Genes Regulated by HPV 16 E6 and High Expression of NFX1-123 in Cervical Cancers

Comparative Analysis of Alpha and Beta HPV E6 Oncoproteins: Insights into Functional Distinctions and Divergent Mechanisms of Pathogenesis

Human papillomaviruses (HPVs) represent a diverse group of DNA viruses that infect epithelial cells of mucosal and cutaneous tissues, leading to a wide spectrum of clinical outcomes. Among various HPVs, alpha (α) and beta (β) types have garnered significant attention due to their associations with human health. α-HPVs are primarily linked to infections of the mucosa, with high-risk subtypes, such as HPV16 and HPV18, being the major etiological agents of cervical and oropharyngeal cancers. In contrast, β-HPVs are predominantly associated with cutaneous infections and are commonly found on healthy skin. However, certain β-types, notably HPV5 and HPV8, have been implicated in the development of non-melanoma skin cancers in immunocompromised individuals, highlighting their potential role in pathogenicity. In this review, we comprehensively analyze the similarities and differences between α- and β-HPV E6 oncoproteins, one of the major drivers of viral replication and cellular transformation, and how these impact viral fitness and the capacity to induce malignancy. In particular, we compare the mechanisms these oncoproteins use to modulate common cellular processes-apoptosis, DNA damage repair, cell differentiation, and the immune response-further shedding light on their shared and distinct features, which enable them to replicate at divergent locations of the human body and cause different types of cancer.

NFX1-123: A potential therapeutic target in cervical cancer

NFX1-123 is a splice variant isoform of the NFX1 gene. It is highly expressed in cervical cancers caused by HPV, and NFX1-123 is a protein partner with the HPV oncoprotein E6. Together, NFX1-123 and E6 affect cellular growth, longevity, and differentiation. The expression status of NFX1-123 in cancers beyond cervical and head and neck cancers, and its potential as therapeutic target, have not been investigated. TSVdb of TCGA was used to quantify NFX1-123 expression in 24 cancers compared with normal tissues. The NFX1-123 protein structure was predicted and then submitted to retrieve suitable drug molecules. The top four compounds, found to bind in silico to NFX1-123, were tested experimentally to determine their effects on NFX1-123-related cellular growth, survival, and migration. 46% of cancers (11 of 24 had significant differences in NFX1-123 expression, with nine having had greater NFX1-123 expression, when compared with adjacent normal tissues. Bioinformatics and proteomic predictive analysis modeled the three-dimensional structure of NFX1-123, and drug libraries were screened for high-binding affinity compounds using this modeled structure. Seventeen drugs with binding energies ranging from -1.3 to -10 Kcal/mol were identified. The top four compounds were used to treat HPV- and HPV+ cervical cancer cell lines, three of which (Ropitoin, R428 and Ketoconazole) reduced NFX1-123 protein levels, inhibited cellular growth, survival, and migration, and enhanced the cytotoxicity of Cisplatin. These findings highlight cancers expressing high levels of NFX1-123, and drugs that target it, may reduce cellular growth, survival, and migration, making NFX1-123 a potential novel therapeutic target.

Changes in the Cervical Microbiota of Women with Different High-Risk Human Papillomavirus Loads

The cervical microbiota is essential in female sexual health, and its altered states seem to have a central role in the dynamic of high-risk papillomavirus (hrHPV) infections. This study aimed to evaluate the variation in bacterial communities' compositions according to hrHPV. We collected two samples per woman, with a difference of 12 ± 1 months between them, and performed a follow-up on 66 of these women. The viral load (VL) of the hrHPV was estimated by quantitative PCR (qPCR), then it was normalized (using the HMBS gene as reference) and transformed to the Log₁₀ scale to facilitate the interpretation. The VL was categorized as Negative, without hrHPV copies; Low, less than 10⁰ hrHPV copies; Medium, between 10⁰ to 10² hrHPV copies; and High, >10² hrHPV copies. The microbiota composition was described through the Illumina Novaseq PE250 platform. The diversity analyses revealed changes regarding the hrHPV VL, where women with low VL (<10⁰ hrHPV copies) presented high diversity. The community state type (CST) IV was the most common. However, in women with high VL, a lower association with Lactobacillus depletion was found. Lactobacillus gallinarum and L. iners were the most abundant species in women with high VL, whereas women with low VL had a 6.06 greater probability of exhibiting Lactobacillus dominance. We identified conspicuous differences in the abundance of 78 bacterial genera between women with low and high VL, where 26 were depleted (e.g., Gardnerella) and 52 increased (e.g., Mycoplasma). A multilevel mixed-effects linear regression showed changes in the diversity due to the interaction between the measurement time and the VL, with a decrease in diversity in the second follow-up in women with low VL (Coeff. = 0.47), whereas the women with medium VL displayed an increase in diversity (Coeff. = 0.58). Here, we report for the first time that the cervical microbiota is influenced by the number of copies of hrHPV, where a decrease in the abundance of Lactobacillus, greater diversity, and enrichment of bacterial taxa is relevant in women with low VL.

Post-Transcriptional Gene Regulation by HPV 16E6 and Its Host Protein Partners

Human papillomavirus type 16 (HPV 16) is the most common oncogenic type of HPV in cervical, anogenital, and head and neck cancers, making HPV 16 an important high-risk HPV (HR HPV) type. To create an environment permissible for viral maintenance and growth and to initiate and support oncogenesis, the HR HPV protein E6 functions to dysregulate normal cellular processes. HR HPV type 16 E6 (16E6) has previously been shown to bind cellular proteins in order to transcriptionally activate genes and to target regulatory proteins for degradation. We have identified an additional functional model for 16E6. First, 16E6 binds to cellular RNA processing and binding proteins, specifically cytoplasmic poly(A) binding proteins (PABPCs) and NFX1-123. Then, 16E6 hijacks those proteins' functions to post-transcriptionally regulate cellular immortalization, growth, and differentiation genes and pathways in keratinocytes. In this review, we have highlighted studies that introduce this new model of 16E6 functionality. Understanding ways in which HR HPV dysregulates cellular processes-particularly at the level of post-transcriptional gene regulation-presents new ways to consider mechanisms underlying DNA tumor virus function and new areas for therapeutic target development in HPV-associated cancers.

High expression of NFX1-123 in HPV positive head and neck squamous cell carcinomas

BACKGROUND

High-risk human papillomaviruses (HR HPV) cause nearly all cervical cancers and, in the United States, the majority of head and neck cancers (HNSCCs). NFX1-123 is overexpressed in cervical cancers, and NFX1-123 partners with the HR HPV type 16 E6 oncoprotein to affect multiple growth, differentiation, and immune response genes. However, neither the expression of NFX1-123 nor the levels of these genes have been investigated in HPV positive (HPV+) or negative (HPV-) HNSCCs.

METHODS

The Cancer Genome Atlas Splicing Variants Database and HNSCC cell lines were used to quantify expression of NFX1-123 and cellular genes increased in cervical cancers.

RESULTS

NFX1-123 was increased in HPV+ HNSCCs compared to HPV- HNSCCs. LCE1B, KRT16, SPRR2G, and FBN2 were highly expressed in HNSCCs compared to normal tissues. Notch1 and CCNB1IP1 had greater expression in HPV+ HNSCCs compared to HPV- HNSCCs.

CONCLUSION

NFX1-123 and a subset of its known targets were increased in HPV+ HNSCCs.

Development of an in vitro carcinogenesis model of human papillomavirus-induced cervical adenocarcinoma

Cervical adenocarcinoma (ADC) is the second most common pathological subtype of cervical cancer after squamous cell carcinoma. It accounts for approximately 20% of cervical cancers, and the incidence has increased in the past few decades, particularly among young patients. The persistent infection of high‐risk human papillomavirus (HPV) is responsible for most cervical ADC. However, almost all available in vitro models are designed to study the carcinogenesis of cervical squamous cell carcinoma. To gain better insights into molecular background of ADC, we aimed to establish an in vitro carcinogenesis model of ADC. We previously reported the establishment of an in vitro model for cervical squamous cell carcinoma by introducing defined viral and cellular oncogenes, HPV16 E6 and E7, c‐MYC, and activated RAS to human cervical keratinocytes. In this study, the expression of potential lineage‐specifying factors and/or SMAD4 reduction was introduced in addition to the defined four oncogenes to direct carcinogenesis toward ADC. The cell properties associated with the cell lineage were analyzed in monolayer and organoid cultures and the tumors in mouse xenografts. In the cells expressing Forkhead box A2 (FOXA2), apparent changes in cell properties were observed, such as elevated expression of columnar cell markers and decreased expression of squamous cell markers. Strikingly, the histopathology of tumors expressing FOXA2 resembled cervical ADC, proposing that FOXA2 plays a vital role in dictating the histopathology of cervical cancers.

Cervical Cancer Development: Implications of HPV16 E6E7-NFX1-123 Regulated Genes

Simple Summary

High-risk human papillomavirus (HPV) causes 4.5% of cancers and nearly all cervical cancers. HPV’s carcinogenic potential depends on its misappropriation of cellular proteins by HPV’s oncoproteins E6 and E7. High-risk HPV type 16 (HPV16) E6 binds directly to the cellular protein NFX1-123 and dysregulates proliferation, differentiation, and immunity genes. The effect of HPV16 E7 has not been studied in relation to HPV16 E6-NFX1-123-mediated dysregulation. As HPV expresses both oncogenes, and HPV carcinogenesis requires E6 and E7, it is valuable to investigate what dysregulations occur in this context. It is also important to understand their clinical and prognostic ramifications. This study’s goal was to define the gene expression profile regulated by HPV16 E6, E7, and NFX1-123 across cervical precancers and cancers, identify genes correlating with disease progression, assess patient survival, and validate findings in cell models. Finding correlates of survival and disease progression aids in biomarker identification and focuses future studies.

Abstract

High-risk human papillomavirus (HR HPV) causes nearly all cervical cancers, half of which are due to HPV type 16 (HPV16). HPV16 oncoprotein E6 (16E6) binds to NFX1-123, and dysregulates gene expression, but their clinical implications are unknown. Additionally, HPV16 E7’s role has not been studied in concert with NFX1-123 and 16E6. HR HPVs express both oncogenes, and transformation requires their expression, so we sought to investigate the effect of E7 on gene expression. This study’s goal was to define gene expression profiles across cervical precancer and cancer stages, identify genes correlating with disease progression, assess patient survival, and validate findings in cell models. We analyzed NCBI GEO datasets containing transcriptomic data linked with cervical cancer stage and utilized LASSO analysis to identify cancer-driving genes. Keratinocytes expressing 16E6 and 16E7 (16E6E7) and exogenous NFX1-123 were tested for LASSO-identified gene expression. Ten out of nineteen genes correlated with disease progression, including CEBPD, NOTCH1, and KRT16, and affected survival. 16E6E7 in keratinocytes increased CEBPD, KRT16, and SLPI, and decreased NOTCH1. Exogenous NFX1-123 in 16E6E7 keratinocytes resulted in significantly increased CEBPD and NOTCH1, and reduced SLPI. This work demonstrates the clinical relevance of CEBPD, NOTCH1, KRT16, and SLPI, and shows the regulatory effects of 16E6E7 and NFX1-123.

NFX1, Its Isoforms and Roles in Biology, Disease and Cancer

Simple Summary

The NFX1 gene, and its gene products, were identified over 30 years ago. Since then, the literature on NFX1 homologs and NFX1 itself has grown. In this review, we summarize the studies to-date on the NFX1 gene and its proteins across species and in humans, describing their role in gene regulation, embryonic development, cellular growth and differentiation, exogenous stress tolerance and metabolism, and an organism’s immune response. We also highlight the roles NFX1 has in human disease and in cancer, with a strong focus on its collaborative role with high-risk human papillomavirus infections that cause cervical and head and neck cancers. We believe this is the first comprehensive review of NFX1 and its functional significance in organisms ranging from yeast to human.

Abstract

In 1989, two NFX1 protein products were identified as nuclear proteins with the ability to bind to X-box cis-elements. Since that publication, the NFX1 gene and its homologs have been identified, from yeast to humans. This review article summarizes what is known about the NFX1 gene across species. We describe the gene and protein motifs of NFX1 homologs and their functions in cellular biology, then turn to NFX1 in human biology and disease development. In that, we focus on more recent literature about NFX1 and its two splice variants protein products (NFX1-91 and NFX1-123) that are expressed in epithelial cells. We describe new evidence of conserved protein motifs, direct and indirect gene expression regulation, and critical protein-protein interactions. Finally, we stress the emerging roles of these NFX1 splice variants in high-risk human papillomavirus-associated cancers, and the increased expression of the longer splice variant, NFX1-123, found in these cancers.

Nonclinical safety evaluation of oral recombinant anti-human papilloma virus vaccine (RHPV 16 & 18): Regulatory toxicology studies in mice, rats and rabbits - An innovative approach

AIM

The human papilloma virus (HPV) type 16 and 18 causes nearly 70% of uterine cervical cancers. Oral administration of live Salmonella typhi Ty21a, expressing major capsid proteins (L1) of HPV 16 and 18 is a potential choice for immunization in adolescent girls under low resource settings. Present study aimed to assess the nonclinical safety of recombinant S. typhi expressing HPV 16 and 18 (rStHPV) proteins.

METHODOLOGY

The acute toxicity of rStHPV was tested by intranasal single dose administration, of 10 and 50 folds higher than clinical prophylactic dose, in mice and rat followed by monitoring their survival for 14 days. Sub-chronic toxicity was evaluated in rats and rabbits with prophylactic and 5 times (average) to clinical prophylactic dosages on scheduled days (1st, 3rd & 5th day) through oral and intranasal routes. The immune/allergic response of rStHPV was assessed in mice through intranasal and intra-peritoneal routes. Experimental animals were daily monitored for live phase, and clinical chemistry, haematology, immunotoxicology, immunogenic response and histopathological examination of vital organs on 15th, 29th and 93rd days.

RESULTS

No abnormal changes were noticed in live phase activity, clinical chemistry and haematology profile. The gross necropsy, organ weights and histopathology were found to be normal. No immunotoxicity was recorded as evaluated by tier I tests. Allergic immune response, as evaluated with IgE levels was also negative irrespective of test routes. On the other hand, a significant (P < 0.01) increase of anti-HPV IgG levels was noted in mice exposed through intranasal route. Though the pre-terminal mortality was noted in mice (6-15%), rats (10%) and rabbits (15%), the autopsy revealed no signs of toxicity related to rStHPV, as the changes neither significant nor dose dependent; and even noted in vehicle control also.

CONCLUSION

The study results suggested 'no observable adverse effects' of rStHPV even at higher dosages (5, 10 & 50 folds) than intended clinical dose. A significant increase of anti-HPV specific IgG suggests the immunogenicity of vaccine. The innovative approach of current study is nonclinical toxicology evaluation of vaccine through intra-nasal route, an alternate route apart from stipulated regulatory guidelines.