Human papillomavirus E7 enhances hypoxia-inducible factor 1-mediated transcription by inhibiting binding of histone deacetylases

LNMAC Promotes Cervical Squamous Cell Carcinoma Lymphatic Metastasis via Epigenetic Regulation of FGF2-Induced Lymphangiogenesis

The lymph node is the most common site of distant metastasis of cervical squamous cell carcinoma (CSCC), which elicits dismal prognosis and limited efficiency for treatment. Elucidation of the mechanisms underlying CSCC lymphatic metastasis would provide potential therapeutic strategies for nodal metastatic of CSCC. Here, based on in vivo lymphatic metastasis screening model, a circular RNA is identified that is termed as lymph node metastasis associated circRNA (LNMAC), is markedly upregulated in lymphatic metastatic CSCC and correlated with lymph node metastasis. Overexpression of LNMAC dramatically augments the metastatic capability of CSCC cells to the lymph node via inducing lymphangiogenesis. Mechanistically, LNMAC epigenetically upregulates fibroblast growth factor 2 (FGF2) expression by directly associating with histone acacetylase 1 (HDAC1), preventing Importin α6/8-mediated nuclear translocation of HDAC1 and eliciting histone H3K27ac-induced FGF2 transcriptional activation. Treatment with 3F12E7, an anti-FGF2 monoclonal antibody, effectively inhibits LNMAC-induced CSCC lymphatic metastasis. Taken together, these findings indicate that LNMAC plays a crucial role in FGF2-mediated lymphangiogenesis and lymphatic metastasis, highlighting that LNMAC might be a therapeutic target for lymph node metastasis in CSCC patients.

Digital Spatial Profiling identifies distinct patterns of immuno-oncology-related gene expression within oropharyngeal tumours in relation to HPV and p16 status

Background

The incidence of oropharyngeal cancer (OPC) is increasing, due mainly to a rise in Human Papilloma Virus (HPV)-mediated disease. HPV-mediated OPC has significantly better prognosis compared with HPV-negative OPC, stimulating interest in treatment de-intensification approaches to reduce long-term sequelae. Routine clinical testing frequently utilises immunohistochemistry to detect upregulation of p16 as a surrogate marker of HPV-mediation. However, this does not detect discordant p16-/HPV+ cases and incorrectly assigns p16+/HPV- cases, which, given their inferior prognosis compared to p16+/HPV+, may have important clinical implications. The biology underlying poorer prognosis of p16/HPV discordant OPC requires exploration.

Methods

GeoMx digital spatial profiling was used to compare the expression patterns of selected immuno-oncology-related genes/gene families (n=73) within the tumour and stromal compartments of formalin-fixed, paraffin-embedded OPC tumour tissues (n=12) representing the three subgroups, p16+/HPV+, p16+/HPV- and p16-/HPV-.

Results

Keratin (multi KRT) and HIF1A, a key regulator of hypoxia adaptation, were upregulated in both p16+/HPV- and p16-/HPV- tumours relative to p16+/HPV+. Several genes associated with tumour cell proliferation and survival (CCND1, AKT1 and CD44) were more highly expressed in p16-/HPV- tumours relative to p16+/HPV+. Conversely, multiple genes with potential roles in anti-tumour immune responses (immune cell recruitment/trafficking, antigen processing and presentation), such as CXCL9, CXCL10, ITGB2, PSMB10, CD74, HLA-DRB and B2M, were more highly expressed in the tumour and stromal compartments of p16+/HPV+ OPC versus p16-/HPV- and p16+/HPV-. CXCL9 was the only gene showing significant differential expression between p16+/HPV- and p16-/HPV- tumours being upregulated within the stromal compartment of the former.

Conclusions

In terms of immune-oncology-related gene expression, discordant p16+/HPV- OPCs are much more closely aligned with p16-/HPV-OPCs and quite distinct from p16+/HPV+ tumours. This is consistent with previously described prognostic patterns (p16+/HPV+ >> p16+/HPV- > p16-/HPV-) and underlines the need for dual p16 and HPV testing to guide clinical decision making.

Aspartate-β-hydroxylase and hypoxia marker expression in head and neck carcinomas: implications for HPV-associated tumors

BACKGROUND

A proportion of head and neck carcinomas (HNSCCs) are induced by high-risk human papillomaviruses (HPVs) and are associated with better patient outcomes compared to patients with HNSCCs related to tobacco and alcohol abuse. In the microenvironment of solid tumors, including HNSCCs, oxygen levels are often reduced, and a hypoxic state is induced. This can lead to a poor treatment response and a worse patient prognosis. One of the hypoxia-responsive genes is aspartate-β-hydroxylase (ASPH), whose activity promotes the growth, invasiveness, and metastasis of many types of solid tumors.

METHODS

In our study, HNSCC samples were analyzed for the expression of ASPH and selected endogenous hypoxia markers by real-time PCR and/or multiplex fluorescence immunohistochemistry.

RESULTS

Except for the EPAS1 gene, which had higher mRNA expression in the HPV-negative group of HNSCC (p < 0.05), we found no other differences in the expression of the tested genes that were related to HPV status. On the contrary, a statistically significantly higher number of cells producing ASPH (p < 0.0001), HIF1A (p < 0.0001), GLUT1 (p < 0.0001), and MMP13 (p < 0.05) proteins were detected in the HPV-positive tumor group than in the HPV-negative sample group. All the evaluated markers, except for MMP9/13, were more abundant in the tumor parenchyma than in the tumor stroma. The Cox proportional hazard models showed that increased numbers of cells with GLUT1 and HIF1A protein expression were positive prognostic markers for overall and disease-specific survival in patients independent of HPV tumor status.

CONCLUSION

The study examined HNSCC samples and found that elevated ASPH and hypoxia marker proteins, typically associated with poor prognosis, may actually indicate active HPV infection, the strongest prognostic factor in HNSCC patients. In cases where HPV status is uncertain, increased expression of HIF1A and GLUT1 can serve as positive prognostic factors.

Establishment of a prognostic model for hypoxia-associated genes in OPSCC and revelation of intercellular crosstalk

Hypoxia exerts a profound influence on the tumor microenvironment and immune response, shaping treatment outcomes and prognosis. Utilizing consistency clustering, we discerned two hypoxia subtypes in OPSCC bulk sequencing data from GEO. Key modules within OPSCC were identified through weighted gene correlation network analysis (WGCNA). Core modules underwent CIBERSORT immune infiltration analysis and GSEA functional enrichment. Univariate Cox and LASSO analyses were employed to construct prognostic models for seven hypoxia-related genes. Further investigation into clinical characteristics, the immune microenvironment, and TIDE algorithm prediction for immunotherapy response was conducted in high- and low-risk groups. scRNA-seq data were visually represented through TSNE clustering, employing the scissors algorithm to map hypoxia phenotypes. Interactions among cellular subpopulations were explored using the Cellchat package, with additional assessments of metabolic and transcriptional activities. Integration with clinical data unveiled a prevalence of HPV-positive patients in the low hypoxia and low-risk groups. Immunohistochemical validation demonstrated low TDO2 expression in HPV-positive (P16-positive) patients. Our prediction suggested that HPV16 E7 promotes HIF-1α inhibition, leading to reduced glycolytic activity, ultimately contributing to better prognosis and treatment sensitivity. The scissors algorithm effectively segregated epithelial cells and fibroblasts into distinct clusters based on hypoxia characteristics. Cellular communication analysis illuminated significant crosstalk among hypoxia-associated epithelial, fibroblast, and endothelial cells, potentially fostering tumor proliferation and metastasis.

Molecular aspects of cervical cancer: a pathogenesis update

Cervical cancer (CC) is a significant health problem, especially in low-income countries. Functional studies on the human papillomavirus have generated essential advances in the knowledge of CC. However, many unanswered questions remain. This mini-review discusses the latest results on CC pathogenesis, HPV oncogenesis, and molecular changes identified through next-generation technologies. Interestingly, the percentage of samples with HPV genome integrations correlates with the degree of the cervical lesions, suggesting a role in the development of CC. Also, new functions have been described for the viral oncoproteins E5, E6, and E7, resulting in the acquisition and maintenance of cancer hallmarks, including proliferation, immune response evasion, apoptosis, and genomic instability. Remarkably, E5 oncoprotein affects signaling pathways involved in the expression of interferon-induced genes and EGFR-induced proliferation, while E6 and E7 oncoproteins regulate the DNA damage repair and cell cycle continuity pathways. Furthermore, next-generation technologies provide vast amounts of information, increasing our knowledge of changes in the genome, transcriptome, proteome, metabolome, and epigenome in CC. These studies have identified novel molecular traits associated with disease susceptibility, degree of progression, treatment response, and survival as potential biomarkers and therapeutic targets.

Structural analysis of PTPN21 reveals a dominant-negative effect of the FERM domain on its phosphatase activity

PTPN21 belongs to the four-point-one, ezrin, radixin, moesin (FERM) domain-containing protein tyrosine phosphatases (PTP) and plays important roles in cytoskeleton-associated cellular processes like cell adhesion, motility, and cargo transport. Because of the presence of a WPE loop instead of a WPD loop in the phosphatase domain, it is often considered to lack phosphatase activity. However, many of PTPN21's biological functions require its catalytic activity. To reconcile these findings, we have determined the structures of individual PTPN21 FERM, PTP domains, and a complex between FERM-PTP. Combined with biochemical analysis, we have found that PTPN21 PTP is weakly active and is autoinhibited by association with its FERM domain. Disruption of FERM-PTP interaction results in enhanced ERK activation. The oncogenic HPV18 E7 protein binds to PTP at the same location as PTPN21 FERM, indicating that it may act by displacing the FERM domain from PTP. Our results provide mechanistic insight into PTPN21 and benefit functional studies of PTPN21-mediated processes.

Hepatitis B Virus-Encoded MicroRNA (HBV-miR-3) Inhibits FIH-1 Expression to Promote Tumor Angiogenesis in HBV-Related Hepatocellular Carcinoma

Introduction

Hepatocellular carcinoma (HCC) is a solid tumor with a rich blood supply, and anti-angiogenesis has important clinical significance. Hepatitis B Virus-Encoded MicroRNA 3 (HBV-miR-3) has recently been reported to be involved in HCC development. In this study, we aim to elucidate the role of HBV-miR-3 in promoting HBV-related HCC angiogenesis through Factor Inhibiting Hypoxia-inducible factor 1 (FIH-1).

Results

By analyzing HBV-related HCC tissue samples, we found that high expression of HBV-miR-3 was associated with poor overall survival and HBV-miR-3 expression was significantly correlated with VEGFR2 and FIH-1 expressions. In vitro, HBV-miR-3 agomir repressed FIH-1 expression and promoted HIF-1α/VEGFA signaling activation in HepG2 cells, resulting in increased HUVEC lumen formation in HepG2-HUVEC co-culture model. Conversely, HBV-miR-3 antagomir induced FIH-1 expression and inhibited HIF-1α/VEGFA signaling activation in HepG2.2.15 cells, resulting in decreased HUVEC lumen formation in HepG2.2.15-HUVEC co-culture model. The effect of HBV-miR-3 to HCC angiogenesis was also confirmed by a mouse tumor bearing model. We also confirmed that HBV-miR-3 repressed FIH-1 expression via targeting the 3'-UTR of FIH-1 mRNA by luciferase activity assay.

Conclusion

HBV-miR-3 was related to HCC patients' overall survival and it promoted angiogenesis by repressing FIH-1 expression. HBV-miR-3 may be a new marker for predicting prognosis and a novel target for anti-angiogenic treatment of HBV-related HCC.

Acetylation and Phosphorylation in the Regulation of Hypoxia-Inducible Factor Activities: Additional Options to Modulate Adaptations to Changes in Oxygen Levels

O2 is essential for the life of eukaryotic cells. The ability to sense oxygen availability and initiate a response to adapt the cell to changes in O2 levels is a fundamental achievement of evolution. The key switch for adaptation consists of the transcription factors HIF1A, HIF2A and HIF3A. Their levels are tightly controlled by O2 through the involvement of the oxygen-dependent prolyl hydroxylase domain-containing enzymes (PHDs/EGNLs), the von Hippel-Lindau tumour suppressor protein (pVHL) and the ubiquitin-proteasome system. Furthermore, HIF1A and HIF2A are also under the control of additional post-translational modifications (PTMs) that positively or negatively regulate the activities of these transcription factors. This review focuses mainly on two PTMs of HIF1A and HIF2A: phosphorylation and acetylation.

Countenance and implication of Β-sitosterol, Β-amyrin and epiafzelechin in nickel exposed Rat: in-silico and in-vivo approach

The detrimental impact of reactive oxygen species on D.N.A. repair processes is one of the contributing factors to colon cancer. The idea that oxidative stress may be a significant etiological element for carcinogenesis is currently receiving more and more support. The goal of the current study is to evaluate the anti-inflammatory and anticancer activity of three powerful phytocompounds-sitosterol, amyrin, and epiafzelechin-alone and in various therapeutic combinations against colon cancer to identify the critical mechanisms that mitigate nickel's carcinogenic effect. To evaluate the ligand-protein interaction of four selected components against Vascular endothelial growth factor (VEGF), Matrix metalloproteinase-9 (MMP9) inhibitor and Interleukin-10 (IL-10) molecular docking approach was applied using PyRx bioinformatics tool. For in vivo analysis, hundred albino rats were included, divided into ten groups, each containing ten rats of weight 160-200 g. All the groups were injected with 1 ml/kg nickel intraperitoneally per week for three months, excluding the negative control group. Three of the ten groups were treated with β-sitosterol (100 mg/kg b wt), β-amyrin (100 mg/kg b wt), and epiafzelechin (200 mg/kg b wt), respectively, for one month. The later four groups were fed with combinatorial treatments of the three phyto compounds for one month. The last group was administered with commercial drug Nalgin (500 mg/kg b wt). The biochemical parameters Creatinine, Protein carbonyl, 8-hydroxydeoxyguanosine (8-OHdG), VEGF, MMP-9 Inhibitor, and IL-10 were estimated using ELISA kits and Glutathione (G.S.H.), Superoxide dismutase (S.O.D.), Catalase (C.A.T.) and Nitric Oxide (NO) were analyzed manually. The correlation was analyzed through Pearson's correlation matrix. All the parameters were significantly raised in the positive control group, indicating significant inflammation. At the same time, the levels of the foresaid biomarkers were decreased in the serum in all the other groups treated with the three phytocompounds in different dose patterns. However, the best recovery was observed in the group where the three active compounds were administered concomitantly. The correlation matrix indicated a significant positive correlation of IL-10 vs VEGF (r = 0.749**, p = 0.009), MMP-9 inhibitor vs SOD (r = 0.748**, p = 0.0 21). The study concluded that the three phytocompounds β-sitosterol, β-amyrin, and epiafzelechin are important anticancer agents which can target the cancerous biomarkers and might be used as a better therapeutic approach against colon cancer soon.

New insights for gynecological cancer therapies: from molecular mechanisms and clinical evidence to future directions

Advanced and recurrent gynecological cancers lack effective treatment and have poor prognosis. Besides, there is urgent need for conservative treatment for fertility protection of young patients. Therefore, continued efforts are needed to further define underlying therapeutic targets and explore novel targeted strategies. Considerable advancements have been made with new insights into molecular mechanisms on cancer progression and breakthroughs in novel treatment strategies. Herein, we review the research that holds unique novelty and potential translational power to alter the current landscape of gynecological cancers and improve effective treatments. We outline the advent of promising therapies with their targeted biomolecules, including hormone receptor-targeted agents, inhibitors targeting epigenetic regulators, antiangiogenic agents, inhibitors of abnormal signaling pathways, poly (ADP-ribose) polymerase (PARP) inhibitors, agents targeting immune-suppressive regulators, and repurposed existing drugs. We particularly highlight clinical evidence and trace the ongoing clinical trials to investigate the translational value. Taken together, we conduct a thorough review on emerging agents for gynecological cancer treatment and further discuss their potential challenges and future opportunities.

E7 Oncogene HPV58 Variants Detected in Northeast Brazil: Genetic and Functional Analysis

Cervical cancer is associated with persistent infections by high-risk Human Papillomavirus (HPV) types that may have nucleotide polymorphisms and, consequently, different oncogenic potentials. Therefore, this study aimed to evaluate the genetic variability and structural effects of the E7 oncogene of HPV58 in cervical scraping samples from Brazilian women. The study was developed with patients from hospitals in the metropolitan area of Recife, PE, Brazil. The most frequent HPV types were, in descending order of abundance, HPV16, 31, and 58. Phylogenetic analysis demonstrated that the isolates were classified into sublineages A2, C1, and D2. Two positively selected mutations were found in E7: 63G and 64T. The mutations G41R, G63D, and T64A in the E7 protein reduced the stability of the protein structure. Utilizing an NF-kB reporter assay, we observed a decrease in the NK-kB pathway activity with the HPV58-E7 variant 54S compared to the WT E7. The other detected E7 HPV58 variants presented similar NF-kB pathway activity compared to the WT E7. In this study, it was possible to identify mutations that may interfere with the molecular interaction between the viral oncoproteins and host proteins.

Cellular metabolism hijacked by viruses for immunoevasion: potential antiviral targets

Cellular metabolism plays a central role in the regulation of both innate and adaptive immunity. Immune cells utilize metabolic pathways to modulate the cellular differentiation or death. The intricate interplay between metabolism and immune response is critical for maintaining homeostasis and effective antiviral activities. In recent years, immunometabolism induced by viral infections has been extensively investigated, and accumulating evidence has indicated that cellular metabolism can be hijacked to facilitate viral replication. Generally, virus-induced changes in cellular metabolism lead to the reprogramming of metabolites and metabolic enzymes in different pathways (glucose, lipid, and amino acid metabolism). Metabolic reprogramming affects the function of immune cells, regulates the expression of immune molecules and determines cell fate. Therefore, it is important to explore the effector molecules with immunomodulatory properties, including metabolites, metabolic enzymes, and other immunometabolism-related molecules as the antivirals. This review summarizes the relevant advances in the field of metabolic reprogramming induced by viral infections, providing novel insights for the development of antivirals.

Combat Against Gynecological Cancers with Blood Vessels as Entry Point: Anti-Angiogenic Drugs, Clinical Trials and Pre-Clinical Nano-Delivery Platforms

Angiogenesis is an essential mechanism for the progression of gynecological cancers. Although approved anti-angiogenic drugs have demonstrated clinical efficacy in treating gynecological cancers, the full potential of therapeutic strategies based on tumor blood vessels has not yet been realized. This review summarizes the latest angiogenesis mechanisms involved in the progression of gynecological cancers and discusses the current clinical practice of approved anti-angiogenic drugs and related clinical trials. Given the close relationship between gynecological cancers and blood vessels, we highlight more delicate strategies for regulating tumor vessels, including wise drug combinations and smart nano-delivery platforms to achieve highly efficient drug delivery and overall vessel microenvironment regulation. We also address current challenges and future opportunities in this field. We aim to generate interest in therapeutic strategies that target blood vessels as a key entry point and offer new potential and inspiration for combating gynecological cancers.

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.

HDAC4 in cancer: A multitasking platform to drive not only epigenetic modifications

Controlling access to genomic information and maintaining its stability are key aspects of cell life. Histone acetylation is a reversible epigenetic modification that allows access to DNA and the assembly of protein complexes that regulate mainly transcription but also other activities. Enzymes known as histone deacetylases (HDACs) are involved in the removal of the acetyl-group or in some cases of small hydrophobic moieties from histones but also from the non-histone substrate. The main achievement of HDACs on histones is to repress transcription and promote the formation of more compact chromatin. There are 18 different HDACs encoded in the human genome. Here we will discuss HDAC4, a member of the class IIa family, and its possible contribution to cancer development.

Interplay between cellular metabolism and DNA viruses

Viruses as intracellular pathogens take over the host metabolism and reprogram to facilitate optimal virus production. DNA viruses can cause alterations in several metabolic pathways, including aerobic glycolysis also known as the Warburg effect, pentose phosphate pathway activation, and amino acid catabolism such as glutaminolysis, nucleotide biosynthesis, lipid metabolism, and amino acid biosynthesis. The available energy for productive infection can be increased in infected cells via modification of different carbon source utilization. This review discusses the metabolic alterations of the DNA viruses that will be the basis for future novel therapeutic approaches.

Monoclonal antibodies in cervical malignancy-related HPV

Despite many efforts to treat HPV infection, cervical cancer survival is still poor for several reasons, including resistance to chemotherapy and relapse. Numerous treatments such as surgery, radiation therapy, immune cell-based therapies, siRNA combined with various drugs, and immunotherapy are being studied and performed to provide the best treatment. Depending on the stage and size of the tumor, methods such as radical hysterectomy, pelvic lymphadenectomy, or chemotherapy can be utilized to treat cervical cancer. While accepted, these treatments lead to interruptions in cellular pathways and immune system homeostasis. In addition to a low survival rate, cervical neoplasm incidence has been rising significantly. However, new strategies have been proposed to increase patient survival while reducing the toxicity of chemotherapy, including targeted therapy and monoclonal antibodies. In this article, we discuss the types and potential therapeutic roles of monoclonal antibodies in cervical cancer.

HPV16 E7 Nucleotide Variants Found in Cancer-Free Subjects Affect E7 Protein Expression and Transformation

The human papillomavirus (HPV) type 16 E7 oncogene is critical to carcinogenesis and highly conserved. Previous studies identified a preponderance of non-synonymous E7 variants amongst HPV16-positive cancer-free controls compared to those with cervical cancer. To investigate the function of E7 variants, we constructed full-length HPV16 E7 genes and tested variants at positions H9R, D21N, N29S, E33K, T56I, D62N, S63F, S63P, T64M, E80K, D81N, P92L, and P92S (found only in controls); D14E, N29H cervical intraepithelial neoplasia (CIN2), and P6L, H51N, R77S (CIN3). We determined the steady-state level of cytoplasmic and nuclear HPV16 E7 protein. All variants from controls showed a reduced level of E7 protein, with 7/13 variants having lower protein levels. In contrast, 2/3 variants from the CIN3 precancer group had near-wild type E7 levels. We assayed the activity of representative variants in stably transfected NIH3T3 cells. The H9R, E33K, P92L, and P92S variants found in control subjects had lower transforming activity than D14E and N29H variants (CIN2), and the R77S (CIN3) had activity only slightly reduced from wild-type E7. In addition, R77S and WT E7 caused increased migration of NIH3T3 cells in a wound-healing assay compared with H9R, E33K, P92L, and P92S (controls) and D14E (CIN2). These data provide evidence that the E7 variants found in HPV16-positive cancer-free women are partially defective for transformation and cell migration, further demonstrating the importance of fully active E7 in cancer development.

Two cases showing the effects of bevacizumab on recurrent cervical cancer with pleural effusion

The survival rate and quality of life of patients with recurrent cervical cancer and pleural effusion had been extremely poor until bevacizumab was approved. We report two cases of recurrent cervical cancer with remarkably decreased pleural effusion and a long survival rate after combination chemotherapy with bevacizumab. Case 1: A patient was diagnosed with stage IIB cervical adenocarcinoma and treated with concurrent chemoradiotherapy (CCRT), total hysterectomy, and paclitaxel/carboplatin (TC) therapy as the primary treatment. After the first recurrence had been treated with irinotecan-cisplatin therapy and radiotherapy, symptomatic pleural effusion emerged. Paclitaxel-cisplatin-bevacizumab (Pac-Cis-Bev) was administered during 13 cycles of chemotherapy to promptly relieve pleural effusion, respiratory distress, and back pain. She survived for more than a year and a half after starting Pac-Cis-Bev therapy. Case 2: A patient was diagnosed with stage IIIB cervical squamous cell carcinoma and pulmonary recurrence after CCRT. After 21 cycles of TC or Pac-Cis-Bev therapy, pleural effusion emerged. Topotecan-paclitaxel-bevacizumab (Topo-Pac-Bev) was administered for 12 cycles. Respiratory distress was relieved in 2 weeks and pleural effusion almost completely resolved after 2 months. We changed the treatment to ifosfamide and nedaplatin as pleural effusion exacerbated. However, this treatment was not effective; hence the patient was rechallenged with Topo-Pac-Bev therapy. Six cycles of Topo-Pac-Bev rechallenge therapy effectively suppressed pleural effusion. She survived for 2 years after pleural effusion appeared. Chemotherapy with bevacizumab is useful for both symptom relief and improvement in prognosis in patients with recurrent cervical cancer, despite being in the late phase.

Like Brothers in Arms: How Hormonal Stimuli and Changes in the Metabolism Signaling Cooperate, Leading HPV Infection to Drive the Onset of Cervical Cancer

Despite all precautionary actions and the possibility of using vaccinations to counteract infections caused by human papillomaviruses (HPVs), HPV-related cancers still account for approximately 5% of all carcinomas. Worldwide, many women are still excluded from adequate health care due to their social position and origin. Therefore, immense efforts in research and therapy are still required to counteract the challenges that this disease entails. The special thing about an HPV infection is that it is not only able to trick the immune system in a sophisticated way, but also, through genetic integration into the host genome, to use all the resources available to the host cells to complete the replication cycle of the virus without activating the alarm mechanisms of immune recognition and elimination. The mechanisms utilized by the virus are the metabolic, immune, and hormonal signaling pathways that it manipulates. Since the virus is dependent on replication enzymes of the host cells, it also intervenes in the cell cycle of the differentiating keratinocytes and shifts their terminal differentiation to the uppermost layers of the squamocolumnar transformation zone (TZ) of the cervix. The individual signaling pathways are closely related and equally important not only for the successful replication of the virus but also for the onset of cervical cancer. We will therefore analyze the effects of HPV infection on metabolic signaling, as well as changes in hormonal and immune signaling in the tumor and its microenvironment to understand how each level of signaling interacts to promote tumorigenesis of cervical cancer.

The Metabolic Relationship Between Viral Infection and Cancer

Viruses are fundamental tools in cancer research. They were used to discover the first oncogenes in the 1970s, and they are now being modified for use as antitumor therapeutics. Key to both of these oncogenic and oncolytic properties is the ability of viruses to rewire host cell metabolism. In this review, we describe how viral oncogenes alter metabolism to increase the synthesis of macromolecules necessary for both viral replication and tumor growth. We then describe how understanding the specific metabolic requirements of virus-infected cells can help guide strategies to improve the efficacy of oncolytic viruses, and we highlight immunometabolism and tumor microenvironment research that could also increase the therapeutic benefits of oncolytic viruses. We also describe how studies describing the therapeutic effects of dietary nutrient restriction in cancer can suggest new avenues for research into antiviral therapeutics.

High Risk-Human Papillomavirus in HNSCC: Present and Future Challenges for Epigenetic Therapies

Head and Neck Squamous Cell Carcinoma (HNSCC) is a highly heterogeneous group of tumors characterized by an incidence of 650,000 new cases and 350,000 deaths per year worldwide and a male to female ratio of 3:1. The main risk factors are alcohol and tobacco consumption and Human Papillomavirus (HPV) infections. HNSCC cases are divided into two subgroups, the HPV-negative (HPV−) and the HPV-positive (HPV+) which have different clinicopathological and molecular profiles. However, patients are still treated with the same therapeutic regimens. It is thus of utmost importance to characterize the molecular mechanisms underlying these differences to find new biomarkers and novel therapeutic targets towards personalized therapies. Epigenetic alterations are a hallmark of cancer and can be exploited as both promising biomarkers and potential new targets. E6 and E7 HPV oncoviral proteins besides targeting p53 and pRb, impair the expression and the activity of several epigenetic regulators. While alterations in DNA methylation patterns have been well described in HPV+ and HPV− HNSCC, accurate histone post-translational modifications (hPTMs) characterization is still missing. Herein, we aim to provide an updated overview on the impact of HPV on the hPTMs landscape in HNSCC. Moreover, we will also discuss the sex and gender bias in HNSCC and how the epigenetic machinery could be involved in this process, and the importance of taking into account sex and/or gender also in this field.

Angiogenesis: A Pivotal Therapeutic Target in the Drug Development of Gynecologic Cancers

Since the discovery of angiogenesis and its relevance to the tumorigenesis of gynecologic malignancies, a number of therapeutic agents have been developed over the last decade, some of which have become standard treatments in combination with other therapies. Limited clinical activity has been demonstrated with anti-angiogenic monotherapies, and ongoing trials are focused on combination strategies with cytotoxic agents, immunotherapies and other targeted treatments. This article reviews the science behind angiogenesis within the context of gynecologic cancers, the evidence supporting the targeting of these pathways and future directions in clinical trials.

Pathogen-Induced Epigenetic Modifications in Cancers: Implications for Prevention, Detection and Treatment of Cancers in Africa

Cancer is a major public health burden worldwide. Tumor formation is caused by multiple intrinsic and extrinsic factors. Many reports have demonstrated a positive correlation between the burden of infectious pathogens and the occurrence of cancers. However, the mechanistic link between pathogens and cancer development remains largely unclear and is subject to active investigations. Apart from somatic mutations that have been widely linked with various cancers, an appreciable body of knowledge points to alterations of host epigenetic patterns as key triggers for cancer development. Several studies have associated various infectious pathogens with epigenetic modifications. It is therefore plausible to assume that pathogens induce carcinogenesis via alteration of normal host epigenetic patterns. Thus, Africa with its disproportionate burden of infectious pathogens is threatened by a dramatic increase in pathogen-mediated cancers. To curb the potential upsurge of such cancers, a better understanding of the role of tropical pathogens in cancer epigenetics could substantially provide resources to improve cancer management among Africans. Therefore, this review discusses cancer epigenetic studies in Africa and the link between tropical pathogens and cancer burden. In addition, we discuss the potential mechanisms by which pathogens induce cancers and the opportunities and challenges of tropical pathogen-induced epigenetic changes for cancer prevention, detection and management.

Hypoxia and Its Influence on Radiotherapy Response of HPV-Positive and HPV-Negative Head and Neck Cancer

Head and neck squamous cancers are a heterogeneous group of cancers that arise from the upper aerodigestive tract. Etiologically, these tumors are linked to alcohol/tobacco abuse and infections with high-risk human papillomavirus (HPV). HPV-positive HNSCCs are characterized by a different biology and also demonstrate better therapy response and survival compared to alcohol/tobacco-related HNSCCs. Despite this advantageous therapy response and the clear biological differences, all locally advanced HNSCCs are treated with the same chemo-radiotherapy schedules. Although we have a better understanding of the biology of both groups of HNSCC, the biological factors associated with the increased radiotherapy response are still unclear. Hypoxia, i.e., low oxygen levels because of an imbalance between oxygen demand and supply, is an important biological factor associated with radiotherapy response and has been linked with HPV infections. In this review, we discuss the effects of hypoxia on radiotherapy response, on the tumor biology, and the tumor microenvironment of HPV-positive and HPV-negative HNSCCs by pointing out the differences between these two tumor types. In addition, we provide an overview of the current strategies to detect and target hypoxia.

The Not-So-Good, the Bad and the Ugly: HPV E5, E6 and E7 Oncoproteins in the Orchestration of Carcinogenesis

Infection with HPV starts with the access of the viral particles to basal cells in the epidermis, potentially via microtraumas to the skin. The basal cells are able to keep away these pathogens in normal circumstances through a robust immune response from the host, as HPV infections are, in general, cleared within 2 to 3 weeks. However, the rare instances of persistent infection and/or in cases where the host immune system is compromised are major risk factors for the development of lesions potentially leading to malignancy. Evolutionarily, obligatory pathogens such as HPVs would not be expected to risk exposing the host to lethal cancer, as this would entail challenging their own life cycle, but infection with these viruses is highly correlated with cancer and malignancy-as in cancer of the cervix, which is almost always associated with these viruses. Despite this key associative cause and the availability of very effective vaccines against these viruses, therapeutic interventions against HPV-induced cancers are still a challenge, indicating the need for focused translational research. In this review, we will consider the key roles that the viral proteins play in driving the host cells to carcinogenesis, mainly focusing on events orchestrated by early proteins E5, E6 and E7-the not-so-good, the bad and the ugly-and discuss and summarize the major events that lead to these viruses mechanistically corrupting cellular homeostasis, giving rise to cancer and malignancy.

Human Papillomaviruses Target the DNA Damage Repair and Innate Immune Response Pathways to Allow for Persistent Infection

Persistent infection with high-risk human papillomaviruses (HPVs) is the major risk factor associated with development of anogenital and oropharyngeal cancers. Initial infection by HPVs occurs into basal epithelial cells where viral genomes are established as nuclear episomes and persist until cleared by the immune response. Productive replication or amplification occurs upon differentiation and is dependent upon activation of the ataxia-telangiectasia mutated (ATM), ataxia telangiectasia and RAD3-related (ATR) DNA damage repair (DDR) pathways. In addition to activating DDR pathways, HPVs must escape innate immune surveillance mechanisms by antagonizing sensors, adaptors, interferons and antiviral gene expression. Both DDR and innate immune pathways are key host mechanisms that crosstalk with each other to maintain homeostasis of cells persistently infected with HPVs. Interestingly, it is still not fully understood why some HPV infections get cleared while others do not. Targeting of these two processes with antiviral therapies may provide opportunities for treatment of cancers caused by high-risk HPVs.

Viral Manipulation of the Host Epigenome as a Driver of Virus-Induced Oncogenesis

Tumorigenesis due to viral infection accounts for a high fraction of the total global cancer burden (15–20%) of all human cancers. A comprehensive understanding of the mechanisms by which viral infection leads to tumor development is extremely important. One of the main mechanisms by which viruses induce host cell proliferation programs is through controlling the host’s epigenetic machinery. In this review, we dissect the epigenetic pathways through which oncogenic viruses can integrate their genome into host cell chromosomes and lead to tumor progression. In addition, we highlight the potential use of drugs based on histone modifiers in reducing the global impact of cancer development due to viral infection.

HPV and Other Microbiota; Who's Good and Who's Bad: Effects of the Microbial Environment on the Development of Cervical Cancer-A Non-Systematic Review

Cervical cancer is responsible for around 5% of all human cancers worldwide. It develops almost exclusively from an unsolved, persistent infection of the squamocolumnar transformation zone between the endo- and ecto-cervix with various high-risk (HR) human papillomaviruses (HPVs). The decisive turning point on the way to persistent HPV infection and malignant transformation is an immune system weakened by pathobionts and oxidative stress and an injury to the cervical mucosa, often caused by sexual activities. Through these injury and healing processes, HPV viruses, hijacking activated keratinocytes, move into the basal layers of the cervical epithelium and then continue their development towards the distal prickle cell layer (Stratum spinosum). The microbial microenvironment of the cervical tissue determines the tissue homeostasis and the integrity of the protective mucous layer through the maintenance of a healthy immune and metabolic signalling. Pathological microorganisms and the resulting dysbiosis disturb this signalling. Thus, pathological inflammatory reactions occur, which manifest the HPV infection. About 90% of all women contract an HPV infection in the course of their lives. In about 10% of cases, the virus persists and cervical intra-epithelial neoplasia (CIN) develops. Approximately 1% of women with a high-risk HPV infection incur a cervical carcinoma after 10 to 20 years. In this non-systematic review article, we summarise how the sexually and microbial mediated pathogenesis of the cervix proceeds through aberrant immune and metabolism signalling via CIN to cervical carcinoma. We show how both the virus and the cancer benefit from the same changes in the immune and metabolic environment.

The human papillomavirus oncoproteins: a review of the host pathways targeted on the road to transformation

Persistent infection with high-risk human papillomaviruses (HR-HPVs) is the causal factor in over 99 % of cervical cancer cases, and a significant proportion of oropharyngeal and anogenital cancers. The key drivers of HPV-mediated transformation are the oncoproteins E5, E6 and E7. Together, they act to prolong cell-cycle progression, delay differentiation and inhibit apoptosis in the host keratinocyte cell in order to generate an environment permissive for viral replication. The oncoproteins also have key roles in mediating evasion of the host immune response, enabling infection to persist. Moreover, prolonged infection within the cellular environment established by the HR-HPV oncoproteins can lead to the acquisition of host genetic mutations, eventually culminating in transformation to malignancy. In this review, we outline the many ways in which the HR-HPV oncoproteins manipulate the host cellular environment, focusing on how these activities can contribute to carcinogenesis.

Histone Modifying Enzymes in Gynaecological Cancers

Simple Summary

Epigenetics is a process that allows genetic control, without the involvement of sequence changes to DNA or genes. In cancer, epigenetics is a key event in tumour development that can alter the expression of cancer driver genes and result in genomic instability. Due to the critical role of epigenetics in malignant transformation, therapies that target these processes have been developed to treat cancer. Here, we provide a summary of the epigenetic changes that have been described in a variety of gynaecological cancers. We then highlight how these changes are being targeted in preclinical models and clinical trials for gynaecological cancers.

Abstract

Genetic and epigenetic factors contribute to the development of cancer. Epigenetic dysregulation is common in gynaecological cancers and includes altered methylation at CpG islands in gene promoter regions, global demethylation that leads to genome instability and histone modifications. Histones are a major determinant of chromosomal conformation and stability, and unlike DNA methylation, which is generally associated with gene silencing, are amenable to post-translational modifications that induce facultative chromatin regions, or condensed transcriptionally silent regions that decondense resulting in global alteration of gene expression. In comparison, other components, crucial to the manipulation of chromatin dynamics, such as histone modifying enzymes, are not as well-studied. Inhibitors targeting DNA modifying enzymes, particularly histone modifying enzymes represent a potential cancer treatment. Due to the ability of epigenetic therapies to target multiple pathways simultaneously, tumours with complex mutational landscapes affected by multiple driver mutations may be most amenable to this type of inhibitor. Interrogation of the actionable landscape of different gynaecological cancer types has revealed that some patients have biomarkers which indicate potential sensitivity to epigenetic inhibitors. In this review we describe the role of epigenetics in gynaecological cancers and highlight how it may exploited for treatment.

Molecular Analysis of the Interaction between Human PTPN21 and the Oncoprotein E7 from Human Papillomavirus Genotype 18

Human papillomaviruses (HPVs) cause cellular hyperproliferation-associated abnormalities including cervical cancer. The HPV genome encodes two major viral oncoproteins, E6 and E7, which recruit various host proteins by direct interaction for proteasomal degradation. Recently, we reported the structure of HPV18 E7 conserved region 3 (CR3) bound to the protein tyrosine phosphatase (PTP) domain of PTPN14, a well-defined tumor suppressor, and found that this intermolecular interaction plays a key role in E7-driven transformation and tumorigenesis. In this study, we carried out a molecular analysis of the interaction between CR3 of HPV18 E7 and the PTP domain of PTPN21, a PTP protein that shares high sequence homology with PTPN14 but is putatively oncogenic rather than tumor-suppressive. Through the combined use of biochemical tools, we verified that HPV18 E7 and PTPN21 form a 2:2 complex, with a dissociation constant of 5 nM and a nearly identical binding manner with the HPV18 E7 and PTPN14 complex. Nevertheless, despite the structural similarities, the biological consequences of the E7 interaction were found to differ between the two PTP proteins. Unlike PTPN14, PTPN21 did not appear to be subjected to proteasomal degradation in HPV18-positive HeLa cervical cancer cells. Moreover, knockdown of PTPN21 led to retardation of the migration/invasion of HeLa cells and HPV18 E7-expressing HaCaT keratinocytes, which reflects its protumor activity. In conclusion, the associations of the viral oncoprotein E7 with PTPN14 and PTPN21 are similar at the molecular level but play different physiological roles.

Autophagy-Related Signature for Head and Neck Squamous Cell Carcinoma

Background

Head and neck squamous cell carcinoma (HNSCC) is one of the most common malignancies in the world, with low survival and poor quality of life. Autophagy-associated genes (ATGs) have been reported to be involved in the initiation and progression of malignancies. Here, we aimed to investigate the association between autophagy-associated genes and the outcomes in HNSCC patients.

Methods

We obtained ATGs with prognostic values by analyzing the datasets from The Cancer Genome Atlas (TCGA) and Human Autophagy Database (HADb). The enrichment functions of autophagy differential genes were analyzed by Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). The Kaplan-Meier method was applied to the survival curve analysis. A prognostic autophagy-related gene signature was established, and its independence was verified.

Results

We acquired a total of 529 samples and 232 ATGs; further, we identified 45 genes associated with prognosis and built a prognosis autophagy signature based on risk score of 15 genes. Patients were divided into two groups based on risk scores. The Kaplan-Meier curve illustrated that the survival rate of the high-risk group was significantly lower than that of the low-risk group in both the training group and validation group. The ROC curve revealed that the risk score had the highest AUC value in the 3rd and 5th years, reaching 0.703 and 0.724, which are higher than other risk factors such as gender, age, and TNM stage. The nomogram further confirmed its weight in the prognosis of HNSCC patients. Through KEGG and GO enrichment analyses, we observed that ATGs were involved in the tumorigenesis and invasion of tumor by various mediating pathways. We gained 3 hub genes (MAP1LC3B, FADD, and LAMP1) and further analyzed the survival curves, mutations, differential expressions, and their roles in tumors on the online websites.

Conclusion

We identified a novel autophagy-related signature that may provide promising biomarker genes for the treatment and prognosis of HNSCC. We need to validate its prognostic value by applying it to the clinic.

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

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

Significant association between host transcriptome-derived HPV oncogene E6* influence score and carcinogenic pathways, tumor size, and survival in head and neck cancer

BACKGROUND

Human papillomavirus (HPV) oncogenes E6, E7, and shorter isoforms of E6 (E6*) are known carcinogenic factors in head and neck squamous cell carcinoma (HNSCC). Little is known regarding E6* functions.

METHODS

We analyzed RNA-seq data from 68 HNSCC HPV type 16-positive tumors to determine host genes and pathways associated with E6+E7 expression (E6E7) or the percent of full-length E6 (E6%FL). Influence scores of E6E7 and E6%FL were used to test for associations with clinical variables.

RESULTS

For E6E7, we recapitulated all major known affected pathways and revealed additional pathways. E6%FL was found to affect mitochondrial processes, and E6%FL influence score was significantly associated with overall survival and tumor size.

CONCLUSIONS

HPV E6E7 and E6* result in extensive, dose-dependent compensatory effects and dysregulation of key cancer pathways. The switch from E6 to E6* promotes oxidative phosphorylation, larger tumor size, and worse prognosis, potentially serving as a prognostic factor for HPV-positive HNSCC.

Suppression of a Subset of Interferon-Induced Genes by Human Papillomavirus Type 16 E7 via a Cyclin Dependent Kinase 8-Dependent Mechanism

Persistent infection by human papillomaviruses (HPVs), small, double-stranded DNA viruses that infect keratinocytes of the squamous epithelia, can lead to the development of cervical and other cancers. The viral oncoprotein E7 contributes to viral persistence in part by regulating host gene expression through binding host transcriptional regulators, although mechanisms responsible for E7-mediated transcriptional regulation are incompletely understood. Type I IFN signaling promotes the expression of anti-viral genes, called interferon-stimulated genes (ISGs), through the phosphorylation and activation of STAT1. In this study, we have observed that the CR3 domain of E7 contributes to the episomal maintenance of viral genomes. Transcriptome analysis revealed that E7 transcriptionally suppresses a subset of ISGs but not through regulation of STAT1 activation. Instead, we discovered that E7 associates with Mediator kinase CDK8 and this is correlated with the recruitment of CDK8 to ISG promoters and reduced ISG expression. E7 fails to suppress ISGs in the absence of CDK8, indicating that CDK8 function contributes to the suppression of ISGs by E7. Altogether, E7/CDK8 association may be a novel mechanism by which E7 inhibits innate immune signaling.

Enhanced Glycogen Metabolism Supports the Survival and Proliferation of HPV-Infected Keratinocytes in Condylomata Acuminata

Condylomata acuminata (CA) is caused by human papillomavirus (HPV) infections of keratinocytes and is a common sexually transmitted disease. The main clinical feature and risk of CA is the high recurrence of genital warts formed by infected keratinocytes. Metabolic reprogramming of most types of mammalian cells including keratinocytes can provide energy and intermediates essential for their survival. Here, we report that HPV infection develops a hypoxic microenvironment in CA warts by inducing the accumulation of glycogen and increased glycogen metabolism in the infected keratinocytes in a hypoxia-inducible factor 1α (HIF-1α) -dependent pathway. Our in vitro studies show that the increased glycogen metabolism is essential for the survival and proliferation of keratinocytes. Regarding its mechanism of action, glycogenolysis generates glucose-1-phosphate that fluxes into the pentose phosphate pathway and, then, generates abundant nicotinamide adenine dinucleotide phosphate, thereby ensuring high levels of glutathione in keratinocytes under hypoxia. The abrogation of glycogen synthesis and glycogenolysis decreases the ratio of glutathione and glutathione disulfide and increases the level of ROS, further resulting in the impairment of keratinocyte survival. Collectively, our work offers an insight into the metabolic reprogramming in the development of CA and implies that the intervention of glycogen metabolism would be a promising therapeutic target for CA.

Human Papillomavirus 16 E6 and E7 Synergistically Repress Innate Immune Gene Transcription

Human papillomaviruses (HPV) are causative agents in 5% of all cancers, including the majority of anogenital and oropharyngeal cancers. Downregulation of innate immune genes (IIGs) by HPV to promote the viral life cycle is well documented; E6 and E7 are known repressors of these genes. More recently, we demonstrated that E2 could also repress IIGs. These studies have been carried out in cells overexpressing the viral proteins, and to further investigate the role of individual viral proteins in this repression, we introduced stop codons into E6 and/or E7 in the entire HPV16 genome and generated N/Tert-1 cells stably maintaining the HPV16 genomes. We demonstrate that E6 or E7 individually is not sufficient to repress IIG expression in the context of the entire HPV16 genome; both are required for a synergistic repression. The DNA damage response (DDR) is activated by HPV16 irrespective of E6 and E7 expression, presumably due to viral replication; E1 is a known activator of the DDR. In addition, replication stress was apparent in HPV16-positive cells lacking E6 and E7, manifested by attenuated cellular growth and activation of replication stress genes. These studies led us to the following model. Viral replication per se can activate the DDR following infection, and this activation is a known inducer of IIG expression, which may induce cellular senescence. To combat this, E6 and E7 synergistically combine to manipulate the DDR and actively repress innate immune gene expression promoting cellular growth; neither protein by itself is able to do this.IMPORTANCE The role of human papillomavirus 16 (HPV16) in human cancers is well established; however, to date there are no antiviral therapeutics that are available for combatting these cancers. To identify such targets, we must enhance the understanding of the viral life cycle. Innate immune genes (IIGs) are repressed by HPV16, and we have reported that this repression persists through to cancer. Reversal of this repression would boost the immune response to HPV16-positive tumors, an area that is becoming more important given the advances in immunotherapy. This report demonstrates that E6 and E7 synergistically repress IIG expression in the context of the entire HPV16 genome. Removal of either protein activates the expression of IIGs by HPV16. Therefore, gaining a precise understanding of how the viral oncogenes repress IIG expression represents an opportunity to reverse this repression and boost the immune response to HPV16 infections for therapeutic gain.

Histone deacetylases in virus-associated cancers

Oncogenic viruses are one of the most important causes of cancer worldwide. The pathogens contribute to the establishment of human malignancies by affecting various cellular events. Epigenetic mechanisms, such as histone modification methylation/demethylation, are one of the most critical events manipulated by oncogenic viruses to drive tumorigenesis. Histone modifications are mediated by histone acetylation and deacetylation, regulated by histone acetyltransferases (HATs) and histone deacetylases (HDACs), respectively. Dysregulation of HDACs activity affects viral tumorigenesis in several ways, such as manipulating tumor suppressor and viral gene expression. The present review aims to describe the vital interactions between both cancer-caused/associated viruses and the HDAC machinery, particularly by focusing on those viruses involved in gastrointestinal tumors, as some of the most common viral-mediated cancers.

Focus on the glycerophosphocholine pathway in choline phospholipid metabolism of cancer

Activated choline metabolism is a hallmark of carcinogenesis and tumor progression, which leads to elevated levels of phosphocholine and glycerophosphocholine in all types of cancer tested so far. Magnetic resonance spectroscopy applications have played a key role in detecting these elevated choline phospholipid metabolites. To date, the majority of cancer-related studies have focused on phosphocholine and the Kennedy pathway, which constitutes the biosynthesis pathway for membrane phosphatidylcholine. Fewer and more recent studies have reported on the importance of glycerophosphocholine in cancer. In this review article, we summarize the recent literature on glycerophosphocholine metabolism with respect to its cancer biology and its detection by magnetic resonance spectroscopy applications.

Viral hijacking of cellular metabolism

This review discusses the current state of the viral metabolism field and gaps in knowledge that will be important for future studies to investigate. We discuss metabolic rewiring caused by viruses, the influence of oncogenic viruses on host cell metabolism, and the use of viruses as guides to identify critical metabolic nodes for cancer anabolism. We also discuss the need for more mechanistic studies identifying viral proteins responsible for metabolic hijacking and for in vivo studies of viral-induced metabolic rewiring. Improved technologies for detailed metabolic measurements and genetic manipulation will lead to important discoveries over the next decade.

Molecular mechanisms in progression of HPV-associated cervical carcinogenesis

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

How Viral and Intracellular Bacterial Pathogens Reprogram the Metabolism of Host Cells to Allow Their Intracellular Replication

Viruses and intracellular bacterial pathogens (IBPs) have in common the need of suitable host cells for efficient replication and proliferation during infection. In human infections, the cell types which both groups of pathogens are using as hosts are indeed quite similar and include phagocytic immune cells, especially monocytes/macrophages (MOs/MPs) and dendritic cells (DCs), as well as nonprofessional phagocytes, like epithelial cells, fibroblasts and endothelial cells. These terminally differentiated cells are normally in a metabolically quiescent state when they are encountered by these pathogens during infection. This metabolic state of the host cells does not meet the extensive need for nutrients required for efficient intracellular replication of viruses and especially IBPs which, in contrast to the viral pathogens, have to perform their own specific intracellular metabolism to survive and efficiently replicate in their host cell niches. For this goal, viruses and IBPs have to reprogram the host cell metabolism in a pathogen-specific manner to increase the supply of nutrients, energy, and metabolites which have to be provided to the pathogen to allow its replication. In viral infections, this appears to be often achieved by the interaction of specific viral factors with central metabolic regulators, including oncogenes and tumor suppressors, or by the introduction of virus-specific oncogenes. Less is so far known on the mechanisms leading to metabolic reprogramming of the host cell by IBPs. However, the still scant data suggest that similar mechanisms may also determine the reprogramming of the host cell metabolism in IBP infections. In this review, we summarize and compare the present knowledge on this important, yet still poorly understood aspect of pathogenesis of human viral and especially IBP infections.

HPV-Mediated Resistance to TNF and TRAIL Is Characterized by Global Alterations in Apoptosis Regulatory Factors, Dysregulation of Death Receptors, and Induction of ROS/RNS

Persistent infection with high-risk human papilloma virus (HR-HPV) is the main risk factor for the development of invasive cervical cancer although is not sufficient to cause cervical cancer. Several host and environmental factors play a key role in cancer initiation/progression, including cytokines and other immune-response mediators. Here, we characterized the response to the individual and combined action of the pro-inflammatory cytokines tumor necrosis factor (TNF) and TNF-related apoptosis-inducing ligand (TRAIL) on HPV-transformed cells and human keratinocytes ectopically expressing E6 and E7 early proteins from different HPV types. We showed that keratinocytes expressing HPV early proteins exhibited global alterations in the expression of proteins involved in apoptosis regulation/execution, including TNF and TRAIL receptors. Besides, we provided evidence that TNF receptor 1 (TNFR1) was down-regulated and may be retained in the cytoplasm of keratinocytes expressing HPV16 oncoproteins. Finally, fluorescence analysis demonstrated that cytokine treatment induced the production and release of reactive oxygen and nitrogen species (ROS/RNS) in cells expressing HPV oncogenes. Alterations in ROS/RNS production and apoptosis regulatory factors expression in response to inflammatory mediators may favor the accumulation of genetic alterations in HPV-infected cells. Altogether, our results suggested that these events may contribute to lesion progression and cancer onset.

Inhibition of Epstein-Barr Virus Replication in Human Papillomavirus-Immortalized Keratinocytes

Epstein-Barr virus (EBV) is implicated in the pathogenesis of human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OSCC). EBV-associated cancers harbor a latent EBV infection characterized by a lack of viral replication and the expression of viral oncogenes. Cellular changes promoted by HPV are comparable to those shown to facilitate EBV latency, though whether HPV-positive cells support a latent EBV infection has not been demonstrated. Using a model of direct EBV infection into HPV16-immortalized tonsillar cells grown in organotypic raft culture, we showed robust EBV replication in HPV-negative rafts but little to no replication in HPV-immortalized rafts. The reduced EBV replication was independent of immortalization, as human telomerase-immortalized normal oral keratinocytes supported robust EBV replication. Furthermore, we observed reduced EBV lytic gene expression and increased expression of EBER1, a noncoding RNA highly expressed in latently infected cells, in the presence of HPV. The use of human foreskin keratinocyte rafts expressing the HPV16 E6 and/or E7 oncogene(s) (HPV E6 and E7 rafts) showed that E7 was sufficient to reduce EBV replication. EBV replication is dependent upon epithelial differentiation and the differentiation-dependent expression of the transcription factors KLF4 and PRDM1. While KLF4 and PRDM1 levels were unaltered, the expression levels of KLF4 transcriptional targets, including late differentiation markers, were reduced in HPV E6 and E7 rafts compared to their levels in parental rafts. However, the HPV E7-mediated block in EBV replication correlated with delayed expression of early differentiation markers. Overall, this study reveals an HPV16-mediated block in EBV replication, through E7, that may facilitate EBV latency and long-term persistence in the tumor context.IMPORTANCE Using a model examining the establishment of EBV infection in HPV-immortalized tissues, we showed an HPV-induced interruption of the normal EBV life cycle reminiscent of a latent EBV infection. Our data support the notion that a persistent EBV epithelial infection depends upon preexisting cellular alterations and suggest the ability of HPV to promote such changes. More importantly, these findings introduce a model for how EBV coinfection may influence HPV-positive (HPV-pos) OSCC pathogenesis. Latently EBV-infected epithelial cells, as well as other EBV-associated head-and-neck carcinomas, exhibit oncogenic phenotypes commonly seen in HPV-pos OSCC. Therefore, an HPV-induced shift in the EBV life cycle toward latency would not only facilitate EBV persistence but also provide additional viral oncogene expression, which can contribute to the rapid progression of HPV-pos OSCC. These findings provide a step toward defining a role for EBV as a cofactor in HPV-positive oropharyngeal tumors.

HPV-Associated Oropharyngeal Cancer in the HIV/AIDS Patient

Since their discovery as the etiologic agents of cervical cancer in the mid-1970s, human papillomaviruses (HPVs) have been linked with a growing number of epithelial-derived tumors, including head and neck squamous cell carcinomas. HPV demonstrates a particular predilection for causing tumors of the oropharynx, with the majority of cases involving infection with high-oncogenic risk HPV-16. People living with HIV are at increased risk of infection with HPV- and HPV-related oral complications even with adequate control of their HIV infection with antiretroviral therapy. In this chapter, we discuss the molecular mechanisms that underlie HPV-mediated oncogenesis in the oropharynx. We also describe the progress that has been made in understanding the epidemiology of oral HPV infection and the determinants of oral HPV-related pathology. Finally, we examine what can be done to treat and prevent oral HPV infection, benign lesions, and cancer, particularly in the context of the HIV-positive patient.

The lysine acetyltransferase GCN5 contributes to human papillomavirus oncoprotein E7-induced cell proliferation via up-regulating E2F1

General control nondepressible 5 (GCN5), the first identified transcription-related lysine acetyltransferase (KAT), is an important catalytic component of a transcriptional regulatory SAGA (Spt-Ada-GCN5-Acetyltransferase) and ATAC (ADA2A-containing) complex. While GCN5 has been implicated in cancer development, its role in cervical cancer is not known. The human papillomavirus (HPV) oncoprotein E7 abrogates the G1 cell cycle checkpoint and induces genomic instability, which plays a central role in cervical carcinogenesis. In this study, we observed that GCN5 was up-regulated in HPV E7-expressing cells, knockdown of GCN5 inhibited cell cycle progression and DNA synthesis in HPV E7-expressing cells. Notably, GCN5 knockdown reduced the steady-state levels of transcription factor E2F1. Depletion of E2F1 caused G1 arrest while overexpression of E2F1 rescued the inhibitory effects of GCN5 knockdown on G1/S progression in HPV E7-expressing cells. Results from chromatin immunoprecipitation (ChIP) assays demonstrated that GCN5 bound to the E2F1 promoter and increased the extent of histone acetylation within these regions. GCN5 also acetylated c-Myc and increased its ability to bind to the E2F1 promoter. Knockdown of c-Myc reduced the steady-state levels of E2F1 and caused G1 arrest. These results revealed a novel mechanism of E7 function whereby elevated GCN5 acetylates histones and c-Myc to regulate E2F1 expression and cell cycle progression.

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

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

[HPV - A different view on Head and Neck Cancer]

Head and neck cancer is the sixth most common cancer with over 500000 annually reported incident cases worldwide. Besides major risk factors tobacco and alcohol, oropharyngeal squamous cell carcinomas (OSCC) show increased association with human papillomavirus (HPV). HPV-associated and HPV-negative OSCC are 2 different entities regarding biological characteristics, therapeutic response, and patient prognosis. In HPV OSCC, viral oncoprotein activity, as well as genetic (mutations and chromosomal aberrations) and epigenetic alterations plays a key role during carcinogenesis. Based on improved treatment response, the introduction of therapy de-intensification and targeted therapy is discussed for patients with HPV OSCC. A promising targeted therapy concept is immunotherapy. The use of checkpoint inhibitors (e.g. anti-PD1) is currently investigated. By means of liquid biopsies, biomarkers such as viral DNA or tumor mutations in the will soon be available for disease monitoring, as well as detection of treatment failure. By now, primary prophylaxis of HPV OSCC can be achieved by vaccination of girls and boys.

Human papillomavirus E7 induces p63 expression to modulate DNA damage response

Cervical cancer is the third most common malignancy diagnosed in women worldwide. The major aetiological factor underlying the malignant transformation of cervical cells is the persistent infection with high-risk human papillomaviruses (HR-HPV), with more than 99% of cases expressing viral sequences. Here, we report a previously unknown mechanism driven by high-risk human papillomavirus E7 protein to modulate response to DNA damage in cervical cancer cells. Our data shows that HR-HPV E7 oncoprotein induces the transcription of the p53-family member p63, which modulates DNA damage response pathways, to facilitate repair of DNA damage. Based on our findings, we proposed a model, where HR-HPV could interfere with the sensitivity of transformed cells to radiation therapy by modulating DNA damage repair efficiency. Importantly, we have shown for the first time a critical role for p63 in response to DNA damage in cervical cancer cells.