High-risk Human Papillomavirus E6 Research Articles

The Distribution of HR-HPV E6/E7 DNA and mRNA by Histological Grade and the Clinical Performance for Detection of Cervical Cancer and Precancer.

High-risk human papillomavirus (HR-HPV) testing, utilizing both DNA and RNA methods, offers enhanced sensitivity compared to cytology for detecting high-grade cervical intraepithelial neoplasia (CIN2+). Meanwhile, HR-HPV E6 and E7 mRNAs are more likely to differentiate the transient infection from the persistent than DNA. Aptima HPV can not only detect HPV mRNA but also HPV DNA though it is much more efficient at detecting HPV RNA than DNA. Currently, there are few studies on the distribution of HPV E6 and E7 mRNA and DNA in the same individual. It is interesting to compare the clinical performance of the Onclarity and Aptima HPV assays and to assess variations in viral load across different histological grades at both DNA and mRNA levels. The analysis included 1607 women (902 from a cervical cancer screening population and 705 inpatients and outpatients), with cervical cytological samples tested using the Aptima and Onclarity HPV assays. Both assays demonstrated high agreement for HPV types 18/45 and 16. Signal-to-cutoff (S/CO) values and Ct values for various HR-HPV types increased with histological severity from normal tissue to cancer. Notably, HPV18 Ct values exceeded those for HPV16 and 45 in women with ≥ CIN1 lesions but decreased sharply in cancer cases. Across the screening population, both assays showed similar sensitivity and predictive values for detecting CIN2+ lesions. The area under the curve (AUC) for CIN2+ and CIN3+ detection in the study population was robust (CIN2+: 0.880, 0.863; CIN3+: 0.881, 0.863). The DNA level for various HR-HPV types increased with histological severity from normal tissue to cancer, which might impact the performance of Aptima HPV assay. Both assays showed similar sensitivity and predictive values for detecting CIN2+ lesions.

In Silico Drug Designing for the Treatment of Cervical Cancer

Cervical cancer is a significant global health issue, especially in developing countries where limited resources and access to health services pose challenges. Human papillomavirus (HPV) is the primary cause of cervical cancer and plays a crucial role in its development. Despite the availability of prophylactic vaccines, effective treatment options for patients with pre-existing HPV infections or HPV-induced carcinomas remain elusive. High-risk (HR) HPV E6 and E7 oncoproteins serve as biomarkers in cervical cancer progression. Research has focused on these proteins as potential targets for novel therapeutics and to find a novel compound that can overcome the problem of drug ineffectiveness in cancerous cells as they become multi-drug resistant to the existing drugs and treatments. Computational-aided methods, including in silico approaches, have been valuable in discovering and developing small molecules that can block or inhibit the action of the E6 oncoproteins. This review discusses existing small molecules explored as HPV E6 protein blockers and outlines future perspectives in cervical cancer therapy. In molecular docking studies, it is identified that four compounds exhibit the properties of a lead molecule, possess more negative binding energy, and form a highly stable ligand-receptor complex. These four compounds will help in future research and development. Advancing these compounds through further studies will help develop potential and effective drugs for treating cervical cancer.

HPV16 E6-induced M2 macrophage polarization in the cervical microenvironment via exosomal miR-204-5p

The persistent infection of high-risk human papillomavirus (HPV) and the progression of cervical cancer necessitate the involvement of microenvironmental immunity. As cervical lesions advance, there is an observed increase in the infiltration of type 2 (M2) macrophages. However, the precise mechanism driving this increased infiltration of M2 macrophages remains unclear. In this study, we investigated the role of exosomes in polarising M2 macrophages in cervical lesions associated with HPV E6. Through the analysis of bioinformatics data and clinical specimens, we discovered a positive correlation between HPV E6/E7 mRNA copy number and the level of M2 macrophage infiltration. Exosomes derived from HPV E6 overexpressed (HPV E6+) cervical squamous cell carcinoma (CESC) cells were found to induce the polarisation of macrophages towards M2 type. Specifically, miR-204-5p, enriched in HPV E6 + CESC exosomes, was transported into macrophages and triggered M2 macrophage polarisation by inhibiting JAK2. The clinical relevance of exosomal miR-204-5p in the progression of cervical lesions was validated through serum samples from 35 cases. Exosomal miR-204-5p emerges as a critical factor influencing M2 macrophage polarisation and is correlated with the severity of cervical lesions. Consequently, miR-204-5p could be used as a potential treatment and a candidate biomarker for cervical lesions.

HPV18 E7 inhibits LATS1 kinase and activates YAP1 by degrading PTPN14.

High-risk human papillomavirus (HPV) oncoproteins inactivate cellular tumor suppressors to reprogram host cell signaling pathways. HPV E7 proteins bind and degrade the tumor suppressor PTPN14, thereby promoting the nuclear localization of the YAP1 oncoprotein and inhibiting keratinocyte differentiation. YAP1 is a transcriptional coactivator that drives epithelial cell stemness and self-renewal. YAP1 activity is inhibited by the highly conserved Hippo pathway, which is frequently inactivated in human cancers. MST1/2 and LATS1/2 kinases form the core of the Hippo kinase cascade. Active LATS1 kinase is phosphorylated on threonine 1079 and inhibits YAP1 by phosphorylating it on amino acids including serine 127. Here, we tested the effect of high-risk (carcinogenic) HPV18 E7 on Hippo pathway activity. We found that either PTPN14 knockout or PTPN14 degradation by HPV18 E7 decreased the phosphorylation of LATS1 T1079 and YAP1 S127 in human keratinocytes and inhibited keratinocyte differentiation. Conversely, PTPN14-dependent differentiation required LATS kinases and certain PPxY motifs in PTPN14. Neither MST1/2 kinases nor the putative PTPN14 phosphatase active sites were required for PTPN14 to promote differentiation. Together, these data support that PTPN14 inactivation or degradation of PTPN14 by HPV18 E7 reduce LATS1 activity, promoting active YAP1 and inhibiting keratinocyte differentiation.IMPORTANCEThe Hippo kinase cascade inhibits YAP1, an oncoprotein and driver of cell stemness and self-renewal. There is mounting evidence that the Hippo pathway is targeted by tumor viruses including human papillomavirus. The high-risk HPV E7 oncoprotein promotes YAP1 nuclear localization and the carcinogenic activity of high-risk HPV E7 requires YAP1 activity. Blocking HPV E7-dependent YAP1 activation could inhibit HPV-mediated carcinogenesis, but the mechanism by which HPV E7 activates YAP1 has not been elucidated. Here we report that by degrading the tumor suppressor PTPN14, HPV18 E7 inhibits LATS1 kinase, reducing inhibitory phosphorylation on YAP1. These data support that an HPV oncoprotein can inhibit Hippo signaling to activate YAP1 and strengthen the link between PTPN14 and Hippo signaling in human epithelial cells.

HPV18 E7 inhibits LATS1 kinase and activates YAP1 by degrading PTPN14.

High-risk human papillomavirus (HPV) oncoproteins inactivate cellular tumor suppressors to reprogram host cell signaling pathways. HPV E7 proteins bind and degrade the tumor suppressor PTPN14, thereby promoting the nuclear localization of the YAP1 oncoprotein and inhibiting keratinocyte differentiation. YAP1 is a transcriptional coactivator that drives epithelial cell stemness and self-renewal. YAP1 activity is inhibited by the highly conserved Hippo pathway, which is frequently inactivated in human cancers. MST1/2 and LATS1/2 kinases form the core of the Hippo kinase cascade. Active LATS1 kinase is phosphorylated on threonine 1079 and inhibits YAP1 by phosphorylating it on amino acids including serine 127. Here, we tested the effect of high-risk (carcinogenic) HPV18 E7 on Hippo pathway activity. We found that either PTPN14 knockout or PTPN14 degradation by HPV18 E7 decreased phosphorylation of LATS1 T1079 and YAP1 S127 in human keratinocytes and inhibited keratinocyte differentiation. Conversely, PTPN14-dependent differentiation required LATS kinases and certain PPxY motifs in PTPN14. Neither MST1/2 kinases nor the putative PTPN14 phosphatase active site were required for PTPN14 to promote differentiation. Taken together, these data support that PTPN14 inactivation or degradation of PTPN14 by HPV18 E7 reduce LATS1 activity, promoting active YAP1 and inhibiting keratinocyte differentiation.

Structure-Based Discovery of Potential HPV E6 and EBNA1 Inhibitors: Implications for Cervical Cancer Treatment

Cervical cancer is the fourth most diagnosed cancer and the fourth leading cause of cancer death in women globally. Its onset and progression have been attributed to high-risk human papillomavirus (HPV) types, especially 16 and 18, while the Epstein–Barr virus (EBV) is believed to also significantly contribute to cervical cancer growth. The E6 protein associated with high-risk HPV strains, such as HPV16 and HPV18, is known for its role in promoting cervical cancer and other anogenital cancers. E6 proteins contribute to the malignant transformation of infected cells by targeting and degrading tumor suppressor proteins, especially p53. On the other hand, EBV nuclear antigen 1 (EBNA1) plays a crucial role in the maintenance and replication of the EBV genome in infected cells. EBNA1 is believed to increase HPV E6 and E7 levels, as well as c-MYC, and BIRC5 cellular genes in the HeLa cell line, implying that HPV/EBV co-infection accelerates cervical cancer onset and growth. Thus, the E6 and EBNA1 antigens of HPV and EBV, respectively, are attractive targets for cervical cancer immunotherapy. This study, therefore, virtually screened for potential drug candidates with good binding affinity to all three oncoviral proteins, HPV16 E6, HPV18 E6, and EBNA1. The compounds were further subjected to ADMET profiling, biological activity predictions, molecular dynamics (MD) simulations, and molecular mechanics Poisson–Boltzmann surface area (MM/PBSA) calculations. A total of six compounds comprising ZINC000013380012, ZINC000070454124, ZINC000014588133, ZINC000085568136, ZINC000095909247, and ZINC000085597263 demonstrated very strong affinity (≤−60 kJ/mol) to the three oncoviral proteins (EBNA1, HPV16 E6, and HPV18 E6) after being subjected to docking, MD, and MM/PBSA. These compounds demonstrated relatively stronger binding than the controls used, inhibitors of EBNA1 (VK-1727) and HPV E6 (baicalein and gossypetin). Biological activity predictions also corroborated their antineoplastic, p53-enhancing, Pin1 inhibitory, and JAK2 inhibitory activities. Further experimental testing is required to validate the ability of the shortlisted compounds to silence the insidious effects of HPV E6 and EBNA1 proteins in cervical cancers.

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

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

A novel HPV16 splicing enhancer critical for viral oncogene expression and cell immortalization.

High-risk carcinogenic human papillomaviruses (HPVs), e.g. HPV16, express the E6 and E7 oncogenes from two mRNAs that are generated in a mutually exclusive manner by splicing. The HPV16 E7 mRNA, also known as the E6*I/E7 mRNA, is produced by splicing between splice sites SD226 and SA409, while E6 mRNAs retain the intron between these splice sites. We show that splicing between HPV16 splice sites SD226 and SA409 is controlled by a splicing enhancer consisting of a perfect repeat of an adenosine-rich, 11 nucleotide sequence: AAAAGCAAAGA. Two nucleotide substitutions in both 11 nucleotide sequences specifically inhibited production of the spliced E6*I/E7 mRNA. As a result, production of E7 protein was reduced and the ability of HPV16 to immortalize human primary keratinocytes was abolished. The splicing-enhancing effect was mediated by the cellular TRAP150/THRAP3 protein that also enhanced splicing of other high-risk HPV E6*I/E7 mRNAs, but had no effect on low-risk HPV mRNAs. In summary, we have identified a novel splicing enhancer in the E6 coding region that is specific for high-risk HPVs and that is critically linked to HPV16 carcinogenic properties.

A Therapeutic DNA Vaccine Targeting HPV16 E7 in Combination with Anti-PD-1/PD-L1 Enhanced Tumor Regression and Cytotoxic Immune Responses.

Persistent infection of high-risk human papillomavirus (HPV) and the expression of E6 and E7 oncoproteins are the main causes of cervical cancer. Several prophylactic HPV vaccines are used in the clinic, but these vaccines have limited efficacy in patients already infected with HPV. Since HPV E7 is vital for tumor-specific immunity, developing a vaccine against HPV E7 is an attractive strategy for cervical cancer treatment. Here, we constructed an HPV16 E7 mutant that loses the ability to bind pRb while still eliciting a robust immune response. In order to build a therapeutic DNA vaccine, the E7 mutant was packaged in an adenovirus vector (Ad-E7) for efficient expression and enhanced immunogenicity of the vaccine. Our results showed that the Ad-E7 vaccine effectively inhibited tumor growth and increased the proportion of interferon-gamma (IFN-γ)-secreting CD8+ T cells in the spleen, and tumor-infiltrating lymphocytes in a mouse cervical cancer model was achieved by injecting with HPV16-E6/E7-expressing TC-1 cells subcutaneously. Combining the Ad-E7 vaccine with the PD-1/PD-L1 antibody blockade significantly improved the control of TC-1 tumors. Combination therapy elicited stronger cytotoxic T lymphocyte (CTL) responses, and IFN-γ secretion downregulated the proportion of Tregs and MDSCs significantly. The expressions of cancer-promoting factors, such as TNF-α, were also significantly down-regulated in the case of combination therapy. In addition, combination therapy inhibited the number of capillaries in tumor tissues and increased the thickness of the tumor capsule. Thus, Ad-E7 vaccination, in combination with an immune checkpoint blockade, may benefit patients with HPV16-associated cervical cancer.

Human papillomaviruses:Knowns, mysteries, and unchartered territories.

There has been an explosion in the number of papillomaviruses that have been identified and fully sequenced. Yet only a minute fraction of these has been studied in any detail. Most of our molecular research efforts have focused on the E6 and E7 proteins of "high-risk,"cancer-associated human papillomaviruses (HPVs). Interactions of the high-risk HPV E6 and E7 proteins with their respective cellular targets, the p53 and the retinoblastoma tumor suppressors, have been investigated in minute detail. Some have thus questioned if research on papillomaviruses remains an exciting and worthwhile area of investigation. However, fundamentally new insights on the biological activities and cellular targets of the high-risk HPV E6 and E7 proteins have been discovered and previously unstudied HPVs have been newly associated with human diseases. HPV infections continue to be an important cause of human morbidity and mortality and since there are no antivirals to combat HPV infections, research on HPVs should remain attractive to new investigators and biomedical funding agencies, alike.

Methyltransferase-independent function of enhancer of zeste homologue 2 maintains tumorigenicity induced by human oncogenic papillomavirus and polyomavirus

Merkel cell polyomavirus (MCV) and high-risk human papillomavirus (HPV) are human tumor viruses that cause Merkel cell carcinoma (MCC) and oropharyngeal squamous cell carcinoma (OSCC), respectively. HPV E7 and MCV large T (LT) oncoproteins target the retinoblastoma tumor suppressor protein (pRb) through the conserved LxCxE motif. We identified enhancer of zeste homolog 2 (EZH2) as a common host oncoprotein activated by both viral oncoproteins through the pRb binding motif. EZH2 is a catalytic subunit of the polycomb 2 (PRC2) complex that trimethylates histone H3 at lysine 27 (H3K27me3). In MCC tissues EZH2 was highly expressed, irrespective of MCV status. Loss-of-function studies revealed that viral HPV E6/E7 and T antigen expression are required for Ezh2 mRNA expression and that EZH2 is essential for HPV(+)OSCC and MCV(+)MCC cell growth. Furthermore, EZH2 protein degraders reduced cell viability efficiently and rapidly in HPV(+)OSCC and MCV(+)MCC cells, whereas EZH2 histone methyltransferase inhibitors did not affect cell proliferation or viability within the same treatment period. These results suggest that a methyltransferase-independent function of EZH2 contributes to tumorigenesis downstream of two viral oncoproteins, and that direct targeting of EZH2 protein expression could be a promising strategy for the inhibition of tumor growth in HPV(+)OSCC and MCV(+)MCC patients.

Immunotherapy in Anal Cancer

The incidence and mortality of squamous cell carcinoma of the anus has been gradually increasing globally over the last few decades. The evolution of different modalities, including immunotherapies, has changed the treatment paradigm of metastatic anal cancers. Chemotherapy, radiation therapy, and immune-modulating therapies form the backbone of treatment of anal cancer in various stages. Most anal cancers are linked to high-risk human papilloma virus (HPV) infections. HPV oncoproteins E6 and E7 are responsible for an anti-tumor immune response triggering the recruitment of tumor-infiltrating lymphocytes. This has led to the development and utilization of immunotherapy in anal cancers. Current research in anal cancer is moving forward to discover ways to incorporate immunotherapy in the treatment sequencing in various stages of anal cancers. Immune checkpoint inhibitors alone or in combination, adoptive cell therapy, and vaccines are the areas of active investigations in anal cancer in both locally advanced and metastatic settings. Immunomodulating properties of non-immunotherapies are incorporated to enhance immune checkpoint inhibitors' effectiveness in some of the clinical trials. The aim of this review is to summarize the potential role of immunotherapy in anal squamous cell cancers and future directions.

Abstract 3779: Evaluation of anti-cancer efficacy of lipid nanoparticles containing siRNA against HPV16 E6 and E7 combined with cisplatin in xenograft model of cervical cancer

Abstract Background: High-risk human papillomavirus (HPV) type 16 is the major etiological agent found in more than 60% of patients with cervical cancer and associated with cancer development and progression. Persistent expression HPV E6 and E7 oncoproteins are essential for the initiation and maintenance of cervical cancer. The therapeutic approaches targeting HPV E6 and E7 have been proved to be highly efficient in killing malignant cells. The suppression of HPV 16 E6/E7 expression by the short interfering RNA (siRNA) was more effective in combination therapy with cisplatin (CDDP) for cervical cancer. ENB101-LNP is an ionizable lipid nanoparticles (LNPs) encapsulating siRNA against E6/E7 of HPV 16 for delivery to the tumor cells. Methods: To investigate the anticancer efficacy and mechanism of ENB101-LNP combined with cisplatin in cervical cancer; the xenograft model was generated by the injection of CaSki cells subcutaneously into BALB/c nude mice. Mice were randomly divided into six groups: 1) blank control; 2) 1mg/kg ENB101-LNP; 3) 3mg/kg ENB101-LNP; 4) CDDP; 5) 1mg/kg ENB101-LNP-CDDP; 6) 3mg/kg ENB101-LNP-CDDP. ENB101-LNP was treated with intravenous injection three times weekly for 3 weeks and CDDP was treated with IP injection once a week for 3 weeks. Tumor growth curves were plotted to calculate the tumor inhibition rate. Mice were sacrificed one week after the last treatment and the tumor tissues were investigated using histopathology, immunohistochemical staining and western blotting. Results: Compared with the control and the other treatment groups, the tumor growth was significantly inhibited (P < 0.05). The tumor inhibition rate was 29.7% in 1mg/kg ENB101-LNP group, 29.6% in 3mg/kg ENB101-LNP group, 34.0% in CDDP group, 47.0% in 1mg/kg ENB101-LNP-CDDP group. At the dose of 3mg ENB101-LNP/kg combined with CDDP exhibited superior antitumor efficacy, the tumor inhibition rate was 68.8%. The successful ENB101-LNP mediated knockdown (with up to 80%) of HPV16 E6/E7 in tumors of both 1mg/kg and 3mg/kg groups was confirmed by RT-PCR. The ENB101-LNP increased p53 and p21 expression in tumors compared to control and CDDP alone groups and combination treatment with CDDP showed decreased expression of PD-L1 expression compared to CDDP alone group. The treatment of ENB101-LNP and combination with CDDP showed significant increase in apoptotic cells compared to control and single-agent groups respectively. Conclusions: The ENB101-LNP inhibiting E6 and E7 of HPV 16 in combination with CDDP showed promising anticancer activity in the cervical cancer cells xenograft mouse model. Citation Format: Sung Wan Kang, Shin-Wha Lee, Ji-young Lee, Ok Ju Kang, Hyejeong Kim, Yisak Kim, Yong-Man Kim. Evaluation of anti-cancer efficacy of lipid nanoparticles containing siRNA against HPV16 E6 and E7 combined with cisplatin in xenograft model of cervical cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3779.

Overexpression of the telomerase holoenzyme induces EMT and tumorigenesis of HPV-immortalized keratinocytes.

Cervical cancer is the most frequent malignancy of the female genital tract and is associated with persistent infection of the uterine cervix with high-risk human papillomaviruses (HPV). The two HPV oncoproteins, E6 and E7, cooperatively immortalize cervical cells and are essential but insufficient for inducing tumorigenicity. During the progression of HPV-associated cervical dysplasia to carcinoma, the cellular telomerase reverse transcriptase (TERT) gene is activated and the TERC gene amplified. We questioned whether these increases in telomerase components might mediate the acquisition of the tumorigenic phenotype. We therefore transduced the TERT and TERC genes into E6/E7 immortalized keratinocytes that were anchorage-dependent and nontumorigenic. The resultant cells showed a profound morphological change characteristic of epithelial-mesenchymal transitionas well as a corresponding increase in expression of vimentin, N-cadherin, Zinc finger E-Box binding homeobox 1, snail family transcriptional repressor 1and matrix Metallopeptidase 2 and decrease in keratin and E-cadherin. More important, the transduced cells were now anchorage-independent and formed tumors in immunodeficient mice. Our findings indicate that overexpression of the telomerase holoenzyme in HPV-immortalized cells is sufficient to induce the complete transformed phenotype.

Feasibility of self-sampling and human papillomavirus testing in rural and urban areas for cervical cancer prevention in Bolivia: an observational study

Cervical cancer is a major health problem in Latin America. In 2019, the Italian Agency for Development Cooperation (La Paz regional site) conducted a pilot study to estimate the prevalence of high-risk human papillomavirus (HPV) and the feasibility of HPV screening in Bolivia through self-sampling and portable and transportable laboratory instruments for HPV testing in urban and rural areas. Women aged 20-65 years from La Paz (urban area), Torotoro (rural area), and Acasio (rural area) were enrolled by invitation from local public health centres between Dec 1, 2019, and June 30, 2021. Self-sampling was carried out with the Viba-Brush system (Rovers, Oss, Netherlands) and samples were preserved in ThinPrep containers (Hologic Corporation, San Diego, CA, USA). The GeneXpert system (Cepheid, Sunnyvale, CA, USA) for high-risk HPV testing detects HPV E6 and E7 DNA via real-time PCR in a mobile system of easy execution requiring minimal manual intervention. The system provides results in about 1 h. Women with a positive test for HPV types 16, 18, or 45 were invited for a follow-up colposcopy. Data analysis was done considering the following age groups: <20, 20-34, 35-44, and 45-65 years. The study terminated later than expected (in June, 2021, instead of in November, 2020) due to the COVID-19 pandemic, and follow-up test retrieval is still ongoing. 2201 women were enrolled: 622 (28·3%) in La Paz, 768 (34·9%) in Torotoro, and 811 (36·8%) in Acasio. Only one sample was collected from each participant. 2076 (94·3%) of 2201 samples were adequate (yielding a negative or positive result) for HPV testing. 264 (12·7%) samples were positive for high-risk HPV. The observed prevalence was higher in the 20-34 age group (145 [15·5%] of 938) than in the 35-44 age group (60 [10·5%] of 571) and in the 45-65 years age group (37 [8·3%] of 444). Ages were not recorded for 123 samples, which are not included in the prevalence-per-age analysis. HPV positivity was detected in 94 (15·3%) of 614 samples from women from La Paz, 86 (12·9%) of 667 samples from patients from Torotoro, and 84 (10·6%) of 795 samples from patients from Acasio (risk ratio urban vs rural 1·4 [95% CI 1·04-1·80], p=0·029). Overall positivity was 58 (7·3%) of 795 for HPV type 16 and 38 (1·8%) of 2076 for HPV types 18 and 45. From the follow-up data available to date, all high-grade lesions detected on follow-up colposcopy were related to HPV types 16, 18, or 45, isolated or in co-infection with other high-risk HPV types. The total and age-adjusted prevalence of high-risk HPV infection in rural and urban areas in Bolivia, as measured with a validated test for screening, is similar to that observed in Europe and the USA. Our study shows that a screening protocol for HPV testing with self-sampling would be feasible in urban and rural areas in Bolivia, and that the high prevalence of cervical cancer in Bolivia is likely to be related to the scarcity of screening programmes, and not to a higher occurrence of high-risk HPV infections. Carrying out HPV tests locally avoids the issues associated with transport and storage of the material collected, and allows the participant to wait in the clinic for the test result. However, the cost of HPV testing, at about €15 per test, is still a major hurdle for low-income countries. Joint initiatives between the national scientific community, international institutions, and manufacturers could allow widespread testing of HPV to be rolled out in Bolivia and other countries with similar contexts. Italian Agency for Development Cooperation (Italian Ministry of Foreign Affairs), as a part of an ongoing technical assistance programme with the Bolivian Ministry of Health.

Rab31 promotes the invasion and metastasis of cervical cancer cells by inhibiting MAPK6 degradation.

Persistent infection with high-risk human papillomavirus (HPV) is the main risk factor for cervical cancer. Our mass spectrometry data showed that the Ras-associated binding protein Rab31 was upregulated by HPV; however, little is known regarding the role of Rab31 in the metastasis of cervical cancer cells. In this study, we showed that Rab31 was highly expressed in cervical cancer tissues and cells, and both HPV E6 and E7 promoted the expression of Rab31. Rab31 knockdown inhibited while Rab31 overexpression promoted the migration and invasion capabilities of cervical cancer cells. Additionally, Rab31 knockdown inhibited the epithelial-mesenchymal transition (EMT) and cytoskeletal rearrangement in cervical cancer cells. Furthermore, Rab31 interacted with mitogen-activated protein kinase 6 (MAPK6), and Rab31 knockdown inhibited the expression of MAPK6, which was mainly localized in the cytoplasm. More importantly, Rab31 knockdown promoted and Rab31 overexpression inhibited MAPK6 degradation. Accordingly, MAPK6 overexpression restored the decreased migration potential caused by Rab31 knockdown. Finally, a xenograft mouse model showed that Rab31 knockdown in cervical cancer cells led to reduced tumor growth and impaired lung and liver metastasis in vivo. In conclusion, Rab31 plays a crucial role in cervical cancer metastasis by inhibiting MAPK6 degradation. Thus, Rab31 may serve as a novel therapeutic target to manage cervical cancer.

In Silico Approaches: A Way to Unveil Novel Therapeutic Drugs for Cervical Cancer Management.

Cervical cancer (CC) is the fourth most common pathology in women worldwide and presents a high impact in developing countries due to limited financial resources as well as difficulties in monitoring and access to health services. Human papillomavirus (HPV) is the leading cause of CC, and despite the approval of prophylactic vaccines, there is no effective treatment for patients with pre-existing infections or HPV-induced carcinomas. High-risk (HR) HPV E6 and E7 oncoproteins are considered biomarkers in CC progression. Since the E6 structure was resolved, it has been one of the most studied targets to develop novel and specific therapeutics to treat/manage CC. Therefore, several small molecules (plant-derived or synthetic compounds) have been reported as blockers/inhibitors of E6 oncoprotein action, and computational-aided methods have been of high relevance in their discovery and development. In silico approaches have become a powerful tool for reducing the time and cost of the drug development process. Thus, this review will depict small molecules that are already being explored as HR HPV E6 protein blockers and in silico approaches to the design of novel therapeutics for managing CC. Besides, future perspectives in CC therapy will be briefly discussed.

Identification of High-Risk Human Papillomavirus DNA, p16, and E6/E7 Oncoproteins in Laryngeal and Hypopharyngeal Squamous Cell Carcinomas.

Human papillomavirus (HPV) was proven to play a significant role in cancer development in the oropharynx. However, its role in the development of laryngeal (LSCC) and hypopharyngeal squamous cell carcinoma (HPSCC) remains to be clarified. High-risk HPV (HR-HPV) viral proteins E6 and E7 are considered to be pertinent to HPV-related carcinogenesis. Hence, our aim was to estimate LSCC and HPSCC for HR-HPV DNA, p16, and E6/E7 oncoprotein status by using molecular virology and immunohistochemistry methods. The prevalence of HPV16 infection was 22/41 (53.7%) and 20/31 (64.5%) for LSCC and HPSCC, accordingly. The majority of HPV16+ tumor samples were stage III or IV. In most samples, the presence of either HPV16 E6 or HPV16 E7 viral protein in dysplastic or tumor cells was confirmed using immunohistochemistry. Our results suggest a high prevalence of HPV16 as a primary HR-HPV type in LSCC and HPSCC. The lack of HPV E6/E7 oncoproteins in some tumor samples may suggest either the absence of viral integration or the presence of other mechanisms of tumorigenesis. The utilization of p16 IHC as a surrogate marker of HR-HPV infection is impractical in LSCC and HPSCC.

RB1, p16, and Human Papillomavirus in Oropharyngeal Squamous Cell Carcinoma.

While P16 immunohistochemistry (IHC) is a well-established surrogate marker of Human Papillomavirus (HPV) in oropharyngeal squamous cell carcinoma (OSCC), Retinoblastoma 1 (RB1) loss may lead to p16 overexpression in the absence of HPV. We determined the proportion of p16-positive/HPV-negative OSCC with RB1 loss and other alterations in RB1/p16 pathway, and tested RB1 IHC as a prognostic biomarker for OSCC, along with the 8th edition of AJCC staging manual. P16 and RB1 IHC and HPV DNA in situ hybridization (ISH) were performed on 257 OSCC. High risk HPV RNA ISH, RB1 fluorescence in situ hybridization (FISH), and next generation sequencing (NGS) were done on p16-positive/HPV DNA ISH-negative OSCC. Disease free survival (DFS) was used as an endpoint. In the entire cohort and in p16-positive (n = 184) and p16-negative (n = 73) subgroups, AJCC 8th edition staging correlated with DFS (p < 0.01). RB1 IHC showed RB1 loss in p16-positive OSCC only (79/184, 43%). RB1 loss by IHC is associated with a better DFS, without providing additional prognostic information for patients with p16-positive OSCC. HPV RNA ISH was positive in 12 of 14 HPV DNA ISH-negative cases. RB1 IHC showed loss in 10 of 15 HPV DNA ISH-negative cases and in 1 of 2 HPV RNA ISH-negative cases. Overall, only one case of p16-positive/HPV RNA ISH-negative OSCC showed RB1 loss by IHC (1/184, 0.5%). Of the 10 p16-positive and HPV DNA ISH-negative cases with RB1 loss by IHC, 2 had RB1 hemizygous deletion and 3 showed Chromosome 13 monosomy by FISH. No RB1 mutations were detected by NGS. Other molecular alterations in p16-positive/HPV DNA ISH-negative cases included TP53 and TERT mutations and DDX3X loss. HPV-independent RB1 inactivation rarely results in false positive p16 IHC. RB1 inactivation by high risk HPV E7 oncoprotein may co-exist with RB1 deletion. RB1 loss is a favorable prognosticator and occurs exclusively in p16-positive OSCC. The 8th edition of the AJCC staging manual satisfactorily predicts DFS of OSCC patients.

HPV E7 affects the function of cervical cancer cells via the TAL1/lnc‑EBIC/KLHDC7B axis.

High‑risk human papillomavirus (HPV)16 and 18 are the primary cause of cervical cancer (CC) and long non‑coding RNAs (lncRNAs/lncs) are often abnormally expressed in patients with CC. The authors' previous study indicated that oncogenic enhancer of zeste homolog2 (EZH2)‑binding lncRNA in cervical cancer (lnc‑EBIC) serves a role in the tumorigenic activity of the HPV E6 protein in patients with CC. However, whether HPV E7 affects the development of CC through lnc‑EBIC, and the potential mechanisms underlying this remains unclear. Therefore, the present study investigated the effects of lnc‑EBIC and HPV E7 in cervical cancer cell lines HeLa, CaSki and C33A invitro. CCK‑8, EdU and DAPI staining assays, flow cytometry, RT‑qPCR, western blotting and Transwell assay were performed on these cell lines. The results revealed that exogenous expression of HPV16/18 E7 significantly promoted lnc‑EBIC expression, and conversely, lnc‑EBIC was downregulated by silencing endogenous HPV16/18 E7 expression in corresponding CaSki and HeLa cells. Overexpression of lnc‑EBIC significantly increased cellular proliferation, migration and invasion, and inhibited apoptosis in HPV‑ C33A cells. The tumorigenic effects of HPV16/18 E7 in corresponding CaSki and HeLa cells were significantly blocked by the silencing of lnc‑EBIC expression. Molecular analysis revealed that HPV16/18 E7 depended on TAL BHLH transcription factor 1, erythroid differentiation factor inhibition to promote lnc‑EBIC expression, which also resulted in the upregulation of oncogenic Kelch domain‑containing 7B (KLHDC7B) in corresponding CaSki and HeLa cells. Additionally, KLHDC7B knockdown blocked the tumor‑promotive effects of lnc‑EBIC in HPV‑ C33A cells. Collectively, the results of the present study indicated that lnc‑EBIC acts as an oncogenic lncRNA by enhancing KLHDC7B expression in HPV+ and HPV‑ CC cells, and can be exploited by HPV16/18 E7 to accelerate tumorigenic activity in CC. These results further revealed that the lnc‑EBIC/KLHDC7B axis represents a novel molecular mechanism and potential therapeutic target for CC.