explain how they can influence the outcome of an STI. Such a strategy may lead to the development of novel and useful immunotherapeutic approaches to control pathogen progression and prevent transmission.

Insights into the Role of Innate Immunity in Cervicovaginal Papillomavirus Infection from Studies Using Gene-Deficient Mice

We demonstrate that female C57BL/6J mice are susceptible to a transient lower genital tract infection with MmuPV1 mouse papillomavirus and display focal histopathological abnormalities resembling those of human papillomavirus (HPV) infection. We took advantage of strains of genetically deficient mice to study in vivo the role of innate immune signaling in the control of papillomavirus. At 4 months, we sacrificed MmuPV1-infected mice and measured viral 757/3139 spliced transcripts by TaqMan reverse transcription-PCR (RT-PCR), localization of infection by RNAscope in situ hybridization, and histopathological abnormities by hematoxylin and eosin (H&E) staining. Among mice deficient in receptors for pathogen-associated molecular patterns, MyD88^-/- and STING^-/- mice had 1,350 and 80 copies of spliced transcripts/μg RNA, respectively, while no viral expression was detected in MAVS^-/- and Ripk2^-/- mice. Mice deficient in an adaptor molecule, STAT1^-/-, for interferon signaling had 46,000 copies/μg RNA. Among mice with targeted deficiencies in the inflammatory response, interleukin-1 receptor knockout (IL-1R^-/-) and caspase-1^-/- mice had 350 and 30 copies/μg RNA, respectively. Among mice deficient in chemokine receptors, CCR6^-/- mice had 120 copies/μg RNA, while CXCR2^-/- and CXCR3^-/- mice were negative. RNAscope confirmed focal infection in MyD88^-/-, STAT1^-/-, and CCR6^-/- mice but was negative for other gene-deficient mice. Histological abnormalities were seen only in the latter mice. Our findings and the literature support a working model of innate immunity to papillomaviruses involving the activation of a MyD88-dependent pathway and IL-1 receptor signaling, control of viral replication by interferon-stimulated genes, and clearance of virus-transformed dysplastic cells by the action of the CCR6/CCL20 axis.IMPORTANCE Papillomaviruses infect stratified squamous epithelia, and the viral life cycle is linked to epithelial differentiation. Additionally, changes occur in viral and host gene expression, and immune cells are activated to modulate the infectious process. In vitro studies with keratinocytes cannot fully model the complex viral and host responses and do not reflect the contribution of local and migrating immune cells. We show that female C57BL/6J mice are susceptible to a transient papillomavirus cervicovaginal infection, and mice deficient in select genes involved in innate immune responses are susceptible to persistent infection with variable manifestations of histopathological abnormalities. The results of our studies support a working model of innate immunity to papillomaviruses, and the model provides a framework for more in-depth studies. A better understanding of mechanisms of early viral clearance and the development of approaches to induce clearance will be important for cancer prevention and the treatment of HPV-related diseases.

The Interplay between Antiviral Signalling and Carcinogenesis in Human Papillomavirus Infections

Human papillomaviruses (HPV) are the causative agents of the most common sexually transmitted infection worldwide. While infection is generally asymptomatic and can be cleared by the host immune system, when persistence occurs, HPV can become a risk factor for malignant transformation. Progression to cancer is actually an unintended consequence of the complex HPV life cycle. Different antiviral defence mechanisms recognize HPV early in infection, leading to the activation of the innate immune response. However, the virus has evolved several specific strategies to efficiently evade the antiviral immune signalling. Here, we review and discuss the interplay between HPV and the host cell innate immunity. We further highlight the evasion strategies developed by different HPV to escape this cellular response and focus on the correlation with HPV-induced persistence and tumorigenesis.

Human Papillomavirus and carcinogenesis: Novel mechanisms of cell communication involving extracellular vesicles

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A group of mucosal HPVs are the causative agents of cervical cancer and are associated to other cancers.

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Certain cutaneous HPVs are involved in the development of cutaneous squamous cell carcinoma.

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EVs released by HPV⁺ cells convey a specific cargo of mRNAs and microRNAs.

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The EV delivery from HPV⁺ cells to non-infected recipient cells may represent a novel mechanism of tumorigenesis promotion.

A small group of mucosal Human Papillomaviruses are the causative agents of cervical cancer and are also associated with other types of cancers. Certain cutaneous Human Papillomaviruses seem to have a role as co-factors in the UV-induced carcinogenesis of the skin. The main mechanism of the tumorigenesis induced by Human Papillomaviruses is linked to the transforming activity of the viral E6 and E7 oncoproteins. However, other mechanisms, such as the gene expression control by specific microRNAs expression and deregulation of immune inflammatory mediators, may be important in the process of transformation. In this context, the release of Extracellular Vesicles with a specific cargo (microRNAs involved in tumorigenesis, mRNAs of viral oncoproteins, cytokines, chemokines) appears to play a key role.

IL-6 expression promoted by Poly(I:C) in cervical cancer cells regulates cytokine expression and recruitment of macrophages

Poly(I:C) is a promising adjuvant for cancer treatment vaccines to enhance the host anti‐tumour immune response. However, the roles of poly(I:C) in the cervical cancer microenvironment and local immune reactions are not well understood. In this study, we investigated the roles of poly(I:C) in the cervical cancer. We analysed the cytokine transcription and secretion of cervical cancer cell lines and THP‐1–derived macrophages after poly(I:C) treatment, respectively. These results revealed that IL‐6 was significantly up‐regulated, and this up‐regulation was partly dose dependent. poly(I:C)‐stimulated supernatant of cervical cancer cells promoted M1‐type cytokine IL‐1β and IL‐6 expression of THP‐1–derived macrophages, but inhibited the expression of M2‐type cytokine, IL‐10 and CCL22. The recruitment of THP‐1–derived macrophages by poly(I:C)‐stimulated cervical cancer cell supernatant was also enhanced. Inhibition of IL‐6 expression in cervical cancer cells by siRNA transfection almost completely reversed the effects of poly(I:C) treatment. Finally, we found that phosphorylation of the NF‐κB signalling pathway in cervical cancer cells occurred quickly after poly(I:C) treatment. Moreover, the NF‐κB signalling pathway inhibitor PDTC significantly inhibited poly(I:C)‐induced IL‐6 expression. Taken together, these results suggest that poly(I:C) might regulate the effects of cervical cancer cells on tumour‐infiltrated macrophages, and subsequently promote a pro‐inflammatory tumour microenvironment.

Human Papillomavirus 16 E5 Inhibits Interferon Signaling and Supports Episomal Viral Maintenance

Human papillomaviruses (HPVs) infect keratinocytes of stratified epithelia. Long-term persistence of infection is a critical risk factor for the development of HPV-induced malignancies. Through the actions of its oncogenes, HPV evades host immune responses to facilitate its productive life cycle. In this work, we discovered a previously unknown function of the HPV16 E5 oncoprotein in the suppression of interferon (IFN) responses. This suppression is focused on keratinocyte-specific IFN-κ and is mediated through E5-induced changes in growth factor signaling pathways, as identified through phosphoproteomics analysis. The loss of E5 in keratinocytes maintaining the complete HPV16 genome results in the derepression of IFNK transcription and subsequent JAK/STAT-dependent upregulation of several IFN-stimulated genes (ISGs) at both the mRNA and protein levels. We also established a link between the loss of E5 and the subsequent loss of genome maintenance and stability, resulting in increased genome integration.IMPORTANCE Persistent human papillomavirus infections can cause a variety of significant cancers. The ability of HPV to persist depends on evasion of the host immune system. In this study, we show that the HPV16 E5 protein can suppress an important aspect of the host immune response. In addition, we find that the E5 protein is important for helping the virus avoid integration into the host genome, which is a frequent step along the pathway to cancer development.

The Human Papillomavirus (HPV) E1 protein regulates the expression of cellular genes involved in immune response

The Human Papillomavirus (HPV) E1 protein is the only viral protein with enzymatic activity. The main known function of this protein is the regulation of the viral DNA replication. Nevertheless, it has been demonstrated that the ablation of HPV18 E1 mRNA in HeLa cells promotes a deregulation of several genes, particularly those involved in host defense mechanisms against viral infections; however, the specific contribution of E1 protein in HPV-independent context has not been studied. The aim of this work was to determine the effect of the HPV E1 protein in the regulation of cellular gene expression profiles evaluated through RNA-seq. We found that E1 proteins from HPV16 and 18 induced an overexpression of different set of genes associated with proliferation and differentiation processes, as well as downregulation of immune response genes, including IFNβ1 and IFNλ1 and Interferon-stimulated gene (ISG), which are important components involved in the antiviral immune response. Together, our results indicate that HR-(High-Risk) and LR-(Low-Risk) HPV E1 proteins play an important role in inhibiting the anti-viral immune response.

Comparative transcriptome analysis of the human endocervix and ectocervix during the proliferative and secretory phases of the menstrual cycle

Despite extensive studies suggesting increased susceptibility to HIV during the secretory phase of the menstrual cycle, the molecular mechanisms involved remain unclear. Our goal was to analyze transcriptomes of the endocervix and ectocervix during the proliferative and secretory phases using RNA sequencing to explore potential molecular signatures of susceptibility to HIV. We identified 202 differentially expressed genes (DEGs) between the proliferative and secretory phases of the cycle in the endocervix (adjusted p < 0.05). The biofunctions and pathways analysis of DEGs revealed that cellular assembly and epithelial barrier function in the proliferative phase and inflammatory response/cellular movement in the secretory phase were among the top biofunctions and pathways. The gene set enrichment analysis of ranked DEGs (score = log fold change/p value) in the endocervix and ectocervix revealed that (i) unstimulated/not activated immune cells gene sets positively correlated with the proliferative phase and negatively correlated with the secretory phase in both tissues, (ii) IFNγ and IFNα response gene sets positively correlated with the proliferative phase in the ectocervix, (iii) HIV restrictive Wnt/β-catenin signaling pathway negatively correlated with the secretory phase in the endocervix. Our data show menstrual cycle phase-associated changes in both endocervix and ectocervix, which may modulate susceptibility to HIV.

Homozygous NLRP1 gain-of-function mutation in siblings with a syndromic form of recurrent respiratory papillomatosis

Juvenile-onset recurrent respiratory papillomatosis (JRRP) is a rare and debilitating childhood disease that presents with recurrent growth of papillomas in the upper airway. Two common human papillomaviruses (HPVs), HPV-6 and -11, are implicated in most cases, but it is still not understood why only a small proportion of children develop JRRP following exposure to these common viruses. We report 2 siblings with a syndromic form of JRRP associated with mild dermatologic abnormalities. Whole-exome sequencing of the patients revealed a private homozygous mutation in NLRP1, encoding Nucleotide-Binding Domain Leucine-Rich Repeat Family Pyrin Domain-Containing 1. We find the NLRP1 mutant allele to be gain of function (GOF) for inflammasome activation, as demonstrated by the induction of inflammasome complex oligomerization and IL-1β secretion in an overexpression system. Moreover, patient-derived keratinocytes secrete elevated levels of IL-1β at baseline. Finally, both patients displayed elevated levels of inflammasome-induced cytokines in the serum. Six NLRP1 GOF mutations have previously been described to underlie 3 allelic Mendelian diseases with differing phenotypes and modes of inheritance. Our results demonstrate that an autosomal recessive, syndromic form of JRRP can be associated with an NLRP1 GOF mutation.

Reduced Expression of IL-1β and IL-18 Proinflammatory Interleukins Increases the Risk of Developing Cervical Cancer

Background:

The objective of this study was to analyze the gene expression profile of the proinflammatory interleukins, (IL-1β and IL-18) in patients with premalignant lesions and cervical cancer.

Methods:

Total IL-1β and IL-18 mRNA was quantified by qPCR to obtain the expression data in cervical tissues. A total of 74 cervical biopsies were obtained from women undergoing a colposcopy. The samples were divided into: normal (19), low level lesions (LSIL) or NIC I (17), high level lesions (HSIL) or CIN II and CIN III (29) and cancer (9). The normal cervical tissue samples were included as controls. The OR and 95% CI were calculated for the determination of the risk of progression between each type of lesion and cancer using logistic regression.

Results:

The results showed that an increase in the risk of progression of pre-neoplastic lesions to cancer was between 2.5 and 2.08 times higher in women with lower IL-1β and IL-18 expression, respectively.

Conclusions:

This study provided evidence that IL-1β and IL-18 are potential biomarkers that can be explored in further studies for monitoring the evolution of pre-neoplastic lesions and avoiding overtreatment or undertreatment of the patients.

Tissue-Specific Gene Expression during Productive Human Papillomavirus 16 Infection of Cervical, Foreskin, and Tonsil Epithelium

Epidemiological data confirm a much higher incidence of high-risk human papillomavirus 16 (HPV16)-mediated carcinogenesis of the cervical epithelium than for other target sites. In order to elucidate tissue-specific responses to virus infection, we compared gene expression changes induced by productive HPV16 infection of cervical, foreskin, and tonsil organotypic rafts. These rafts closely mimic persistent HPV16 infection, long before carcinogenesis sets in. The total number of gene expression changes varied considerably across the tissue types, with only 32 genes being regulated in common. Among them, we confirmed the Kelch-like family protein KLHL35 and the laminin-5 complex to be upregulated and downregulated, respectively, in all the three tissues. HPV16 infection induces upregulation of genes involved in cell cycle control, cell division, mitosis, DNA replication, and DNA damage repair in all the three tissues, indicative of a hyperproliferative environment. In the cervical and tonsil epithelium, we observe significant downregulation of genes involved in epidermis development, keratinocyte differentiation, and extracellular matrix organization. On the other hand, in HPV16-positive foreskin (HPV16 foreskin) tissue, several genes involved in interferon-mediated innate immunity, cytokine signaling, and cellular defenses were downregulated. Furthermore, pathway analysis and experimental validations identified important cellular pathways like STAT1 and transforming growth factor β (TGF-β) to be differentially regulated among the three tissue types. The differential modulation of important cellular pathways like TGF-β1 and STAT1 can explain the sensitivity of tissues to HPV cancer progression.IMPORTANCE Although the high-risk human papillomavirus 16 infects anogenital and oropharyngeal sites, the cervical epithelium has a unique vulnerability to progression of cancer. Host responses during persistent infection and preneoplastic stages can shape the outcome of cancer progression in a tissue-dependent manner. Our study for the first time reports differential regulation of critical cellular functions and signaling pathways during productive HPV16 infection of cervical, foreskin, and tonsil tissues. While the virus induces hyperproliferation in infected cells, it downregulates epithelial differentiation, epidermal development, and innate immune responses, according to the tissue type. Modulation of these biological functions can determine virus fitness and pathogenesis and illuminate key cellular mechanisms that the virus employs to establish persistence and finally initiate disease progression.

The role of the innate and adaptive immune response in HPV-associated oropharyngeal squamous cell carcinoma

Human papilloma virus (HPV) has been implicated in the development of oropharyngeal squamous cell carcinoma (OPSCC) and is directly attributed to its increasing incidence. The immune microenvironment surrounding HPV‐associated OPSCC tumors is complex and plays a critical role in the carcinogenic process. The neoplastic mechanism includes cells of the innate immunity such as macrophages, and dendritic cells as well as cells of the adaptive immune process such as CD8+ T‐cells. The intricate interactions between these two arms of the immune system allow for a pro‐inflammatory and pro‐tumorigenic environment. Intensive efforts are underway to gain a greater understanding of the mechanisms involved in the immune system's role in tumor development. This study seeks to summarize the current knowledge pertaining to role of the innate and adaptive immune response in HPV‐associated OPSCC.

Level of Evidence

3a

Human papillomavirus 16 infection alters the Toll-like receptors and downstream signaling cascade: A plausible early event in cervical squamous cell carcinoma development

OBJECTIVE

Toll-like receptors constitute an important component of innate immune mechanism. HPV is a known etiological factor of cervical cancer and is known to interfere with the expression of TLRs and downstream signaling pathway. It remains poorly understood whether HPV modulates the expression of TLRs. Hence, understanding HPV mediated immune alterations might aid in identifying novel therapeutic targets. The aim was to study the relative gene expression of TLRs & downstream signaling pathway in cervical carcinoma.

METHODS

Cervical squamous cell carcinoma (CSCC) and normal cervical tissues were obtained. Subsequent to HPV genotyping, mRNA expression profiling using PCR Array was performed. Protein expression of relevant genes with western blot was studied. Levels of cytokines in cervicovaginal washes were estimated using a Luminex multiplex platform.

RESULTS

All cases of cervical cancer were HR-HPV positive and predominant subtype was HPV16 (71.1%). Significant TLR4 upregulation and TLR2,7 downregulation were observed in HR-HPV infected cervix. TLR4,7 demonstrated low expression in CSCC. Molecules from cancer allied pathways; RELA, AKT, CDKN2A, and MDM2 demonstrated upregulation in CSCC. Protein expression data corroborated with gene expression profile. A diminished level of Th1 cytokines TNF-α, IFN-ɣ, IL-17, and IL-12 was observed in CSCC. Significantly increased levels of IL-1β, IL-6 and IL-2 were detected in HR-HPV infected cervix. Kaplan Meier curve demonstrated high TLR4 and low TLR7 expression was associated with poor prognosis.

CONCLUSION

The study demonstrates the HPV mediated dampening of the innate immune response in CSCC and provides support for exploring potential TLR2, 7 agonists as an adjunct therapy in CSCC patients.

E6/E7 and E6* From HPV16 and HPV18 Upregulate IL-6 Expression Independently of p53 in Keratinocytes

Keratinocyte infection with high-risk human papillomavirus genotypes has been linked to cancer development. In cervix, the alpha HPV16 and HPV18 have been reported as the mayor causative agents of cervical cancer. Oncogenic progression and chronic inflammation are closely related processes, with IL-6 as one of the main pro-inflammatory cytokines involved. However, there are limited studies about the regulation of IL-6 by low and high risk HPVs and the HPV proteins implicated in this modulation. In this work, we report the overexpression of IL-6 in HPV infected cervical cancer derived cell lines (HeLa and SiHa) compared to non-tumorigenic keratinocytes (HaCaT), and in Cervical Intraepithelial Neoplasia grade 1 HPV16 and HPV18 positive cervical samples compared to HPV negative samples without lesions. Moreover, we generated HaCaT keratinocytes that express E5, E6, and E7 from high risk (16 or 18) or low risk (62 and 84) HPVs. E5 proteins do not modify IL-6 expression, while E7 modestly increase it. Interestingly, E6 proteins in HaCaT cells upregulate IL-6 mRNA expression and protein secretion. Indeed, in HaCaT cells that express high risk HPV16E6 or HPV18E6 proteins, only the truncated E6^* isoforms were expressed, showing the stronger IL-6 overexpression, while in HaCaT cells that express low risk HPV62 and HPV84 full length E6 proteins, IL-6 was also upregulated but not so drastically. Since HaCaT cells have a mutated p53 form that is not degraded by the introduction of E6 or E6/E7, it seems that E6/E7 regulate IL-6 by an additional mechanism independent of p53. In addition, basal keratinocytes showed a strong expression of IL-6R using immunohistochemistry, suggesting an autocrine mechanism over proliferative cells. Altogether, IL-6 cytokine expression in keratinocytes is upregulated by E6 and E7 proteins from HPVs 16, 18, 62, and 84, especially by high risk HPV16 and HPV18 E6^*, which may contribute to promote a pro-inflammatory and highly proliferative microenvironment that can persist over time and lead to cervical tumorigenesis.

The Host-Microbe Interplay in Human Papillomavirus-Induced Carcinogenesis

Every year nearly half a million new cases of cervix cancer are diagnosed worldwide, making this malignancy the fourth commonest cancer in women. In 2018, more than 270,000 women died of cervix cancer globally with 85% of them being from developing countries. The majority of these cancers are caused by the infection with carcinogenic strains of human papillomavirus (HPV), which is also causally implicated in the development of other malignancies, including cancer of the anus, penis cancer and head and neck cancer. HPV is by far the most common sexually transmitted infection worldwide, however, most infected people do not develop cancer and do not even have a persistent infection. The development of highly effective HPV vaccines against most common high-risk HPV strains is a great medical achievement of the 21st century that could prevent up to 90% of cervix cancers. In this article, we review the current understanding of the balanced virus-host interaction that can lead to either virus elimination or the establishment of persistent infection and ultimately malignant transformation. We also highlight the influence of certain factors inherent to the host, including the immune status, genetic variants and the coexistence of other microbe infections and microbiome composition in the dynamic of HPV infection induced carcinogenesis.

Virome and Inflammasomes, a Finely Tuned Balance with Important Consequences for the Host Health

BACKGROUND

The virome is a network of viruses normally inhabiting humans. It forms a conspicuous portion of the so-called microbiome, once generically referred to as resident flora. Indeed, viruses infecting humans without leading to clinical disease are increasingly recognized as part of the microbiome and have an impact on the development of our immune system. In addition, they activate inflammasomes, multiprotein complexes that assemble in cells and that are responsible for the downstream effects of sensing pathogens.

OBJECTIVE

This review aims at summarizing the evidence on the role of the virome in modulating inflammation and emphasizes evidence for Anelloviruses as useful molecular markers to monitor inflammatory processes and immune system competence.

METHOD

We carried out a review of the literature published in the last 5 years and summarized older literature to take into account ground-breaking discoveries concerning inflammasome assembly and virome.

RESULTS

A massive amount of data recently emerging demonstrate that the microbiome closely reflects what we eat, and many other unexpected variables. Composition, location, and amount of the microbiome have an impact on innate and adaptive immune defences. Viruses making up the virome contribute to shaping the immune system. Anelloviruses, the best known of such viruses, are present in most human beings, persistently without causing apparent disease. Depending on their interplay with such viruses, inflammasomes instruct host defences to tolerate or forfeit a specific microorganism.

CONCLUSION

The virome plays an important role in shaping human immune defences and contributes to inflammatory processes by quenching or increasing them.

Cross-talk of cutaneous beta human papillomaviruses and the immune system: determinants of disease penetrance

Human papillomaviruses (HPVs) infect the epithelia of skin or mucosa, where they can induce hyperproliferative lesions. More than 220 different HPV types have been characterized and classified into five different genera. Mucosal high-risk HPVs are causative for cancers of the anogenital region and oropharynx. Clinical data from patients with the rare genetic disorder epidermodysplasia verruciformis (EV) indicate that genus beta-HPVs cooperate with ultraviolet (UV) radiation in the development of cutaneous squamous cell carcinoma. In addition, epidemiological and biological findings indicate that beta-HPV types play a role in UV-mediated skin carcinogenesis also in non-EV individuals. However, the mechanisms used by these cutaneous viruses to promote epithelial carcinogenesis differ significantly from those of mucosal HPVs. Recent studies point to a delicate cross-talk of beta-HPVs with the cell-autonomous immunity of the host keratinocytes and the local immune microenvironment that eventually determines the fate of cutaneous HPV infection and the penetrance of disease. This review gives an overview of the critical interactions of genus beta-HPVs with the local immune system that allow the virus to complete its life cycle, to escape from extrinsic immunity, and eventually to cause chronic inflammation contributing to skin carcinogenesis. This article is part of the theme issue 'Silent cancer agents: multi-disciplinary modelling of human DNA oncoviruses'.

Long Noncoding RNA HCP5, a Hybrid HLA Class I Endogenous Retroviral Gene: Structure, Expression, and Disease Associations

The HCP5 RNA gene (NCBI ID: 10866) is located centromeric of the HLA-B gene and between the MICA and MICB genes within the major histocompatibility complex (MHC) class I region. It is a human species-specific gene that codes for a long noncoding RNA (lncRNA), composed mostly of an ancient ancestral endogenous antisense 3′ long terminal repeat (LTR, and part of the internal pol antisense sequence of endogenous retrovirus (ERV) type 16 linked to a human leukocyte antigen (HLA) class I promoter and leader sequence at the 5′-end. Since its discovery in 1993, many disease association and gene expression studies have shown that HCP5 is a regulatory lncRNA involved in adaptive and innate immune responses and associated with the promotion of some autoimmune diseases and cancers. The gene sequence acts as a genomic anchor point for binding transcription factors, enhancers, and chromatin remodeling enzymes in the regulation of transcription and chromatin folding. The HCP5 antisense retroviral transcript also interacts with regulatory microRNA and immune and cellular checkpoints in cancers suggesting its potential as a drug target for novel antitumor therapeutics.

Cervical Cancer-Instructed Stromal Fibroblasts Enhance IL23 Expression in Dendritic Cells to Support Expansion of Th17 Cells

Persistent infection with high-risk human papillomavirus (HPV) is a prerequisite for the development of cervical cancer. HPV-transformed cells actively instruct their microenvironment, promoting chronic inflammation and cancer progression. We previously demonstrated that cervical cancer cells contribute to Th17 cell recruitment, a cell type with protumorigenic properties. In this study, we analyzed the expression of the Th17-promoting cytokine IL23 in the cervical cancer micromilieu and found CD83⁺ mature dendritic cells (mDC) coexpressing IL23 in the stroma of cervical squamous cell carcinomas in situ. This expression of IL23 correlated with stromal Th17 cells, advanced tumor stage, lymph node metastasis, and cervical cancer recurrence. Cocultures of cervical cancer-instructed mDCs and cervical fibroblasts led to potent protumorigenic expansion of Th17 cells in vitro but failed to induce antitumor Th1 differentiation. Correspondingly, cervical cancer-instructed fibroblasts increased IL23 production in cocultured cervical cancer-instructed mDCs, which mediated subsequent Th17 cell expansion. In contrast, production of the Th1-polarizing cytokine IL12 in the cancer-instructed mDCs was strongly reduced. This differential IL23 and IL12 regulation was the consequence of an increased expression of the IL23 subunits IL23p19 and IL12p40 but decreased expression of the IL12 subunit IL12p35 in cervical cancer-instructed mDCs. Cervical cancer cell-derived IL6 directly suppressed IL12p35 in mDCs but indirectly induced IL23 expression in fibroblast-primed mDCs via CAAT/enhancer-binding protein β (C/EBPβ)-dependent induction of IL1β. In summary, our study defines a mechanism by which the cervical cancer micromilieu supports IL23-mediated Th17 expansion associated with cancer progression. SIGNIFICANCE: Cervical cancer cells differentially regulate IL23 and IL12 in DC fibroblast cocultures in an IL6/C/EBPβ/IL1β-dependent manner, thereby supporting the expansion of Th17 cells during cancer progression.

Interplay among Vaginal Microbiome, Immune Response and Sexually Transmitted Viral Infections

The vaginal ecosystem is important for women's health and for a successful reproductive life, and an optimal host-microbial interaction is required for the maintenance of eubiosis. The vaginal microbiota is dominated by Lactobacillus species in the majority of women. Loss of Lactobacillus dominance promotes the colonization by anaerobic bacterial species with an increase in microbial diversity. Vaginal dysbiosis is a very frequent condition which affects the immune homeostasis, inducing a rupture in the epithelial barrier and favoring infection by sexually transmitted pathogens. In this review, we describe the known interactions among immune cells and microbial commensals which govern health or disease status. Particular attention is given to microbiota compositions which, through interplay with immune cells, facilitate the establishment of viral infections, such as Human Immunodeficiency Virus (HIV), Human Papilloma Virus (HPV), Herpes Simplex Virus 2 (HSV2).

The Human Papillomavirus (HPV) E6 Oncoprotein Regulates CD40 Expression via the AT-Hook Transcription Factor AKNA

Persistent infection with high-risk Human Papillomavirus (HR-HPV) is the main requisite for cervical cancer development. Normally, HPV is limited to the site of infection and regulates a plethora of cellular elements to avoid the immune surveillance by inducing an anti-inflammatory state, allowing the progress through the viral cycle and the carcinogenic process. Recent findings suggest that the AT-hook transcriptional factor AKNA could play a role in the development of cervical cancer. AKNA is strongly related to the expression of co-stimulatory molecules such CD40/CD40L to achieve an anti-tumoral immune response. To date, there is no evidence demonstrating the effect of the HPV E6 oncoprotein on the AT-hook factor AKNA. In this work, minimal expression of AKNA in cervical carcinoma compared to normal tissue was found. We show the ability of E6 from high-risk HPVs 16 and 18 to interact with and down-regulate AKNA as well as its co-stimulatory molecule CD40 in a proteasome dependent manner. We also found that p53 interacts with AKNA and promotes AKNA expression. Our results indicate that the de-regulation of CD40 and AKNA is induced by the HPV E6 oncoprotein, and this event involves the action of p53 suggesting that the axis E6/p53A/AKNA might play an important role in the de-regulation of the immune system during the carcinogenic process induced by HR-HPV.

Effect of Productive Human Papillomavirus 16 Infection on Global Gene Expression in Cervical Epithelium

Human papillomavirus (HPV) infection is the world's most common sexually transmitted infection and is responsible for most cases of cervical cancer. Previous studies of global gene expression changes induced by HPV infection have focused on the cancerous stages of infection, and therefore, not much is known about global gene expression changes at early preneoplastic stages of infection. We show for the first time the global gene expression changes during early-stage HPV16 infection in cervical tissue using 3-dimensional organotypic raft cultures, which produce high levels of progeny virions. cDNA microarray analysis showed that a total of 594 genes were upregulated and 651 genes were downregulated at least 1.5-fold with HPV16 infection. Gene ontology analysis showed that biological processes including cell cycle progression and DNA metabolism were upregulated, while skin development, immune response, and cell death were downregulated with HPV16 infection in cervical keratinocytes. Individual genes were selected for validation at the transcriptional and translational levels, including UBC, which was central to the protein association network of immune response genes, and top downregulated genes RPTN, SERPINB4, KRT23, and KLK8 In particular, KLK8 and SERPINB4 were shown to be upregulated in cancer, which contrasts with the gene regulation during the productive replication stage. Organotypic raft cultures, which allow full progression of the HPV life cycle, allowed us to identify novel gene modulations and potential therapeutic targets of early-stage HPV infection in cervical tissue. Additionally, our results suggest that early-stage productive infection and cancerous stages of infection are distinct disease states expressing different host transcriptomes.IMPORTANCE Persistent HPV infection is responsible for most cases of cervical cancer. The transition from precancerous to cancerous stages of HPV infection is marked by a significant reduction in virus production. Most global gene expression studies of HPV infection have focused on the cancerous stages. Therefore, little is known about global gene expression changes at precancerous stages. For the first time, we measured global gene expression changes at the precancerous stages of HPV16 infection in human cervical tissue producing high levels of virus. We identified a group of genes that are typically overexpressed in cancerous stages to be significantly downregulated at the precancerous stage. Moreover, we identified significantly modulated genes that have not yet been studied in the context of HPV infection. Studying the role of these genes in HPV infection will help us understand what drives the transition from precancerous to cancerous stages and may lead to the development of new therapeutic targets.

Innate immunity and HPV: friends or foes

Most human papillomavirus infections are readily cleared by the host immune response. However, in some individuals, human papillomavirus can establish a persistent infection. The persistence of high-risk human papillomavirus infection is the major risk factor for cervical cancer development. These viruses have developed mechanisms to evade the host immune system, which is an important step in persistence and, ultimately, in tumor development. Several cell types, receptors, transcription factors and inflammatory mediators involved in the antiviral immune response are viral targets and contribute to tumorigenesis. These targets include antigen-presenting cells, macrophages, natural killer cells, Toll-like receptors, nuclear factor kappa B and several cytokines and chemokines, such as interleukins, interferon and tumor necrosis factor. In the present review, we address both the main innate immune response mechanisms involved in HPV infection clearance and the viral strategies that promote viral persistence and may contribute to cancer development. Finally, we discuss the possibility of exploiting this knowledge to develop effective therapeutic strategies.

Mechanisms of persistence by small DNA tumor viruses

Virus infection contributes to nearly 15% of human cancers worldwide. Many of the oncogenic viruses tend to cause cancer in immunosuppressed individuals, but maintain asymptomatic, persistent infection for decades in the general population. In this review, we discuss the tactics employed by two small DNA tumor viruses, Human papillomavirus (HPV) and Merkel cell polyomavirus (MCPyV), to establish persistent infection. We will also highlight recent key findings as well as outstanding questions regarding the mechanisms by which HPV and MCPyV evade host immune control to promote their survival. Since persistent infection enables virus-induced tumorigenesis, identifying the mechanisms by which small DNA tumor viruses achieve latent infection may inform new approaches for preventing and treating their respective human cancers.

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.

Oncostatin M treatment increases the responsiveness toward cisplatin-based chemoradiotherapy in cervical cancer cells in a STAT3-dependent manner

Cervical cancer stage-dependent therapies include surgery, chemotherapy, radiotherapy and chemoradiotherapy. Concurrent cisplatin-based chemoradiotherapy (CCRT) is the standard therapy for locally advanced cervical carcinoma (FIGO>IIB), however therapy resistance in a subset of patients is still a major clinical challenge. The present study aimed to analyze the impact of Oncostatin M (OSM) stimulation on CCRT-induced cell death. The present study used cells derived from cervical squamous cell carcinomas (SW756, 808, CaSki and 879) and adenocarcinoma (HeLa). The cervical carcinoma cells were HPV18-positive (HeLa, SW756, 808) or HPV16-positive (CaSki, 879). In addition to the established cell lines HeLa, SW756 and CaSki, the more recently generated cervical cancer cells 808 and 879 were also used. To analyze their radiosensitivity, cells were treated with increasing doses of irradiation (0-8 Gy). To mimic chemotherapy, radiotherapy or CCRT in vitro, the cells were challenged with 0.975 µg/ml cisplatin, irradiated with 6 Gy or a combination. A total of 10 ng/ml OSM was applied for 2 h prior to the respective therapy. The responsiveness toward radiation alone varied among the cervical carcinoma cells. CaSki, 808 and 879 cells were resistant to irradiation up to 8 Gy. OSM pre-treatment sensitized two out of five cell lines (HeLa and 879) to irradiation. Notably, all tested cells were sensitized by OSM for CCRT-treatment, particularly in the less radiosensitive cells. Cell death enhancement was dependent on phosphorylated signal transducer and activator of transcription 3 (STAT3; Tyr705) signaling activation as demonstrated with a dominant-negative version of STAT3 interfering with phosphorylation at Tyr705 (dnSTAT3-Y705F). In conclusion, OSM pre-treatment was able to override resistance to CCRT via the STAT3 signaling pathway.