Role of HPV16 E1 in cervical carcinogenesis

Mechanisms of Viral DNA Replication of Human Papillomavirus: E2 Protein-Dependent Recruitment of E1 DNA Helicase to the Origin of DNA Replication

Human papillomaviruses (HPVs) are small double-stranded DNA viruses that infect epithelial cells and cause cervical, anogenital, and oropharyngeal cancers. HPV genome replication relies on the viral E1 and E2 proteins to initiate DNA replication. The first step is the assembly of the E1-E2 complex at the origin of replication. We have examined the role of full-length HPV E1 helicase and its interaction with E2 in pre-initiation complex formation. Electrophoretic mobility shift assays (EMSAs) with purified E1 and E2 proteins revealed that the HPV genome does not have a specific E1 binding site, or such a sequence is not required for pre-initiation complex formation. E1 alone did not show any binding to the origin DNA sequences, while E2 facilitated E1 recruitment to the origin, forming the E1-E2-DNA ternary complex. Formation of such a complex required at least two E2 binding sites. These findings led us to propose a novel mechanism in which E2 dimers serve as the primary recruiters of E1 to form the pre-initiation complex. This study provides new insights into the mechanistic role of E2 in the recruitment of E1 at the origin of HPV DNA replication, enhancing our understanding of HPV biology and potentially informing future therapeutic strategies.

Advances in cervical cancer: current insights and future directions

In alignment with the World Health Organization's strategy to eliminate cervical cancer, substantial progress has been made in the treatment of this malignancy. Cervical cancer, largely driven by human papillomavirus (HPV) infection, is considered preventable and manageable because of its well-established etiology. Advancements in precision screening technologies, such as DNA methylation triage, HPV integration detection, liquid biopsies, and artificial intelligence-assisted diagnostics, have augmented traditional screening methods such as HPV nucleic acid testing and cytology. Therapeutic strategies aimed at eradicating HPV and reversing precancerous lesions have been refined as pivotal measures for disease prevention. The controversy surrounding surgery for early-stage cervical cancer revolves around identifying optimal candidates for minimally invasive and conservative procedures without compromising oncological outcomes. Recent clinical trials have yielded promising results for the development of systemic therapies for advanced cervical cancer. Immunotherapies, such as immune checkpoint inhibitors (ICIs), antibody-drug conjugates (ADCs), and targeted therapy have demonstrated significant effectiveness, marking a substantial advancement in cervical cancer management. Various combination therapies have been validated, and ongoing trials aim to enhance outcomes through the development of novel drugs and optimized combination regimens. The prospect of eradicating cervical cancer as the first malignancy to be eliminated is now within reach. In this review, we provide a comprehensive overview of the latest scientific insights, with a particular focus on precision managements for various stages of cervical disease, and explore future research directions in cervical cancer.

Roles of human papillomavirus in cancers: oncogenic mechanisms and clinical use

Human papillomaviruses, particularly high-risk human papillomaviruses, have been universally considered to be associated with the oncogenesis and progression of various cancers. The genome of human papillomaviruses is circular, double-stranded DNA that encodes early and late proteins. Each of the proteins is of crucial significance in infecting the epithelium of host cells persistently and supporting viral genome integrating into host cells. Notably, E6 and E7 proteins, classified as oncoproteins, trigger the incidence of cancers by fostering cell proliferation, hindering apoptosis, evading immune surveillance, promoting cell invasion, and disrupting the balance of cellular metabolism. Therefore, targeting human papillomaviruses and decoding molecular mechanisms by which human papillomaviruses drive carcinogenesis are of great necessity to better treat human papillomaviruses-related cancers. Human papillomaviruses have been applied clinically to different facets of human papillomavirus-related cancers, including prevention, screening, diagnosis, treatment, and prognosis. Several types of prophylactic vaccines have been publicly utilized worldwide and have greatly decreased the occurrence of human papillomavirus-related cancers, which have benefited numerous people. Although various therapeutic vaccines have been developed and tested clinically, none of them have been officially approved to date. Enhancing the efficacy of vaccines and searching for innovative technologies targeting human papillomaviruses remain critical challenges that warrant continuous research and attention in the future.

Upregulation of HPV16E1 and E7 expression and FOXO3a mRNA downregulation in high-grade cervical neoplasia

Background

Cervical cancer remains a significant global health concern, ranking as the fourth most prevalent cancer among women worldwide. Human papillomaviruses (HPV) transcribe many genes that might be responsible for cervical cancer development. This study aims to investigate the correlation between the expression of HPV16 early genes and the mRNA expression of human FOXO3a, a tumor suppressor gene, in association with various stages of cervical precancerous lesions.

Methods

Eighty-five positive HPV16 DNA cervical swab samples were recruited and categorized based on cytology stages, i.e., negative for intraepithelial lesion or malignancy (NILM), atypical squamous cells of undetermined significance (ASC-US), low-grade squamous intraepithelial lesion (LSIL), atypical squamous cell cannot exclude HSIL (ASC-H), high-grade squamous intraepithelial lesion (HSIL). RT-qPCR was performed to amplify HPV16E1, E4, E6, E6*I, E7, and human FOXO3a mRNA expression in all samples. The relative expression of those genes was calculated using GAPDH as a control. Detection of FOXO3a mRNA expression in the cervical cancer cell line by RT-qPCR and meta-analysis of FOXO3a expression using the RNA-Seq dataset by GEPIA2 were analyzed to support the conclusions.

Results

Among the cervical samples, HPV16E1 and E7 were significantly increased expression correlating to disease severity. HPV16E4 mRNA expression was 100% detected in all LSIL samples, with a significant increase observed from normal to LSIL stages. Conversely, FOXO3a mRNA expression decreased with disease severity, and the lowest expression was observed in HSIL/squamous cell carcinoma (SCC) samples. In addition, similar results of FOXO3a downregulation were also found in the cervical cancer cell line and RNA-Seq dataset of cervical cancer samples.

Conclusion

HPV16 early mRNA levels, including E1 and E7, increase during cancer progression, and downregulation of FOXO3a mRNA is a characteristic of cervical cancer cells and HSIL/SCC. Additionally, HPV16E4 mRNA expression was consistently detected in all LSIL samples, suggesting the presence of active viral replication. These findings might lead to further investigation into the interplay between HPV gene expression and host cell factors for targeted therapeutic strategies in cervical cancer management.

Structural biology of the human papillomavirus

Human papillomavirus (HPV), known for its oncogenic properties, is the primary cause of cervical cancer and significantly contributes to mortality rates. It also plays a considerable role in the globally rising incidences of head and neck cancers. These cancers pose a substantial health burden worldwide. Current limitations in diagnostic and treatment strategies, along with inadequate coverage of preventive vaccines in low- and middle-income countries, hinder the progress toward the World Health Organization (WHO) HPV prevention and control targets set for 2030. In response to these challenges, extensive research in structural virology has explored the properties of HPV proteins, yielding crucial insights into the mechanisms of HPV infection that are important for the development of prevention and therapeutic strategies. This review highlights recent advances in understanding the structures of HPV proteins and discusses achievements and future opportunities for HPV vaccine development.

Comprehensive insights into human papillomavirus and cervical cancer: Pathophysiology, screening, and vaccination strategies

This article provides an in-depth review of the Human Papillomavirus (HPV), a predominant etiological factor in cervical cancer, exploring its pathophysiology, epidemiology, and mechanisms of oncogenesis. We examine the role of proteins, DNA methylation markers, and non-coding RNAs as predictive biomarkers in cervical cancer, highlighting their potential in refining diagnostic and prognostic practices. The evolution and efficacy of cervical cancer screening methods, including the Papanicolaou smear, HPV testing, cytology and HPV test, and colposcopy techniques, are critically analyzed. Furthermore, the article delves into the current landscape and future prospects of prophylactic HPV vaccines and therapeutic vaccines, underscoring their significance in the prevention and potential treatment of HPV-related diseases. This comprehensive review aims to synthesize recent advances and ongoing challenges in the field, providing a foundation for future research and clinical strategies in the prevention and management of cervical cancer.

Comparative Molecular Docking of Apigenin and Luteolin versus Conventional Ligands for TP-53, pRb, APOBEC3H, and HPV-16 E6: Potential Clinical Applications in Preventing Gynecological Malignancies

This study presents a comparative analysis of molecular docking data, focusing on the binding interactions of the natural compounds apigenin and luteolin with the proteins TP-53, pRb, and APOBEC, in comparison to conventional pharmacological ligands. Advanced bioinformatics techniques were employed to evaluate and contrast binding energies, showing that apigenin and luteolin demonstrate significantly higher affinities for TP-53, pRb, and APOBEC, with binding energies of -6.9 kcal/mol and -6.6 kcal/mol, respectively. These values suggest strong potential for therapeutic intervention against HPV-16. Conventional ligands, by comparison, exhibited lower affinities, with energies ranging from -4.5 to -5.5 kcal/mol. Additionally, protein-protein docking simulations were performed to assess the interaction between HPV-16 E6 oncoprotein and tumor suppressors TP-53 and pRb, which revealed high binding energies around -976.7 kcal/mol, indicative of their complex interaction. A conversion formula was applied to translate these protein-protein interaction energies to a comparable scale for non-protein interactions, further underscoring the superior binding potential of apigenin and luteolin. These findings highlight the therapeutic promise of these natural compounds in preventing HPV-16-induced oncogenesis, warranting further experimental validation for clinical applications.

Viral vector-based therapeutic HPV vaccines

Replication-defective viral vector vaccines have several advantages over conventional subunit vaccines, including potent antibody responses, cellular responses critical for eliminating pathogen-infected cells, and the induction of highly immunogenic and durable immune responses without adjuvants. The Human papillomavirus (HPV), a microorganism with over 200 genotypes, plays a crucial role in inducing human tumors, with the majority of HPV-related malignancies expressing HPV proteins. Tumors associated with HPV infection, most of which result from HPV16 infection, include those affecting the cervix, anus, vagina, penis, vulva, and oropharynx. In recent years, the development of therapeutic HPV vaccines utilizing viral vectors for the treatment of premalignant lesions or tumors caused by HPV infection has experienced rapid growth, with numerous research pipelines currently underway. Simultaneously, screening for optimal antigens requires more basic research and more optimized methods. In terms of preclinical research, we present the various models used to assess vaccine efficacy, highlighting their respective advantages and disadvantages. Further, we present current research status of therapeutic vaccines using HPV viral vectors, especially the indications, initial efficacy, combination drugs, etc. In general, this paper summarizes current viral vector therapeutic HPV vaccines in terms of HPV infection, antigen selection, vectors, efficacy evaluation, and progress in clinical trials.

Emerging paradigms: unmasking the role of oxidative stress in HPV-induced carcinogenesis

The contribution of the human papillomavirus (HPV) to cancer is significant but not exclusive, as carcinogenesis involves complex mechanisms, notably oxidative stress. Oxidative stress and HPV can independently cause genome instability and DNA damage, contributing to tumorigenesis. Oxidative stress-induced DNA damage, especially double-strand breaks, aids in the integration of HPV into the host genome and promotes the overexpression of two viral proteins, E6 and E7. Lifestyle factors, including diet, smoking, alcohol, and psychological stress, along with genetic and epigenetic modifications, and viral oncoproteins may influence oxidative stress, impacting the progression of HPV-related cancers. This review highlights various mechanisms in oxidative-induced HPV-mediated carcinogenesis, including altered mitochondrial morphology and function leading to elevated ROS levels, modulation of antioxidant enzymes like Superoxide Dismutase (SOD), Glutathione (GSH), and Glutathione Peroxidase (GPx), induction of chronic inflammatory environments, and activation of specific cell signaling pathways like the Phosphoinositide 3-kinase, Protein kinase B, Mammalian target of rapamycin (PI3K/AKT/mTOR) and the Extracellular signal-regulated kinase (ERK) signaling pathway. The study highlights the significance of comprehending and controlling oxidative stress in preventing and treating cancer. We suggested that incorporating dietary antioxidants and targeting cancer cells through mechanisms involving ROS could be potential interventions to mitigate the impact of oxidative stress on HPV-related malignancies.

Advancements in the Understanding of Small-Cell Neuroendocrine Cervical Cancer: Where We Stand and What Lies Ahead

Small-cell neuroendocrine cervical carcinoma (SCNCC) is a rare yet aggressive gynecological malignancy associated with dismal clinical outcomes. Its rarity has led to a limited number of retrospective studies and an absence of prospective research, posing significant challenges for evidence-based treatment approaches. As a result, most gynecologic oncology centers have limited experience with this tumor, emphasizing the urgent need for a comprehensive review and summary. This article systematically reviews the pathogenesis, immunohistochemical and molecular characteristics, prognostic factors, and clinical management of gynecologic SCNCC. We specifically focused on reviewing the distinct genomic characteristics of SCNCC identified via next-generation sequencing technologies, including loss of heterozygosity (LOH), somatic mutations, structural variations (SVs), and microRNA alterations. The identification of these actionable genomic events offers promise for discovering new molecular targets for drug development and enhancing therapeutic outcomes. Additionally, we delve deeper into key clinical challenges, such as determining the optimal treatment modality between chemoradiation and surgery for International Federation of Gynecology and Obstetrics (FIGO) stage I phase patients within a precision stratification framework, as well as the role of targeted therapy within the homologous recombination (HR) pathway, immune checkpoint inhibitors (ICIs), and prophylactic cranial irradiation (PCI) in the management of SCNCC. Finally, we anticipate the utilization of multiple SCNCC models, including cancer tissue-originated spheroid (CTOS) lines and patient-derived xenografts (PDXs), to decipher driver events and develop individualized therapeutic strategies for clinical application.

Designing a Novel Multiepitope Vaccine from the Human Papilloma Virus E1 and E2 Proteins for Indonesia with Immunoinformatics and Molecular Dynamics Approaches

One of the deadliest malignant cancer in women globally is cervical cancer. Specifically, cervical cancer is the second most common type of cancer in Indonesia. The main infectious agent of cervical cancer is the human papilloma virus (HPV). Although licensed prophylactic vaccines are available, cervical cancer cases are on the rise. Therapy using multiepitope-based vaccines is a very promising therapy for cervical cancer. This study aimed to develop a multiepitope vaccine based on the E1 and E2 proteins of HPV 16, 18, 45, and 52 using in silico. In this study, we develop a novel multiepitope vaccine candidate using an immunoinformatic approach. We predicted the epitopes of the cytotoxic T lymphocyte (CTL) and helper T lymphocyte (HTL) and evaluated their immunogenic properties. Population coverage analysis of qualified epitopes was conducted to determine the successful use of the vaccine worldwide. The epitopes were constructed into a multiepitope vaccine by using AAY linkers between the CTL epitopes and GPGPG linkers between the HTL epitopes. The tertiary structure of the multiepitope vaccine was modeled with AlphaFold and was evaluated by Prosa-web. The results of vaccine construction were analyzed for B-cell epitope prediction, molecular docking with Toll like receptor-4 (TLR4), and molecular dynamics simulation. The results of epitope prediction obtained 4 CTL epitopes and 7 HTL epitopes that are eligible for construction of multiepitope vaccines. Prediction of the physicochemical properties of multiepitope vaccines obtained good results for recombinant protein production. The interaction showed that the interaction of the multiepitope vaccine-TLR4 complex is stable based on the binding free energy value -106.5 kcal/mol. The results of the immune response simulation show that multiepitope vaccine candidates could activate the adaptive and humoral immune systems and generate long-term B-cell memory. According to these results, the development of a multiepitope vaccine with a reverse vaccinology approach is a breakthrough to develop potential cervical cancer therapeutic vaccines.

HPV16E1 downregulation altered the cell characteristics involved in cervical cancer development

The primary causes of cervical cancer are human papillomavirus type 16 (HPV16) and/or other high-risk (Hr -) HPV infections. Hr-HPVE5, E6, and E7 have been identified as oncoproteins that play roles in the development of cancer. However, other HPV proteins, especially E1, may also be involved in cancer development. In this study, the role of HPV16E1 in cervical carcinogenesis was examined by siRNA knockdown experiments using SiHa cells as a model. The results showed that HPV16E1 regulated P-FOXO3a and HPV16E7 expression. Various cell functions associated with the hallmarks of cancer, including cell viability, colony formation, invasion, and anchorage-independent cell growth, were altered when HPV16E1 was downregulated. However, no effect on cell migration and apoptosis properties was found. Moreover, HPV16E1 downregulation resulted in an increase in cisplatin susceptibility. In conclusion, this is the first demonstration that HPV16E1 might be regarded as a possible novel oncoprotein involved in several processes related to oncogenesis.

New insights into Chlamydia pathogenesis: Role of leukemia inhibitory factor

Chlamydia trachomatis (Ct) is the leading cause of bacterial sexually transmitted infections worldwide. Since the symptoms of Ct infection are often subtle or absent, most people are unaware of their infection until they are tested or develop severe complications such as infertility. It is believed that the primary culprit of Ct-associated tissue damage is unresolved chronic inflammation, resulting in aberrant production of cytokines, chemokines, and growth factors, as well as dysregulated tissue influx of innate and adaptive immune cells. A member of the IL-6 cytokine family, leukemia inhibitory factor (LIF), is one of the cytokines induced by Ct infection but its role in Ct pathogenesis is unclear. In this article, we review the biology of LIF and LIF receptor (LIFR)-mediated signaling pathways, summarize the physiological role of LIF in the reproductive system, and discuss the impact of LIF in chronic inflammatory conditions and its implication in Ct pathogenesis. Under normal circumstances, LIF is produced to maintain epithelial homeostasis and tissue repair, including the aftermath of Ct infection. However, LIF/LIFR-mediated signaling – particularly prolonged strong signaling – can gradually transform the microenvironment of the fallopian tube by altering the fate of epithelial cells and the cellular composition of epithelium. This harmful transformation of epithelium may be a key process that leads to an enhanced risk of infertility, ectopic pregnancy and cancer following Ct infection.