The human papillomavirus type 16 E7 oncoprotein induces a transcriptional repressor complex on the Toll-like receptor 9 promoter

The Epithelial Immune Response to Human Papillomavirus Infection

The skin is a complex organ, containing an intricate network of immune cells that are crucial for host barrier function and defence against pathogens. Human papillomavirus (HPV) exclusively infects the skin, and its lifecycle is intimately associated with epithelial cell division and differentiation. There are over 450 HPV types, 12 of which are classified as carcinogenic. The primary focus of this review is the epithelial immune response to HPV infection of the cervix during the initial stages of infection, productive infection, and disease progression. During the early stages of infection, cells are HPV-positive; however, there are no attributable histological changes to the epithelium. The HPV-infected cells have the capacity for innate sensing and signalling through toll-like receptors in response to viral nucleic acids. However, HPV has evolved multiple mechanisms to evade the innate response. During productive infection, all viral antigens are expressed and there are visible histological changes to the epithelium, including koilocytosis. Disease regression is associated with Tbet positive cells in the infected epithelium and the presence of CD4 and CD8 T cells in the lamina propria. Disease progression is associated with the overexpression of the E6 and E7 oncoproteins after integration of viral genomes into the host chromosomal DNA. Histologically, the epithelium is less differentiated, and changes to cells include a higher nuclear-to-cytoplasmic ratio and an increased mitotic index. Immune changes associated with disease progression include increased numbers of cells expressing suppressor molecules, such as FoxP3, Blimp-1, and HMGB1, and myeloid cell infiltrates with an M2-like phenotype. This review highlights the gaps in the understanding of the immune response in HPV-positive cervical neoplasia, and in regression and progression of disease. This knowledge is critical for the development of effective immunotherapies that reliably cause HPV-positive cervical neoplasia to regress.

Nuclear warfare: pathogen manipulation of the nuclear pore complex and nuclear functions

Viruses and bacteria exploit the nuclear pore complex (NPC) and host nuclear functions to bypass cellular barriers and manipulate essential processes. Viruses frequently engage directly with NPC components, such as nucleoporins, to enable genome import and evade immune defenses. In contrast, bacterial pathogens rely on secreted effector proteins to disrupt nuclear transport and reprogram host transcription. These strategies reflect a remarkable evolutionary convergence, with both types of pathogens targeting the NPC and nuclear functions to promote infection. This minireview explores the overlapping and unique mechanisms by which pathogens hijack the host nucleus, shedding light on their roles in disease and potential avenues for therapeutic intervention.

Sexually transmitted human papillomavirus and related sequelae

SUMMARYMore than 40 types of sexually transmitted human papillomavirus (HPV) infect the oropharyngeal and anogenital mucosa-high-risk types are associated with precancerous and cancerous lesions of the cervix, vagina, vulva, penis, anus, and oropharynx, and low-risk types cause non-malignant disease, such as anogenital warts. Though most HPV infections resolve spontaneously, immunodeficiencies may result in persistent infection and increased risk of HPV-related sequelae. The mechanism by which HPV results in malignant transformation is multifaceted, involving interactions with numerous cellular pathways, the host immune system, and potentially the host microbiome. Vaccination against HPV is highly efficacious in the prevention of infection and related sequelae, and there now exist several approved formulations that protect against both high- and low-risk types. Despite the advent of vaccination, early detection and treatment of cervical and anal precancerous lesions continues to be integral to secondary prevention-molecular HPV testing, cytology, and tissue biopsy allow for triaging of patients, after which appropriate treatment with close follow-up can avert cancer development.

TGF-β Induces the Secretion of Extracellular Vesicles Enriched with CD39 and CD73 from Cervical Cancer Cells

The presence of TGF-β in the tumor microenvironment of cervical cancer (CC) is important for tumor progression. In this study, we analyzed the effect of TGF-β on the expression of the ectonucleotidases CD39 and CD73, which are involved in the generation of adenosine (Ado), in CC cells and in extracellular vesicles (EVs) secreted by these cells. Treatment of HeLa and CaSki cells for 72 h with recombinant human TGF-β increased the expression of CD39 and CD73 by 20 and 30% and by 40 and 100%, respectively. The addition of SB505124, an inhibitor of the TGF-β1 receptor, or GW4869, an inhibitor of exosome formation and release, reduced the expression and release of both ectonucleotidases in CC cells. Furthermore, TGF-β promoted the secretion of medium-large EVs (>130 nm) in HeLa cells (HeLa + TGF-β/EVs) and CaSki cells (CaSki + TGF-β/EVs), which increased the expression of CD39 (>20%) and CD73 (>60%), and EVs obtained from cells treated with TGF-β had a greater capacity to generate Ado than did EVs obtained from cells cultured in the absence of this factor (HeLa/EVs and CaSki/EVs). These findings suggest that the production of TGF-β in the CC TME can promote neoplastic progression through the secretion of EVs enriched with CD39 and CD73. Therefore, the inhibition of CD39+ CD73+ EVs could be a strategy for the treatment of CC.

Unraveling HPV-associated cancer complexity: From molecular insights to innovative therapies

Human papillomavirus (HPV) contributes to a high global incidence of sexually transmitted infections, predominantly associated with cervical cancer, as well as head and neck, penile, anal, vaginal, and vulvar cancers. Despite efforts through improved screening and HPV vaccination campaigns, challenges persist, influencing the frequency of HPV-related malignancies. Collaborative scientific endeavors strive to pioneer groundbreaking approaches, aiming to alleviate the adverse consequences of HPV-related malignancies on individuals and communities. The present review is focused on exhaustively covering HPV-associated cancers, particularly cervical cancer. This study highlights the initiation, progression, immune invasion, and treatment strategies of HPV-associated cancers. The role of viral oncoproteins E6 and E7 responsible for immune evasion and subsequent latent infection is also elaborated. The article also sheds light on the pivotal role of HPV vaccination in averting high-risk HPV infections and associated cancers. The scope of this review encompasses HPV-associated cancer epidemiology, regional disparities, and the distinctive challenges faced in the context of India. This will be a value addition to the knowledge repertoire beneficial for creating awareness and designing health policies.

Human papillomavirus E6 alters Toll-like receptor 9 transcripts and chemotherapy responses in breast cancer cells in vitro

BACKGROUND

Toll-like receptor 9 (TLR9) is a DNA recognizing receptor expressed also in several cancers. Decreased TLR9 expression is associated with poor prognosis in triple negative breast cancer (TNBC), but the role of TLR9 in breast cancer pathophysiology is currently unclear. Regulation of TLR9 expression in breast cancer is poorly understood. Human papillomavirus (HPV) infections suppress TLR9 expression in cervical cancers but the association between HPV and breast cancer has remained controversial. The aim of this study was to test if HPV16 can suppress TLR9 expression in breast cancer cells and affect cell behavior.

METHODS AND RESULTS

Human T-47D and MDA-MB-231 breast cancer cells were transduced with lentivirus encoding HPV16 E6 oncoprotein. The effects of E6 on TLR9 mRNA and protein expression, and cell proliferation, migration, invasion and sensitivity to chemotherapy were studied in vitro. Breast cancer tissue samples (n = 37) were analyzed for the presence of HPV DNA. E6 expression decreased TLR9 mRNA expression in MDA-MB-231 and T-47D cells in hypoxia. E6 expression altered breast cancer cell proliferation and made cells significantly less sensitive to the growth inhibitory effects of chemotherapeutic agents. HPV L1 gene was not detected in a small pilot cohort of clinical breast cancer specimens.

CONCLUSION

HPV16 may influence breast cancer cell TLR9 transcription and chemotherapy responses and could thereby affect breast cancer prognosis. These results suggest that HPV may have a previously unrecognized role in breast cancer pathophysiology and warrant further studies on the topic.

Cutaneous human papillomavirus E6 impairs the cGAS-STING pathway

Beta genus human papillomaviruses (β-HPVs) are ubiquitous double stranded DNA (dsDNA) viruses that may promote skin cancers by destabilizing the host genome. Supporting this, expression of the E6 gene from a β-HPV (β-HPV 8 E6) results in increased micronuclei that should induce an innate immune response that eliminates these cells. Yet, β-HPV 8 E6 promotes rather than restricts proliferation. We hypothesize that β-HPV 8 E6 accomplishes this by attenuating the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway, an innate immune pathway that becomes activated in response to cytosolic micronuclear dsDNA. Here, we show that in response to stimulation by transfection of pLVX-GFP plasmid, β-HPV 8 E6 reduced the magnitude and intensity of cGAS-STING pathway activation in immunoblot experiments. These data also demonstrate that impairment of the cGAS-STING pathway is strongest downstream of STING phosphorylation. Further, RNA-sequencing suggests that β-HPV 8 E6 downregulates other innate immune pathways. We also show that cGAS is recruited to micronuclei induced by β-HPV 8 E6. These data suggest a mechanism by which β-HPV 8 E6 facilitates proliferation of cells destabilized by micronuclei and support the hypothesis that the prevalence of β-HPV infections is in part due to the impairment of the cGAS-STING innate immune response.

The roles of DNA damage repair and innate immune surveillance pathways in HPV pathogenesis

Human papillomaviruses (HPV) infect epithelial tissues and induce a variety of proliferative lesions. A subset of HPV types are also the causative agents of many anogenital as well as oropharyngeal cancers. Following infection of basal epithelial cells, HPVs establish their genomes as episomes in undifferentiated cells and require differentiation for their productive life cycles. During HPV infections, viral oncoproteins alter cellular pathways such as those for DNA damage repair and innate immune surveillances to regulate their productive life cycles. These pathways provide potential targets for therapeutic intervention.

A molecular viewpoint of the intricate relationships among HNSCC, HPV infections, and the oral microbiota dysbiosis

HPV infection and the type of host microbiota play a role in the formation of HNCs. In contrast to other forms of OSCC, where the relationship between HPV and the cancer is less obvious, HPV-HNSCC is a particular type of oropharyngeal cancer. HPV has infected a stratified squamous epithelium, which includes the throat, mouth, anogenital tract, respiratory tract, and skin on the hands and feet. HPV DNA was found in high amounts in the saliva and gargle samples of patients with HPV-related HNSCC. It has been discovered that the specificity of oral mRNA (HPV) and HPV DNA identification varies from 23 % to 82 % in the identification of OPSCCs. The higher rate of HPV transmission through vaginal-oral compared to penile-oral sexual activity may be the reason for the difference in HPV-positive HNSCC patients between males and females. The researchers postulate that HPV-inactive tumours signify an advanced stage of HPV-positive HNSCC, which explains why there are racial disparities in gene expression that correspond to different disease progressions in Black and White patients. The increase of CD8+ T cells in the cancer microenvironment, linked to P16 activation, extends life expectancy in OSCC. tumour markers methylation caused by HPV and suggested using them as possible HNC biomarkers. Fusobacterium levels are much higher in patients with OSCC, while Actinobacteria phylum and Firmicutes are significantly lower. It also serves as a biomarker for notable variations found in Firmicutes, Actinobacteria, Fusobacteriales, Fusobacteriia, Fusobacterium, and Fusobacteriaceae. Therefore, based on this we evidence, we could investigate the role of oral microbiota as a maker for the HPV associated HNSCC.

The cGAS-STING pathway and female reproductive system diseases

The cGAS-STING pathway has become a crucial role in the detection of cytosolic DNA and the initiation of immune responses. The cGAS-STING pathway not only mediates protective immune defense against various DNA-containing pathogens but also detects tumor-derived DNA to generate intrinsic anti-tumor immunity. However, abnormal activation of the cGAS-STING pathway by self-DNA can also lead to autoimmune diseases and inflammatory disorders. This article reviews the mechanisms and functions of the cGAS-STING pathway, as well as the latest research progress in female reproductive-related diseases. We focus on the regulatory mechanisms and roles of this pathway in common female reproductive disorders, discuss the clinical potential of the cGAS-STING pathway as biomarkers and therapeutic agents for female reproductive diseases, as well as the research controversies, technical issues, and biological knowledge gaps that need to be resolved. Furthermore, we provide new ideas for the treatment and prevention of these diseases.

Curcumin suppressed the proliferation and apoptosis of HPV-positive cervical cancer cells by directly targeting the E6 protein

Most human papillomavirus (HPV) types, including HPV16 and HPV18, are closely related to the occurrence of cervical cancer, predominantly through the action of viral oncoproteins E6 and E7. Curcumin, the active ingredient of the turmeric plant, has been gaining attention over the past two decades as an antioxidant, anti-inflammatory, and anticancer agent. In the present study, the HPV-positive cervical cancer cells HeLa and CaSki were treated with curcumin, and the results showed that curcumin has a dose-dependent and time-dependent inhibitory effect on cell viability. In addition, apoptosis induction was further quantitatively confirmed through flow cytometric analysis. Furthermore, the influence of different concentrations of curcumin on the mitochondrial membrane potential was evaluated through JC-1 staining and found to dramatically decrease the membrane potential in treated HeLa and CaSki cells, suggesting the critical role of the mitochondrial pathway in their apoptosis-inducing effect. This study also demonstrated the wound-healing potential of curcumin, and the results of transwell assays showed that curcumin treatment inhibited HeLa and CaSki cell invasion and migration in a dose-dependent manner compared with the control treatment. Curcumin also downregulated the expression of Bcl-2, N-cadherin, and Vimentin and upregulated the expression of Bax, C-caspase-3, and E-cadherin in both cell lines. Further research showed that curcumin also selectively inhibited the expression of the viral oncoproteins E6 and E7, as demonstrated by western blot analysis; moreover, the downregulation of E6 was more significant than that of E7. Our research also showed that coculture with cells infected with siE6 lentivirus (siE6 cells) can inhibit the proliferation, invasion, and metastasis of HPV-positive cells. While the siE6 cells were also treated with curcumin, the effect of curcumin monotherapy was offset. In summary, our research shows that curcumin regulates the apoptosis, migration, and invasion of cervical cancer cells, and the mechanism may be related to its ability to downregulate E6. This study provides a foundation for future research on the prevention and treatment of cervical cancer.

Head and neck cancer: pathogenesis and targeted therapy

Head and neck cancer (HNC) is a highly aggressive type of tumor characterized by delayed diagnosis, recurrence, metastasis, relapse, and drug resistance. The occurrence of HNC were associated with smoking, alcohol abuse (or both), human papillomavirus infection, and complex genetic and epigenetic predisposition. Currently, surgery and radiotherapy are the standard treatments for most patients with early-stage HNC. For recurrent or metastatic (R/M) HNC, the first-line treatment is platinum-based chemotherapy combined with the antiepidermal growth factor receptor drug cetuximab, when resurgery and radiation therapy are not an option. However, curing HNC remains challenging, especially in cases with metastasis. In this review, we summarize the pathogenesis of HNC, including genetic and epigenetic changes, abnormal signaling pathways, and immune regulation mechanisms, along with all potential therapeutic strategies such as molecular targeted therapy, immunotherapy, gene therapy, epigenetic modifications, and combination therapies. Recent preclinical and clinical studies that may offer therapeutic strategies for future research on HNC are also discussed. Additionally, new targets and treatment methods, including antibody-drug conjugates, photodynamic therapy, radionuclide therapy, and mRNA vaccines, have shown promising results in clinical trials, offering new prospects for the treatment of HNC.

Global transcriptomic network analysis of the crosstalk between microbiota and cancer-related cells in the oral-gut-lung axis

Background

The diagnosis and treatment of lung, colon, and gastric cancer through the histologic characteristics and genomic biomarkers have not had a strong impact on the mortality rates of the top three global causes of death by cancer.

Methods

Twenty-five transcriptomic analyses (10 lung cancer, 10 gastric cancer, and 5 colon cancer datasets) followed our own bioinformatic pipeline based on the utilization of specialized libraries from the R language and DAVID´s gene enrichment analyses to identify a regulatory metafirm network of transcription factors and target genes common in every type of cancer, with experimental evidence that supports its relationship with the unlocking of cell phenotypic plasticity for the acquisition of the hallmarks of cancer during the tumoral process. The network's regulatory functional and signaling pathways might depend on the constant crosstalk with the microbiome network established in the oral-gut-lung axis.

Results

The global transcriptomic network analysis highlighted the impact of transcription factors (SOX4, TCF3, TEAD4, ETV4, and FOXM1) that might be related to stem cell programming and cancer progression through the regulation of the expression of genes, such as cancer-cell membrane receptors, that interact with several microorganisms, including human T-cell leukemia virus 1 (HTLV-1), the human papilloma virus (HPV), the Epstein-Barr virus (EBV), and SARS-CoV-2. These interactions can trigger the MAPK, non-canonical WNT, and IFN signaling pathways, which regulate key transcription factor overexpression during the establishment and progression of lung, colon, and gastric cancer, respectively, along with the formation of the microbiome network.

Conclusion

The global transcriptomic network analysis highlights the important interaction between key transcription factors in lung, colon, and gastric cancer, which regulates the expression of cancer-cell membrane receptors for the interaction with the microbiome network during the tumorigenic process.

Nature of the Association between Rheumatoid Arthritis and Cervical Cancer and Its Potential Therapeutic Implications

It is now established that patients with rheumatoid arthritis (RA) have an increased risk of developing cervical cancer (CC) or its precursor, cervical intraepithelial neoplasia (CIN). However, the underlying mechanisms of this association have not been elucidated. RA is characterized by unresolved chronic inflammation. It is suggested that human papillomavirus (HPV) infection in RA patients exacerbates inflammation, increasing the risk of CC. The tumor microenvironment in RA patients with CC is also marked by chronic inflammation, which aggravates the manifestations of both conditions. Gut and vaginal dysbiosis are also considered potential mechanisms that contribute to the chronic inflammation and aggravation of RA and CC manifestations. Numerous clinical and pre-clinical studies have demonstrated the beneficial effects of various nutritional approaches to attenuate chronic inflammation, including polyunsaturated fatty acids and their derivatives, specialized pro-resolving mediators (SPMs), probiotics, prebiotics, and certain diets. We believe that successful resolution of chronic inflammation and correction of dysbiosis, in combination with current anti-RA and anti-CC therapies, is a promising therapeutic approach for RA and CC. This approach could also reduce the risk of CC development in HPV-infected RA patients.

MDSCs use a complex molecular network to suppress T-cell immunity in a pulmonary model of fungal infection

Background

Paracoccidioidomycosis (PCM) is a systemic endemic fungal disease prevalent in Latin America. Previous studies revealed that host immunity against PCM is tightly regulated by several suppressive mechanisms mediated by tolerogenic plasmacytoid dendritic cells, the enzyme 2,3 indoleamine dioxygenase (IDO-1), regulatory T-cells (Tregs), and through the recruitment and activation of myeloid-derived suppressor cells (MDSCs). We have recently shown that Dectin-1, TLR2, and TLR4 signaling influence the IDO-1-mediated suppression caused by MDSCs. However, the contribution of these receptors in the production of important immunosuppressive molecules used by MDSCs has not yet been explored in pulmonary PCM.

Methods

We evaluated the expression of PD-L1, IL-10, as well as nitrotyrosine by MDSCs after anti-Dectin-1, anti-TLR2, and anti-TLR4 antibody treatment followed by P. brasiliensis yeasts challenge in vitro. We also investigated the influence of PD-L1, IL-10, and nitrotyrosine in the suppressive activity of lung-infiltrating MDSCs of C57BL/6-WT, Dectin-1KO, TLR2KO, and TLR4KO mice after in vivo fungal infection. The suppressive activity of MDSCs was evaluated in cocultures of isolated MDSCs with activated T-cells.

Results

A reduced expression of IL-10 and nitrotyrosine was observed after in vitro anti-Dectin-1 treatment of MDSCs challenged with fungal cells. This finding was further confirmed in vitro and in vivo by using Dectin-1KO mice. Furthermore, MDSCs derived from Dectin-1KO mice showed a significantly reduced immunosuppressive activity on the proliferation of CD4+ and CD8+ T lymphocytes. Blocking of TLR2 and TLR4 by mAbs and using MDSCs from TLR2KO and TLR4KO mice also reduced the production of suppressive molecules induced by fungal challenge. In vitro, MDSCs from TLR4KO mice presented a reduced suppressive capacity over the proliferation of CD4+ T-cells.

Conclusion

We showed that the pathogen recognition receptors (PRRs) Dectin-1, TLR2, and TLR4 contribute to the suppressive activity of MDSCs by inducing the expression of several immunosuppressive molecules such as PD-L1, IL-10, and nitrotyrosine. This is the first demonstration of a complex network of PRRs signaling in the induction of several suppressive molecules by MDSCs and its contribution to the immunosuppressive mechanisms that control immunity and severity of pulmonary PCM.

High-risk HPV oncoproteins E6 and E7 and their interplay with the innate immune response: Uncovering mechanisms of immune evasion and therapeutic prospects

Human papillomaviruses (HPVs) are double-stranded DNA (dsDNA) tumor viruses causally associated with 5% of human cancers, comprising both anogenital and upper aerodigestive tract carcinomas. Despite the availability of prophylactic vaccines, HPVs continue to pose a significant global health challenge, primarily due to inadequate vaccine access and coverage. These viruses can establish persistent infections by evading both the intrinsic defenses of infected tissues and the extrinsic defenses provided by professional innate immune cells. Crucial for their evasion strategies is their unique intraepithelial life cycle, which effectively shields them from host detection. Thus, strategies aimed at reactivating the innate immune response within infected or transformed epithelial cells, particularly through the production of type I interferons (IFNs) and lymphocyte-recruiting chemokines, are considered viable solutions to counteract the adverse effects of persistent infections by these oncogenic viruses. This review focuses on the complex interplay between the high-risk HPV oncoproteins E6 and E7 and the innate immune response in epithelial cells and HPV-associated cancers. In particular, it details the molecular mechanisms by which E6 and E7 modulate the innate immune response, highlighting significant progress in our comprehension of these processes. It also examines forward-looking strategies that exploit the innate immune system to ameliorate existing anticancer therapies, thereby providing crucial insights into future therapeutic developments.

The HPV viral regulatory mechanism of TLRs and the related treatments for HPV-associated cancers

Infection with human papillomavirus (HPV) typically leads to cervical cancer, skin related cancers and many other tumors. HPV is mainly responsible for evading immune tumor monitoring in HPV related cancers. Toll like receptors (TLRs) are particular pattern recognition molecules. When the body is facing immune danger, it can lead to innate and direct adaptive immunity. TLR plays an important role in initiating antiviral immune responses. HPV can affect the expression level of TLR and interfere with TLR related signaling pathways, resulting in sustained viral infection and even carcinogenesis. This paper introduces the HPV virus and HPV related cancers. We discussed the present comprehension of TLR, its expression and signaling, as well as its role in HPV infection. We also provided a detailed introduction to immunotherapy methods for HPV related diseases based on TLR agonists. This will provide insights into methods that support the therapeutic method of HPV related conditions with TLR agonists.

The role of NF-κB in carcinogenesis of cervical cancer: opportunities and challenges

The nuclear factor-κB (NF-κB) family, consisting of several transcription factors, has been implicated in the regulation of cell proliferation and invasion, as well as inflammatory reactions and tumor development. Cervical cancer (CC) results from long-term interactions of multiple factors, among which persistent high-risk human papillomavirus (hrHPV) infection is necessary. During different stages from early to late after HPV infection, the activity of NF-κB varies and plays various roles in carcinogenesis and progress of CC. As the center of the cell signaling transduction network, NF-κB can be activated through classical and non-classical pathways, and regulate the expression of downstream target genes involved in regulating the tumor microenvironment and acquiring hallmark traits of CC cells. Targeting NF-κB may help treat CC and overcome the resistance to radiation and chemotherapy. Even though NF-κB inhibitors have not been applied in clinical treatment as yet, due to limitations such as dose-restrictive toxicity and poor tumor-specificity, it is still considered to have significant therapeutic potential and application prospects. In this review, we focus on the role of NF-κB in the process of CC occurrence and hallmark capabilities acquisition. Finally, we summarize relevant NF-κB-targeted treatments, providing ideas for the prevention and treatment of CC.

The Killer's Web: Interconnection between Inflammation, Epigenetics and Nutrition in Cancer

Inflammation is a key contributor to both the initiation and progression of tumors, and it can be triggered by genetic instability within tumors, as well as by lifestyle and dietary factors. The inflammatory response plays a critical role in the genetic and epigenetic reprogramming of tumor cells, as well as in the cells that comprise the tumor microenvironment. Cells in the microenvironment acquire a phenotype that promotes immune evasion, progression, and metastasis. We will review the mechanisms and pathways involved in the interaction between tumors, inflammation, and nutrition, the limitations of current therapies, and discuss potential future therapeutic approaches.

Impact of HPV strains on molecular mechanisms of cervix cancer

PURPOSE

Cervical cancer accounts for a high number of deaths worldwide. Risk factors are extensive for cervix cancer but Human papillomavirus (HPV) plays a prime role in its development. Different strains of HPV are prevalent globally, which show different grades of mortality and morbidity among women. This study is planned to evaluate the molecular mechanism of different strains of HPV infection and progression leading to cervix cancer.

METHODS

This review includes different research articles on cervix cancer progression reported from India and all over the world.

RESULTS

HPV 16 and 18 are prevalent strains using heparan sulfate-independent and dependent pathways for viral replication inside the cell. It also uses transcription mechanisms through NF-kappa B, FOXA-1, and AP-1 genes while strains like HPV-35, 45, and 52 are also predominant in India, which showed a very slow mechanism of progression due to which mortality rate is low after their infection with these strains.

CONCLUSION

HPV uses E6 and E7 proteins which activate NF-kappa B and AP-1 pathway which suppresses the tumor suppressor gene and activates cytokine production, causing inflammation and leading to a decrease in apoptosis due to Caspase-3 activation. In contrast, the E7 protein involves HOXA genes and decreases apoptotic factors due to which mortality and incidence rates are low in viruses that use E7 motifs. Some HPV strains employ the cap-dependent pathway, which is also associated with lower mortality and infection rates.

Immunotherapy that leverages HPV-specific immune responses for precancer lesions of cervical cancer

Cervical cancer and its precursor lesion, cervical intraepithelial neoplasia (CIN), are caused by high-risk human papillomavirus (HPV) viral infection and are highly susceptible to host immunity targeting of HPV viral proteins, which include both foreign antigens and cancer antigens expressed by tumors. Immunotherapy that induces Th1 immunoreactivity against viral proteins is expected to take advantage of this immunological regression mechanism. However, although cancer immunotherapies for cervical cancer and CIN have been developed over the past several decades, none have been commercialized. Most of these immunotherapies target the viral cancer proteins E6 and E7, which are generally the same. The reasons for the underdevelopment of HPV-targeted immunotherapy differ depending on whether the target is invasive cancer or CIN. We here summarize the developmental history of cancer immunotherapy for CIN and discuss strategies for solving the problems that led to this underdevelopment. We note that CIN is a mucosal lesion and propose that inducing mucosal immunity may be the key.

Implications of oral dysbiosis and HPV infection in head and neck cancer: from molecular and cellular mechanisms to early diagnosis and therapy

Head and neck cancer (HNC) is the sixth most common type of cancer, with more than half a million new cases annually. This review focuses on the role of oral dysbiosis and HPV infection in HNCs, presenting the involved taxons, molecular effectors and pathways, as well as the HPV-associated particularities of genetic and epigenetic changes and of the tumor microenvironment occurred in different stages of tumor development. Oral dysbiosis is associated with the evolution of HNCs, through multiple mechanisms such as inflammation, genotoxins release, modulation of the innate and acquired immune response, carcinogens and anticarcinogens production, generation of oxidative stress, induction of mutations. Thus, novel microbiome-derived biomarkers and interventions could significantly contribute to achieving the desideratum of personalized management of oncologic patients, regarding both early diagnosis and treatment. The results reported by different studies are not always congruent regarding the variations in the abundance of different taxons in HNCs. However, there is a consistent reporting of a higher abundance of Gram-negative species such as Fusobacterium, Leptotrichia, Treponema, Porphyromonas gingivalis, Prevotella, Bacteroidetes, Haemophilus, Veillonella, Pseudomonas, Enterobacterales, which are probably responsible of chronic inflammation and modulation of tumor microenvironment. Candida albicans is the dominant fungi found in oral carcinoma being also associated with shorter survival rate. Specific microbial signatures (e.g., F. nucleatum, Bacteroidetes and Peptostreptococcus) have been associated with later stages and larger tumor, suggesting their potential to be used as biomarkers for tumor stratification and prognosis. On the other hand, increased abundance of Corynebacterium, Kingella, Abiotrophia is associated with a reduced risk of HNC. Microbiome could also provide biomarkers for differentiating between oropharyngeal and hypopharyngeal cancers as well as between HPV-positive and HPV-negative tumors. Ongoing clinical trials aim to validate non-invasive tests for microbiome-derived biomarkers detection in oral and throat cancers, especially within high-risk populations. Oro-pharyngeal dysbiosis could also impact the HNCs therapy and associated side-effects of radiotherapy, chemotherapy, and immunotherapy. HPV-positive tumors harbor fewer mutations, as well as different DNA methylation pattern and tumor microenvironment. Therefore, elucidation of the molecular mechanisms by which oral microbiota and HPV infection influence the HNC initiation and progression, screening for HPV infection and vaccination against HPV, adopting a good oral hygiene, and preventing oral dysbiosis are important tools for advancing in the battle with this public health global challenge.

Upregulation of IFNE in cervical biopsies of patients with high-risk human papillomavirus infections

PROBLEM

Interferon epsilon (IFN-ε) is constitutively expressed in the epithelium of female reproductive tract and confers vital protection against sexually transmitted pathogens in mouse models. However, there is limited insight into the role of IFN-ε in human sexually transmitted infections such as human papillomavirus (HPV).

METHOD OF STUDY

Cervical biopsies were obtained from high-risk (HR) HPV positive (n = 28) and HR-HPV negative (n = 10) women. mRNA expression of IFN-ε in cervical tissues was measured by qPCR. Expression of the IFN-ε protein was determined by Western blot analysis, immunohistochemistry and immunofluorescence staining.

RESULTS

mRNA expression of IFN-ε was higher in the ectocervix than that of other IFNs, and was further upregulated in HR-HPV positive women compared with HR-HPV negative women. Expression of the IFN-ε protein was comparable between HR-HPV infected patients and healthy controls.

CONCLUSIONS

These results reveal differential expression of IFN-ε mRNA between individuals with or without HR-HPV infection, and imply direct or indirect regulatory mechanisms for IFN-ε transcription by HPV. Expression of IFN-ε protein in HPV infections would require further validation.

Arginase is upregulated in healthy women infected by oncogenic HPV types

INTRODUCTION

The implication of arginase enzyme in Human Papillomavirus (HPV) infections has not been clearly elucidated. The present study investigates whether HPV infection is correlated with changes in plasmatic arginase activity and cervical ARG1 and ARG2 mRNA expression among infected women negative for intraepithelial lesions (NIL).

MATERIEL AND METHODS

The present study included 300 women. The plasmatic arginase activity was evaluated by a colorimetric assay. Cervical HPV was detected by real-time PCR. The circulating viral load and ARG1 and ARG2 mRNA expression quantification were performed by quantitative real-time PCR.

RESULTS

A significant increase in plasma arginase activity and ARG1 and ARG2 mRNA expression levels in cervical cells was observed among HPV-positive women compared to the HPV-negative group. The highest levels were significantly associated with oncogenic HPV, and increased arginase activity was associated with a high HPV circulating viral load. Moreover, the highest levels of arginase activity were observed in oncogenic HPV-positive inflammatory smears.

DISCUSSION

These data suggest that HPV could modulate arginase activity and expression, which may restrict arginine bioavailability and inhibit this amino acid's antiviral properties.

CONCLUSION

Our findings revealed that arginase activity and isoform gene expression were upregulated in women with HPV infection, particularly the oncogenic HPV types.

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.

HPV co-infections with other pathogens in cancer development: A comprehensive review

High-risk human papillomaviruses (HR-HPVs) cause various malignancies in the anogenital and oropharyngeal regions. About 70% of cervical and oropharyngeal cancers are caused by HPV types 16 and 18. Notably, some viruses including herpes simplex virus, Epstein-Barr virus, and human immunodeficiency virus along with various bacteria often interact with HPV, potentially impacting its replication, persistence, and cancer progression. Thus, HPV infection can be significantly influenced by co-infecting agents that influence infection dynamics and disease progression. Bacterial co-infections (e.g., Chlamydia trachomatis) along with bacterial vaginosis-related species also interact with HPV in genital tract leading to viral persistence and disease outcomes. Co-infections involving HPV and diverse infectious agents have significant implications for disease transmission and clinical progression. This review explores multiple facets of HPV infection encompassing the co-infection dynamics with other pathogens, interaction with the human microbiome, and its role in disease development.

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.

Virus hijacking of host epigenetic machinery to impair immune response

Epigenetic modifications, such as DNA hypermethylation, histone acetylation/methylation, or nucleosome positioning, result in differential gene expression. These modifications can have an impact on various pathways, including host antiviral immune responses. In this review, we summarize the current understanding of epigenetic modifications induced by viruses to counteract host antiviral immune responses, which are crucial for establishing and maintaining infection of viruses. Finally, we provide insights into the potential use of epigenetic modulators in combating viral infections and virus-induced diseases.

Unraveling Immunological Dynamics: HPV Infection in Women-Insights from Pregnancy

During pregnancy, hormonal and immune adaptations are vital for supporting the genetically distinct fetus during elevated infection risks. The global prevalence of HPV necessitates its consideration during pregnancy. Despite a seemingly mild immune response, historical gestational viral infections underscore its significance. Acknowledging the established HPV infection risks during pregnancy, our review explores the unfolding immunological changes in pregnant women with HPV. Our analysis aims to uncover strategies for safely modulating the immune system, mitigating adverse pregnancy consequences, and enhancing maternal and child health. This comprehensive narrative review delves into the existing knowledge and studies on this topic.

Tumor Immune Microenvironment in Gynecologic Cancers

Gynecologic cancers have varying response rates to immunotherapy due to the heterogeneity of each cancer's molecular biology and features of the tumor immune microenvironment (TIME). This article reviews key features of the TIME and its role in the pathophysiology and treatment of ovarian, endometrial, cervical, vulvar, and vaginal cancer. Knowledge of the role of the TIME in gynecologic cancers has been rapidly developing with a large body of preclinical studies demonstrating an intricate yet dichotomous role that the immune system plays in either supporting the growth of cancer or opposing it and facilitating effective treatment. Many targets and therapeutics have been identified including cytokines, antibodies, small molecules, vaccines, adoptive cell therapy, and bacterial-based therapies but most efforts in gynecologic cancers to utilize them have not been effective. However, with the development of immune checkpoint inhibitors, we have started to see the rapid and successful employment of therapeutics in cervical and endometrial cancer. There remain many challenges in utilizing the TIME, particularly in ovarian cancer, and further studies are needed to identify and validate efficacious therapeutics.

Distinguishing Genetic Drift from Selection in Papillomavirus Evolution

Pervasive purifying selection on non-synonymous substitutions is a hallmark of papillomavirus genome history, but the role of selection on and the drift of non-coding DNA motifs on HPV diversification is poorly understood. In this study, more than a thousand complete genomes representing Alphapapillomavirus types, lineages, and SNP variants were examined phylogenetically and interrogated for the number and position of non-coding DNA sequence motifs using Principal Components Analyses, Ancestral State Reconstructions, and Phylogenetic Independent Contrasts. For anciently diverged Alphapapillomavirus types, composition of the four nucleotides (A, C, G, T), codon usage, trimer usage, and 13 established non-coding DNA sequence motifs revealed phylogenetic clusters consistent with genetic drift. Ancestral state reconstruction and Phylogenetic Independent Contrasts revealed ancient genome alterations, particularly for the CpG and APOBEC3 motifs. Each evolutionary analytical method we performed supports the unanticipated conclusion that genetic drift and different evolutionary drivers have structured Alphapapillomavirus genomes in distinct ways during successive epochs, even extending to differences in more recently formed variant lineages.

Histone demethylases in the regulation of immunity and inflammation

Pathogens or danger signals trigger the immune response. Moderate immune response activation removes pathogens and avoids excessive inflammation and tissue damage. Histone demethylases (KDMs) regulate gene expression and play essential roles in numerous physiological processes by removing methyl groups from lysine residues on target proteins. Abnormal expression of KDMs is closely associated with the pathogenesis of various inflammatory diseases such as liver fibrosis, lung injury, and autoimmune diseases. Despite becoming exciting targets for diagnosing and treating these diseases, the role of these enzymes in the regulation of immune and inflammatory response is still unclear. Here, we review the underlying mechanisms through which KDMs regulate immune-related pathways and inflammatory responses. In addition, we also discuss the future applications of KDMs inhibitors in immune and inflammatory diseases.

Carcinogenesis and management of human papillomavirus-associated cervical cancer

Approximately 95% of cervical cancer are caused by human papillomavirus (HPV) infection. Although it is estimated that HPV-associated cervical cancer will decrease with the widespread use of HPV vaccine, it may take time for HPV-associated cervical cancer to be eliminated. For the appropriate management of HPV-associated cervical cancer, it is important to understand the detailed mechanisms of cervical cancer development. First, the cellular origin of most cervical cancers is thought to be cells in the squamocolumnar junction (SCJ) of the uterine cervix. Therefore, it is important to understand the characteristics of SCJ for cervical cancer screening and treatment. Second, cervical cancer is caused by high risk HPV (HR-HPV) infection, however, the manner of progression to cervical cancer differs depending on the type of HR-HPV: HPV16 is characterized by a stepwise carcinogenesis, HPV18 is difficult to detect in precancerous lesions, and HPV52, 58 tends to remain in the state of cervical intraepithelial neoplasia (CIN). Third, in addition to the type of HPV, the involvement of the human immune response is also important in the progression and regression of cervical cancer. In this review, we demonstrate the carcinogenesis mechanism of HPV-associated cervical cancer, management of CIN, and the current treatment of CIN and cervical cancer.

Tumor microenvironment promotes lymphatic metastasis of cervical cancer: its mechanisms and clinical implications

Although previous studies have shed light on the etiology of cervical cancer, metastasis of advanced cervical cancer remains the main reason for the poor outcome and high cancer-related mortality rate. Cervical cancer cells closely communicate with immune cells recruited to the tumor microenvironment (TME), such as lymphocytes, tumor-associated macrophages, and myeloid-derived suppressor cells. The crosstalk between tumors and immune cells has been clearly shown to foster metastatic dissemination. Therefore, unraveling the mechanisms of tumor metastasis is crucial to develop more effective therapies. In this review, we interpret several characteristics of the TME that promote the lymphatic metastasis of cervical cancer, such as immune suppression and premetastatic niche formation. Furthermore, we summarize the complex interactions between tumor cells and immune cells within the TME, as well as potential therapeutic strategies to target the TME.

Association of TLR4 and TLR9 gene polymorphisms with cervical HR-HPV infection status in Chinese Han population

BACKGROUND

Toll-like receptors (TLRs) may be involved in the natural history of human papillomavirus (HPV) infection. In our study, we aimed to investigate the association of TLR4 (rs10116253, rs1927911, rs10759931) and TLR9 (rs187084, rs352140) gene polymorphisms with cervical persistent high-risk HPV (HR-HPV) infection, as well as multiple HR-HPV infections.

METHODS

A total of 269 study subjects were enrolled and grouped by retrospectively analyzing the HR-HPV testing results and other clinical data of 2647 gynecological outpatients from Jingzhou Hospital Affiliated to Yangtze University. We conducted a case-control study to compare the role of TLR4/TLR9 gene polymorphisms between HR-HPV transient and persistent infections, as well as between HR-HPV single and multiple infections. HR-HPV genotypes were detected using Real-time polymerase chain reaction (RT-PCR). PCR-restriction fragment length polymorphism (PCR-RFLP) was used to determine TLR4 and TLR9 gene polymorphisms. Analyses of the different outcome variables (HR-HPV infection status and time for HR-HPV clearance) with respect to TLR4/TLR9 polymorphisms were carried out. Logistic regression analysis was used to determine the association of TLR4/TLR9 genotypes and alleles with HR-HPV infection status. The Kaplan-Meier method with the log-rank test was used to analyze the relationship between TLR4/TLR9 genotypes and the time for HR-HPV clearance.

RESULTS

The mutant genotypes of TLR9 rs187084 and rs352140 were associated with persistent (rs187084: CT and CT+CC; rs352140: CT and CT+TT) and multiple (rs187084: CT and CT+CC; rs352140: CT+TT) (all P < 0.05) HR-HPV infection. However, no association was found between TLR4 polymorphisms and HR-HPV infection status. Kaplan-Meier time to HR-HPV clearance analysis demonstrated that women carrying rs187084 and rs352140 mutant genotypes take longer duration to clear HR-HPV infection compared with wild-type genotype carriers (P1 = 0.012; P2 = 0.031).

CONCLUSION

Our results suggested that TLR9 polymorphisms, but not TLR4, were associated with cervical persistent and multiple HR-HPV infections, which could be useful as a potential predictor of HR-HPV infection status.

"Open Sesame" to the complexity of pattern recognition receptors of myeloid-derived suppressor cells in cancer

Pattern recognition receptors are primitive sensors that arouse a preconfigured immune response to broad stimuli, including nonself pathogen-associated and autologous damage-associated molecular pattern molecules. These receptors are mainly expressed by innate myeloid cells, including granulocytes, monocytes, macrophages, and dendritic cells. Recent investigations have revealed new insights into these receptors as key players not only in triggering inflammation processes against pathogen invasion but also in mediating immune suppression in specific pathological states, including cancer. Myeloid-derived suppressor cells are preferentially expanded in many pathological conditions. This heterogeneous cell population includes immunosuppressive myeloid cells that are thought to be associated with poor prognosis and impaired response to immune therapies in various cancers. Identification of pattern recognition receptors and their ligands increases the understanding of immune-activating and immune-suppressive myeloid cell functions and sheds light on myeloid-derived suppressor cell differences from cognate granulocytes and monocytes in healthy conditions. This review summarizes the different expression, ligand recognition, signaling pathways, and cancer relations and identifies Toll-like receptors as potential new targets on myeloid-derived suppressor cells in cancer, which might help us to decipher the instruction codes for reverting suppressive myeloid cells toward an antitumor phenotype.

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 [...].

Synonymous nucleotide changes drive papillomavirus evolution

Papillomaviruses have been evolving alongside their hosts for at least 450 million years. This review will discuss some of the insights gained into the evolution of this diverse family of viruses. Papillomavirus evolution is constrained by pervasive purifying selection to maximize viral fitness. Yet these viruses need to adapt to changes in their environment, e.g., the host immune system. It has long been known that these viruses evolved a codon usage that doesn't match the infected host. Here we discuss how papillomavirus genomes evolve by acquiring synonymous changes that allow the virus to avoid detection by the host innate immune system without changing the encoded proteins and associated fitness loss. We discuss the implications of studying viral evolution, lifecycle, and cancer progression.

Human Papillomavirus-Associated Head and Neck Cancers. Where are We Now? A Systematic Review

BACKGROUND

Human papillomavirus targets the skin and mucous membranes, producing benign hyperplastic lesions and precancerous and cancerous lesions. An increasing number of head and neck cancersin particular, oropharyngeal squamous cell carcinoma, laryngeal squamous cell carcinoma, and oral squamous cell carcinoma, are attributable to HPV infection. HPV-induced HNCs typically affect younger, nonsmoking patients with no prior history of heavy alcohol use, more extensive sexual history, and higher socioeconomic status.

AIM

The purpose of the review is to present the most recent and well-established findings concerning HPV-induced head and neck cancers and consequently to provide medical specialists with essential information regarding the epidemiology, the role of HPV in HNC cancerogenesis, prevention, diagnosis, and treatment.

MATERIAL AND METHODS

All authors independently have searched The EMbase, Medline/Pubmed, and Cochrane databases by using the following keywords "head and neck cancer", "human papillomavirus", "HPV", "HPV biology", "oropharyngeal squamous cell carcinoma", "carcinogenesis", "transoral surgery", "robotic surgery". The last search was conducted in March 2022. The references of the publications of interest were also screened for relevant papers. There were no limitations in regard to the publication date.

CONCLUSION

Aiming to avoid the epidemic of HPV-induced HNC, it is paramount to improve the access to vaccination as well as resolve parental concerns regarding vaccine safety. Physicians should rely on reduced-dose radiation and aim to reduce the overall treatment time. Thanks to a more elaborate understanding of the genomic background of HPV-induced HNC, precision medicine could become a relevant part of patients' management. In comparison to traditional techniques and non-operative treatment, transoral robotic surgery (TORS) offers similar oncologic and functional outcomes, with a possible benefit on long-term quality of life. However, more research is needed to establish clear guidelines indicating when TORS resections should be supported with adjuvant therapy.

Alteration of the IFN-Pathway by Human Papillomavirus Proteins: Antiviral Immune Response Evasion Mechanism

A persistent infection with the so-called high-risk Human Papillomaviruses (hr-HPVs) plays a fundamental role in the development of different neoplasms. The expression of the HPV proteins throughout the different steps of the viral life cycle produce a disruption of several cellular processes, including immune response, which can lead to cell transformation. The interferon-mediated response plays an important role in eliminating HPV-infected and -transformed cells. The ability of HPV to disrupt the proper function of the interferon response is based on a series of molecular mechanisms coordinated by HPV proteins intended to prevent clearance of infection, ultimately producing an immunotolerant environment that facilitates the establishment of persistence and cancer. In this review, we focus on the molecular actions performed by HPV E1, E2, E5, E6 and E7 proteins on IFN signaling elements and their contribution to the establishment of infection, viral persistence and the progression to cancer.

The association of cervicovaginal Langerhans cells with clearance of human papillomavirus

Human papillomavirus (HPV) clearance is important in eliminating cervical cancer which contributes to high morbidity and mortality in women. Nevertheless, it remains largely unknown about key players in clearing pre-existing HPV infections. HPV antigens can be detected by the most important cervical antigen-presenting cells (Langerhans cells, LCs), of which the activities can be affected by cervicovaginal microbiota. In this review, we first introduce persistent HPV infections and then describe HPV-suppressed LCs activities, including but not limited to antigen uptake and presentation. Given specific transcriptional profiling of LCs in cervical epithelium, we also discuss the impact of cervicovaginal microbiota on LCs activation as well as the promise of exploring key microbial players in activating LCs and HPV-specific cellular immunity.

Human Virome in Cervix Controlled by the Domination of Human Papillomavirus

Although other co-viral infections could also be considered influencing factors, cervical human papillomavirus (HPV) infection is the main cause of cervical cancer. Metagenomics have been employed in the NGS era to study the microbial community in each habitat. Thus, in this investigation, virome capture sequencing was used to examine the virome composition in the HPV-infected cervix. Based on the amount of HPV present in each sample, the results revealed that the cervical virome of HPV-infected individuals could be split into two categories: HPV-dominated (HD; ≥60%) and non-HPV-dominated (NHD; <60%). Cervical samples contained traces of several human viral species, including the molluscum contagiosum virus (MCV), human herpesvirus 4 (HHV4), torque teno virus (TTV), and influenza A virus. When compared to the HD group, the NHD group had a higher abundance of several viruses. Human viral diversity appears to be influenced by HPV dominance. This is the first proof that the diversity of human viruses in the cervix is impacted by HPV abundance. However, more research is required to determine whether human viral variety and the emergence of cancer are related.

Regulation of the Innate Immune Response during the Human Papillomavirus Life Cycle

High-risk human papillomaviruses (HR HPVs) are associated with multiple human cancers and comprise 5% of the human cancer burden. Although most infections are transient, persistent infections are a major risk factor for cancer development. The life cycle of HPV is intimately linked to epithelial differentiation. HPVs establish infection at a low copy number in the proliferating basal keratinocytes of the stratified epithelium. In contrast, the productive phase of the viral life cycle is activated upon epithelial differentiation, resulting in viral genome amplification, high levels of late gene expression, and the assembly of virions that are shed from the epithelial surface. Avoiding activation of an innate immune response during the course of infection plays a key role in promoting viral persistence as well as completion of the viral life cycle in differentiating epithelial cells. This review highlights the recent advances in our understanding of how HPVs manipulate the host cell environment, often in a type-specific manner, to suppress activation of an innate immune response to establish conditions supportive of viral replication.

The Interaction of Human Papillomavirus Infection and Prostaglandin E2 Signaling in Carcinogenesis: A Focus on Cervical Cancer Therapeutics

Chronic infection by high-risk human papillomaviruses (HPV) and chronic inflammation are factors associated with the onset and progression of several neoplasias, including cervical cancer. Oncogenic proteins E5, E6, and E7 from HPV are the main drivers of cervical carcinogenesis. In the present article, we review the general mechanisms of HPV-driven cervical carcinogenesis, as well as the involvement of cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2) and downstream effectors in this pathology. We also review the evidence on the crosstalk between chronic HPV infection and PGE2 signaling, leading to immune response weakening and cervical cancer development. Finally, the last section updates the current therapeutic and preventive options targeting PGE2-derived inflammation and HPV infection in cervical cancer. These treatments include nonsteroidal anti-inflammatory drugs, prophylactic and therapeutical vaccines, immunomodulators, antivirals, and nanotechnology. Inflammatory signaling pathways are closely related to the carcinogenic nature of the virus, highlighting inflammation as a co-factor for HPV-dependent carcinogenesis. Therefore, blocking inflammatory signaling pathways, modulating immune response against HPV, and targeting the virus represent excellent options for anti-tumoral therapies in cervical cancer.

Human Papillomavirus 16 E6 and E7 Oncoproteins Alter the Abundance of Proteins Associated with DNA Damage Response, Immune Signaling and Epidermal Differentiation

The high-risk human papillomaviruses are oncogenic viruses associated with almost all cases of cervical carcinomas, and increasing numbers of anal, and oral cancers. Two oncogenic HPV proteins, E6 and E7, are capable of immortalizing keratinocytes and are required for HPV associated cell transformation. Currently, the influence of these oncoproteins on the global regulation of the host proteome is not well defined. Liquid chromatography coupled with quantitative tandem mass spectrometry using isobaric-tagged peptides was used to investigate the effects of the HPV16 oncoproteins E6 and E7 on protein levels in human neonatal keratinocytes (HEKn). Pathway and gene ontology enrichment analyses revealed that the cells expressing the HPV oncoproteins have elevated levels of proteins related to interferon response, inflammation and DNA damage response, while the proteins related to cell organization and epithelial development are downregulated. This study identifies dysregulated pathways and potential biomarkers associated with HPV oncoproteins in primary keratinocytes which may have therapeutic implications. Most notably, DNA damage response pathways, DNA replication, and interferon signaling pathways were affected in cells transduced with HPV16 E6 and E7 lentiviruses. Moreover, proteins associated with cell organization and differentiation were significantly downregulated in keratinocytes expressing HPV16 E6 + E7. High-risk HPV E6 and E7 oncoproteins are necessary for the HPV-associated transformation of keratinocytes. However their influence on the global dysregulation of keratinocyte proteome is not well documented. Here shotgun proteomics using TMT-labeling detected over 2500 significantly dysregulated proteins associated with E6 and E7 expression. Networks of proteins related to interferon response, inflammation and DNA damage repair pathways were altered.

Context-dependent functions of pattern recognition receptors in cancer

The immune system plays a critical role in shaping all facets of cancer, from the early initiation stage through to metastatic disease and resistance to therapy. Our understanding of the importance of the adaptive arm of the immune system in antitumour immunity has led to the implementation of immunotherapy with immune checkpoint inhibitors in numerous cancers, albeit with differing efficacy. By contrast, the clinical utility of innate immunity in cancer has not been exploited, despite dysregulated innate immunity being a feature of at least one-third of all cancers associated with tumour-promoting chronic inflammation. The past two decades have seen innate immune pattern recognition receptors (PRRs) emerge as critical regulators of the immune response to microbial infection and host tissue damage. More recently, it has become apparent that in many cancer types, PRRs play a central role in modulating a vast array of tumour-inhibiting and tumour-promoting cellular responses both in immune cells within the tumour microenvironment and directly in cancer cells. Herein, we provide a comprehensive overview of the fast-evolving field of PRRs in cancer, and discuss the potential to target PRRs for drug development and biomarker discovery in a wide range of oncology settings.

Human Beta Papillomavirus Type 8 E1 and E2 Proteins Suppress the Activation of the RIG-I-like Receptor MDA5

Persistent infections of the skin with the human papillomavirus of genus beta (β-HPV) in immunocompetent individuals are asymptomatic, but in immunosuppressed patients, β-HPV infections exhibit much higher viral loads on the skin and are associated with an increased risk of skin cancer. Unlike with HPV16, a high-risk α-HPV, the impact of β-HPV early genes on the innate immune sensing of viral nucleic acids has not been studied. Here, we used primary skin keratinocytes and U2OS cells expressing HPV8 or distinct HPV8 early genes and well-defined ligands of the nucleic-acid-sensing receptors RIG-I, MDA5, TLR3, and STING to analyze a potential functional interaction. We found that primary skin keratinocytes and U2OS cells expressed RIG-I, MDA5, TLR3, and STING, but not TLR7, TLR8, or TLR9. While HPV16-E6 downregulated the expression of RIG-I, MDA5, TLR3, and STING and, in conjunction with HPV16-E7, effectively suppressed type I IFN in response to MDA5 activation, the presence of HPV8 early genes showed little effect on the expression of these immune receptors, except for HPV8-E2, which was associated with an elevated expression of TLR3. Nevertheless, whole HPV8 genome expression, as well as the selective expression of HPV8-E1 or HPV8-E2, was found to suppress MDA5-induced type I IFN and the proinflammatory cytokine IL-6. Furthermore, RNA isolated from HPV8-E2 expressing primary human keratinocytes, but not control cells, stimulated a type I IFN response in peripheral blood mononuclear cells, indicating that the expression of HPV8-E2 in keratinocytes leads to the formation of stimulatory RNA ligands that require the active suppression of immune recognition. These results identify HPV8-E1 and HPV8-E2 as viral proteins that are responsible for the immune escape of β-HPV from the innate recognition of viral nucleic acids, a mechanism that may be necessary for establishing persistent β-HPV infections.

The Involvement of Human Papilloma Virus in Gastrointestinal Cancers

Human Papilloma Virus (HPV) is one of the most common sexually transmitted infections worldwide. HPV infection has a strong relationship with the onset of cervix uteri, vagina, penis, anus, and oropharynx, but also tonsils and tongue cancers. Some epidemiological data indicate that except for gynecologic cancers, HPV infection can be one of the risk factors associated with a greater risk of induction and progression of gastrointestinal cancers. Data, however, remain contradictory and definite conclusions cannot be drawn, so far. The following review aims to organize recent evidence and summarize the current state of knowledge regarding the association between HPV infection and gastrointestinal tumors primarily focusing on esophageal, liver, gastric, colorectal, and anal cancers.

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.