A Randomized Phase 2 Study of ADXS11-001 Listeria monocytogenes-Listeriolysin O Immunotherapy With or Without Cisplatin in Treatment of Advanced Cervical Cancer

Cancer therapy with the viral and bacterial pathogens: The past enemies can be considered the present allies

Cancer continues to be one of the leading causes of mortality worldwide despite significant advancements in cancer treatment. Many difficulties have arisen as a result of the detrimental consequences of chemotherapy and radiotherapy as a common cancer therapy, such as drug inability to penetrate deep tumor tissue, and also the drug resistance in tumor cells continues to be a major concern. These obstacles have increased the need for the development of new techniques that are more selective and effective against cancer cells. Bacterial-based therapies and the use of oncolytic viruses can suppress cancer in comparison to other cancer medications. The tumor microenvironment is susceptible to bacterial accumulation and proliferation, which can trigger immune responses against the tumor. Oncolytic viruses (OVs) have also gained considerable attention in recent years because of their potential capability to selectively target and induce apoptosis in cancer cells. This review aims to provide a comprehensive summary of the latest literature on the role of bacteria and viruses in cancer treatment, discusses the limitations and challenges, outlines various strategies, summarizes recent preclinical and clinical trials, and emphasizes the importance of optimizing current strategies for better clinical outcomes.

Understanding the HPV associated cancers: A comprehensive review

Human papillomavirus (HPV), a common cause of sexually transmitted diseases, may cause warts and lead to various types of cancers, which makes it important to understand the risk factors associated with it. HPV is the leading risk factor and plays a crucial role in the progression of cervical cancer. Viral oncoproteins E6 and E7 play a pivotal role in this process. Beyond cervical cancer, HPV-associated cancers of the mouth and throat are also increasing. HPV can also contribute to other malignancies like penile, vulvar, and vaginal cancers. Emerging evidence links HPV to these cancers. Research on the oncogenic effect of HPV is still ongoing and explorations of screening techniques, vaccination, immunotherapy and targeted therapeutics are all in progress. The present review offers valuable insight into the current understanding of the role of HPV in cancer and its potential implications for treatment and prevention in the future.

Fine-tuning the gut ecosystem: the current landscape and outlook of artificial microbiome therapeutics

The gut microbiome is acknowledged as a key determinant of human health, and technological progress in the past two decades has enabled the deciphering of its composition and functions and its role in human disorders. Therefore, manipulation of the gut microbiome has emerged as a promising therapeutic option for communicable and non-communicable disorders. Full exploitation of current therapeutic microbiome modulators (including probiotics, prebiotics, and faecal microbiota transplantation) is hindered by several factors, including poor precision, regulatory and safety issues, and the impossibility of providing reproducible and targeted treatments. Artificial microbiota therapeutics (which include a wide range of products, such as microbiota consortia, bacteriophages, bacterial metabolites, and engineered probiotics) have appeared as an evolution of current microbiota modulators, as they promise safe and reproducible effects, with variable levels of precision via different pathways. We describe the landscape of artificial microbiome therapeutics, from those already on the market to those still in the pipeline, and outline the major challenges for positioning these therapeutics in clinical practice.

Therapeutic Vaccines for HPV-Associated Cervical Malignancies: A Systematic Review

IMPORTANCE

Despite widespread prophylactic vaccination, cervical cancer continues to be a major health problem with considerable mortality. Currently, therapeutic vaccines for HPV-associated cervical malignancies are being evaluated as a potential complement to the standard treatment.

OBJECTIVE

The present systematic review was conducted on randomized controlled trials (RCTs) to investigate the effects of therapeutic vaccines on the treatment of patients with cervical cancer and cervical intraepithelial neoplasia (CIN) of Grades 2 and 3.

EVIDENCE REVIEW

The PubMed, Embase, and Cochrane Central Register of Controlled Trials databases were searched. Only articles in English published up until 31 January 2024 were selected. Also, reference lists of the selected original papers and recent review articles were manually searched for additional sources. Data on study characteristics were extracted from the selected articles. Data on outcomes of interest were synthesized, and vaccine efficacy endpoints (histological lesion regression, clinical response, and overall survival) were selected as the basis for grouping the studies.

FINDINGS

After screening 831 articles, nine RCTs with 800 participants were included, of which seven studies with 677 participants involved CIN2 and CIN3 and examined lesion regression to ≤CIN1 as the efficacy endpoint. Results of two of these studies were deemed to have a high risk of bias, and another one did not contain statistical analyses. Results of the other four studies were quantitively synthesized, and the pooling of p-values revealed a significant difference between the vaccine and placebo groups in terms of lesion regression (p-values of 0.135, 0.049, and 0.034 in RCTs, yielding a combined p-value of 0.010). The certainty of the evidence was rated as moderate. Patients with advanced cervical cancers were studied in two RCTs with 123 participants. Clinical response and overall survival were taken as endpoints, and the results were reported as not significant. The certainty of the evidence of these results was rated as very low, mainly due to the very small number of events. All studies reported good tolerance for the vaccines.

CONCLUSIONS AND RELEVANCE

The results indicate the potential for therapeutic vaccines in the regression of CIN2 and CIN3 lesions. Moreover, a potential gap in evidence is identified regarding the very low number of RCTs in patients with advanced cervical cancer.

Pharmacotherapy for the treatment of recurrent cervical cancer: an update of the literature

INTRODUCTION

Cervical cancer is the fourth most common cause of cancer-related death worldwide. High-risk locally advanced or recurrent/metastatic cervical cancers have a poor prognosis with routine treatments. The objective of this study is to analyze the data available in the literature on therapies and molecules currently in use to improve the prognosis of recurrent cervical cancer.

AREAS COVERED

An extensive literature search was conducted by authors to identify relevant trials on various databases. Articles in English published until September 2023 that investigate different pharmacotherapy strategies for the treatment of recurrent cervical cancer, were included. Results of various pharmacological regimens including different combinations of chemotherapy, immune checkpoint inhibitors, DNA damage repair inhibitors and antibody-drug conjugates were analyzed.

EXPERT OPINION

In recent years, there have been significant improvements in the outcomes of recurrent/metastatic cervical cancer. However, these improvements do not address the unmet need in terms of oncological outcomes. The introduction of immunotherapy and targeted therapies showed advantages in cervical cancer patients. New therapies and combination strategies must be implemented. Centralization of care and enrollment in clinical trials are of paramount importance. Primary and secondary prevention remains the fundamental goal to reduce the burden of cervical cancer.

Genetically engineered bacteria: a new frontier in targeted drug delivery

Genetically engineered bacteria (GEB) have shown significant promise to revolutionize modern medicine. These engineered bacteria with unique properties such as enhanced targeting, versatility, biofilm disruption, reduced drug resistance, self-amplification capabilities, and biodegradability represent a highly promising approach for targeted drug delivery and cancer theranostics. This innovative approach involves modifying bacterial strains to function as drug carriers, capable of delivering therapeutic agents directly to specific cells or tissues. Unlike synthetic drug delivery systems, GEB are inherently biodegradable and can be naturally eliminated from the body, reducing potential long-term side effects or complications associated with residual foreign constituents. However, several pivotal challenges such as safety and controllability need to be addressed. Researchers have explored novel tactics to improve their capabilities and overcome existing challenges, including synthetic biology tools (e.g., clustered regularly interspaced short palindromic repeats (CRISPR) and bioinformatics-driven design), microbiome engineering, combination therapies, immune system interaction, and biocontainment strategies. Because of the remarkable advantages and tangible progress in this field, GEB may emerge as vital tools in personalized medicine, providing precise and controlled drug delivery for various diseases (especially cancer). In this context, future directions include the integration of nanotechnology with GEB, the focus on microbiota-targeted therapies, the incorporation of programmable behaviors, the enhancement in immunotherapy treatments, and the discovery of non-medical applications. In this way, careful ethical considerations and regulatory frameworks are necessary for developing GEB-based systems for targeted drug delivery. By addressing safety concerns, ensuring informed consent, promoting equitable access, understanding long-term effects, mitigating dual-use risks, and fostering public engagement, these engineered bacteria can be employed as promising delivery vehicles in bio- and nanomedicine. In this review, recent advances related to the application of GEB in targeted drug delivery and cancer therapy are discussed, covering crucial challenging issues and future perspectives.

Bacteria-driven cancer therapy: Exploring advancements and challenges

Cancer, a serious fatal disease caused by the uncontrolled growth of cells, is the biggest challenge flagging around medicine and health fields. Conventionally, various treatments-based strategies such as radiotherapy, chemotherapy, and alternative cancer therapies possess drugs that cannot reach the cancerous tissues and make them toxic to noncancerous cells. Cancer immunotherapy has made outstanding achievements in reducing the chances of cancer. Our considerable attention towards cancer-directed immune responses and the mechanisms behind which immune cells kill cancer cells have progressively been helpful in the advancement of new therapies. Among them, bacteria-based cancer immunotherapy has achieved much more attention due to smart and robust mechanisms in activating the host anti-tumor response. Moreover, bacterial-based therapy can be utilized as a single monotherapy or in combination with multiple anticancer immunotherapies to accelerate productive clinical results. Herein, we comprehensively reviewed recent advancements, challenges, and future perspectives in developing bacterial-based cancer immunotherapies.

Immunotherapies landscape and associated inhibitors for the treatment of cervical cancer

Cervical cancer ranks as the fourth most common form of cancer worldwide. There is a large number of situations that may be examined in the developing world. The risk of contracting HPV (Human Papillomavirus) due to poor sanitation and sexual activity is mostly to blame for the disease's alarming rate of expansion. Immunotherapy is widely regarded as one of the most effective medicines available. The immunotherapy used to treat cervical cancer cells relies on inhibitors that block the immune checkpoint. The poly adenosine diphosphate ribose polymer inhibited cervical cancer cells by activating both the programmed death 1 (PD-1) and programmed death ligand 1 (CTLA-1) checkpoints, a strategy that has been shown to have impressive effects. Yet, immunotherapy directed towards tumors that have already been invaded by lymphocytes leaves a positive imprint on the healing process. Immunotherapy is used in conjunction with other treatments, including chemotherapy and radiation, to provide faster and more effective outcomes. In this combination therapy, several medications such as Pembrolizumab, Durvalumab, Atezolizumab, and so on are employed in clinical trials. Recent developments and future predictions suggest that vaccinations will soon be developed with the dual goal of reducing the patient's susceptibility to illness while simultaneously strengthening their immune system. Many clinical and preclinical studies are now investigating the effectiveness of immunotherapy in slowing the progression of cervical cancer. The field of immunotherapy is expected to witness more progress toward improving outcomes. Immunotherapies landscape and associated inhibitors for the treatment of Cervical Cancer.

Listeria monocytogenes: a promising vector for tumor immunotherapy

Cancer receives enduring international attention due to its extremely high morbidity and mortality. Immunotherapy, which is generally expected to overcome the limits of traditional treatments, serves as a promising direction for patients with recurrent or metastatic malignancies. Bacteria-based vectors such as Listeria monocytogenes take advantage of their unique characteristics, including preferential infection of host antigen presenting cells, intracellular growth within immune cells, and intercellular dissemination, to further improve the efficacy and minimize off-target effects of tailed immune treatments. Listeria monocytogenes can reshape the tumor microenvironment to bolster the anti-tumor effects both through the enhancement of T cells activity and a decrease in the frequency and population of immunosuppressive cells. Modified Listeria monocytogenes has been employed as a tool to elicit immune responses against different tumor cells. Currently, Listeria monocytogenes vaccine alone is insufficient to treat all patients effectively, which can be addressed if combined with other treatments, such as immune checkpoint inhibitors, reactivated adoptive cell therapy, and radiotherapy. This review summarizes the recent advances in the molecular mechanisms underlying the involvement of Listeria monocytogenes vaccine in anti-tumor immunity, and discusses the most concerned issues for future research.

Bacterial Drug Delivery Systems for Cancer Therapy: "Why" and "How"

Cancer is one of the major diseases that endanger human health. However, the use of anticancer drugs is accompanied by a series of side effects. Suitable drug delivery systems can reduce the toxic side effects of drugs and enhance the bioavailability of drugs, among which targeted drug delivery systems are the main development direction of anticancer drug delivery systems. Bacteria is a novel drug delivery system that has shown great potential in cancer therapy because of its tumor-targeting, oncolytic, and immunomodulatory properties. In this review, we systematically describe the reasons why bacteria are suitable carriers of anticancer drugs and the mechanisms by which these advantages arise. Secondly, we outline strategies on how to load drugs onto bacterial carriers. These drug-loading strategies include surface modification and internal modification of bacteria. We focus on the drug-loading strategy because appropriate strategies play a key role in ensuring the stability of the delivery system and improving drug efficacy. Lastly, we also describe the current state of bacterial clinical trials and discuss current challenges. This review summarizes the advantages and various drug-loading strategies of bacteria for cancer therapy and will contribute to the development of bacterial drug delivery systems.

The landscape of T cell antigens for cancer immunotherapy

The remarkable capacity of immunotherapies to induce durable regression in some patients with metastatic cancer relies heavily on T cell recognition of tumor-presented antigens. As checkpoint-blockade therapy has limited efficacy, tumor antigens have the potential to be exploited for complementary treatments, many of which are already in clinical trials. The surge of interest in this topic has led to the expansion of the tumor antigen landscape with the emergence of new antigen categories. Nonetheless, how different antigens compare in their ability to elicit efficient and safe clinical responses remains largely unknown. Here, we review known cancer peptide antigens, their attributes and the relevant clinical data and discuss future directions.

TIME Is Ticking for Cervical Cancer

Cervical cancer (CC) is a major health problem among reproductive-age females and comprises a leading cause of cancer-related deaths. Human papillomavirus (HPV) is the major risk factor associated with CC incidence. However, lifestyle is also a critical factor in CC pathogenesis. Despite HPV vaccination introduction, the incidence of CC is increasing worldwide. Therefore, it becomes critical to understand the CC tumor immune microenvironment (TIME) to develop immune cell-based vaccination and immunotherapeutic approaches. The current article discusses the immune environment in the normal cervix of adult females and its role in HPV infection. The subsequent sections discuss the alteration of different immune cells comprising CC TIME and their targeting as future therapeutic approaches.

Advances in immunotherapy for gynecological malignancies

To date, surgery, chemotherapy and radiotherapy are mainly used to treat or remove gynecological malignancies. However, these approaches have their limitations when facing complicated female diseases such as advanced cervical and endometrial cancer (EC), chemotherapy-resistant gestational trophoblastic neoplasia and platinum-resistant ovarian cancer. Instead, immunotherapy, as an alternative, could significantly improve prognosis of those patients receiving traditional treatments, with better antitumor activities and possibly less cellular toxicities. Its' development is still not fast enough to meet the current clinical needs. More preclinical studies and larger-scale clinical trials are required. This review aims to introduce the landscape and up-to-date status of immunotherapy against gynecological malignancies, with a discussion of the challenges and future direction.

Society for Immunotherapy of Cancer (SITC) clinical practice guideline on immunotherapy for the treatment of gynecologic cancer

Advanced gynecologic cancers have historically lacked effective treatment options. Recently, immune checkpoint inhibitors (ICIs) have been approved by the US Food and Drug Administration for the treatment of cervical cancer and endometrial cancer, offering durable responses for some patients. In addition, many immunotherapy strategies are under investigation for the treatment of earlier stages of disease or in other gynecologic cancers, such as ovarian cancer and rare gynecologic tumors. While the integration of ICIs into the standard of care has improved outcomes for patients, their use requires a nuanced understanding of biomarker testing, treatment selection, patient selection, response evaluation and surveillance, and patient quality of life considerations, among other topics. To address this need for guidance, the Society for Immunotherapy of Cancer (SITC) convened a multidisciplinary panel of experts to develop a clinical practice guideline. The Expert Panel drew on the published literature as well as their own clinical experience to develop evidence- and consensus-based recommendations to provide guidance to cancer care professionals treating patients with gynecologic cancer.

Engineer a double team of short-lived and glucose-sensing bacteria for cancer eradication

Rationally designed and engineered bacteria represent an emerging unique approach for cancer treatment. Here, we engineer a short-lived bacterium, mp105, that is effective against diverse cancer types and safe for intravenous administration. We reveal that mp105 combats cancer by direct oncolysis, depletion of tumor-associated macrophages, and elicitation of CD4⁺ T cell immunity. We further engineer a glucose-sensing bacterium named m6001 that selectively colonizes solid tumors. When intratumorally injected, m6001 clears tumors more efficiently than mp105 due to its post-delivery replication in tumors and potent oncolytic capacity. Finally, we combine intravenous injection of mp105 and intratumoral injection of m6001, forming a double team against cancer. The double team enhances cancer therapy compared with single treatment for subjects carrying both intratumorally injectable and uninjectable tumors. The two anticancer bacteria and their combination are applicable to different scenarios, turning bacterial therapy for cancer into a feasible solution.

Tuning Bacterial Morphology to Enhance Anticancer Vaccination

Morphology tuning is a potent strategy to modulate physiological effects of synthetic biomaterials, but it is rarely explored in microbe-based biochemicals due to the lack of artificial adjustability. Inspired by the interesting phenomenon of microbial transformation, Escherichia coli is rationally adjusted into filamentous morphology-adjusted bacteria (MABac) via chemical stimulation to prepare a bacteria-based vaccine adjuvant/carrier. Inactivated MABac display stronger immunogenicity and special delivery patterns (phagosome escape and cytoplasmic retention) that are sharply distinct from the short rod-shaped bacteria parent (Bac). Transcriptomic study further offers solid evidence for deeply understanding the in vivo activity of MABac-based vaccine, which more effectively motivates multiple cytosolic immune pathways (such as NOD-like receptors and STING) and induces pleiotropic immune responses in comparison with Bac. Harnessing the special functions caused by morphology tuning, the MABac-based adjuvant/carrier significantly improves the immunogenicity and delivery profile of cancer antigens in vivo, thus boosting cancer-specific immunity against the melanoma challenge. This study validates the feasibility of tuning bacterial morphology to improve their biological effects, establishing a facile engineering strategy that upgrades bacterial properties and functions without complex procedures like gene editing.

Systemic therapy for advanced cervical cancer: Leveraging the historical threshold of overall survival

Cervical cancer (CC) is a worldwide problem, especially in low- and middle-income countries, where patients are often diagnosed with locally advanced disease. Until recently, all chemotherapy drugs achieved low ORR and 12-month overall survival (12- month OS) for advanced CC after failure for platinum compounds. Advances in systemic therapy with immunotherapy, targeted therapy, and antibody-drug conjugates (ADC) have leveraged the 12-month OS limit. Recently, immunotherapy (pembrolizumab) has become the standard of care in first-line advanced CC combined with platinum and taxane and in second-line after platinum doublet failure.

Updates on HPV Vaccination

Cervical cancer still poses a significant global challenge. Developed countries have mitigated this challenge by the introduction of structured screening programmes and, more recently, the HPV vaccine. Countries that have successfully introduced national HPV vaccination programmes are on course for cervical cancer elimination in a few decades. In developing countries that lack structured screening and HPV vaccination programmes, cervical cancer remains a major cause of morbidity and mortality. The HPV vaccine is key to addressing the disproportionate distribution of cervical cancer incidence, with much to be gained from increasing vaccine coverage and uptake globally. This review covers the history and science of the HPV vaccine, its efficacy, effectiveness and safety, and some of the considerations and challenges posed to the achievement of global HPV vaccination coverage and the consequent elimination of cervical cancer.

Synergistic potential of immune checkpoint inhibitors and therapeutic cancer vaccines

Cancer vaccines and immune checkpoint inhibitors (ICIs) function at different stages of the cancer immune cycle due to their distinct mechanisms of action. Therapeutic cancer vaccines enhance the activation and infiltration of cytotoxic immune cells into the tumor microenvironment (TME), while ICIs, prevent and/or reverse the dysfunction of these immune cells. The efficacy of both classes of immunotherapy has been evaluated in monotherapy, but they have been met with several challenges. Although therapeutic cancer vaccines can activate anti-tumor immune responses, these responses are susceptible to attenuation by immunoregulatory molecules. Similarly, ICIs are ineffective in the absence of tumor-infiltrating lymphocytes (TILs). Further, ICIs are often associated with immune-related adverse effects that may limit quality of life and compliance. However, the combination of the improved immunogenicity afforded by cancer vaccines and restrained immunosuppression provided by immune checkpoint inhibitors may provide a suitable platform for therapeutic synergism. In this review, we revisit the history and various classifications of therapeutic cancer vaccines. We also provide a summary of the currently approved ICIs. Finally, we provide mechanistic insights into the synergism between ICIs and cancer vaccines.

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.

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.

Tumor Colonization and Therapy by Escherichia coli Nissle 1917 Strain in Syngeneic Tumor-Bearing Mice Is Strongly Affected by the Gut Microbiome

In the past, different bacterial species have been tested for cancer therapy in preclinical and clinical studies. The success of bacterial cancer therapy is mainly dependent on the ability of the utilized bacteria to overcome the host immune defense system to colonize the tumors and to initiate tumor-specific immunity. In recent years, several groups have demonstrated that the gut microbiome plays an important role of modulation of the host immune response and has an impact on therapeutic responses in murine models and in cohorts of human cancer patients. Here we analyzed the impact of the gut microbiome on tumor colonization and tumor therapy by the Escherichia coli Nissle 1917 (EcN) strain. This EcN strain is a promising cancer therapy candidate with probiotic properties. In our study, we observed significantly better tumor colonization by EcN after antibiotic-induced temporal depletion of the gut microbiome and after two intranasal applications of the EcN derivate (EcN/pMUT-gfp Kn^r) in 4T1 tumor-bearing syngeneic BALB/c mice. In addition, we demonstrated significant reduction in tumor growth and extended survival of the EcN-treated mice in contrast to phosphate-buffered saline (PBS)-treated tumor-bearing control animals. Multispectral imaging of immune cells revealed that depletion of the gut microbiome led to significantly lower infiltration of cytotoxic and helper T cells (CD4 and CD8 cells) in PBS tumors of mice pretreated with antibiotics in comparison with antibiotic untreated PBS-or EcN treated mice. These findings may help in the future advancement of cancer treatment strategies using E. coli Nissle 1917.

Reduced MHC Class I and II Expression in HPV-Negative vs. HPV-Positive Cervical Cancers

Cervical cancer (CC) is the second most common cancer in women worldwide and the fourth leading cause of cancer-associated death in women. Although human papillomavirus (HPV) infection is associated with nearly all CC, it has recently become clear that HPV-negative (HPV-) CC represents a distinct disease phenotype with increased mortality. HPV-positive (HPV+) and HPV- CC demonstrate different molecular pathology, prognosis, and response to treatment. Furthermore, CC caused by HPV α9 types (HPV16-like) often have better outcomes than those caused by HPV α7 types (HPV18-like). This study systematically and comprehensively compared the expression of genes involved in major histocompatibility complex (MHC) class I and II presentation within CC caused by HPV α9 types, HPV α7 types, and HPV- CC. We observed increased expression of MHC class I and II classical and non-classical genes in HPV+ CC and overall higher expression of genes involved in their antigen loading and presentation apparatus as well as transcriptional regulation. Increased expression of MHC I-related genes differs from previous studies using cell culture models. These findings identify crucial differences between antigen presentation within the tumor immune microenvironments of HPV+ and HPV- CC, as well as modest differences between HPV α9 and α7 CC. These differences may contribute to the altered patient outcomes and responses to immunotherapy observed between these distinct cancers.

Recent Advances in Bacteria-Based Cancer Treatment

Simple Summary

Cancer refers to a disease involving abnormal cells that proliferate uncontrollably and can invade normal body tissue. It was estimated that at least 9 million patients are killed by cancer annually. Recent studies have demonstrated that bacteria play a significant role in cancer treatment and prevention. Owing to its unique mechanism of abundant pathogen-associated molecular patterns in antitumor immune responses and preferentially accumulating and proliferating within tumors, bacteria-based cancer immunotherapy has recently attracted wide attention. We aim to illustrate that naïve bacteria and their components can serve as robust theranostic agents for cancer eradication. In addition, we summarize the recent advances in efficient antitumor treatments by genetically engineering bacteria and bacteria-based nanoparticles. Further, possible future perspectives in bacteria-based cancer immunotherapy are also inspected.

Abstract

Owing to its unique mechanism of abundant pathogen-associated molecular patterns in antitumor immune responses, bacteria-based cancer immunotherapy has recently attracted wide attention. Compared to traditional cancer treatments such as surgery, chemotherapy, radiotherapy, and phototherapy, bacteria-based cancer immunotherapy exhibits the versatile capabilities for suppressing cancer thanks to its preferentially accumulating and proliferating within tumors. In particular, bacteria have demonstrated their anticancer effect through the toxins, and other active components from the cell membrane, cell wall, and dormant spores. More importantly, the design of engineering bacteria with detoxification and specificity is essential for the efficacy of bacteria-based cancer therapeutics. Meanwhile, bacteria can deliver the cytokines, antibody, and other anticancer theranostic nanoparticles to tumor microenvironments by regulating the expression of the bacterial genes or chemical and physical loading. In this review, we illustrate that naïve bacteria and their components can serve as robust theranostic agents for cancer eradication. In addition, we summarize the recent advances in efficient antitumor treatments by genetically engineering bacteria and bacteria-based nanoparticles. Further, possible future perspectives in bacteria-based cancer immunotherapy are also inspected.

Recurrent or primary metastatic cervical cancer: current and future treatments

Despite screening programs for early detection and the approval of human papillomavirus vaccines, around 6% of women with cervical cancer (CC) are discovered with primary metastatic disease. Moreover, one-third of the patients receiving chemoradiation followed by brachytherapy for locally advanced disease will have a recurrence. At the end, the vast majority of recurrent or metastatic CC not amenable to locoregional treatments are considered incurable disease with very poor prognosis. Historically, cisplatin monotherapy, then a combination of cisplatin and paclitaxel were considered the standard of care. Ten years ago, the addition of bevacizumab to chemotherapy demonstrated favorable data in terms of response rate and overall survival. Even with this improvement, novel therapies are needed for the treatment of recurrent CC in first as well as later lines. In the last decades, a better understanding of the interactions between human papillomavirus infection and the host immune system response has focused interest on the use of immunotherapeutic drugs in CC patients. Indeed, immune checkpoint inhibitors (pembrolizumab, cemiplimab, and others) have recently emerged as novel therapeutic pillars that could provide durable responses with impact on overall survival in patients in the primary (in addition to chemotherapy) or recurrent (monotherapy) settings. Tisotumab vedotin, an antibody–drug conjugate targeting the tissue factor, is another emerging drug. Several trials in monotherapy or in combination with immunotherapy, chemotherapy, or bevacizumab showed very promising results. There is a high need for more potent biomarkers to better accurately determine which patients would receive the greatest benefit from all these aforementioned drugs, but also to identify patients with specific molecular characteristics that could benefit from other targeted therapies. The Cancer Genome Atlas Research Network identified several genes significantly mutated, potentially targetable. These molecular data have highlighted the molecular heterogeneity of CC.

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The majority of recurrent or metastatic CCs are considered incurable disease.

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Combination of chemotherapy with bevacizumab and pembrolizumab (PD-L1 CPS ≥1) is the new standard of care in first line.

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Tisotumab vedotin, an antibody–drug conjugate targeting the tissue factor, is another emerging drug.

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Need for more potent biomarkers to accurately determine which patients would receive the greatest benefit from these drugs.

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.

Magnetic Particle Imaging of Magnetotactic Bacteria as Living Contrast Agents Is Improved by Altering Magnetosome Arrangement

Superparamagnetic iron oxide nanoparticles (SPIONs) can be used as imaging agents to differentiate between normal and diseased tissue or track cell movement. Magnetic particle imaging (MPI) detects the magnetic properties of SPIONs, providing quantitative and sensitive image data. MPI performance depends on the size, structure, and composition of nanoparticles. Magnetotactic bacteria produce magnetosomes with properties similar to those of synthetic nanoparticles, and these can be modified by mutating biosynthetic genes. The use of Magnetospirillum gryphiswaldense, MSR-1 with a mamJ deletion, containing clustered magnetosomes instead of typical linear chains, resulted in improved MPI signal and resolution. Bioluminescent MSR-1 with the mamJ deletion were administered into tumor-bearing and healthy mice. In vivo bioluminescence imaging revealed the viability of MSR-1, and MPI detected signals in livers and tumors. The development of living contrast agents offers opportunities for imaging and therapy with multimodality imaging guiding development of these agents by tracking the location, viability, and resulting biological effects.

Review of the Standard and Advanced Screening, Staging Systems and Treatment Modalities for Cervical Cancer

Simple Summary

This review discusses the timeline and development of the recommended screening tests, diagnosis system, and therapeutics implemented in clinics for precancer and cancer of the uterine cervix. The incorporation of the latest automation, machine learning modules, and state-of-the-art technologies into these aspects are also discussed.

Abstract

Cancer arising from the uterine cervix is the fourth most common cause of cancer death among women worldwide. Almost 90% of cervical cancer mortality has occurred in low- and middle-income countries. One of the major aetiologies contributing to cervical cancer is the persistent infection by the cancer-causing types of the human papillomavirus. The disease is preventable if the premalignant lesion is detected early and managed effectively. In this review, we outlined the standard guidelines that have been introduced and implemented worldwide for decades, including the cytology, the HPV detection and genotyping, and the immunostaining of surrogate markers. In addition, the staging system used to classify the premalignancy and malignancy of the uterine cervix, as well as the safety and efficacy of the various treatment modalities in clinical trials for cervical cancers, are also discussed. In this millennial world, the advancements in computer-aided technology, including robotic modules and artificial intelligence (AI), are also incorporated into the screening, diagnostic, and treatment platforms. These innovations reduce the dependence on specialists and technologists, as well as the work burden and time incurred for sample processing. However, concerns over the practicality of these advancements remain, due to the high cost, lack of flexibility, and the judgment of a trained professional that is currently not replaceable by a machine.

Engaging Pattern Recognition Receptors in Solid Tumors to Generate Systemic Antitumor Immunity

Malignant tumors frequently exploit innate immunity to evade immune surveillance. The priming, function, and polarization of antitumor immunity fundamentally depends upon context provided by the innate immune system, particularly antigen presenting cells. Such context is determined in large part by sensing of pathogen specific and damage associated features by pathogen recognition receptors (PRRs). PRR activation induces the delivery of T cell priming cues (e.g. chemokines, co-stimulatory ligands, and cytokines) from antigen presenting cells, playing a decisive role in the cancer immunity cycle. Indeed, endogenous PRR activation within the tumor microenvironment (TME) has been shown to generate spontaneous antitumor T cell immunity, e.g., cGAS-STING mediated activation of antigen presenting cells after release of DNA from dying tumor cells. Thus, instigating intratumor PRR activation, particularly with the goal of generating Th1-promoting inflammation that stokes endogenous priming of antitumor CD8⁺ T cells, is a growing area of clinical investigation. This approach is analogous to in situ vaccination, ultimately providing a personalized antitumor response against relevant tumor associated antigens. Here I discuss clinical stage intratumor modalities that function via activation of PRRs. These approaches are being tested in various solid tumor contexts including melanoma, colorectal cancer, glioblastoma, head and neck squamous cell carcinoma, bladder cancer, and pancreatic cancer. Their mechanism (s) of action relative to other immunotherapy approaches (e.g., antigen-defined cancer vaccines, CAR T cells, dendritic cell vaccines, and immune checkpoint blockade), as well as their potential to complement these approaches are also discussed. Examples to be reviewed include TLR agonists, STING agonists, RIG-I agonists, and attenuated or engineered viruses and bacterium. I also review common key requirements for effective in situ immune activation, discuss differences between various strategies inclusive of mechanisms that may ultimately limit or preclude antitumor efficacy, and provide a summary of relevant clinical data.

Targeted treatment options for the management of metastatic/persistent and recurrent cervical cancer

INTRODUCTION

Cervical cancer is the overall fourth most common malignancy and the fourth most common cause of cancer related deaths worldwide. Despite vaccination and screening programs, many women continue to present with advanced stage cervical cancer, wherein the treatment options have been limited.

AREAS COVERED

In this review, immunotherapy and the potential targeted therapies that have demonstrated promise in the treatment of persistent, recurrent, and metastatic cervical cancer are discussed.

EXPERT OPINION

Our global goal in the gynecologic oncology community is to eliminate cervical cancer, by increasing the uptake of preventive vaccination and screening programs. For unfortunate patients who present with metastatic, persistent, and recurrent cervical cancer, pembrolizumab with chemotherapy, with or without bevacizumab is the new first line therapy for PD-L1 positive patients. For this patient population as a second line therapy, tisotumab vedotin (i.e. ADC) has shown significant efficacy in Phase II trials, leading to FDA approval. Combination regimens inclusive of immune checkpoint inhibitors, DNA damage repair inhibitors, antibody drug conjugates are potential breakthrough treatment strategies and are currently being investigated.

Cervical cancer therapies: current challenges and future perspectives

Cervical cancer is the fourth most common female cancer worldwide and results in over 300 000 deaths globally. The causative agent of cervical cancer is persistent infection with high-risk subtypes of the human papillomavirus and the E5, E6 and E7 viral oncoproteins cooperate with host factors to induce and maintain the malignant phenotype. Cervical cancer is a largely preventable disease and early-stage detection is associated with significantly improved survival rates. Indeed, in high-income countries with established vaccination and screening programs it is a rare disease. However, the disease is a killer for women in low- and middle-income countries who, due to limited resources, often present with advanced and untreatable disease. Treatment options include surgical interventions, chemotherapy and/or radiotherapy either alone or in combination. This review describes the initiation and progression of cervical cancer and discusses in depth the advantages and challenges faced by current cervical cancer therapies, followed by a discussion of promising and efficacious new therapies to treat cervical cancer including immunotherapies, targeted therapies, combination therapies, and genetic treatment approaches.

Pattern of F-18 FDG Uptake in Colon Cancer after Bacterial Cancer Therapy Using Engineered Salmonella Typhimurium: A Preliminary In Vivo Study

Purpose. Bacterial cancer therapy (BCT) research using engineered Salmonella typhimurium has increased in recent years. 2-Deoxy-2[18F] fluoro-D-glucose positron emission tomography (FDG PET) is widely used in cancer patients to detect cancer, monitor treatment responses, and predict prognoses. The aim of this pilot study was to investigate FDG uptake patterns in a mouse tumor model after BCT. Procedures. BCT was performed via the intravenous injection of attenuated S. typhimurium (SLΔppGpp/lux) into female mice bearing a tumor (derived from CT26 murine colon cancer cells) in the right thigh. 18F-FDG PET images acquired before BCT and at different time points after BCT. In vivo bioluminescence imaging confirmed bacterial presence in the tumor. The tumor volume, standardized uptake value (SUV) of FDG (SUVmax and SUVmean), early SUV reduction%, and normalized tumor volume change were analyzed. Results. Early after BCT (1 or 2 days post-injection (dpi)), FDG tumor uptake decreased in 10 out of 11 mice and then increased at later stages. FDG uptake before BCT was correlated with normalized tumor volume change after BCT. Early FDG reduction% after BCT was correlated with normalized volume change after BCT. Conclusions. Early after BCT, FDG tumor uptake decreased and then increased at later stages. The higher the FDG tumor uptake before BCT, the better the BCT response. FDG uptake patterns were related to tumor volume change after BCT. Therefore, FDG uptake was a good candidate for evaluating BCT.

Recent Update on Bacteria as a Delivery Carrier in Cancer Therapy: From Evil to Allies

Cancer is associated with a comprehensive burden that significantly affects patient’s quality of life. Even though patients’ disease condition is improving following conventional therapies, researchers are studying alternative tools that can penetrate solid tumours to deliver the therapeutics due to issues of developing resistance by the cancer cells. Treating cancer is not the only the goal in cancer therapy; it also includes protecting non-cancerous cells from the toxic effects of anti-cancer agents. Thus, various advanced techniques, such as cell-based drug delivery, bacteria-mediated therapy, and nanoparticles, are devised for site-specific delivery of drugs. One of the novel methods that can be targeted to deliver anti-cancer agents is by utilising genetically modified non-pathogenic bacterial species. This is due to the ability of bacterial species to multiply selectively or non-selectively on tumour cells, resulting in biofilms that leads to disruption of metastasis process. In preclinical studies, this technology has shown significant results in terms of efficacy, and some are currently under investigation. Therefore, researchers have conducted studies on bacteria transporting the anti-cancer drug to targeted tumours. Alternatively, bacterial ghosts and bacterial spores are utilised to deliver anti-cancer drugs. Although in vivo studies of bacteria-mediated cancer therapy have shown successful outcome, further research on bacteria, specifically their targeting mechanism, is required to establish a complete clinical approach in cancer treatment. This review has focused on the up-to-date understanding of bacteria as a therapeutic carrier in the treatment of cancer as an emerging field.

T-Cell Responses to Immunodominant Listeria Epitopes Limit Vaccine-Directed Responses to the Colorectal Cancer Antigen, Guanylyl Cyclase C

The Gram-positive bacterium Listeria monocytogenes (Lm) is an emerging platform for cancer immunotherapy. To date, over 30 clinical trials have been initiated testing Lm cancer vaccines across a wide variety of cancers, including lung, cervical, colorectal, and pancreatic. Here, we assessed the immunogenicity of an Lm vaccine against the colorectal tumor antigen GUCY2C (Lm-GUCY2C). Surprisingly, Lm-GUCY2C vaccination did not prime naïve GUCY2C-specific CD8+ T-cell responses towards the dominant H-2Kd-restricted epitope, GUCY2C254-262. However, Lm-GUCY2C produced robust CD8+ T-cell responses towards Lm-derived peptides suggesting that GUCY2C254-262 peptide may be subdominant to Lm-derived peptides. Indeed, incorporating immunogenic Lm peptides into an adenovirus-based GUCY2C vaccine previously shown to induce robust GUCY2C254-262 immunity completely suppressed GUCY2C254-262 responses. Comparison of immunogenic Lm-derived peptides to GUCY2C254-262 revealed that Lm-derived peptides form highly stable peptide-MHC complexes with H-2Kd compared to GUCY2C254-262 peptide. Moreover, amino acid substitution at a critical anchoring residue for H-2Kd binding, producing GUCY2CF255Y, significantly improved stability with H-2Kd and rescued GUCY2C254-262 immunogenicity in the context of Lm vaccination. Collectively, these studies suggest that Lm antigens may compete with and suppress the immunogenicity of target vaccine antigens and that use of altered peptide ligands with enhanced peptide-MHC stability may be necessary to elicit robust immune responses. These studies suggest that optimizing target antigen competitiveness with Lm antigens or alternative immunization regimen strategies, such as prime-boost, may be required to maximize the clinical utility of Lm-based vaccines.

Potential Utility of Induced Translocation of Engineered Bacteria as a Therapeutic Agent for Mounting a Personalized Neoantigen-Based Tumor Immune Response

Today, an unprecedented understanding of the cancer genome, along with major breakthroughs in oncoimmunotherapy, and a resurgence of nucleic acid vaccines against cancer are being achieved. However, in most cases, the immune system response is still insufficient to react against cancer, especially in those tumors showing low mutational burden. One way to counteract tumor escape can be the induction of bacterial translocation, a phenomenon associated with autoimmune diseases which consists of a leakage in the colonic mucosa barrier, causing the access of gut bacteria to sterile body compartments such as blood. Certain commensal or live-attenuated bacteria can be engineered in such a way as to contain nucleic acids coding for tumor neoantigens previously selected from individual tumor RNAseq data. Hypothetically, these modified bacteria, previously administered orally to a cancer patient, can be translocated by several compounds acting on colonic mucosa, thus releasing neoantigens in a systemic environment in the context of an acute inflammation. Several strategies for selecting neoantigens, suitable bacteria strains, genetic constructs, and translocation inducers to achieve tumor-specific activations of CD4 and CD8 T-cells are discussed in this hypothesis.

Bugs as drugs: neglected but a promising future therapeutic strategy in cancer

Effective cancer treatment is an urgent need due to the rising incidence of cancer. One of the most promising future strategies in cancer treatment is using microorganisms as cancer indicators, prophylactic agents, immune activators, vaccines or vectors in antitumor therapy. The success of bacteria-mediated chemotherapy will be dependent on the balance of therapeutic benefit and the control of bacterial infection in the body. Additionally, protozoans and viruses have the potential to be used in cancer therapy. This review summarizes how these microorganisms interact with tumor microenvironments and the challenges of a 'bugs as drugs' approach in cancer therapy. Several standpoints are discussed, such as bacteria as vectors for gene therapy that shuttle therapeutic compounds into tumor tissues, their intrinsic antitumor activities and their combination with chemotherapy or radiotherapy. Bug-based cancer therapy is a two-edged sword and we need to find the opportunities by overcoming the challenges.

Bacteria and bacterial derivatives as delivery carriers for immunotherapy

There is growing interest in the role of microorganisms in human health and disease, with evidence showing that new types of biotherapy using engineered bacterial therapeutics, including bacterial derivatives, can address specific mechanisms of disease. The complex interactions between microorganisms and metabolic/immunologic pathways underlie many diseases with unmet medical needs, suggesting that targeting these interactions may improve patient treatment. Using tools from synthetic biology and chemical engineering, non-pathogenic bacteria or bacterial products can be programmed and designed to sense and respond to environmental signals to deliver therapeutic effectors. This review describes current progress in biotherapy using live bacteria and their derivatives to achieve therapeutic benefits against various diseases.

Efficacy and Safety of Immunotherapy for Cervical Cancer—A Systematic Review of Clinical Trials

Purpose: To systematically review the current body of evidence on the efficacy and safety of immunotherapy for cervical cancer (CC). Material and Methods: Medline, the Cochrane Central Register of Controlled Trials and Web of Science were searched for prospective trials assessing immunotherapy in CC patients in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Full-text articles in English and German reporting outcomes of survival, response rates or safety were eligible. Results: Of 4655 screened studies, 51 were included (immune checkpoint inhibitors (ICI) n=20; therapeutic vaccines n = 25; adoptive cell transfer therapy n=9). Of these, one qualified as a phase III randomized controlled trial and demonstrated increased overall survival following treatment with pembrolizumab, chemotherapy and bevacizumab. A minority of studies included a control group (n = 7) or more than 50 patients (n = 15). Overall, response rates were low to moderate. No response to ICIs was seen in PD-L1 negative patients. However, few remarkable results were achieved in heavily pretreated patients. There were no safety concerns in any of the included studies. Conclusion: Strong evidence on the efficacy of strategies to treat recurrent or metastatic cervical cancer is currently limited to pembrolizumab in combination with chemotherapy and bevacizumab, which substantiates an urgent need for large confirmatory trials on alternative immunotherapies. Overall, there is sound evidence on the safety of immunotherapy in CC.

Immuno-Oncology for Gynecologic Malignancies

Patients with advanced and/or recurrent gynecologic cancers derive limited benefit from currently available cytotoxic and targeted therapies. Successes of immunotherapy in other difficult-to-treat malignancies such as metastatic melanoma and advanced lung cancer have led to intense interest in clinical testing of these treatments in patients with gynecologic cancers. Currently, in the realm of gynecologic oncology, the FDA-approved use of immune checkpoint inhibitors is limited to microsatellite instability-high cancers, cancers with high tumor mutational burden, and PD-L1-positive cervical cancer. However, there has been an exponential growth of clinical trials testing immunotherapy approaches both alone and in combination with chemotherapy and/or targeted agents in patients with gynecologic cancers. This chapter will review some of the major reported and ongoing immunotherapy clinical trials in patients with endometrial, cervical, and epithelial ovarian cancer.

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.

Bacterial-Based Cancer Therapy (BBCT): Recent Advances, Current Challenges, and Future Prospects for Cancer Immunotherapy

Currently approximately 10 million people die each year due to cancer, and cancer is the cause of every sixth death worldwide. Tremendous efforts and progress have been made towards finding a cure for cancer. However, numerous challenges have been faced due to adverse effects of chemotherapy, radiotherapy, and alternative cancer therapies, including toxicity to non-cancerous cells, the inability of drugs to reach deep tumor tissue, and the persistent problem of increasing drug resistance in tumor cells. These challenges have increased the demand for the development of alternative approaches with greater selectivity and effectiveness against tumor cells. Cancer immunotherapy has made significant advancements towards eliminating cancer. Our understanding of cancer-directed immune responses and the mechanisms through which immune cells invade tumors have extensively helped us in the development of new therapies. Among immunotherapies, the application of bacteria and bacterial-based products has promising potential to be used as treatments that combat cancer. Bacterial targeting of tumors has been developed as a unique therapeutic option that meets the ongoing challenges of cancer treatment. In comparison with other cancer therapeutics, bacterial-based therapies have capabilities for suppressing cancer. Bacteria are known to accumulate and proliferate in the tumor microenvironment and initiate antitumor immune responses. We are currently well-informed regarding various methods by which bacteria can be manipulated by simple genetic engineering or synthetic bioengineering to induce the production of anti-cancer drugs. Further, bacterial-based cancer therapy (BBCT) can be either used as a monotherapy or in combination with other anticancer therapies for better clinical outcomes. Here, we review recent advances, current challenges, and prospects of bacteria and bacterial products in the development of BBCTs.

Innovative Approaches of Engineering Tumor-Targeting Bacteria with Different Therapeutic Payloads to Fight Cancer: A Smart Strategy of Disease Management

Conventional therapies for cancer eradication like surgery, radiotherapy, and chemotherapy, even though most widely used, still suffer from some disappointing outcomes. The limitations of these therapies during cancer recurrence and metastasis demonstrate the need for better alternatives. Some bacteria preferentially colonize and proliferate inside tumor mass; thus these bacteria can be used as ideal candidates to deliver antitumor therapeutic agents. The bacteria like Bacillus spp., Clostridium spp., E. coli, Listeria spp., and Salmonella spp. can be reprogrammed to produce, transport, and deliver anticancer agents, eg, cytotoxic agents, prodrug converting enzymes, immunomodulators, tumor stroma targeting agents, siRNA, and drug-loaded nanoformulations based on clinical requirements. In addition, these bacteria can be genetically modified to express various functional proteins and targeting ligands that can enhance the targeting approach and controlled drug-delivery. Low tumor-targeting and weak penetration power deep inside the tumor mass limits the use of anticancer drug-nanoformulations. By using anticancer drug nanoformulations and other therapeutic payloads in combination with antitumor bacteria, it makes a synergistic effect against cancer by overcoming the individual limitations. The tumor-targeting bacteria can be either used as a monotherapy or in addition with other anticancer therapies like photothermal therapy, photodynamic therapy, and magnetic field therapy to accomplish better clinical outcomes. The toxicity issues on normal tissues is the main concern regarding the use of engineered antitumor bacteria, which requires deeper research. In this article, the mechanism by which bacteria sense tumor microenvironment, role of some anticancer agents, and the recent advancement of engineering bacteria with different therapeutic payloads to combat cancers has been reviewed. In addition, future prospective and some clinical trials are also discussed.

Impact of Value Frameworks on the Magnitude of Clinical Benefit: Evaluating a Decade of Randomized Trials for Systemic Therapy in Solid Malignancies

In the era of rapid development of new, expensive cancer therapies, value frameworks have been developed to quantify clinical benefit (CB). We assessed the evolution of CB since the 2015 introduction of The American Society of Clinical Oncology and The European Society of Medical Oncology value frameworks. Randomized clinical trials (RCTs) assessing systemic therapies for solid malignancies from 2010 to 2020 were evaluated and CB (Δ) in 2010–2014 (pre-value frameworks (PRE)) were compared to 2015–2020 (POST) for overall survival (OS), progression-free survival (PFS), response rate (RR), and quality of life (QoL). In the 485 studies analyzed (12% PRE and 88% POST), the most common primary endpoint was PFS (49%), followed by OS (20%), RR (12%), and QoL (6%), with a significant increase in OS and decrease in RR as primary endpoints in the POST era (p = 0.011). Multivariable analyses revealed significant improvement in ΔOS POST (OR 2.86, 95% CI 0.46 to 5.26, p = 0.02) while controlling for other variables. After the development of value frameworks, median ΔOS improved minimally. The impact of value frameworks has yet to be fully realized in RCTs. Efforts to include endpoints shown to impact value, such as QoL, into clinical trials are warranted.

The Evolution and Future of Targeted Cancer Therapy: From Nanoparticles, Oncolytic Viruses, and Oncolytic Bacteria to the Treatment of Solid Tumors

While many classes of chemotherapeutic agents exist to treat solid tumors, few can generate a lasting response without substantial off-target toxicity despite significant scientific advancements and investments. In this review, the paths of development for nanoparticles, oncolytic viruses, and oncolytic bacteria over the last 20 years of research towards clinical translation and acceptance as novel cancer therapeutics are compared. Novel nanoparticle, oncolytic virus, and oncolytic bacteria therapies all start with a common goal of accomplishing therapeutic drug activity or delivery to a specific site while avoiding off-target effects, with overlapping methodology between all three modalities. Indeed, the degree of overlap is substantial enough that breakthroughs in one therapeutic could have considerable implications on the progression of the other two. Each oncotherapeutic modality has accomplished clinical translation, successfully overcoming the potential pitfalls promising therapeutics face. However, once studies enter clinical trials, the data all but disappears, leaving pre-clinical researchers largely in the dark. Overall, the creativity, flexibility, and innovation of these modalities for solid tumor treatments are greatly encouraging, and usher in a new age of pharmaceutical development.

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.

The profile analysis of circular RNAs in cervical cancer

Cervical cancer (CC) is the third most common cancer among women and has a high mortality rate at the advanced stage. The mechanisms underlying the development and progression of CC are still elusive. Circular RNAs (circRNAs) play an important role in various physiological and pathological processes. The aim of this study was to identify the circRNAs significantly associated with cervical squamous cell carcinoma (CSCC), in order to discover novel diagnostic markers and elucidate their mechanistic basis.The circRNA expression profiles of CSCC and paired para-cancerous cervical tissues was downloaded from the Gene Expression Omnibus. Bioinformatics analysis were used to screen for the differentially expressed circRNAs (DECRs). The expression levels of hsa_circ_0000745, hsa_circ_0084927, hsa_circ_0002762, hsa_circ_0075341, hsa_circ_0007905, hsa_circ_0031027, hsa_circ_0065898, hsa_circ_0070190, and hsa_circ_0078383 were verified in CC and normal cervical tissues by quantitative real-time PCR.A total of 197 DECRs were identified between the CSCC and normal tissues, including 87 upregulated and 110 downregulated circRNAs. In addition, 37 miRNAs were predicted for the upregulated circRNAs and 39 for the downregulated circRNAs. Functional analysis showed that the DECRs were associated with positive regulation of substrate adhesion-dependent cell spreading, metabolism, positive regulation of GTPase activity, protein regulation, and intercellular adhesion. The MAPK signaling pathway that plays a significant role in the progression of CC, was also enriched. Consistent with the in-silico analysis, hsa_circ_0000745, hsa_circ_0084927, hsa_circ_0002762, hsa_circ_0007905 were upregulated and hsa_circ_0078383 was downregulated in CC tissues (P < .001), whereas hsa_circ_0075341 (P < .001) and hsa_circ_0031027 (P = .001) showed opposite trends.We identified novel diagnostic and therapeutic biomarkers of CSCC along with the mechanistic basis.

The Role of Immunotherapy in the Treatment of Advanced Cervical Cancer: Current Status and Future Perspectives

Cervical cancer remains one of the most common cancers in women around the world however therapeutic options in the advanced and recurrent setting are limited. Immune checkpoint inhibitors (ICI) have been considered an attractive option given the viral etiology of cervical cancer although the majority of patients do not benefit from their use. This review summarises current knowledge and use of immune checkpoint blockade in cervical cancer as well as discussing the challenges faced in their clinical application, namely, the role of biomarker-driven ICI use, potential mechanisms of resistance, strategies to overcome such resistance and additional immunotherapy options beyond ICI.

Bacteria-based immune therapies for cancer treatment

Engineered bacterial therapies that target the tumor immune landscape offer a new class of cancer immunotherapy. Salmonella enterica and Listeria monocytogenes are two species of bacteria that have been engineered to specifically target tumors and serve as delivery vessels for immunotherapies. Therapeutic bacteria have been engineered to deliver cytokines, gene silencing shRNA, and tumor associated antigens that increase immune activation. Bacterial therapies stimulate both the innate and adaptive immune system, change the immune dynamics of the tumor microenvironment, and offer unique strategies for targeting tumors. Bacteria have innate adjuvant properties, which enable both the delivered molecules and the bacteria themselves to stimulate immune responses. Bacterial immunotherapies that deliver cytokines and tumor-associated antigens have demonstrated clinical efficacy. Harnessing the diverse set of mechanisms that Salmonella and Listeria use to alter the tumor-immune landscape has the potential to generate many new and effective immunotherapies.