Regression of human papillomavirus intraepithelial lesions is induced by MVA E2 therapeutic vaccine

Enhancement of HPV therapeutic peptide-based vaccine efficacy through combination therapies and improved delivery strategies: A review

Human papillomavirus (HPV) has been linked to the development of various cancers, including head and neck, cervical, vaginal, penile, and anal cancers. The development of therapeutic vaccines against HPV-positive tumors is crucial for protecting individuals already infected with HPV, preventing tumor progression, and effectively treating the disease. The HPV therapeutic peptide-based vaccines demonstrate specificity and safety advantages by targeting specific epitopes while minimizing the risk of allergic or autoimmune reactions. However, HPV therapeutic peptide-based vaccines typically lack immunogenicity and frequently fail to induce effective immune responses. Therefore, there is a need for more effective approaches to improve the immunogenicity of HPV peptide-based vaccines. Here, we review relevant research and possible uses for increasing the immunogenicity and therapeutic efficacy of HPV peptide-based vaccines through combined therapy and improved delivery strategies. Additional research is necessary to validate the application of combination therapy and delivery strategy modifications as standard treatment approaches for HPV therapeutic peptide-based vaccines.

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.

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.

Advances in molecular basis of response to immunotherapy for penile cancer: better screening of responders

Penile cancer is a rare malignant tumor of the male urinary system. The treatment benefit of standard first-line chemotherapy is not ideal for patients with locally advanced or metastatic lymph nodes. Immunotherapy has brought new treatment strategies and opportunities for patients with penile cancer. At present, clinical studies on immunotherapy for penile cancer have been reported, and the results show that it is effective but not conclusive. With the development of immunotherapy and the progress of molecular research technology, we can better screen the immunotherapy response population and explore new combination treatment regimens to evaluate the best combination regimen and obtain the optimal treatment options, which is also an important research direction for the immunotherapy of penile cancer in the future.

Development of an mRNA-based therapeutic vaccine mHTV-03E2 for high-risk HPV-related malignancies

Human papillomavirus (HPV) 16 and 18 infections are related to many human cancers. Despite several preventive vaccines for high-risk (hr) HPVs, there is still an urgent need to develop therapeutic HPV vaccines for targeting pre-existing hrHPV infections and lesions. In this study, we developed a lipid nanoparticle (LNP)-formulated mRNA-based HPV therapeutic vaccine (mHTV)-03E2, simultaneously targeting the E2/E6/E7 of both HPV16 and HPV18. mHTV-03E2 dramatically induced antigen-specific cellular immune responses, leading to significant CD8+ T cell infiltration and cytotoxicity in TC-1 tumors derived from primary lung epithelial cells of C57BL/6 mice expressing HPV E6/E7 antigens, mediated significant tumor regression, and prolonged animal survival, in a dose-dependent manner. We further demonstrated significant T cell immunity against HPV16/18 E6/E7 antigens for up to 4 months post-vaccination in immunological and distant tumor rechallenging experiments, suggesting robust memory T cell immunity against relapse. Finally, mHTV-03E2 synergized with immune checkpoint blockade to inhibit tumor growth and extend animal survival, indicating the potential in combination therapy. We conclude that mHTV-03E2 is an excellent candidate therapeutic mRNA vaccine for treating malignancies caused by HPV16 or HPV18 infections.

Therapeutic Role of HPV Vaccination on Benign HPV-induced Epithelial Proliferations in Immunocompetent and Immunocompromised Patients: Case Study and Review of the Literature

Human papillomavirus (HPV) vaccination represents a milestone in primary prevention of sexually transmitted infections. However, little is known about its possible effects on already established HPV infections. We report the case of a 9-year-old immunosuppressed girl with refractory warts, successfully treated with the nonavalent-HPV vaccine and review the literature about the therapeutic effects of HPV vaccination on benign HPV-induced epithelial proliferations in immunocompetent and immunosuppressed patients. In the literature, promising results were shown on cutaneous warts after HPV vaccination, especially in children and young adults, also in immunosuppressed patients, whereas controverse results were found on anogenital warts. These findings suggest a critical need for randomized clinical trials to assess the efficacy of HPV vaccination in the treatment of benign HPV-induced epithelial proliferations.

Current status and future directions for the development of human papillomavirus vaccines

The development of human papillomavirus (HPV) vaccines has made substantive progress, as represented by the approval of five prophylactic vaccines since 2006. Generally, the deployment of prophylactic HPV vaccines is effective in preventing newly acquired infections and incidences of HPV-related malignancies. However, there is still a long way to go regarding the prevention of all HPV infections and the eradication of established HPV infections, as well as the subsequent progression to cancer. Optimizing prophylactic HPV vaccines by incorporating L1 proteins from more HPV subtypes, exploring adjuvants that reinforce cellular immune responses to eradicate HPV-infected cells, and developing therapeutic HPV vaccines used either alone or in combination with other cancer therapeutic modalities might bring about a new era getting closer to the vision to get rid of HPV infection and related diseases. Herein, we summarize strategies for the development of HPV vaccines, both prophylactic and therapeutic, with an emphasis on the selection of antigens and adjuvants, as well as implications for vaccine efficacy based on preclinical studies and clinical trials. Additionally, we outline current cutting-edge insights on formulation strategies, dosing schedules, and age expansion among HPV vaccine recipients, which might play important roles in addressing barriers to vaccine uptake, such as vaccine hesitancy and vaccine availability.

Immunogenicity and effectiveness of an mRNA therapeutic vaccine for HPV-related malignancies

Human papillomavirus (HPV) infections account for several human cancers. There is an urgent need to develop therapeutic vaccines for targeting preexisting high-risk HPV (such as HPV 16 and 18) infections and lesions, which are insensitive to preventative vaccines. In this study, we developed a lipid nanoparticle-formulated mRNA-based HPV therapeutic vaccine (mHTV), mHTV-02, targeting the E6/E7 of HPV16 and HPV-18. mHTV-02 dramatically induced antigen-specific cellular immune response and robust memory T-cell immunity in mice, besides significant CD8+ T-cell infiltration and cytotoxicity in TC-1 tumors expressing HPV E6/E7, resulting in tumor regression and prolonged survival in mice. Moreover, evaluation of routes of administration found that intramuscular or intratumoral injection of mHTV-02 displayed significant therapeutic effects. In contrast, intravenous delivery of the vaccine barely showed any benefit in reducing tumor size or improving animal survival. These data together support mHTV-02 as a candidate therapeutic mRNA vaccine via specific administration routes for treating malignancies caused by HPV16 or HPV18 infections.

Structured Literature Review to Identify Human Papillomavirus's Natural History Parameters for Dynamic Population Models of Vaccine Impacts

Human papillomavirus (HPV) is a common sexually transmitted virus that can cause cervical cancer and other diseases. Dynamic transmission models (DTMs) have been developed to evaluate the health and economic impacts of HPV vaccination. These models typically include many parameters, such as natural history of the disease, transmission, demographic, behavioral, and screening. To ensure the accuracy of DTM projections, it is important to parameterize them with the best available evidence. This study aimed to identify and synthesize data needed to parametrize DTMs on the natural history of HPV infection and related diseases. Parameters describing data of interest were grouped by their anatomical location (genital warts, recurrent respiratory papillomatosis, and cervical, anal, vaginal, vulvar, head and neck, and penile cancers), and natural history (progression, regression, death, cure, recurrence, detection), and were identified through a systematic literature review (SLR) and complementary targeted literature reviews (TLRs). The extracted data were then synthesized by pooling parameter values across publications, and summarized using the range of values across studies reporting each parameter and the median value from the most relevant study. Data were extracted and synthesized from 223 studies identified in the SLR and TLRs. Parameters frequently reported pertained to cervical cancer outcomes, while data for other anatomical locations were less available. The synthesis of the data provides a large volume of parameter values to inform HPV DTMs, such as annual progression rates from cervical intraepithelial neoplasia (CIN) 1 to CIN 2+ (median of highest quality estimate 0.0836), CIN 2 to CIN 3+ (0.0418), carcinoma in situ (CIS) 2 to local cancer+ (0.0396), and regional to distant cancer (0.0474). Our findings suggest that while there is a large body of evidence on cervical cancer, parameter values featured substantial heterogeneity across studies, and further studies are needed to better parametrize the non-cervical components of HPV DTMs.

Human Papillomavirus and Associated Cancers: A Review

The human papillomavirus is the most common sexually transmitted infection in the world. Most HPV infections clear spontaneously within 2 years of infection; however, persistent infection can result in a wide array of diseases, ranging from genital warts to cancer. Most cases of cervical, anal, and oropharyngeal cancers are due to HPV infection, with cervical cancer being one of the leading causes of cancer death in women worldwide. Screening is available for HPV and cervical cancer, but is not available everywhere, particularly in lower-resource settings. HPV infection disproportionally affects individuals living with HIV, resulting in decreased clearance, increased development of cancer, and increased mortality. The development of the HPV vaccine has shown a drastic decrease in HPV-related diseases. The vaccine prevents cervical cancer with near 100% efficacy, if given prior to first sexual activity. Vaccination uptake remains low worldwide due to a lack of access and limited knowledge of HPV. Increasing awareness of HPV and access to vaccination are necessary to decrease cancer and HPV-related morbidity and mortality worldwide.

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.

Advances in vaccine development for Chlamydia trachomatis

Chlamydia trachomatis is the most prevalent bacterial sexually transmitted infection globally. Antibiotic treatment is highly effective, but infection is often asymptomatic resulting in most individuals going undetected and untreated. This untreated infection can ascend to the upper female genital tract to cause pelvic inflammatory disease, tubal factor infertility, and ectopic pregnancy. Chlamydia screening and treatment programs have failed to control this epidemic and demonstrate the need for an efficacious vaccine to prevent transmission and disease. Animal models and human epidemiological data reveal that natural immunity can provide partial or short-lived sterilizing immunity. These data further demonstrate the importance of eliciting interferon gamma (IFNγ)-producing cluster of differentiation 4 (CD4) T cells (Th1 and Th1/17 cells) that can likely synergize with antibody-mediated opsonophagocytosis to provide optimal protection. These studies have guided preclinical rational vaccine design for decades and the first Phase 1 clinical trials have recently been completed. Recent advances have led to improvements in vaccine platforms and clinically safe adjuvants that help provide a path forward. This review describes vaccine models, correlates of immunity, antigen and adjuvant selection, and future clinical testing for Chlamydia vaccine development.

Safety, Efficacy, and Immunogenicity of Therapeutic Vaccines for Patients with High-Grade Cervical Intraepithelial Neoplasia (CIN 2/3) Associated with Human Papillomavirus: A Systematic Review

Despite the knowledge that HPV is responsible for high-grade CIN and cervical cancer, little is known about the use of therapeutic vaccines as a treatment. We aimed to synthesize and critically evaluate the evidence from clinical trials on the safety, efficacy, and immunogenicity of therapeutic vaccines in the treatment of patients with high-grade CIN associated with HPV. A systematic review of clinical trials adhering to the PRISMA 2020 statement in MEDLINE/PubMed, Embase, CENTRAL Cochrane, Web of Science, Scopus, and LILACS was undertaken, with no data or language restrictions. Primary endpoints related to the safety, efficacy, and immunogenicity of these vaccines were assessed by reviewing the adverse/toxic effects associated with the therapeutic vaccine administration via histopathological regression of the lesion and/or regression of the lesion size and via viral clearance and through the immunological response of individuals who received treatment compared to those who did not or before and after receiving the vaccine, respectively. A total of 1184 studies were identified, and 16 met all the criteria. Overall, the therapeutic vaccines were heterogeneous regarding their formulation, dose, intervention protocol, and routes of administration, making a meta-analysis unfeasible. In most studies (n = 15), the vaccines were safe and well tolerated, with clinical efficacy regarding the lesions and histopathological regression or viral clearance. In addition, eleven studies showed favorable immunological responses against HPV, and seven studies showed a positive correlation between immunogenicity and the clinical response, indicating promising results that should be further investigated. In summary, therapeutic vaccines, although urgently needed to avoid progression of CIN 2/3 patients, still present sparse data, requiring greater investments in a well-designed phase III RCT.

A Novel Recombinant Modified Vaccinia Ankara Virus expressing Interleukin-13 Receptor α2 Antigen for Potential Cancer Immunotherapy

BACKGROUND

Genetically altered recombinant poxviruses hold great therapeutic promise in animal models of cancer. Poxviruses can induce effective cellmediated immune responses against tumor-associated antigens. Preventive and therapeutic vaccination with a DNA vaccine expressing IL-13Rα2 can mediate partial regression of established tumors in vivo, indicating that host immune responses against IL-13Rα2 need further augmentation.

OBJECTIVE

The aim of the study is developing a recombinant modified vaccinia Ankara (MVA) expressing IL-13Rα2 (rMVA-IL13Rα2) virus and study in vitro infectivity and efficacy against IL-13Rα2 positive cell lines.

METHODS

We constructed a recombinant MVA expressing IL-13Rα2 and a green fluorescent protein (GFP) reporter gene. Purified virus titration by infection of target cells and immunostaining using anti-vaccinia and anti-IL-13Rα2 antibodies was used to confirm the identity and purity of the rMVA-IL13Rα2.

RESULTS

Western Blot analysis confirmed the presence of IL-13Rα2 protein (~52 kDa). Flow cytometric analysis of IL-13Rα2 negative T98G glioma cells when infected with rMVA-IL13Rα2 virus demonstrated cell-surface expression of IL-13Rα2, indicating the infectivity of the recombinant virus. Incubation of T98G-IL13Rα2 cells with varying concentrations (0.1-100 ng/ml) of interleukin-13 fused to truncated Pseudomonas exotoxin (IL13-PE) resulted in depletion of GFP+ fluorescence in T98G-IL13Rα2 cells. IL13-PE (10-1000 ng/ml) at higher concentrations also inhibited the protein synthesis in T98G-IL13Rα2 cells compared to cells infected with the control pLW44-MVA virus. IL13- PE treatment of rMVA-IL13Rα2 infected chicken embryonic fibroblast and DF-1 cell line reduced virus titer compared to untreated cells.

CONCLUSION

rMVA-IL13Rα2 virus can successfully infect mammalian cells to express IL-13Rα2 in a biologically active form on the surface of infected cells. To evaluate the efficacy of rMVA-IL13Rα2, immunization studies are planned in murine tumor models.

Vaccines for HPV-associated diseases

Human papillomavirus (HPV) infection represents a significant global health concern owing to its role in the etiology of conditions ranging from benign low-grade lesions to cancers of the cervix, head and neck, anus, vagina, vulva, and penis. Prophylactic vaccination programs, primarily targeting adolescent girls, have achieved dramatic reductions in rates of HPV infection and cervical cancer in recent years. However, there is a clear demand for a strategy to manage the needs of the many people who are already living with persistent HPV infection and/or HPV-associated conditions. Unlike prophylactic vaccines, which act to prevent HPV infection, therapeutic vaccination presents an opportunity to induce cellular immunity against established HPV infections and lesions and prevent progression to cancer. Several HPV vaccines are undergoing clinical development, using a range of platforms. Peptide- or protein-based vaccines, vector-based vaccines, whole-cell vaccines, and nucleic acid vaccines each offer relative merits and limitations for the delivery of HPV antigens and the subsequent generation of targeted immune responses. There has been particular interest in DNA-based vaccines, which elicit both cellular and humoral immune responses to provide long-lasting immunity. DNA vaccines offer several practical advantages over other vaccine platforms, including the potential for rapid and scalable manufacturing, targeting of many different antigens, and potential for repeat boosting. Furthermore, unlike vectored approaches, DNA vaccines are thermostable over extended time periods, which may enable shipping and storage. Several delivery strategies are available to address the main challenge of DNA vaccines, namely their relatively low transfection efficiency. We review the latest clinical data supporting the development of DNA vaccines and reflect on this exciting prospect in the management of HPV-related disease.

Epidemiology, Molecular Pathogenesis, Immuno-Pathogenesis, Immune Escape Mechanisms and Vaccine Evaluation for HPV-Associated Carcinogenesis

Human papillomavirus (HPV) is implicated in over 90% of cervical cancer cases, with factors like regional variability, HPV genotype, the population studied, HPV vaccination status, and anatomical sample collection location influencing the prevalence and pathology of HPV-induced cancer. HPV-16 and -18 are mainly responsible for the progression of several cancers, including cervix, anus, vagina, penis, vulva, and oropharynx. The oncogenic ability of HPV is not only sufficient for the progression of malignancy, but also for other tumor-generating steps required for the production of invasive cancer, such as coinfection with other viruses, lifestyle factors such as high parity, smoking, tobacco chewing, use of contraceptives for a long time, and immune responses such as stimulation of chronic stromal inflammation and immune deviation in the tumor microenvironment. Viral evasion from immunosurveillance also supports viral persistence, and virus-like particle-based prophylactic vaccines have been licensed, which are effective against high-risk HPV types. In addition, vaccination awareness programs and preventive strategies could help reduce the rate and incidence of HPV infection. In this review, we emphasize HPV infection and its role in cancer progression, molecular and immunopathogenesis, host immune response, immune evasion by HPV, vaccination, and preventive schemes battling HPV infection and HPV-related cancers.

Advances in Cancer Vaccine Research

The use of cancer vaccines is considered a promising therapeutic strategy in clinical oncology, which is achieved by stimulating antitumor immunity with tumor antigens delivered in the form of cells, peptides, viruses, and nucleic acids. The ideal cancer vaccine has many advantages, including low toxicity, specificity, and induction of persistent immune memory to overcome tumor heterogeneity and reverse the immunosuppressive microenvironment. Many therapeutic vaccines have entered clinical trials for a variety of cancers, including melanoma, breast cancer, lung cancer, and others. However, many challenges, including single antigen targeting, weak immunogenicity, off-target effects, and impaired immune response, have hindered their broad clinical translation. In this review, we introduce the principle of action, components (including antigens and adjuvants), and classification (according to applicable objects and preparation methods) of cancer vaccines, summarize the delivery methods of cancer vaccines, and review the clinical and theoretical research progress of cancer vaccines. We also present new insights into cancer vaccine technologies, platforms, and applications as well as an understanding of potential next-generation preventive and therapeutic vaccine technologies, providing a broader perspective for future vaccine design.

Efficacy and safety of therapeutic HPV vaccines to treat CIN 2/CIN 3 lesions: a systematic review and meta-analysis of phase II/III clinical trials

OBJECTIVES

We aim to assess the efficacy and safety of therapeutic human papillomavirus (HPV) vaccines to treat cervical intraepithelial neoplasia of grade 2 or 3 (CIN 2/3).

DESIGN

Systematic review and meta-analysis, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations.

DATA SOURCES

PubMed, Embase, Web of Science, Global Index Medicus and CENTRAL Cochrane were searched up to 31 January 2022.

ELIGIBILITY CRITERIA

Phase II/III randomised controlled trials (RCTs) and single-arm studies reporting the efficacy of therapeutic vaccines to achieve regression of CIN 2/3 lesions were included. Studies evaluating only safety and side effects of the vaccine were excluded.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted data and evaluated study quality. A random-effect model was used to pool the proportions of regression and/or HPV clearance.

RESULTS

12 trials met the inclusion criteria. Out of 734 women (all studies considered) receiving therapeutic HPV vaccine for CIN 2/3, 414 regressed to normal/CIN 1 with an overall proportion of regression of 0.54 (95% CI 0.39 to 0.69) for vaccinated group; 166 women (from five RCTs) receiving placebo only achieving a pooled normal/CIN 1 regression of 0.27 (95% CI 0.20 to 0.34). When including only the five two-arm studies, the regression proportion for the 410 vaccine group participants was higher than that of the 166 control group participants (relative risk (RR) 1.52; 95% CI 1.14 to 2.04). The pooled proportion of high-risk human papillomavirus (hrHPV) clearance was 0.42 (95% CI 0.32 to 0.52) in the vaccine group (six studies with a total of 357 participants) and 0.17 (95% CI 0.11 to 0.26) in the control group (three RCTs with a total of 104 participants). Based on these three RCTs, the hrHPV clearance was significantly higher in the vaccinated group (250 participants) compared with the control group (RR 2.03; 95% CI 1.30 to 3.16). Similar results were found regarding HPV 16/18 clearance. No significant unsolicited adverse events have been consistently reported.

CONCLUSIONS

The efficacy of the therapeutic vaccines in the treatment of CIN 2/3 was modest. Implementation issues such as feasibility, acceptability, adoption and cost-effectiveness need to be further studied.

PROSPERO REGISTRATION NUMBER

CRD42022307418.

Immunoinformatics applications in the development of therapeutic vaccines against human papillomavirus-related infections and cervical cancer

The human papillomavirus (HPV) represents the most prevalent sexually transmitted infectious agent worldwide. HPV penetrates the epithelium through microlesions and establishes an infectious focus that can lead to the development of cervical cancer. Prophylactic HPV vaccines are available, but do not affect already-established infections. Using in silico prediction tools is a promising strategy for identifying and selecting vaccine candidate T cell epitopes. An advantage of this strategy is that epitopes can be selected according to the degree of conservation within a group of antigenic proteins. This makes achieving comprehensive genotypic coverage possible with a small set of epitopes. Therefore, this paper revises the general characteristics of HPV biology and the current knowledge on developing therapeutic peptide vaccines against HPV-related infections and cervical cancer.

HPV pathogenesis, various types of vaccines, safety concern, prophylactic and therapeutic applications to control cervical cancer, and future perspective

Over 98% of cervical cancers (CC) are caused by regular infections with "high risk" genotype of the human papilloma virus (HPV). However, this is not always the causative factor. Therefore, production of HPV vaccinations represents a significant chance to minimize the risk of CC. Phase III studies for a number of preventative HPV vaccines based on L1-virus-like particle (VLPs) have just been completed and the preliminary results are very convincing. However, there are a lot of practical concerns that need to be resolved before the use of these vaccinations. These vaccines were challenged with obvious queries such as protection time, subject receiving vaccines, time of vaccination, and how to include them into ongoing screening programs. Although these vaccines were 90% effective at preventing HPV infection as these offered only modest advantages for the removal of pre-existing infections. New advancements in the creation of therapeutic vaccinations have been explored for further improvement and post-vaccination surveillance. Therapeutic vaccines attempted to boost cell-mediated immunities and these are detrimental to the infected cell as opposed to neutralizing antibodies (different from prophylactic vaccines).

Identification of HPV16 E1 and E2-specific T cells in the oropharyngeal cancer tumor microenvironment

BACKGROUND

High-risk human papillomavirus (HPV) is a primary cause of an increasing number of oropharyngeal squamous cell carcinomas (OPSCCs). The viral etiology of these cancers provides the opportunity for antigen-directed therapies that are restricted in scope compared with cancers without viral components. However, specific virally-encoded epitopes and their corresponding immune responses are not fully defined.

METHODS

To understand the OPSCC immune landscape, we conducted a comprehensive single-cell analysis of HPV16+ and HPV33+ primary tumors and metastatic lymph nodes. We used single-cell analysis with encoded peptide-human leukocyte antigen (HLA) tetramers to analyze HPV16+ and HPV33+ OPSCC tumors, characterizing the ex vivo cellular responses to HPV-derived antigens presented in major Class I and Class II HLA alleles.

RESULTS

We identified robust cytotoxic T-cell responses to HPV16 proteins E1 and E2 that were shared across multiple patients, particularly in HLA-A*01:01 and HLA-B*08:01. Responses to E2 were associated with loss of E2 expression in at least one tumor, indicating the functional capacity of these E2-recognizing T cells and many of these interactions validated in a functional assay. Conversely, cellular responses to E6 and E7 were limited in quantity and cytotoxic capacity, and tumor E6 and E7 expression persisted.

CONCLUSIONS

These data highlight antigenicity beyond HPV16 E6 and E7 and nominate candidates for antigen-directed therapies.

Experimental Validation of MHC Class I and II Peptide-Based Potential Vaccine Candidates for Human Papilloma Virus Using Sprague-Dawly Models

Human papilloma virus (HPV) causes cervical and many other cancers. Recent trend in vaccine design is shifted toward epitope-based developments that are more specific, safe, and easy to produce. In this study, we predicted eight immunogenic peptides of CD4+ and CD8+ T-lymphocytes (MHC class I and II as M1 and M2) including early proteins (E2 and E6), major (L1) and minor capsid protein (L2). Male and female Sprague Dawly rats in groups were immunized with each synthetic peptide. L1M1, L1M2, L2M1, and L2M2 induced significant immunogenic response compared to E2M1, E2M2, E6M1 and E6M2. We observed optimal titer of IgG antibodies (>1.25 g/L), interferon-γ (>64 ng/L), and granzyme-B (>40 pg/mL) compared to control at second booster dose (240 µg/500 µL). The induction of peptide-specific IgG antibodies in immunized rats indicates the T-cell dependent B-lymphocyte activation. A substantial CD4+ and CD8+ cell count was observed at 240 µg/500 µL. In male and female rats, CD8+ cell count for L1 and L2 peptide is 3000 and 3118, and CD4+ is 3369 and 3484 respectively compared to control. In conclusion, we demonstrated that L1M1, L1M2, L2M1, L2M2 are likely to contain potential epitopes for induction of immune responses supporting the feasibility of peptide-based vaccine development for HPV.

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

BACKGROUND

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

AIM

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

MATERIAL AND METHODS

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

CONCLUSION

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

Can Adjuvant HPV Vaccination Be Helpful in the Prevention of Persistent/Recurrent Cervical Dysplasia after Surgical Treatment?—A Literature Review

Simple Summary

Primary prophylactic, early detection and the treatment of precancerous lesions are the main goals of cervical cancer screening. Despite effective surgical treatment methods, using loop electrosurgical excision procedures and conization, the overall risk of the recurrence of HSIL lesions remains at approximately 6.6%. There is increasing evidence of the potential role of HPV vaccines in the adjuvant setting and their impact on the reduction of disease recurrence. This review aims to analyze the up-to-date research concerning the use and efficacy of secondary human papilloma virus (HPV) vaccination as an adjuvant method to surgical treatment in patients diagnosed with cervical HSILs.

Abstract

Cervical cancer formation is preceded by precursor lesions, including low-grade squamous intraepithelial lesions (LSILs) and high-grade squamous intraepithelial lesions (HSILs), which are usually diagnosed in women of reproductive age. Despite the recent advanced diagnostic and treatment methods, including colposcopy, the loop electrosurgical excision procedure (LEEP), and surgical conization, the recurrence or residual disease affects as many as 6.6% of patients. The lesions are often associated with human papilloma virus (HPV) infection. As HPV persistence is the leading and only modifiable factor affecting the risk of progression of CIN lesions into high-grade cervical dysplasia and cancer, it has been proposed to conduct adjuvant vaccination in patients treated for high-grade cervical dysplasia. To date, no vaccine has been approved for therapeutic use in patients diagnosed with HSILs; however, attempts have been made to determine the use of HPV prophylactic vaccination to reduce recurrent HSILs and prevent cervical cancer. The aim of this review was to analyze the up-to-date literature concerning the possible use of secondary human papilloma virus (HPV) vaccination as an adjuvant method to surgical treatment in patients diagnosed with cervical HSILs. Adjuvant HPV vaccination after surgical treatment may reduce the risk of recurrent cervical dysplasia.

Cervical cancer screening, treatment and prophylaxis in Brazil: Current and future perspectives for cervical cancer elimination

As a middle-income country, Brazil has one of the largest public health systems worldwide, which deals with free and universal access to health care. Regarding cervical cancer, the country possesses a large infrastructure for the screening of premalignant and malignant lesions, but yet based on old technology, having Papanicolaou as the major screening method, followed by colposcopy and treatment. Also, large disparities in access are present, which makes effectiveness of screening and treatment in different regions of the country highly unequal. In this review, we describe and evaluate the current screening, treatment and prophylactic (HPV vaccination) strategies to combat cervical cancer in Brazil, and discuss potential incorporation of more recent technologies in these areas in the country to pave its way toward cervical cancer elimination.

Current Vaccine Platforms in Enhancing T-Cell Response

The induction of T cell-mediated immunity is crucial in vaccine development. The most effective vaccine is likely to employ both cellular and humoral immune responses. The efficacy of a vaccine depends on T cells activated by antigen-presenting cells. T cells also play a critical role in the duration and cross-reactivity of vaccines. Moreover, pre-existing T-cell immunity is associated with a decreased severity of infectious diseases. Many technical and delivery platforms have been designed to induce T cell-mediated vaccine immunity. The immunogenicity of vaccines is enhanced by controlling the kinetics and targeted delivery. Viral vectors are attractive tools that enable the intracellular expression of foreign antigens and induce robust immunity. However, it is necessary to select an appropriate viral vector considering the existing anti-vector immunity that impairs vaccine efficacy. mRNA vaccines have the advantage of rapid and low-cost manufacturing and have been approved for clinical use as COVID-19 vaccines for the first time. mRNA modification and nanomaterial encapsulation can help address mRNA instability and translation efficacy. This review summarizes the T cell responses of vaccines against various infectious diseases based on vaccine technologies and delivery platforms and discusses the future directions of these cutting-edge platforms.

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

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

The effect of “early” proteins E2, E6 and E7 of papillomavirus of high-risk cancerogenous type HPV16 on cancer HeLa cells, inducing tumour growths in mice lungs

The goal of investigation was the development of oral therapeutic vaccine against cancer on basis of antigenic regulatory protein HPV16 E2 encoded by the “early” hpv16 E2 gene.The aim. To study tumour growths in mice lungs inoculated with cancer HeLa cells and then vaccinated with vaccine material of transgenic tomato with the gene/protein HPV16 E2, and to study the activation of the immunogenesis of T-lymphocytes in mice after oral vaccination with HPV16 E2.Materials and methods. Proliferating cancer HeLa cells, mice peripheric blood mononuclear cells, splenocytes, intact and isolated lungs of mice were used in the study. Elispot was used for the evaluation of increasing of immunogenicity.Results. “Early” proteins HPV16 E6 or HPV16 E7 did not reveal any effect on HeLa cells. The regulatory antigenic “early” protein HPV16 E2 drastically degraded HeLa cells recorded by trypane blue. Four types of tumours were found in mice lung lobes placed in the suspension of cancer HeLa cells for 2–5 days: 1 – peripheral round tumours on epithelium, 2 – central tumours in the area of tracheal carina, 3 – pneumonialike peripheral cancer on lung lobes which was very similar to small-round-cell lung sarcoma with hyperchromic nuclei and 4 – Pancoast-like cancer in apical parts of lung lobe. Patterns of normal developed lung tissues were viewed on slices of lungs infected with HeLa in the presence of E2 simultaneously. The very high contents of γ‑interferon, CD4/CD8 T lymphocytes, T cell receptor and apoptotic enzymes: granzyme B, perforin and granulysine – were detected in blood and splenocytes of mice vaccinated with HPV16 E2.Conclusion. The study is promising for the development of an oral therapeutic vaccine based on a plant expression system (tomatoes) with the HPV16 E2 antigenic protein against lung cancer, cervical cancer and other types of cancer.

Prophylactic and Therapeutic HPV Vaccines: Current Scenario and Perspectives

Persistent human papillomavirus (HPV) infection is recognized as the main cause of cervical cancer and other malignant cancers. Although early detection and treatment can be achieved by effective HPV screening methods and surgical procedures, the disease load has not been adequately mitigated yet, especially in the underdeveloped areas. Vaccine, being regarded as a more effective solution, is expected to prevent virus infection and the consequent diseases in the phases of both prevention and treatment. Currently, there are three licensed prophylactic vaccines for L1-VLPs, namely bivalent, quadrivalent and nonavalent vaccine. About 90% of HPV infections have been effectively prevented with the implementation of vaccines worldwide. However, no significant therapeutic effect has been observed on the already existed infections and lesions. Therapeutic vaccine designed for oncoprotein E6/E7 activates cellular immunity rather than focuses on neutralizing antibodies, which is considered as an ideal immune method to eliminate infection. In this review, we elaborate on the classification, mechanism, and clinical effects of HPV vaccines for disease prevention and treatment, in order to make improvements to the current situation of HPV vaccines by provoking new ideas.

Effectiveness and Safety of Therapeutic Vaccines for Precancerous Cervical Lesions: A Systematic Review and Meta-Analysis

Objective

This study systematically evaluated the effectiveness and safety of therapeutic vaccines for precancerous cervical lesions, providing evidence for future research.

Methods

We systematically searched the literature in 10 databases from inception to February 18, 2021. Studies on the effectiveness and safety of therapeutic vaccines for precancerous cervical lesions were included. Then, we calculated the overall incidence rates of four outcomes, for which we used the risk ratio (RR) and 95% confidence interval (95% CI) to describe the effects of high-grade squamous intraepithelial lesions (HSILs) on recurrence.

Results

A total of 39 studies were included, all reported in English, published from 1989 to 2021 in 16 countries. The studies covered 22,865 women aged 15-65 years, with a total of 5,794 vaccinated, and 21 vaccines were divided into six types. Meta-analysis showed that the overall incidence rate of HSIL regression in vaccine therapies was 62.48% [95% CI (42.80, 80.41)], with the highest rate being 72.32% for viral vector vaccines [95% CI (29.33, 99.51)]. Similarly, the overall incidence rates of HPV and HPV16/18 clearance by vaccines were 48.59% [95% CI (32.68, 64.64)] and 47.37% [95% CI (38.00, 56.81)], respectively, with the highest rates being 68.18% [95% CI (45.13, 86.14)] for bacterial vector vaccines and 55.14% [95% CI (42.31, 67.66)] for DNA-based vaccines. In addition, a comprehensive analysis indicated that virus-like particle vaccines after conization reduced the risk of HSIL recurrence with statistical significance compared to conization alone [RR = 0.46; 95% CI (0.29, 0.74)]. Regarding safety, only four studies reported a few severe adverse events, indicating that vaccines for precancerous cervical lesions are generally safe.

Conclusion

Virus-like particle vaccines as an adjuvant immunotherapy for conization can significantly reduce the risk of HSIL recurrence. Most therapeutic vaccines have direct therapeutic effects on precancerous lesions, and the effectiveness in HSIL regression, clearance of HPV, and clearance of HPV16/18 is great with good safety. That is, therapeutic vaccines have good development potential and are worthy of further research.

Systematic Review Registration

PROSPERO https://www.crd.york.ac.uk/PROSPERO/, CRD42021275452.

Immunotherapy for Cervical Cancer: Are We Ready for Prime Time?

The prognosis of invasive cervical cancer (CC) remains poor, with a treatment approach that has remained the same for several decades. Lately, a better understanding of the interactions between the disease and the host immune system has allowed researchers to focus on the employment of immune therapy in various clinical settings. The most advanced strategy is immune checkpoint inhibitors (ICIs) with numerous phase II and III trials recently concluded with very encouraging results, assessing single agent therapy, combinations with chemotherapy and radiotherapy. Apart from ICIs, several other compounds have gained the spotlight. Tumor Infiltrating Lymphocytes (TILs) due to their highly selective tumoricidal effect and manageable adverse effect profile have received the FDA’s Breakthrough Therapy designation in 2019. The antibody drug conjugate (ADC) Tisotumab-Vedotin has shown activity in metastatic CC relapsed after at least one line of chemotherapy, with a phase III trial currently actively enrolling patients. Moreover, the deeper understanding of the ever-changing immune landscape of CC carcinogenesis has resulted in the development of active therapeutic vaccines. This review highlights the different immunotherapeutic strategies being explored reflects on what role immunotherapy might have in therapeutic algorithms of CC and addresses the role of predictive biomarkers.

Therapeutic DNA Vaccines against HPV-Related Malignancies: Promising Leads from Clinical Trials

In 2014 and 2021, two nucleic-acid vaccine candidates named MAV E2 and VGX-3100 completed phase III clinical trials in Mexico and U.S., respectively, for patients with human papillomavirus (HPV)-related, high-grade squamous intraepithelial lesions (HSIL). These well-tolerated but still unlicensed vaccines encode distinct HPV antigens (E2 versus E6+E7) to elicit cell-mediated immune responses; their clinical efficacy, as measured by HSIL regression or cure, was modest when compared with placebo or surgery (conization), but both proved highly effective in clearing HPV infection, which should help further optimize strategies for enhancing vaccine immunogenicity, toward an ultimate goal of preventing malignancies in millions of patients who are living with persistent, oncogenic HPV infection but are not expected to benefit from current, prophylactic vaccines. The major roadblocks to a highly efficacious and practical product remain challenging and can be classified into five categories: (i) getting the vaccines into the right cells for efficient expression and presentation of HPV antigens (fusion proteins or epitopes); (ii) having adequate coverage of oncogenic HPV types, beyond the current focus on HPV-16 and -18; (iii) directing immune protection to various epithelial niches, especially anogenital mucosa and upper aerodigestive tract where HPV-transformed cells wreak havoc; (iv) establishing the time window and vaccination regimen, including dosage, interval and even combination therapy, for achieving maximum efficacy; and (v) validating therapeutic efficacy in patients with poor prognosis because of advanced, recurrent or non-resectable malignancies. Overall, the room for improvements is still large enough that continuing efforts for research and development will very likely extend into the next decade.

Local radiotherapy and E7 RNA-LPX vaccination show enhanced therapeutic efficacy in preclinical models of HPV16+ cancer

Human papilloma virus (HPV) infection is a causative agent for several cancers types (genital, anal and head and neck region). The HPV E6 and E7 proteins are oncogenic drivers and thus are ideal candidates for therapeutic vaccination. We recently reported that a novel ribonucleic acid lipoplex (RNA-LPX)-based HPV16 vaccine, E7 RNA-LPX, mediates regression of mouse HPV16⁺ tumors and establishes protective T cell memory. An HPV16 E6/E7 RNA-LPX vaccine is currently being investigated in two phase I and II clinical trials in various HPV-driven cancer types; however, it remains a high unmet medical need for treatments for patients with radiosensitive HPV16⁺ tumors. Therefore, we set out to investigate the therapeutic efficacy of E7 RNA-LPX vaccine combined with standard-of-care local radiotherapy (LRT). We demonstrate that E7 RNA-LPX synergizes with LRT in HPV16⁺ mouse tumors, with potent therapeutic effects exceeding those of either monotherapy. Mode of action studies revealed that the E7 RNA-LPX vaccine induced high numbers of intratumoral-E7-specific CD8⁺ T cells, rendering cold tumors immunologically hot, whereas LRT primarily acted as a cytotoxic therapy, reducing tumor mass and intratumor hypoxia by predisposing tumor cells to antigen-specific T cell-mediated killing. Overall, LRT enhanced the effector function of E7 RNA-LPX-primed T cell responses. The therapeutic synergy was dependent on total radiation dose, rather than radiation dose-fractionation. Together, these results show that LRT synergizes with E7 RNA-LPX and enhances its anti-tumor activity against HPV16⁺ cancer models. This work paves into a new translational therapy for HPV16⁺ cancer patients.

Novel Antigenic Targets of HPV Therapeutic Vaccines

Human papillomavirus (HPV) infection is the cause of the majority of cervical cancers and head and neck cancers worldwide. Although prophylactic vaccines and cervical cancer screening programs have shown efficacy in preventing HPV-associated cervical cancer, cervical cancer is still a major cause of morbidity and mortality, especially in third world countries. Furthermore, head and neck cancer cases caused by HPV infection and associated mortality are increasing. The need for better therapy is clear, and therapeutic vaccination generating cytotoxic T cells against HPV proteins is a promising strategy. This review covers the current scene of HPV therapeutic vaccines in clinical development and discusses relevant considerations for the design of future HPV therapeutic vaccines and clinical trials, such as HPV protein expression patterns, immunogenicity, and exhaustion in relation to the different stages and types of HPV-associated lesions and cancers. Ultimately, while the majority of the HPV therapeutic vaccines currently in clinical testing target the two HPV oncoproteins E6 and E7, we suggest that there is a need to include more HPV antigens in future HPV therapeutic vaccines to increase efficacy and find that especially E1 and E2 could be promising novel targets.

Physiopathology and effectiveness of therapeutic vaccines against human papillomavirus

Human papillomavirus (HPV) is a well-known sexually transmitted disorder globally. Human papillomavirus (HPV) is the 3rd most common cancer that causes cervical carcinoma, and globally it accounts for 275,000 deaths every year. The load of HPV-associated abrasions can be lessened through vaccination. At present, three forms of prophylactic vaccines, Cervarix, Gadrasil, and Gardasil 9, are commercially accessible but all these prophylactic vaccines have not the ability to manage and control developed abrasions or infections. Therefore, a considerable amount of the population is not secured from HPV infectivity. Consequently, the development of therapeutic HPV vaccines is a crucial requirement of this era, for the treatment of persisting infections, and to stop the progression of HPV-associated cancers. Therapeutic vaccines are a developing trial approach. Because of the constitutive expression of E6 and E7 early genes in cancerous and pre-cancerous tissues, and their involvement in disturbance of the cell cycle, these are best targets for this therapeutic vaccine treatment. For the synthesis and development of therapeutic vaccines, various approaches have been examined comprising cell-based vaccines, peptide/protein-based vaccines, nucleic acid-based vaccines, and live-vector vaccines all proceeding towards clinical trials. This review emphasizes the development, progress, current status, and future perspective of several vaccines for the cure of HPV-related abrasions and cancers. This review also provides an insight to assess the effectiveness, safety, efficacy, and immunogenicity of therapeutic vaccines in the cure of patients infected with HPV-associated cervical cancer.

Evolution of Cancer Vaccines-Challenges, Achievements, and Future Directions

The development of cancer vaccines has been intensively pursued over the past 50 years with modest success. However, recent advancements in the fields of genetics, molecular biology, biochemistry, and immunology have renewed interest in these immunotherapies and allowed the development of promising cancer vaccine candidates. Numerous clinical trials testing the response evoked by tumour antigens, differing in origin and nature, have shed light on the desirable target characteristics capable of inducing strong tumour-specific non-toxic responses with increased potential to bring clinical benefit to patients. Novel delivery methods, ranging from a patient’s autologous dendritic cells to liposome nanoparticles, have exponentially increased the abundance and exposure of the antigenic payloads. Furthermore, growing knowledge of the mechanisms by which tumours evade the immune response has led to new approaches to reverse these roadblocks and to re-invigorate previously suppressed anti-tumour surveillance. The use of new drugs in combination with antigen-based therapies is highly targeted and may represent the future of cancer vaccines. In this review, we address the main antigens and delivery methods used to develop cancer vaccines, their clinical outcomes, and the new directions that the vaccine immunotherapy field is taking.

Immunodiagnosis and Immunotherapeutics Based on Human Papillomavirus for HPV-Induced Cancers

Infection with human papillomavirus (HPV) is one of the main causes of malignant neoplasms, especially cervical, anogenital, and oropharyngeal cancers. Although we have developed preventive vaccines that can protect from HPV infection, there are still many new cases of HPV-related cancers worldwide. Early diagnosis and therapy are therefore important for the treatment of these diseases. As HPVs are the major contributors to these cancers, it is reasonable to develop reagents, kits, or devices to detect and eliminate HPVs for early diagnosis and therapeutics. Immunological methods are precise strategies that are promising for the accurate detection and blockade of HPVs. During the last decades, the mechanism of how HPVs induce neoplasms has been extensively elucidated, and several oncogenic HPV early proteins, including E5, E6, and E7, have been shown to be positively related to the oncogenesis and malignancy of HPV-induced cancers. These oncoproteins are promising biomarkers for diagnosis and as targets for the therapeutics of HPV-related cancers. Importantly, many specific monoclonal antibodies (mAbs), or newly designed antibody mimics, as well as new immunological kits, devices, and reagents have been developed for both the immunodiagnosis and immunotherapeutics of HPV-induced cancers. In the current review, we summarize the research progress in the immunodiagnosis and immunotherapeutics based on HPV for HPV-induced cancers. In particular, we depict the most promising serological methods for the detection of HPV infection and several therapeutical immunotherapeutics based on HPV, using immunological tools, including native mAbs, radio-labelled mAbs, affitoxins (affibody-linked toxins), intracellular single-chain antibodies (scFvs), nanobodies, therapeutical vaccines, and T-cell-based therapies. Our review aims to provide new clues for researchers to develop novel strategies and methods for the diagnosis and treatment of HPV-induced tumors.

Vaccination Strategies for the Control and Treatment of HPV Infection and HPV-Associated Cancer

Human papillomavirus (HPV) is the most common sexually transmitted infection, currently affecting close to 80 million Americans. Importantly, HPV infection is recognized as the etiologic factor for numerous cancers, including cervical, vulval, vaginal, penile, anal, and a subset of oropharyngeal cancers. The prevalence of HPV infection and its associated diseases are a significant problem, affecting millions of individuals worldwide. Likewise, the incidence of HPV infection poses a significant burden on individuals and the broader healthcare system. Between 2011 and 2015, there were an estimated 42,700 new cases of HPV-associated cancers each year in the United States alone. Similarly, the global burden of HPV is high, with around 630,000 new cases of HPV-associated cancer occurring each year. In the last decade, a total of three preventive major capsid protein (L1) virus-like particle-based HPV vaccines have been licensed and brought to market as a means to prevent the spread of HPV infection. These prophylactic vaccines have been demonstrated to be safe and efficacious in preventing HPV infection. The most recent iteration of the preventive HPV vaccine, a nanovalent, L1-VLP vaccine, protects against a total of nine HPV types (seven high-risk and two low-risk HPV types), including the high-risk types HPV16 and HPV18, which are responsible for causing the majority of HPV-associated cancers. Although current prophylactic HPV vaccines have demonstrated huge success in preventing infection, existing barriers to vaccine acquisition have limited their widespread use, especially in low- and middle-income countries, where the burden of HPV-associated diseases is highest. Prophylactic vaccines are unable to provide protection to individuals with existing HPV infections or HPV-associated diseases. Instead, therapeutic HPV vaccines capable of generating T cell-mediated immunity against HPV infection and associated diseases are needed to ameliorate the burden of disease in individuals with existing HPV infection. To generate a cell-mediated immune response against HPV, most therapeutic vaccines target HPV oncoproteins E6 and E7. Several types of therapeutic HPV vaccine candidates have been developed including live-vector, protein, peptide, dendritic cell, and DNA-based vaccines. This chapter will review the commercially available prophylactic HPV vaccines and discuss the recent progress in the development of therapeutic HPV vaccines.

Chapter XX Antiviral Treatment and Cancer Control

Hepatitis B virus (HBV), hepatitis C virus (HCV), human papilloma virus (HPV), Epstein-Barr virus (EBV), human T-cell lymphotropic virus type 1 (HTLV-1), Kaposi's sarcoma-associated herpesvirus (KSHV), and Merkel cell polyomavirus (MCV) contribute to about 10-15% global burden of human cancers. Conventional chemotherapy or molecular target therapies have been used to treat virus-associated cancers. However, a more proactive approach would be the use of antiviral treatment to suppress or eliminate viral infections to prevent the occurrence of cancer in the first place. Antiviral treatments against chronic HBV and HCV infection have achieved this goal, with significant reduction in the incidence of hepatocellular carcinoma in treated patients. Antiviral treatments for EBV, KSHV, and HTLV-1 had limited success in treating refractory EBV-associated lymphoma and post-transplant lymphoproliferative disorder, KSHV-associated Kaposi's sarcoma in AIDS patients, and HTLV-1-associated acute, chronic, and smoldering subtypes of adult T-cell lymphoma, respectively. Therapeutic HPV vaccine and RNA interference-based therapies for treating HPV-associated infection or cervical cancers also showed some encouraging results. Taken together, antiviral therapies have yielded promising results in cancer prevention and treatment. More large-scale studies in a real-world setting are necessary to confirm the efficacy of antiviral therapy. Further investigation for more effective and convenient antiviral regimens warrants more attention.

Employing ATP as a New Adjuvant Promotes the Induction of Robust Antitumor Cellular Immunity by a PLGA Nanoparticle Vaccine

Tumor vaccines based on synthetic human papillomavirus (HPV) oncoprotein E7 and/or E6 peptides have shown encouraging results in preclinical model studies and human clinical trials. However, the clinical efficacy may be limited by the disadvantages of vulnerability to enzymatic degradation and low immunogenicity of peptides. To further improve the potency of vaccine, we developed a poly(lactide-co-glycolide)-acid (PLGA) nanoparticle, which encapsulated the antigenic peptide HPV16 E7_44-62, and used adenosine triphosphate (ATP), one of the most important intracellular metabolites and an endogenous extracellular danger signal for the immune system, as a new adjuvant component. The results showed that PLGA nanoparticles increased the in vivo stability, lymph node accumulation, and dendritic cell (DC) uptake of the E7 peptide; in addition, ATP further increased the migration, nanoparticle uptake, and maturation of DCs. Preventive immunization with ATP-adjuvanted nanoparticles completely abolished the growth of TC-1 tumors in mice and produced long-lasting immunity against tumor rechallenge. When tumors were fully established, therapeutic immunization with ATP-adjuvanted nanoparticles still significantly inhibited tumor progression. Mechanistically, ATP-adjuvanted nanoparticles significantly improved the systemic generation of antitumor effector cells, boosted the local functional status of these cells in tumors, and suppressed the generation and tumor infiltration of immunosuppressive Treg cells and myeloid-derived suppressor cells. These findings indicate that ATP is an effective vaccine adjuvant and that nanoparticles adjuvanted with ATP were able to elicit robust antitumor cellular immunity, which may provide a promising therapeutic vaccine candidate for the treatment of clinical malignancies, such as cervical cancer.

Application of Viral Vectors for Vaccine Development with a Special Emphasis on COVID-19

Viral vectors can generate high levels of recombinant protein expression providing the basis for modern vaccine development. A large number of different viral vector expression systems have been utilized for targeting viral surface proteins and tumor-associated antigens. Immunization studies in preclinical animal models have evaluated the elicited humoral and cellular responses and the possible protection against challenges with lethal doses of infectious pathogens or tumor cells. Several vaccine candidates for both infectious diseases and various cancers have been subjected to a number of clinical trials. Human immunization trials have confirmed safe application of viral vectors, generation of neutralizing antibodies and protection against challenges with lethal doses. A special emphasis is placed on COVID-19 vaccines based on viral vectors. Likewise, the flexibility and advantages of applying viral particles, RNA replicons and DNA replicon vectors of self-replicating RNA viruses for vaccine development are presented.

HNSCC: Tumour Antigens and Their Targeting by Immunotherapy

Head and neck squamous cell carcinomas (HNSCC) are a heterogeneous group of malignant tumours typically caused by alcohol and tobacco consumption, although an increasing number of HNSCC arise due to persistent infection with high-risk human papilloma virus (HPV). The treatment of HNSCC remains challenging, and the first-line setting is focused on surgery and chemoradiotherapy. A substantial proportion of HNSCC patients die from their disease, especially those with recurrent and metastatic disease. Among factors linked with good outcome, immune cell infiltration appears to have a major role. HPV-driven HNSCC are often T-cell rich, reflecting the presence of HPV antigens that are immunogenic. Tumour-associated antigens that are shared between patients or that are unique to an individual person may also induce varying degrees of immune response; studying these is important for the understanding of the interaction between the host immune system and the cancer. The resulting knowledge is critical for the design of better immunotherapies. Key questions are: Which antigens lead to an adaptive immune response in the tumour? Which of these are exploitable for immunotherapy? Here, we review the current thinking regarding tumour antigens in HNSCC and what has been learned from early phase clinical trials.

Enhancement of specific T-lymphocyte responses by monocyte-derived dendritic cells pulsed with E2 protein of human papillomavirus 16 and human p16INK4A

Introduction

Prophylactic vaccines are already available for prevention of human papillomavirus (HPV) infection. However, we still await development of therapeutic vaccines with high efficiency for stimulating specific T lymphocytes to clear HPV infection.

Objective

This study investigates the potential for subunits of human p16INK4a protein and E2 protein of HPV16 to stimulate dendritic cells and enhance the specific response of T lymphocytes against HPV-infected cells.

Methodology

Immunogenic epitopes of HPV16 E2 and p16INK4a proteins were predicted through the common HLA class I and II alleles present in the Thai population. Then, monocyte-derived dendritic cells (MDCs) were pulsed with HPV16 E2 and/or p16INK4a protein s and their maturity assessed. MDCs pulsed with either or both of these proteins at optimal concentrations were used for activation of autologous T lymphocytes and IFN-γ production was measured for specific response function.

Results

HPV16 E2 and p16INK4a proteins contain various immunogenic epitopes which can be presented by antigen-presenting cells via both HLA class I and II molecules. The stimulation of MDCs with either HPV16 E2 or p16INK4a proteins increased percentages and mean fluorescence intensity (MFI) of CD83⁺ MDCs in a dose-dependent manner. An optimum concentration of 250 ng/mL and 150 ng/mL of HPV16 E2 and p16INK4a proteins, respectively, stimulated MDCs via the MAPK pathway (confirmed by use of MAPK inhibitors). T lymphocytes could be activated by MDCs pulsed with these proteins, leading to high percentages of both CD4⁺ IFN-γ⁺ T lymphocytes and CD8⁺ IFN-γ⁺ T lymphocytes. The production of IFN-γ was higher in co-cultures containing MDCs pulsed with HPV16 E2 protein than those pulsed with p16INK4a. Interestingly, MDCs pulsed with a combination of HPV16 E2 and p16INK4a significantly increased IFN-γ production of T lymphocytes. The IFN-γ production was inhibited by both HLA class I and II blockade, particularly in co-cultures with MDCs pulsed with a combination of HPV16 E2 and p16INK4a.

Conclusions

This suggests that MDCs pulsed with both proteins enhances specific response of both CD4⁺ and CD8⁺ T lymphocytes. This study might provide a strategy for further in vivo study of stimulation of T lymphocytes for therapy of HPV-associated cancer.

Targeted Gene Delivery Therapies for Cervical Cancer

Despite being largely preventable through early vaccination and screening strategies, cervical cancer is the most common type of gynecological malignancy worldwide and constitutes one of the leading causes of cancer deaths in women. Patients with advanced or recurrent disease have a very poor prognosis; hence, novel therapeutic modalities to improve clinical outcomes in cervical malignancy are needed. In this regard, targeted gene delivery therapy is presented as a promising approach, which leads to the development of multiple strategies focused on different aspects. These range from altered gene restoration, immune system potentiation, and oncolytic virotherapy to the use of nanotechnology and the design of improved and enhanced gene delivery systems, among others. In the present manuscript, we review the current progress made in targeted gene delivery therapy for cervical cancer, the advantages and drawbacks and their clinical application. At present, multiple targeted gene delivery systems have been reported with encouraging preclinical results. However, the translation to humans has not yet shown a significant clinical benefit due principally to the lack of efficient vectors. Real efforts are being made to develop new gene delivery systems, to improve tumor targeting and to minimize toxicity in normal tissues.

Advances in therapeutic vaccines for treating human papillomavirus-related cervical intraepithelial neoplasia

AIM

Human papillomavirus (HPV) is the etiologic agent of the majority of cervical intraepithelial lesions (CIN) and cervical cancers. While prophylactic HPV vaccines prevent infections from the main high-risk HPV types associated with cervical cancer, alternative nonsurgical and nonablative therapeutics to treat HPV infection and preinvasive HPV diseases have been experimentally investigated. Therapeutic vaccines are an emerging investigational strategy. This review aims to introduce the results of the main clinical trials on the use of therapeutic vaccines for treating HPV infection and -related CIN, reporting the ongoing studies on this field.

METHODS

Data research was conducted using MEDLINE, EMBASE, Web of Sciences, Scopus, ClinicalTrial.gov, OVID and Cochrane Library querying for all articles related to therapeutic vaccines for the treatment of HPV-related CIN. Selection criteria included randomized clinical trials, nonrandomized controlled studies and review articles.

RESULTS

Preliminary data are available on the evaluation of therapeutic vaccines for treating cervical HPV infections and CIN. Despite having in vitro demonstrated to obtain humoral and cytotoxic responses, therapeutic vaccines have not yet clinically demonstrated consistent success; moreover, each class of therapeutic vaccines has advantages and limitations. Early clinical data are available in the literature for these compounds, except for MVA E2, which reached the phase III clinical trial status, obtaining positive clinical outcomes.

CONCLUSION

Despite promising results, to date many obstacles are still present before hypothesize an introduction in the clinical practice within the next years. Further studies will draw a definitive conclusion on the role of therapeutic vaccines in this setting.

The Use of Both Therapeutic and Prophylactic Vaccines in the Therapy of Papillomavirus Disease

Human papillomavirus (HPV) is the most common sexually transmitted virus. The high-risk HPV types (i.e., HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59) are considered to be the main etiological agents of genital tract cancers, such as cervical, vulvar, vaginal, penile, and anal cancers, and of a subset of head and neck cancers. Three prophylactic HPV vaccines are available that are bivalent (vs. HPV16, 18), tetravalent (vs. HPV6, 11, 16, 18), and non-avalent (vs. HPV6, 11, 16, 18, 31, 33,45, 52, 58). All of these vaccines are based on recombinant DNA technology, and they are prepared from the purified L1 protein that self-assembles to form the HPV type-specific empty shells (i.e., virus-like particles). These vaccines are highly immunogenic and induce specific antibodies. Therapeutic vaccines differ from prophylactic vaccines, as they are designed to generate cell-mediated immunity against transformed cells, rather than neutralizing antibodies. Among the HPV proteins, the E6 and E7 oncoproteins are considered almost ideal as targets for immunotherapy of cervical cancer, as they are essential for the onset and evolution of malignancy and are constitutively expressed in both premalignant and invasive lesions. Several strategies have been investigated for HPV therapeutic vaccines designed to enhance CD4⁺ and CD8⁺ T-cell responses, including genetic vaccines (i.e., DNA/ RNA/virus/ bacterial), and protein-based, peptide-based or dendritic-cell-based vaccines. However, no vaccine has yet been licensed for therapeutic use. Several studies have suggested that administration of prophylactic vaccines immediately after surgical treatment of CIN2 cervical lesions can be considered as an adjuvant to prevent reactivation or reinfection, and other studies have described the relevance of prophylactic vaccines in the management of genital warts. This review summarizes the leading features of therapeutic vaccines, which mainly target the early oncoproteins E6 and E7, and prophylactic vaccines, which are based on the L1 capsid protein. Through an analysis of the specific immunogenic properties of these two types of vaccines, we discuss why and how prophylactic vaccines can be effective in the treatment of HPV-related lesions and relapse.