Clearance of persistent HPV infection and cervical lesion by therapeutic DNA vaccine in CIN3 patients

Therapeutic Response to Treatment of a Papillomatous Ocular Surface Squamous Neoplasia With Intramuscular Human Papillomavirus Vaccine

PURPOSE

The purpose of this study was to describe the response of a papillomatous ocular surface squamous neoplasia (OSSN) to the intramuscular (IM) 9-valent human papillomavirus (HPV) vaccine after failed medical and surgical interventions.

METHODS

A 79-year-old White man with a conjunctival lesion underwent a biopsy which revealed OSSN and positivity for high-risk HPV. Initially treated with medical therapy and surgical excisions, the patient developed a recurrence and refused further surgery. He was given 4 doses of IM HPV vaccine at the 6-week interval.

RESULTS

A dramatic reduction in lesion size and reduced epithelial thickening and hyperreflectivity was noted on slitlamp examination and high-resolution anterior segment optical coherence tomography after receiving the IM HPV vaccine. Although lesion size was markedly reduced, the therapy did not achieve total resolution, resulting in further treatment with topical 1% 5-fluorouracil (5-FU) eye drops and later 0.04% mitomycin C eye drops. The patient then elected to discontinue further treatment and solely observe.

CONCLUSIONS

This case report adds to the growing literature demonstrating the potential therapeutic use of vaccines in cancer treatment. Although HPV vaccination is currently approved for prophylaxis, the use of HPV vaccines as a therapeutic option for various HPV-mediated diseases, including OSSN, should be further explored. The HPV vaccine yielded significant initial improvement in this patient who refused further surgical interventions. The use of IM HPV vaccine as an adjunctive treatment of papillomatous OSSN may represent a potential therapeutic option in cases refractory to standard treatment modalities.

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.

Advanced micro/nano-electroporation for gene therapy: recent advances and future outlook

Gene therapy is a promising disease treatment approach by editing target genes, and thus plays a fundamental role in precision medicine. To ensure gene therapy efficacy, the effective delivery of therapeutic genes into specific cells is a key challenge. Electroporation utilizes short electric pulses to physically break the cell membrane barrier, allowing gene transfer into the cells. It dodges the off-target risks associated with viral vectors, and also stands out from other physical-based gene delivery methods with its high-throughput and cargo-accelerating features. In recent years, with the help of advanced micro/nanotechnology, micro/nanostructure-integrated electroporation (micro/nano-electroporation) techniques and devices have significantly improved cell viability, transfection efficiency and dose controllability of the electroporation strategy, enhancing its application practicality especially in vivo. This technical advancement makes micro/nano-electroporation an effective and versatile tool for gene therapy. In this review, we first introduce the evolution of electroporation technique with a brief explanation of the perforation mechanism, and then provide an overview of the recent advancements and prospects of micro/nano-electroporation technology in the field of gene therapy. To comprehensively showcase the latest developments of micro/nano-electroporation technology in gene therapy, we focus on discussing micro/nano-electroporation devices and current applications at both in vitro and in vivo levels. Additionally, we outline the ongoing clinical studies of gene electrotransfer (GET), revealing the tremendous potential of electroporation-based gene delivery in disease treatment and healthcare. Lastly, the challenges and future directions in this field are discussed.

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.

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.

Materials-Based Approaches for Cancer Vaccination

Therapeutic cancer vaccines offer the promise of stimulating the immune system to specifically eradicate tumor cells and establish long-term memory to prevent tumor recurrence. However, despite showing benign safety profiles and the ability to generate Ag-specific cellular responses, cancer vaccines have been hampered by modest clinical efficacy. Lessons learned from these studies have led to the emergence of innovative materials-based strategies that aim to boost the clinical activity of cancer vaccines. In this Brief Review, we provide an overview of the key elements needed for an effective vaccine-induced antitumor response, categorize current approaches to therapeutic cancer vaccination, and explore recent advances in materials-based strategies to potentiate cancer vaccines.

Superior efficacy of a skin-applied microprojection device for delivering a novel Zika DNA vaccine

Zika virus (ZIKV) infections are spreading silently with limited global surveillance in at least 89 countries and territories. There is a pressing need to develop an effective vaccine suitable for equitable distribution globally. Consequently, we previously developed a proprietary DNA vaccine encoding secreted non-structural protein 1 of ZIKV (pVAX-tpaNS1) to elicit rapid protection in a T cell-dependent manner in mice. In the current study, we evaluated the stability, efficacy, and immunogenicity of delivering this DNA vaccine into the skin using a clinically effective and proprietary high-density microarray patch (HD-MAP). Dry-coating of pVAX-tpaNS1 on the HD-MAP device resulted in no loss of vaccine stability at 40°C storage over the course of 28 days. Vaccination of mice (BALB/c) with the HD-MAP-coated pVAX-tpaNS1 elicited a robust anti-NS1 IgG response in both the cervicovaginal mucosa and systemically and afforded protection against live ZIKV challenge. Furthermore, the vaccination elicited a significantly higher magnitude and broader NS1-specific T helper and cytotoxic T cell response in vivo compared with traditional needle and syringe intradermal vaccination. Overall, the study highlights distinctive immunological advantages coupled with an excellent thermostability profile of using the HD-MAP device to deliver a novel ZIKV DNA vaccine.

Key considerations for the development of novel mRNA candidate vaccines in LMICs: A WHO/MPP mRNA Technology Transfer Programme meeting report

The WHO/MPP mRNA Technology Transfer Programme, initiated in 2021, focuses on establishing mRNA vaccine manufacturing capacity in LMICs. On 17-21 April 2023, Programme partners were convened to review technology transfer progress, discuss sustainability aspects and promote mRNA product development for diseases relevant to LMICs. To help guide product development, this report introduces key considerations for for understanding the likelihood of technical and regulatory success and of policy development and procurement for mRNA vaccines to be developed and manufactured in LMICs. The report underscores the potential for LMICs to establish sustainable mRNA R&D pipelines.

Natural and synthetic drugs and formulations for intravaginal HPV clearance

BACKGROUND

Except for a few preventative Human Papillomavirus (HPV) vaccines, there is currently no cure for HPV infection. There are a number of cutting-edge strategies and potent medications or herbal formulations that can be applied topically for early clearance of HPV infection before HPV DNA gets integrated into host cell genome. This is facilitated due to cervical cancer having distinct and well-recognized long precancerous stages.

OBJECTIVES

This review aims to outline every possible medication and formulation, both natural and synthetic, that can be applied topically as intravaginal application to help remove HPV infection at an early precancerous stage.

RESULTS

Several anti-HPV/HPV clearance compounds and formulations for high-grade lesions are undergoing clinical trials. However, the majority of compounds are still in the early stages of development and require additional research to become viable HPV clearance candidates. Synthetic drugs may be more promising because they may have a more targeted effect; however, they may also have significant adverse effects. On the other hand, natural medications are safer to use. They are less specific, but have minimal to no adverse effects.

CONCLUSIONS

This article may serve as a valuable resource of information for managing and preventing precancerous carcinogenic HPV infections. Research could be directed toward developing candidate drugs to make evidence-based decisions about advancing them to clinical trials and, eventually, to the market for potential use in the prevention and control of cervical cancer, which is almost always preventable or even curable if detected early.

Current Status of Human Papillomavirus-Targeted Therapies Development in Head and Neck Cancer

PURPOSE

While the incidence of smoking-related head and neck squamous cell carcinoma (HNSCC) has been declining, that of human papillomavirus (HPV)-mediated HNSCC has rapidly increased in the past decades worldwide. Despite rapid advances in therapeutics for solid tumors with novel immunotherapy and targeted therapeutic agents, no breakthroughs have yet been made in the treatment of advanced HPV+ HNSCCs. This review aims to summarize the concepts and designs, early trial results, and future directions of various HPV-targeted experimental therapeutics for HPV+ HNSCC.

MATERIALS AND METHODS

Guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, a systemic literature search of PubMed was conducted for HPV-targeted therapeutics using the following search terms: HPV, head and neck squamous cell carcinoma, and therapy. For clinical trial data, publications, major oncology conference abstracts, and the National Institutes of Health Clinical Trials Registry (ClinicalTrials.gov) information were reviewed. This review focused on the ones that are in the clinical stage and currently in active ongoing evaluation. The therapeutics not actively evaluated in HNSCC, in the preclinical stage, or terminated for further development were excluded.

RESULTS

Diverse approaches are being actively explored to target HPV+ HNSCC, including therapeutic vaccines of various modalities, HPV-specific immune cell-activating agents, and adaptive cellular therapeutics. All these novel agents use immune-based mechanisms and target constitutively expressed oncogenic HPV E6 and/or E7 viral proteins. Most therapeutics demonstrated excellent safety but single-agent activities are only modest. Many are being tested in combination with immune checkpoint inhibitors.

CONCLUSION

Our review summarized various novel HPV-targeted therapeutics that are in the clinical phase for HPV+ HNSCC. Early-phase trial data suggest the feasibility and promising efficacy. Further strategies, including selecting the optimal combination and understanding and overcoming resistant mechanisms, are warranted for successful development.

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).

Novel canonical and non-canonical viral antigens extend current targets for immunotherapy of HPV-driven cervical cancer

Current immunotherapeutic approaches for human papillomavirus (HPV)-driven cervical cancer target the viral oncogenes E6 and E7. We report viral canonical and alternative reading frame (ARF)-derived sequences presented on cervical tumor cells, including antigens encoded by the conserved viral gene E1. We confirm immunogenicity of the identified viral peptides in HPV-positive women, and women with cervical intraepithelial neoplasia. We observe consistent transcription of the E1, E6, and E7 genes in 10 primary cervical tumor resections from the four most common high-risk HPV subtypes (HPV16, 18, 31, and 45), suggesting the suitability of E1 as therapeutic target. We finally confirm HLA presentation of canonical peptides derived from E6 and E7, and ARF-derived viral peptides from a reverse-strand transcript spanning the HPV E1 and E2 genes in primary human cervical tumor tissue. Our results extend currently known viral immunotherapeutic targets in cervical cancer and highlight E1 as an important cervical cancer antigen.

Combination immunotherapy with synthetic long peptides and chemotherapy or PD-1 blocker for cancers caused by human papilloma virus type 16

Therapeutic vaccination of premalignant conditions and of different stages of cancer can be accomplished with several platforms including DNA vaccines, RNA vaccines, synthetic long peptides (SLP), and recombinant viruses. We successfully used a therapeutic vaccine composed of SLP covering the complete sequence of the two oncogenic proteins E6 and E7 of human papillomavirus type 16 (HPV16) as monotherapy in patients with premalignant disease. However, combination treatment might be required in patients with (advanced) cancer because of the hostile cancer microenvironment for T cells in established HPV16+ cancer, often associated with systemic immunosuppression. In patients with late-stage recurrent or metastatic HPV16+ cancers, we have therefore combined treatment with the SLP vaccine, called ISA101b, with either standard-of-care chemotherapy or with immune checkpoint inhibition with anti-PD-1 monoclonal antibody. A strong vaccine-induced interferon gamma-producing T cell response to HPV16 E6/E7 was associated with significantly better survival. In a second phase 1/2 study, patients with recurrent or metastatic HPV16+ oropharyngeal cancer were treated with the combination of ISA101b and anti-PD-1 (nivolumab). In this trial, the clinical overall response rate (ORR) in 22 patients was 36%, twice the ORR in the nivolumab registration trial for this category of patients, and 2/22 patients had a complete clinical response that is ongoing after 4 1/2 years. Other promising strategies for late-stage cancer recipients are the infusion of expanded tumor-infiltrating lymphocytes or the infusion of T cell receptor transduced T cells, both directed against HPV16.

Therapeutic Vaccination for HPV-Mediated Cancers

Purpose of Review

The goal of this narrative review is to educate clinicians regarding the foundational concepts, efficacy, and future directions of therapeutic vaccines for human papillomavirus (HPV)-mediated cancers.

Recent Findings

Therapeutic HPV vaccines deliver tumor antigens to stimulate an immune response to eliminate tumor cells. Vaccine antigen delivery platforms are diverse and include DNA, RNA, peptides, proteins, viral vectors, microbial vectors, and antigen-presenting cells. Randomized, controlled trials have demonstrated that therapeutic HPV vaccines are efficacious in patients with cervical intraepithelial neoplasia. In patients with HPV-mediated malignancies, evidence of efficacy is limited. However, numerous ongoing studies evaluating updated therapeutic HPV vaccines in combination with immune checkpoint inhibition and other therapies exhibit significant promise.

Summary

Therapeutic vaccines for HPV-mediated malignancies retain a strong biological rationale, despite their limited efficacy to date. Investigators anticipate they will be most effectively used in combination with other regimens, such as immune checkpoint inhibition.

Combinational therapies for the treatment of advanced cervical cancer

INTRODUCTION

From a therapeutic standpoint, invasive cervical cancer can be designated as early, locally advanced, and advanced stages. Systemic treatment remains the primary therapeutical modality for advanced cervical cancer patients who are not candidates for local curative treatments (surgery and radiation).

AREAS COVERED

In this review, the author discusses recent clinical studies published in PubMed on the treatment of advanced cervical carcinoma. The author also provides his expert perspectives on the current state of play.

EXPERT OPINION

Survival outcomes for advanced cervical cancer patients have been steadily improving since 1981, when single-agent cisplatin was adopted as the standard of care. In 2014, bevacizumab increased median overall survival (MOS) to 17 months when combined with standard chemotherapy (platinum-paclitaxel). In 2021, the checkpoint inhibitor (CPI) pembrolizumab, when used in the first line added to platinum-paclitaxel-bevacizumab, increased mOS to 24 months. Two other CPIs are in phase III trials as first-line treatments. As for second-line therapy, cemiplimab has shown increased survival compared to single-agent chemotherapy, and a phase III trial with tisotumab vedotin is currently ongoing. Nevertheless, there is still an unmet need for new more effective treatments and significant efforts are needed in the discovery of drugs for advanced cervical cancer beyond the current 'me-too' drugs.

Development of therapeutic vaccines for the treatment of diseases

Vaccines are one of the most effective medical interventions to combat newly emerging and re-emerging diseases. Prophylactic vaccines against rabies, measles, etc., have excellent effectiveness in preventing viral infection and associated diseases. However, the host immune response is unable to inhibit virus replication or eradicate established diseases in most infected people. Therapeutic vaccines, expressing specific endogenous or exogenous antigens, mainly induce or boost cell-mediated immunity via provoking cytotoxic T cells or elicit humoral immunity via activating B cells to produce specific antibodies. The ultimate aim of a therapeutic vaccine is to reshape the host immunity for eradicating a disease and establishing lasting memory. Therefore, therapeutic vaccines have been developed for the treatment of some infectious diseases and chronic noncommunicable diseases. Various technological strategies have been implemented for the development of therapeutic vaccines, including molecular-based vaccines (peptide/protein, DNA and mRNA vaccines), vector-based vaccines (bacterial vector vaccines, viral vector vaccines and yeast-based vaccines) and cell-based vaccines (dendritic cell vaccines and genetically modified cell vaccines) as well as combinatorial approaches. This review mainly summarizes therapeutic vaccine-induced immunity and describes the development and status of multiple types of therapeutic vaccines against infectious diseases, such as those caused by HPV, HBV, HIV, HCV, and SARS-CoV-2, and chronic noncommunicable diseases, including cancer, hypertension, Alzheimer's disease, amyotrophic lateral sclerosis, diabetes, and dyslipidemia, that have been evaluated in recent preclinical and clinical studies.

Third-Generation Vaccines: Features of Nucleic Acid Vaccines and Strategies to Improve Their Efficiency

Gene immunization comprises mRNA and DNA vaccines, which stand out due to their simple design, maintenance, and high efficacy. Several studies indicate promising results in preclinical and clinical trials regarding immunization against ebola, human immunodeficiency virus (HIV), influenza, and human papillomavirus (HPV). The efficiency of nucleic acid vaccines has been highlighted in the fight against COVID-19 with unprecedented approval of their use in humans. However, their low intrinsic immunogenicity points to the need to use strategies capable of overcoming this characteristic and increasing the efficiency of vaccine campaigns. These strategies include the improvement of the epitopes' presentation to the system via MHC, the evaluation of immunodominant epitopes with high coverage against emerging viral subtypes, the use of adjuvants that enhance immunogenicity, and the increase in the efficiency of vaccine transfection. In this review, we provide updates regarding some characteristics, construction, and improvement of such vaccines, especially about the production of synthetic multi-epitope genes, widely employed in the current gene-based vaccines.

Adoptive tumor infiltrating lymphocytes cell therapy for cervical cancer

Cervical cancer is one of the most common malignancies among females. As a virus-related cancer, cervical cancer has attracted a lot of attention to develop virus-targeted immune therapy, including vaccine and adoptive immune cell therapy (ACT). Adoptive tumor infiltrating lymphocytes (TILs) cell therapy has been found to be able to control advanced disease progression in some cervical cancer patients who have received several lines of treatment in a pilot clinical trial. In addition, sustainable therapeutic effect has been identified in some cases. The safety risks of TIL therapy for patients are minimal or at least manageable. In this review, we focused on the versatility of TILs and tried to summarize potential strategies to improve the therapeutic effect of TILs and discuss related perspectives.

A Therapeutic Antigen-Presenting Cell-Targeting DNA Vaccine VB10.16 in HPV16-Positive High-Grade Cervical Intraepithelial Neoplasia: Results from a Phase I/IIa Trial

PURPOSE

To evaluate the safety, immunogenicity and efficacy of a therapeutic DNA vaccine VB10.16, using a unique modular vaccine technology that is based on linking antigens to CCL3L1 targeting module, in women with HPV16-positive high-grade cervical intraepithelial neoplasia (CIN).

PATIENTS AND METHODS

We conducted a first-in-human, open-label, phase I/IIa clinical trial of VB10.16 in subjects with confirmed HPV16-positive CIN 2/3. The primary endpoint was the proportion of participants with adverse events, including dose-limiting toxicities. Secondary outcome measures included measuring the E6/E7-specific cellular immune response. In the Expansion cohort HPV16 clearance, regression of CIN lesion size and grading were assessed during a 12-month follow-up period.

RESULTS

A total of 34 women were enrolled: 16 in two dose cohorts and 18 in the expansion cohort. No serious adverse events or dose-limiting toxicities were observed, and none of the subjects discontinued treatment with VB10.16 due to an adverse event. Mild to moderate injection site reactions were the most commonly reported adverse event (79%). HPV16-specific T-cell responses were observed after vaccination in the majority of the subjects. In the expansion cohort, HPV16 clearance was seen in 8 of 17 evaluable subjects (47%). Reductions in lesion size were seen in 16 subjects (94%) and 10 subjects (59%) had regression to CIN 0/1. Correlation between strong IFNγ T-cell responses and lesion size reduction was statistically significant (P < 0.001).

CONCLUSIONS

The novel therapeutic DNA vaccine VB10.16 was well tolerated and showed promising evidence of efficacy and strong HPV16-specific T-cell responses in subjects with high-grade CIN.

Immunological evaluation of recombination PRRSV GP3 and GP5 DNA vaccines in vivo

The porcine reproductive and respiratory syndrome virus (PRRSV) is a threat to the health of pigs worldwide, but commercially available vaccines offer limited protection against PRRSV infection. It is necessary to develop a more effective DNA vaccine. The immunological effects of DNA vaccines with three adjuvants were examined in pigs (Susscrofa domestica) challenged with PRRSV. These DNA vaccines, which encoded PRRSV GP3 and GP5, were formulated with A1, A2, and A3. Serum specific and neutralizing antibodies, IL-4, IFN-γ, IL-2, IL-10, CD4⁺ and CD8⁺T-lymphocytes, health status, histopathology, and viral loads were determined. The results showed that the use of adjuvant A3 led to higher levels of neutralizing antibodies and a lower viral load in pigs compared to the other adjuvants. The neutralizing antibody titers of the pVAX-GP35+A1 and pVAX-GP35+A3 groups reached a peak of 1:19 at 35 dpi. The maximum concentration of IL-4 was 136.77 pg/mL in the pVAX-GP35+A3 group. At 35 dpi, the IFN-γ concentration in the pVAX-GP35+A1 group was 227.4 pg/mL. pVAX-GP35+A3 group shows the highest IL-2 and IL-10 expression to the peak of 597.6 pg/mL and 189.1 pg/mL, respectively. We found a formulation demonstrated beneficial immune outcomes. This study provides an alternative vaccine to protect pigs from PRRSV.

Governing HPV-related carcinoma using vaccines: Bottlenecks and breakthroughs

Human papillomavirus (HPV) contributes to sexually transmitted infection, which is primarily associated with pre-cancerous and cancerous lesions in both men and women and is among the neglected cancerous infections in the world. At global level, two-, four-, and nine-valent pure L1 protein encompassed vaccines in targeting high-risk HPV strains using recombinant DNA technology are available. Therapeutic vaccines are produced by early and late oncoproteins that impart superior cell immunity to preventive vaccines that are under investigation. In the current review, we have not only discussed the clinical significance and importance of both preventive and therapeutic vaccines but also highlighted their dosage and mode of administration. This review is novel in its way and will pave the way for researchers to address the challenges posed by HPV-based vaccines at the present time.

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.

Cancer vaccines: the next immunotherapy frontier

After several decades, therapeutic cancer vaccines now show signs of efficacy and potential to help patients resistant to other standard-of-care immunotherapies, but they have yet to realize their full potential and expand the oncologic armamentarium. Here, we classify cancer vaccines by what is known of the included antigens, which tumors express those antigens and where the antigens colocalize with antigen-presenting cells, thus delineating predefined vaccines (shared or personalized) and anonymous vaccines (ex vivo or in situ). To expedite clinical development, we highlight the need for accurate immune monitoring of early trials to acknowledge failures and advance the most promising vaccines.

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.

Immunotherapeutic Approaches for the Treatment of HPV-Associated (Pre-)Cancer of the Cervix, Vulva and Penis

Human papillomavirus (HPV) infection drives tumorigenesis in almost all cervical cancers and a fraction of vulvar and penile cancers. Due to increasing incidence and low vaccination rates, many will still have to face HPV-related morbidity and mortality in the upcoming years. Current treatment options (i.e., surgery and/or chemoradiation) for urogenital (pre-)malignancies can have profound psychosocial and psychosexual effects on patients. Moreover, in the setting of advanced disease, responses to current therapies remain poor and nondurable, highlighting the unmet need for novel therapies that prevent recurrent disease and improve clinical outcome. Immunotherapy can be a useful addition to the current therapeutic strategies in various settings of disease, offering relatively fewer adverse effects and potential improvement in survival. This review discusses immune evasion mechanisms accompanying HPV infection and HPV-related tumorigenesis and summarizes current immunotherapeutic approaches for the treatment of HPV-related (pre-)malignant lesions of the uterine cervix, vulva, and penis.

An Update on Human Papilloma Virus Vaccines: History, Types, Protection, and Efficacy

Human papillomavirus (HPV) is the most common sexually transmitted agent worldwide. Early prevention with HPV vaccination is a safe and effective method against this disease. HPV vaccines provided more protection against several oncogenic HPV strains. Three prophylactic HPV vaccines have been approved to target high-risk HPV types and protect against HPV-related disorders. These existing vaccines are based on the recombinant DNA technology and purified L1 protein that is assembled to form HPV empty shells. The prophylactic vaccines are highly immunogenic and can induce production of specific neutralizing antibodies. However, therapeutic vaccines are different from these prophylactic vaccines. They induced cell-mediated immunity against transformed cells, instead of neutralizing antibodies. The second generation of prophylactic HPV vaccines, made from alternative viral components using cost-effective production strategies, is undergoing clinical evaluation. The purpose of this review is to provide a complete and up-to-date review of the types of HPV vaccines and the efficiency of each of them for readers.

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.

Active immunization combined with cisplatin confers enhanced therapeutic protection and prevents relapses of HPV-induced tumors at different anatomical sites

The active immunotherapy concept relies on the use of vaccines that are capable of inducing antitumor immunity, reversion of the suppressive immunological environment, and long-term memory responses. Previously, antitumor vaccines based on a recombinant plasmid (pgDE7h) or a purified protein (gDE7) led to regression of early-established human papillomavirus (HPV)-associated tumors in a preclinical model. In this work, the anticancer vaccines were combined with cisplatin to treat HPV-induced tumors at advanced growth stages. The antitumor effects were evaluated in terms of tumor regression, induction of specific CD8⁺ T cells, and immune modulation of the tumor microenvironment. Acute toxicity induced by the treatment was measured by weight loss and histological alterations in the liver and kidneys. Our results revealed that the combination of cisplatin with either one of the tested immunotherapies (pgDE7h or gDE7) led to complete tumor regression in mice. Also, the combined treatment resulted in synergistic effects, particularly among mice immunized with gDE7, including activation of systemic and tumor-infiltrating E7-specific CD8⁺ T cells, tumor infiltration of macrophages and dendritic cells, and prevention of tumor relapses at different anatomical sites. Furthermore, the protocol allowed the reduction of cisplatin dosage and its intrinsic toxic effects, without reducing antitumor outcomes. These results expand our knowledge of active immunotherapy protocols and open perspectives for alternative treatments of HPV-associated tumors.

The Efficacy of Therapeutic DNA Vaccines Expressing the Human Papillomavirus E6 and E7 Oncoproteins for Treatment of Cervical Cancer: Systematic Review

Cervical cancer is recognized as a serious public health problem since it remains one of the most common cancers with a high mortality rate among women despite existing preventative, screening, and treatment approaches. Since Human Papillomavirus (HPV) was recognized as the causative agent, the preventative HPV vaccines have made great progress over the last few years. However, people already infected with the virus require an effective treatment that would ensure long-term survival and a cure. Currently, clinical trials investigating HPV therapeutic vaccines show a promising vaccine-induced T-cell mediated immune response, resulting in cervical lesion regression and viral eradication. Among existing vaccine types (live vector, protein-based, nucleic acid-based, etc.), deoxyribonucleic acid (DNA) therapeutic vaccines are the focus of the study, since they are safe, cost-efficient, thermostable, easily produced in high purity and distributed. The aim of this study is to assess and compare existing DNA therapeutic vaccines in phase I and II trials, expressing HPV E6 and E7 oncoproteins for the prospective treatment of cervical cancer based on clinical efficacy, immunogenicity, viral clearance, and side effects. Five different DNA therapeutic vaccines (GX-188E, VGX-3100, pNGVL4a-CRT/E7(detox), pNGVL4a-Sig/E7(detox)/HSP70, MEDI0457) were well-tolerated and clinically effective. Clinical implementation of DNA therapeutic vaccines into treatment regimen as a sole approach or in combination with conservative treatment holds great potential for effective cancer treatment.

Preclinical evaluation of a candidate naked plasmid DNA vaccine against SARS-CoV-2

New generation plasmid DNA vaccines may be a safe, fast and simple emergency vaccine platform for preparedness against emerging viral pathogens. Applying platform optimization strategies, we tested the pre-clinical immunogenicity and protective effect of a candidate DNA plasmid vaccine specific for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The DNA vaccine induced spike-specific binding IgG and neutralizing antibodies in mice, rabbits, and rhesus macaques together with robust Th1 dominant cellular responses in small animals. Intradermal and intramuscular needle-free administration of the DNA vaccine yielded comparable immune responses. In a vaccination-challenge study of rhesus macaques, the vaccine demonstrated protection from viral replication in the lungs following intranasal and intratracheal inoculation with SARS-CoV-2. In conclusion, the candidate plasmid DNA vaccine encoding the SARS-CoV-2 spike protein is immunogenic in different models and confers protection against lung infection in nonhuman primates. Further evaluation of this DNA vaccine candidate in clinical trials is warranted.

Role of interleukin-17 in human papillomavirus infection and associated malignancies

Human papillomavirus infection is among the leading viral infections in the world, causing severe mortality and morbidity. The virus mainly targets the female genital tract-cervix, vulva, anus but it is also reported to infect the lungs and oropharyngeal region of the body. The host immune response plays a vital role in the persistence of viral infection. Interleukin 17 (IL-17) is mainly secreted by Th17 cells and mediates the immune response that enhances the disease severity in HPV infection. IL-17 is reported to promote lesions and tumour progression by creating a hyperinflammatory condition leading to cancer. The current minireview summarizes the pathogenic role of IL-17 in HPV infection and HPV-induced malignancies. Further study on IL-17 associated pathology of HPV infection would be useful in developing therapeutic measures.

Therapeutic cancer vaccines: reasons to believe

Our hopes of using the power of the immune system to control tumours have been partially fulfilled with anti-PD1 antibodies and other checkpoint inhibitors and the use of engineered T cells targeting lineage-specific surface markers with chimeric antigen receptors. Can these successes be generalised? Therapeutic cancer vaccines aim to educate or re-educate the immune system to recognise tumour specific or tumour associated antigens. After many false dawns, some positive data for the effectiveness of such an approach is starting to emerge in advanced solid tumours, albeit as combination therapies with checkpoint inhibitors. But is the field targeting the right antigens? Interventions using the most effective vaccine platforms to target certain sets of antigens in patients with low disease burden might bring impressive long-term benefits to patients as single agents.

A New Generation of Vaccines in the Age of Immunotherapy

PURPOSE OF REVIEW

Cancer vaccines are one of the most extensively studied immunotherapy type in solid tumors. Despite favorable presuppositions, so far, the use of cancer vaccines has been associated with disappointing results. However, a new generation of vaccines has been developed, promising to revolutionize the immunotherapy field.

RECENT FINDINGS

In this review, we aim to highlight the advances in cancer vaccines and the remaining hurdles to overcome. Cancer vaccination has experienced tremendous progress in the last decade, with myriad promising developments. Future efforts should focus on optimization of target identification, streamlining of most appropriate vaccination strategies, and adjuvant development, as well as predictive biomarker identification. Cautious optimism is warranted in the face of early successes seen in recent clinical trials for oncolytic vaccines. If an approach were to prove successful, it could revolutionize cancer therapy the way ICIs did in the previous decade.

The Current Status of COVID-19 Vaccines

The current COVID-19 pandemic has substantially accelerated the demands for efficient vaccines. A wide spectrum of approaches includes live attenuated and inactivated viruses, protein subunits and peptides, viral vector-based delivery, DNA plasmids, and synthetic mRNA. Preclinical studies have demonstrated robust immune responses, reduced viral loads and protection against challenges with SARS-CoV-2 in rodents and primates. Vaccine candidates based on all delivery systems mentioned above have been subjected to clinical trials in healthy volunteers. Phase I clinical trials have demonstrated in preliminary findings good safety and tolerability. Evaluation of immune responses in a small number of individuals has demonstrated similar or superior levels of neutralizing antibodies in comparison to immunogenicity detected in COVID-19 patients. Both adenovirus- and mRNA-based vaccines have entered phase II and study protocols for phase III trials with 30,000 participants have been finalized.

Comprehensive study of a novel immune-related lncRNA for prognosis and drug treatment of cervical squamous cell carcinoma

A comprehensive study focusing on immune-related long non-coding RNAs (lncRNAs) in cervical cancer (CC) was performed. Through the integration of TCGA data, a total of 266 immune-related lncRNAs were obtained. We defined all samples as an entire set, and randomly divided them into train set and test set at a ratio of 1:1. Univariate, LASSO and multivariate Cox regression analyses were carried out based on train set for key lncRNAs (UBL7-AS1, AC083809.1, LIPE-AS1, PCED1B-AS1, ELFN1-AS1 and NCK1-DT) to construct a prognostic model, while the others were used for validation. The overall survival (OS) suggested that we may have longer survival expectations for patients classified into the low-risk group. The P values of risk score in univariate analysis and multivariate analysis were all less than 0.05, indicating the ability of risk score to independently assess the prognosis of patients. For clinical application, a nomogram with a high degree of agreement between the predicted curve and the actual curve was constructed. Subsequently, immune status and chemotherapy response were investigated in two prognostic subtypes. The associations between risk score and immune cell were estimated, in which CD8+ T cells showed the highest positive correlation and activated mast cell showed the highest negative correlation. In addition, checkpoint proteins (CTLA4, LAG3, PD-1, and TIGIT) showing negative correlation with risk score were found to be upregulated in low-risk group. A total of 3 chemotherapy drugs including paclitaxel, vinorelbine and methotrexate were considered effective in patients of high-risk group. Using 6 key immune-related lncRNAs, we identified two prognostic subtypes and provided new insights for CC immunotherapy.

Early approval of COVID-19 vaccines: Pros and cons

The development of safe and effective vaccines has been an overriding priority for controlling the 2019-coronavirus disease (COVID-19) pandemic. From the onset, COVID-19 has caused high mortality and economic losses and yet has also offered an opportunity to advance novel therapeutics such as DNA and mRNA vaccines. Although it is hoped that the swift acceptance of such vaccines will prevent loss of life, rejuvenate economies and restore normal life, there could also be significant pitfalls. This perspective provides an overview of future directions and challenges in advancing promising vaccine platforms to widespread therapeutic use.

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.

High-throughput 5' UTR engineering for enhanced protein production in non-viral gene therapies

Despite significant clinical progress in cell and gene therapies, maximizing protein expression in order to enhance potency remains a major technical challenge. Here, we develop a high-throughput strategy to design, screen, and optimize 5' UTRs that enhance protein expression from a strong human cytomegalovirus (CMV) promoter. We first identify naturally occurring 5' UTRs with high translation efficiencies and use this information with in silico genetic algorithms to generate synthetic 5' UTRs. A total of ~12,000 5' UTRs are then screened using a recombinase-mediated integration strategy that greatly enhances the sensitivity of high-throughput screens by eliminating copy number and position effects that limit lentiviral approaches. Using this approach, we identify three synthetic 5' UTRs that outperform commonly used non-viral gene therapy plasmids in expressing protein payloads. In summary, we demonstrate that high-throughput screening of 5' UTR libraries with recombinase-mediated integration can identify genetic elements that enhance protein expression, which should have numerous applications for engineered cell and gene therapies.

Methods to improve the immunogenicity of plasmid DNA vaccines

DNA vaccines have emerged as innovative approaches that have great potential to overcome the limitations of current conventional vaccines. Plasmid DNA vaccines are often safer than other vaccines because they carry only antigen genetic information, are more stable and easier to produce, and can stimulate both humoral and cellular immune responses. Although the results of ongoing clinical trials are very promising, some limitations compromise the immunogenicity of these vaccines. Thus, this review describes different strategies that can be explored to improve the immunogenicity of plasmid DNA vaccines, including the optimization of the plasmid vector backbone, the use of different methods for vaccine delivery, the use of alternative administration routes and the inclusion of adjuvants. In combination, these improvements could lead to the successful clinical use of plasmid DNA vaccines.

Combination immunotherapy with two attenuated Listeria strains carrying shuffled HPV-16 E6E7 protein causes tumor regression in a mouse tumor model

Cervical cancer continues to impose a heavy burden worldwide, and human papilloma virus (HPV) infection, especially persistent infection with type 16 (HPV-16), is known to be the primary etiological factor. Therapeutic vaccines are urgently needed because prophylactic vaccines are ineffective at clearing pre-existing HPV infection. Here, two recombinant Listeria strains (LMΔ-E6E7 & LIΔ-E6E7) with deletions of the actA and plcB genes, expressing the shuffled HPV-16 E6E7 protein were constructed. The strains were delivered into the spleen and liver by intravenous inoculation, induced antigen-specific cellular immunity and were eliminated completely from the internal organs several days later. Intravenously treating with single strain for three times, or with both strains alternately for three times significantly reduced the tumor size and prolonged the survival time of model mice. Combination immunotherapy with two strains seemed more effective than immunotherapy with single strain in that it enhanced the survival of the mice, and the LMΔ-E6E7-prime-LIΔ-E6E7-boost strategy showed significant stronger efficacy than single treatment with the LIΔ-E6E7 strain. The antitumor effect of this treatment might due to its ability to increase the proportion of CD8⁺ T cells and reduce the proportion of T regulatory cells (Tregs) in the intratumoral milieu. This is the first report regarding Listeria ivanovii-based therapeutic vaccine candidate against cervical cancer. Most importantly we are the first to confirm that combination therapy with two different recombinant Listeria strains has a more satisfactory antitumor effect than administration of a single strain. Thus, we propose a novel prime-boost treatment strategy.

Therapeutic cancer vaccines

Therapeutic cancer vaccines have undergone a resurgence in the past decade. A better understanding of the breadth of tumour-associated antigens, the native immune response and development of novel technologies for antigen delivery has facilitated improved vaccine design. The goal of therapeutic cancer vaccines is to induce tumour regression, eradicate minimal residual disease, establish lasting antitumour memory and avoid non-specific or adverse reactions. However, tumour-induced immunosuppression and immunoresistance pose significant challenges to achieving this goal. In this Review, we deliberate on how to improve and expand the antigen repertoire for vaccines, consider developments in vaccine platforms and explore antigen-agnostic in situ vaccines. Furthermore, we summarize the reasons for failure of cancer vaccines in the past and provide an overview of various mechanisms of resistance posed by the tumour. Finally, we propose strategies for combining suitable vaccine platforms with novel immunomodulatory approaches and standard-of-care treatments for overcoming tumour resistance and enhancing clinical efficacy.

Cooperation of genes in HPV16 E6/E7-dependent cervicovaginal carcinogenesis trackable by endoscopy and independent of exogenous estrogens or carcinogens

Human papillomavirus (HPV) infection is necessary but insufficient for progression of epithelial cells from dysplasia to carcinoma-in situ (CIS) to invasive cancer. The combination of mutant cellular and viral oncogenes that regulate progression of cervical cancer (CC) remains unclear. Using combinations of HPV16 E6/E7 (E+), mutant Kras (mKras) (K+) and/or loss of Pten (P-/-), we generated autochthonous models of CC without exogenous estrogen, carcinogen or promoters. Furthermore, intravaginal instillation of adenoCre virus enabled focal activation of the oncogenes/inactivation of the tumor suppressor gene. In P+/+ mice, E6/E7 alone (P+/+E+K-) failed to cause premalignant changes, while mKras alone (P+/+E-K+) caused persistent mucosal abnormalities in about one-third of mice, but no cancers. To develop cancer, P+/+ mice needed both E6/E7 and mKras expression. Longitudinal endoscopies of P+/+E+K+ mice predicted carcinoma development by detection of mucosal lesions, found on an average of 23 weeks prior to death, unlike longitudinal quantitative PCRs of vaginal lavage samples from the same mice. Endoscopy revealed that individual mice differed widely in the time required for mucosal lesions to appear after adenoCre and in the time required for these lesions to progress to cancer. These cancers developed in the transition zone that extends, unlike in women, from the murine cervix to the distal vagina. The P-/-E+K+ genotype led to precipitous cancer development within a few weeks and E6/E7-independent cancer development occurred in the P-/-E-K+ genotype. In the P-/-E+K- genotype, mice only developed CIS. Thus, distinct combinations of viral and cellular oncogenes are involved in distinct steps in cervical carcinogenesis.

Plant-based vaccines and cancer therapy: Where are we now and where are we going?

Therapeutic vaccines are an effective approach in cancer therapy for treating the disease at later stages. The Food and Drug Administration (FDA) recently approved the first therapeutic cancer vaccine, and further studies are ongoing in clinical trials. These are expected to result in the future development of vaccines with relatively improved efficacy. Several vaccination approaches are being studied in pre-clinical and clinical trials, including the generation of anti-cancer vaccines by plant expression systems.This approach has advantages, such as high safety and low costs, especially for the synthesis of recombinant proteins. Nevertheless, the development of anti-cancer vaccines in plants is faced with some technical obstacles.Herein, we summarize some vaccines that have been used in cancer therapy, with an emphasis on plant-based vaccines.

Cervical Cancer Immunotherapy: Facts and Hopes

It is a sad fact that despite being almost completely preventable through human papillomavirus (HPV) vaccination and screening, cervical cancer remains the fourth most common cancer to affect women worldwide. Persistent high-risk HPV (hrHPV) infection is the primary etiologic factor for cervical cancer. Upward of 70% of cases are driven by HPV types 16 and 18, with a dozen other hrHPVs associated with the remainder of cases. Current standard-of-care treatments include radiotherapy, chemotherapy, and/or surgical resection. However, they have significant side effects and limited efficacy against advanced disease. There are a few treatment options for recurrent or metastatic cases. Immunotherapy offers new hope, as demonstrated by the recent approval of programmed cell death protein 1-blocking antibody for recurrent or metastatic disease. This might be augmented by combination with antigen-specific immunotherapy approaches, such as vaccines or adoptive cell transfer, to enhance the host cellular immune response targeting HPV-positive cancer cells. As cervical cancer progresses, it can foster an immunosuppressive microenvironment and counteract host anticancer immunity. Thus, approaches to reverse suppressive immune environments and bolster effector T-cell functioning are likely to enhance the success of such cervical cancer immunotherapy. The success of nonspecific immunostimulants like imiquimod against genital warts also suggest the possibility of utilizing these immunotherapeutic strategies in cervical cancer prevention to treat precursor lesions (cervical intraepithelial neoplasia) and persistent hrHPV infections against which the licensed prophylactic HPV vaccines have no efficacy. Here, we review the progress and challenges in the development of immunotherapeutic approaches for the prevention and treatment of cervical cancer.

Characterization of recombinant gorilla adenovirus HPV therapeutic vaccine PRGN-2009

There are approximately 44,000 cases of human papillomavirus-associated (HPV-associated) cancer each year in the United States, most commonly caused by HPV types 16 and 18. Prophylactic vaccines successfully prevent healthy people from acquiring HPV infections via HPV-specific antibodies. In order to treat established HPV-associated malignancies, however, new therapies are necessary. Multiple recombinant gorilla adenovirus HPV vaccine constructs were evaluated in NSG-β2m-/- peripheral blood mononuclear cell-humanized mice bearing SiHa, a human HPV16+ cervical tumor, and/or in the syngeneic HPV16+ TC-1 model. PRGN-2009 is a therapeutic gorilla adenovirus HPV vaccine containing multiple cytotoxic T cell epitopes of the viral oncoproteins HPV 16/18 E6 and E7, including T cell enhancer agonist epitopes. PRGN-2009 treatment reduced tumor volume and increased CD8+ and CD4+ T cells in the tumor microenvironment of humanized mice bearing the human cervical tumor SiHa. PRGN-2009 monotherapy in the syngeneic TC-1 model also reduced tumor volumes and weights, generated high levels of HPV16 E6-specific T cells, and increased multifunctional CD8+ and CD4+ T cells in the tumor microenvironment. These studies provide the first evaluation to our knowledge of a therapeutic gorilla adenovirus HPV vaccine, PRGN-2009, showing promising preclinical antitumor efficacy and induction of HPV-specific T cells, along with the rationale for its evaluation in clinical trials.

Soluble Spike DNA Vaccine Provides Long-Term Protective Immunity against SARS-CoV-2 in Mice and Nonhuman Primates

The unprecedented and rapid spread of SARS-CoV-2 (severe acute respiratory syndrome-coronavirus-2) has motivated the need for a rapidly producible and scalable vaccine. Here, we developed a synthetic soluble SARS-CoV-2 spike (S) DNA-based vaccine candidate, GX-19. In mice, immunization with GX-19 elicited not only S-specific systemic and pulmonary antibody responses but also Th1-biased T cell responses in a dose-dependent manner. GX-19-vaccinated nonhuman primates seroconverted rapidly and exhibited a detectable neutralizing antibody response as well as multifunctional CD4+ and CD8+ T cell responses. Notably, when the immunized nonhuman primates were challenged at 10 weeks after the last vaccination with GX-19, they had reduced viral loads in contrast to non-vaccinated primates as a control. These findings indicate that GX-19 vaccination provides a durable protective immune response and also support further development of GX-19 as a vaccine candidate for SARS-CoV-2.

IL-6 and IL-10 in the serum and exfoliated cervical cells of patients infected with high-risk human papillomavirus

Persistent infection by high-risk human papillomavirus (HR-HPV) is the main cause of cervical cancer and its precursor lesions. While some cytokines help immune cells in virus clearance, others contribute to the persistence of infection and neoplastic progression. Here, the levels of interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-10, IL-6, IL-4, and IL-2 were quantified in the serum and exfoliated cervical cells (ECCs) of patients with HR-HPV, and the presence of IL-6⁺ cells was investigated in uterine cervix biopsies. Cytokine levels in the serum and ECCs of 26 HR-HPV DNA-positive patients and 18 HPV DNA-negative patients were measured using flow cytometry. Fifteen uterine cervix biopsy samples embedded in paraffin were subjected to immunohistochemical analysis for the detection of IL-6⁺ cells. HR-HPV-positive patients showed increased IL-6 and IL-10 in the ECCs and serum, respectively. Compared with HPV DNA-positive patients, HPV DNA-negative patients had higher levels of IL-6 in ECCs. Patients with multiple infections of HPV had higher levels of IL-6 in their ECCs than those with a single infection. Immunostaining of uterine cervix biopsy samples revealed no differences in IL-6 expression between the different classes of histopathological lesions. However, differences were observed in the expression levels of IL-6 and IL-10 at the systemic and local levels in HR-HPV-positive patients without cervical lesions. Considering the functional characteristics of these cytokines, it can be inferred that such patients are prone to persistent HPV infection.

CpG Oligonucleotides as Vaccine Adjuvants

CpG Oligonucleotides (ODN) are immunomodulatory synthetic oligonucleotides specifically designed to stimulate Toll-like receptor 9. TLR9 is expressed on human plasmacytoid dendritic cells and B cells and triggers an innate immune response characterized by the production of Th1 and pro-inflammatory cytokines. This chapter reviews recent progress in understanding the mechanism of action of CpG ODN and provides an overview of human clinical trial results using CpG ODN to improve vaccines for the prevention/treatment of cancer, allergy, and infectious disease.