Bacillus Calmette–Guérin treatment of bladder cancer: a systematic review and commentary on recent publications

Roles for Androgen Receptor, ADAR2, and PD-L1 in Primary Urothelial Carcinoma In Situ of the Bladder Treated with Bacillus Calmette-Guérin Therapy

In this retrospective observational multicenter study, we identified tumors and immune markers that are related to each other, which could help in selecting patients with bladder primary urothelial carcinoma in situ (CIS) who responded better to Bacillus Calmette-Guérin (BCG) therapy. Seventy-three patients with primary bladder CIS who were homogeneously treated with BCG were studied. Tumor-infiltrating lymphocytes (TILs) measured as CD4/CD8 ratio, androgen receptor (AR), adenosine deaminase acting on RNA 1 (ADAR1), adenosine deaminase acting on RNA 2 (ADAR2), and programmed death ligand 1 (PD-L1) expression were analyzed using immunohistochemistry, whereas miR-200a-3p and INF-γ were correlated with clinicopathological features and recurrence-free survival. High AR levels in CIS were significantly associated with higher ADAR1 expression, lower ADAR2 expression, higher PD-L1 TPS, higher CD4/CD8 ratio, and multifocality of CIS (P < .001). All patients with the above-mentioned characteristics had significantly worse recurrence-free survival (P < .0001). Multivariate and multiple regression analyses confirmed the predictive role of AR, ADAR2, and PD-L1, especially when all 3 parameters were combined. Additionally, we demonstrated that patients with lower AR and higher ADAR2 expressions had significantly higher levels of miR-200a-3p and INF-γ than those with higher AR and lower ADAR2 expression (P = .0011 and P = .0002, respectively). Our findings highlight the role of AR in the response to BCG therapy by modulating PD-L1 expression and TILs through the ADAR2, miR-200a-3p, and INF-γ pathways. Furthermore, our data provide valuable insights for optimizing BCG therapy in patients with CIS, paving the way for other possible combined treatment strategies.

Intratumoral administration of mRNA COVID-19 vaccine delays melanoma growth in mice

Immunotherapies are effective for cancer treatment but are limited in 'cold' tumor microenvironments due to a lack of infiltrating CD8+ T cells, key players in the anti-cancer immune response. The onset of the COVID-19 pandemic sparked the widespread use of mRNA-formulated vaccines and is well documented that vaccination induces a Th1-skewed immune response. Here, we evaluated the effects of an intratumoral injection of the mRNA COVID-19 vaccine in subcutaneous melanoma tumor mouse models. Tumor growth and survival studies following a single intratumoral injection of the COVID-19 vaccine showed significant tumor suppression and prolonged survival in established B16F10 subcutaneous tumor-bearing mice. mRNA vaccine treatment resulted in a significant increase in CD8+ T cell infiltration into the tumor microenvironment, as observed using intravital imaging and flow cytometry. Further tumor growth suppression was achieved using additional mRNA vaccine treatments. Combination administration of mRNA vaccine with immune checkpoint therapies demonstrated enhanced effects, further delaying tumor growth and improving the survival time of tumor-bearing mice. This study demonstrates that mRNA vaccines may be used as adjuvants for immunotherapies.

Bacillus Calmette-Guérin (BCG) Vaccine in America and Overseas: A Narrative Review

This narrative review examines the role of the Bacillus Calmette-Guérin (BCG) vaccine in global tuberculosis (TB) control efforts, with particular emphasis on the differences in vaccination policies between countries, such as the US, where routine BCG administration is not practiced. A significant complication of the BCG vaccine is false positive results in the tuberculin skin test (TST), often leading to misdiagnoses and unnecessary treatments. To address these issues, interferon-gamma release assays (IGRAs) have emerged as a more specific diagnostic tool that reduces false positives associated with prior BCG vaccination. However, despite advancements, public health challenges persist in accurately detecting latent and active TB, particularly in populations previously vaccinated with BCG. This review synthesizes existing literature to assess these challenges, emphasizing the need for updated policies and improved diagnostic tools for BCG-vaccinated populations in the US and globally. Recommendations include integrating IGRAs into routine practice and tailoring TB control strategies to mitigate the diagnostic complications of BCG.

Microbial Therapeutics in Oncology: A Comprehensive Review of Bacterial Role in Cancer Treatment

Conventional cancer therapies, including chemotherapy, radiotherapy, and immunotherapy, have significantly advanced cancer treatment. However, these modalities often face limitations such as systemic toxicity, lack of specificity, and the emergence of resistance. Recent advancements in genetic engineering and synthetic biology have rekindled interest in using bacteria as a novel therapeutic approach in oncology. This comprehensive review explores the potential of microbial therapeutics, particularly bacterial therapies, in the treatment of cancer. Bacterial therapies offer several unique advantages, such as the ability to selectively target and colonize hypoxic and necrotic regions of tumors, areas typically resistant to conventional treatments. The review delves into the mechanisms through which bacteria exert antitumor effects, including direct tumor cell lysis, modulation of the immune response, and delivery of therapeutic agents like cytotoxins and enzymes. Various bacterial species, such as Salmonella, Clostridium, Lactobacillus, and Listeria, have shown promise in preclinical and clinical studies, demonstrating diverse mechanisms of action and therapeutic potential. Moreover, the review discusses the challenges associated with bacterial therapies, such as safety concerns, immune evasion, and the need for precise targeting, and how recent advances in genetic engineering are being used to overcome these hurdles. Current clinical trials and combination strategies with conventional therapies are also highlighted to provide a comprehensive overview of the ongoing developments in this field. In conclusion, while bacterial therapeutics present a novel and promising avenue in cancer treatment, further research and clinical validation is required to fully realize their potential. This review aims to inspire further exploration into microbial oncology, paving the way for innovative and more effective cancer therapies.

Unraveling the Dietary Puzzle: Exploring the Influence of Diet, Nutraceuticals, and Supplements on Bladder Cancer Risk, Outcomes, and Immunotherapy Efficacy: Insights from the BLOSSOM Study and Beyond

Bladder cancer is considered a global health concern characterized by significant morbidity and mortality rates. The complex relationship between diet and bladder cancer is examined, with a specific focus on the role of diet in risk, outcomes, and treatment efficacy. Attention is drawn to the burgeoning field of immunotherapy in bladder cancer treatment, and the possible influence of diet on its outcomes is explored. While evidence remains limited, prior studies in other cancer types have suggested a potential connection between diet and immunotherapy response. To address this knowledge gap, the ongoing BLOSSOM study is presented, which aims to investigate the link between dietary factors, lifestyle, and the effectiveness of immunotherapy in patients with non-muscle-invasive bladder cancer. Ongoing efforts to decipher the intricate relationship between diet and bladder cancer care are highlighted, emphasizing the quest to unravel the dietary puzzle for the improvement of bladder cancer management.

Microbial cancer immunotherapy reprograms hematopoietic stem cells to enhance anti-tumor immunity

Mycobacterium bovis BCG is the vaccine against tuberculosis and an immunotherapy for bladder cancer. When administered intravenously, BCG reprograms bone marrow hematopoietic stem and progenitor cells (HSPCs), leading to heterologous protection against infections. Whether HSPC-reprogramming contributes to the anti-tumor effects of BCG administered into the bladder is unknown. We demonstrate that BCG administered in the bladder in both mice and humans reprograms HSPCs to amplify myelopoiesis and functionally enhance myeloid cell antigen presentation pathways. Reconstitution of naive mice with HSPCs from bladder BCG-treated mice enhances anti-tumor immunity and tumor control, increases intratumor dendritic cell infiltration, reprograms pro-tumorigenic neutrophils, and synergizes with checkpoint blockade. We conclude that bladder BCG acts systemically, reprogramming HSPC-encoded innate immunity, highlighting the broad potential of modulating HSPC phenotypes to improve tumor immunity.

BCG and Alternative Therapies to BCG Therapy for Non-Muscle-Invasive Bladder Cancer

Bladder cancer is a heterogeneous disease. Treatment decisions are mostly decided based on disease stage (non-muscle invasive or muscle invasive). Patients with muscle-invasive disease will be offered a radical treatment combined with systemic therapy, while in those with non-muscle-invasive disease, an attempt to resect the tumor endoscopically will usually be followed by different intravesical instillations. The goal of intravesical therapy is to decrease the recurrence and/or progression of the tumor. In the current landscape of bladder cancer treatment, BCG is given intravesically to induce an inflammatory response and recruit immune cells to attack the malignant cells and induce immune memory. While the response to BCG treatment has changed the course of bladder cancer management and spared many "bladders", some patients may develop BCG-unresponsive disease, leaving radical surgery as the best choice of curative treatment. As a result, a lot of effort has been put into identifying novel therapies like systemic pembrolizumab and Nadofaragene-Firadenovac to continue sparing bladders if BCG is ineffective. Moreover, recent logistic issues with BCG production caused a worldwide BCG shortage, re-sparking interest in alternative BCG treatments including mitomycin C, sequential gemcitabine with docetaxel, and others. This review encompasses both the historic and current role of BCG in the treatment of non-muscle-invasive bladder cancer, revisiting BCG alternative therapies and reviewing the novel therapeutics that were approved for the BCG-unresponsive stage or are under active investigation.

Drug Repurposing in the Chemotherapy of Infectious Diseases

Repurposing is a universal mechanism for innovation, from the evolution of feathers to the invention of Velcro tape. Repurposing is particularly attractive for drug development, given that it costs more than a billion dollars and takes longer than ten years to make a new drug from scratch. The COVID-19 pandemic has triggered a large number of drug repurposing activities. At the same time, it has highlighted potential pitfalls, in particular when concessions are made to the target product profile. Here, we discuss the pros and cons of drug repurposing for infectious diseases and analyze different ways of repurposing. We distinguish between opportunistic and rational approaches, i.e., just saving time and money by screening compounds that are already approved versus repurposing based on a particular target that is common to different pathogens. The latter can be further distinguished into divergent and convergent: points of attack that are divergent share common ancestry (e.g., prokaryotic targets in the apicoplast of malaria parasites), whereas those that are convergent arise from a shared lifestyle (e.g., the susceptibility of bacteria, parasites, and tumor cells to antifolates due to their high rate of DNA synthesis). We illustrate how such different scenarios can be capitalized on by using examples of drugs that have been repurposed to, from, or within the field of anti-infective chemotherapy.

FGFBP1 as a potential biomarker predicting bacillus Calmette–Guérin response in bladder cancer

Accurate prediction of Bacillus Calmette–Guérin (BCG) response is essential to identify bladder cancer (BCa) patients most likely to respond sustainably, but no molecular marker predicting BCG response is available in clinical routine. Therefore, we first identified that fibroblast growth factor binding protein 1 (FGFBP1) was upregulated in failures of BCG therapy, and the increased FGFBP1 had a poor outcome for BCa patients in the E-MTAB-4321 and GSE19423 datasets. These different expression genes associated with FGFBP1 expression are mainly involved in neutrophil activation, neutrophil-mediated immunity, and tumor necrosis factor-mediated signal pathways in biological processes. A significant positive correlation was observed between FGFBP1 expression and regulatory T-cell (Treg) infiltration by the Spearman correlation test in the BCG cohort (r = 0.177) and The Cancer Genome Atlas (TCGA) cohort (r = 0.176), suggesting that FGFBP1 may influence the response of BCa patients to BCG immunotherapy through immune escape. Though FGFBP1 expression was positively correlated with the expressions of PD-L1, CTLA4, and PDCD1 in TCGA cohort, a strong association between FGFBP1 and PD-L1 expression was only detected in the BCG cohort (r = 0.750). Furthermore, elevated FGFBP1 was observed in BCa cell lines and tissues in comparison to corresponding normal controls by RT-qPCR, Western blotting, and immunohistochemical staining. Increased FGFBP1 was further detected in the failures than in the responders by immunohistochemical staining. Notably, FGFBP1 is positively associated with PD-L1 expression in BCa patients with BCG treatment. To sum up, FGFBP1 in BCa tissue could be identified as a promising biomarker for the accurate prediction of BCG response in BCa.

Molecular Oncology of Bladder Cancer from Inception to Modern Perspective

Within the last forty years, seminal contributions have been made in the areas of bladder cancer (BC) biology, driver genes, molecular profiling, biomarkers, and therapeutic targets for improving personalized patient care. This overview includes seminal discoveries and advances in the molecular oncology of BC. Starting with the concept of divergent molecular pathways for the development of low- and high-grade bladder tumors, field cancerization versus clonality of bladder tumors, cancer driver genes/mutations, genetic polymorphisms, and bacillus Calmette-Guérin (BCG) as an early form of immunotherapy are some of the conceptual contributions towards improving patient care. Although beginning with a promise of predicting prognosis and individualizing treatments, "-omic" approaches and molecular subtypes have revealed the importance of BC stem cells, lineage plasticity, and intra-tumor heterogeneity as the next frontiers for realizing individualized patient care. Along with urine as the optimal non-invasive liquid biopsy, BC is at the forefront of the biomarker field. If the goal is to reduce the number of cystoscopies but not to replace them for monitoring recurrence and asymptomatic microscopic hematuria, a BC marker may reach clinical acceptance. As advances in the molecular oncology of BC continue, the next twenty-five years should significantly advance personalized care for BC patients.

Effects of Mycobacterium bovis Calmette et Guérin (BCG) in oncotherapy: Bladder cancer and beyond

The Mycobacterium bovis Bacillus Calmette et Guérin (BCG) vaccine was generated in 1921 with the efforts of a team of investigators, Albert Calmette and Camille Guérin, dedicated to the determination to develop a vaccine against active tuberculosis (TB) disease. Since then, BCG vaccination is used globally for protection against childhood and disseminated TB; however, its efficacy at protecting against pulmonary TB in adult and aging populations is highly variable. Due to the BCG generated immunity, this vaccine later proved to have an antitumor activity; though the standing mechanisms behind are still unclear. Recent studies indicate that both innate and adaptive cell responses may play an important role in BCG eradication and prevention of bladder cancer. Thus, cells such as natural killer (NK) cells, macrophages, dendritic cells, neutrophils but also MHC-restricted CD4 and CD8 T cells and γδ T cells may play an important role and can be one the main effectors in BCG therapy. Here, we discuss the role of BCG therapy in bladder cancer and other cancers, including current strategies and their impact on the generation and sustainability of protective antitumor immunity against bladder cancer.

Bladder tumor ILC1s undergo Th17-like differentiation in human bladder cancer

PURPOSE

Human innate lymphoid cells (hILCs) are lineage-negative immune cells that do not express rearranged adaptive antigen receptors. Natural killer (NK) cells are hILCs that contribute to cancer defense. The role of non-NK hILCs in cancer is unclear. Our study aimed to characterize non-NK hILCs in bladder cancer.

EXPERIMENTAL DESIGN

Mass cytometry was used to characterize intratumoral non-NK hILCs based on 35 parameters, including receptors, cytokines, and transcription factors from 21 muscle-invasive bladder tumors. Model-based clustering was performed on t-distributed stochastic neighbor embedding (t-SNE) coordinates of hILCs, and the association of hILCs with tumor stage was analyzed.

RESULTS

Most frequent among intratumoral non-NK hILCs were hILC1s, which were increased in higher compared with lower stage tumors. Intratumoral hILC1s were marked by Th17-like phenotype with high RORγt, IL-17, and IL-22 compared to Th1 differentiation markers, including Tbet, perforin, and IFN-γ. Compared with intratumoral hILC2s and hILC3s, hILC1s also had lower expression of activation markers (NKp30, NKp46, and CD69) and increased expression of exhaustion molecules (PD-1 and Tim3). Unsupervised clustering identified nine clusters of bladder hILCs, which were not defined by the primary hILC subtypes 1-3. hILC1s featured in all the nine clusters indicating that intratumoral hILC1s displayed the highest phenotypic heterogeneity among all hILCs.

CONCLUSIONS

hILC1s are increased in higher stage tumors among patients with muscle-invasive bladder cancer. These intratumoral hILC1s exhibit an exhausted phenotype and Th17-like differentiation, identifying them as potential targets for immunotherapy.

A 25-year perspective on evaluation and understanding of biomarkers in urologic cancers

The past 25 years have witnessed an explosion of investigative attempts to identify clinically useful biomarkers which can have meaningful impacts for patients with urologic cancers. However, in spite of the enormous amount of research aiming to identify markers with the hope of impacting patient care, only a handful have proven to have true clinical utility. Improvements in targeted imaging, pan-omics evaluation, and genetic sequencing at the tissue and single-cell levels have yielded many potential targets for continued biomarker investigation. This article, as one in this series for the 25th Anniversary Issue of Urologic Oncology: Seminars and Original Investigations, serves to give a perspective on our progress and failures over the past quarter-century in our highest volume urologic cancers: prostate, bladder, and kidney cancers.

Educational Case: Bladder Urothelial Cell Carcinoma TNM Stage, Prognosis and Management

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, see http://journals.sagepub.com/doi/10.1177/2374289517715040. ¹.

Clinicopathological Criteria Predictive of Recurrence Following Bacillus Calmette-Guérin Therapy Initiation in Non-Muscle-Invasive Bladder Cancer: Retrospective Cohort Study

Background

Bacillus Calmette-Guérin (BCG) is currently the most clinically effective intravesical treatment for non–muscle-invasive bladder cancer (NMIBC), particularly for patients with high-risk NMIBC such as those with carcinoma in situ. BCG treatments could be optimized to improve patient safety and conserve supply by predicting BCG efficacy based on tumor characteristics or clinicopathological criteria.

Objective

The aim of this study is to assess the ability of specific clinicopathological criteria to predict tumor recurrence in patients with NMIBC who received BCG therapy along various treatment timelines.

Methods

A total of 1331 patients (stage Ta, T1, or carcinoma in situ) who underwent transurethral resection of a bladder tumor between 2006 and 2017 were included. Univariate analysis, including laboratory tests (eg, complete blood panels, creatinine levels, and hemoglobin A_1c levels) within 180 days of BCG therapy initiation, medications, and clinical and demographic variables to assess their ability to predict NMIBC recurrence, was completed. This was followed by multivariate regression that included the elements of the Club Urológico Español de Tratamiento Oncológico (CUETO) scoring model and variables that were significant predictors of recurrence in univariate analysis.

Results

BCG was administered to 183 patients classified as intermediate or high risk, and 76 (41.5%) experienced disease recurrence. An abnormal neutrophil-to-lymphocyte ratio measured within 180 days of induction BCG therapy was a significant predictor (P=.047) of future cancer recurrence and was a stronger predictor than the CUETO score or the individual variables included in the CUETO scoring model through multivariate analysis.

Conclusions

An abnormal neutrophil-to-lymphocyte ratio within 180 days of BCG therapy initiation is predictive of recurrence and could be suggestive of additional or alternative interventions.

Bladder Cancer Immunotherapy by BCG Is Associated with a Significantly Reduced Risk of Alzheimer's Disease and Parkinson's Disease

Bacillus Calmette–Guerin (BCG) is a live attenuated form of Mycobacterium bovis that was developed 100 years ago as a vaccine against tuberculosis (TB) and has been used ever since to vaccinate children globally. It has also been used as the first-line treatment in patients with nonmuscle invasive bladder cancer (NMIBC), through repeated intravesical applications. Numerous studies have shown that BCG induces off-target immune effects in various pathologies. Accumulating data argue for the critical role of the immune system in the course of neurodegenerative diseases such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). In this study, we tested whether repeated exposure to BCG during the treatment of NMIBC is associated with the risk of developing AD and PD. We presented a multi-center retrospective cohort study with patient data collected between 2000 and 2019 that included 12,185 bladder cancer (BC) patients, of which 2301 BCG-treated patients met all inclusion criteria, with a follow-up of 3.5 to 7 years. We considered the diagnosis date of AD and nonvascular dementia cases for BC patients. The BC patients were partitioned into those who underwent a transurethral resection of the bladder tumor followed by BCG therapy, and a disjoint group that had not received such treatment. By applying Cox proportional hazards (PH) regression and competing for risk analyses, we found that BCG treatment was associated with a significantly reduced risk of developing AD, especially in the population aged 75 years or older. The older population (≥75 years, 1578 BCG treated, and 5147 controls) showed a hazard ratio (HR) of 0.726 (95% CI: 0.529–0.996; p-value = 0.0473). While in a hospital-based cohort, BCG treatment resulted in an HR of 0.416 (95% CI: 0.203–0.853; p-value = 0.017), indicating a 58% lower risk of developing AD. The risk of developing PD showed the same trend with a 28% reduction in BCG-treated patients, while no BCG beneficial effect was observed for other age-related events such as Type 2 diabetes (T2D) and stroke. We attributed BCG’s beneficial effect on neurodegenerative diseases to a possible activation of long-term nonspecific immune effects. We proposed a prospective study in elderly people for testing intradermic BCG inoculation as a potential protective agent against AD and PD.

Strategies to Get Drugs across Bladder Penetrating Barriers for Improving Bladder Cancer Therapy

Bladder cancer is a significant public health concern and social burden due to its high recurrence risk. Intravesical drug instillation is the primary therapy for bladder cancer to prevent recurrence. However, the intravesical drug therapeutic effect is limited by bladder penetrating barriers. The inadequate intravesical treatment might cause the low drug concentration in lesions, resulting in a high recurrence/progression rate of bladder cancer. Many strategies to get drugs across bladder penetrating barriers have been developed to improve intravesical treatment, including physical and chemical methods. This review summarizes the classical and updated literature and presents insights into great therapeutic potential strategies to overcome bladder penetrating barriers for improving the intravesical treatment of bladder cancer.

Intravitreal thalidomide ameliorates inflammation in a model of experimental uveitis induced by BCG

Uveitis encompasses a heterogeneous and complex group of conditions characterized by intraocular inflammation, frequently affecting young individuals and representing an important cause of irreversible blindness worldwide. Animal models have been critical to understand etiology and pathogenesis of uveitis, being also employed to assess new therapeutic strategies, preceding human studies. However, there is still a need of developing and studying different models, due to the difficulties in recapitulating all forms of human uveitis effectively. Although corticosteroids are usually the first-line therapy for non-infectious uveitis, their long-term use is limited by potentially serious side effects in all possible delivery routes. Thus, thalidomide, a drug with anti-inflammatory and antiangiogenic properties, was investigated in a novel experimental model of uveitis, induced by Mycobacterium bovis Calmette-Guérin Bacillus (BCG), in rabbits. The experimental protocol consisted of two subcutaneous injections of BCG, followed by two intravitreal injections of the same antigen, inducing panuveitis. Animals were treated with a single intravitreal injection of thalidomide suspension or PBS. Clinical manifestations of uveitis improved after intravitreal thalidomide, involving both anterior and posterior segments. Protein content, N-acetyl-b-glucosaminidase (NAG) and myeloperoxidase (MPO) activities were elevated in ocular tissues after disease induction, further decreasing post-treatment with intravitreal thalidomide. This therapeutic response was also confirmed on ocular electrophysiology, as well as histopathology. This experimental model induced panuveitis in rabbits using a low-cost mycobacterial antigen, with intraocular inflammation subsequently improving after treatment. Intravitreal thalidomide may be a potential alternative to treat intraocular inflammation in corticosteroid-sparing therapies.