PA-MSHA induces apoptosis and suppresses metastasis by tumor associated macrophages in bladder cancer cells

Recent animal models of bladder cancer and their application in drug discovery: an update of the literature

INTRODUCTION

Bladder cancer presents a significant health problem worldwide, with environmental and genetic factors contributing to its incidence. Histologically, it can be classified as carcinoma in situ, non-muscle invasive and muscle-invasive carcinoma, each one with distinct genetic alterations impacting prognosis and response to therapy. While traditional transurethral resection is commonly performed in carcinoma in situ and non-muscle invasive carcinoma, it often fails to prevent recurrence or progression to more aggressive phenotypes, leading to the frequent need for additional treatment such as intravesical chemotherapy or immunotherapy. Despite the advances made in recent years, treatment options for bladder cancer are still lacking due to the complex nature of this disease. So, animal models may hold potential for addressing these limitations, because they not only allow the study of disease progression but also the evaluation of therapies and the investigation of drug repositioning.

AREAS COVERED

This review discusses the use of animal models over the past decade, highlighting key discoveries and discussing advantages and disadvantages for new drug discovery.

EXPERT OPINION

Over the past decade animal models have been employed to evaluate new mechanisms underlying the responses to standard therapies, aiming to optimize bladder cancer treatment. The authors propose that molecular engineering techniques and AI may hold promise for the future development of more precise and effective targeted therapies in bladder cancer.

PA-MSHA exerts potent activity against cetuximab-resistant colorectal cancer through the miR-7-5p/Akt3/Wnt-β-catenin pathway

Background

The prognosis and survival of individuals with cetuximab-resistant colorectal cancer (CRC) remain severely impacted by therapy for this disease. The study investigated the underlying mechanisms of Pseudomonas aeruginosa-mannose sensitive hemagglutinin (PA-MSHA), a type of therapeutic biological product approved in China, for cetuximab-resistant CRC.

Methods

Cell proliferation, apoptosis, migration and invasion were detected by cell counting kit-8 (CCK-8) assay, flow cytometry, wound healing assay and transwell assay. Massively parallel sequencing of cetuximab-resistant CRC cells with PA-MSHA treatment was used to screen the differential expression profile of miRNAs. The directly target gene of miR-7-5p was revealed by dual luciferase assay. Apoptosis and invasion related proteins were detected by Western blot.

Results

PA-MSHA could successfully stop the migrating and invading of cetuximab-resistant CRC cells while also inducing apoptosis. Tumor-bearing experiments in nude mice showed that PA-MSHA slowed tumor growth and lengthened mouse life. The sequencing data showed that miR-7-5p was considerably upregulated after PA-MSHA treatment. As anticipated, miR-7-5p overexpression improved PA-MSHA's anticancer properties both in vitro and in vivo. The target gene of miR-7-5p was confirmed to be Akt3 by dual luciferase assay, and Akt3 silencing undid the inhibition of PA-MSHA efficacy caused by miR-7-5p downregulation. Additionally, PA-MSHA therapy significantly reduced the activation of Wnt-β-catenin pathway, and Akt3 expression was positively linked with several important Wnt-β-catenin pathway genes, including Wnt and CTNNB1. Finally, we discovered that patients with CRC who had developed cetuximab resistance or disease progression had remarkably decreased serum miR-7-5p levels.

Conclusions

PA-MSHA controlled the miR-7-5p/Akt3/Wnt-β-catenin pathway to provide substantial efficacy against cetuximab-resistant CRC.

Trends in Anti-Tumor Effects of Pseudomonas aeruginosa Mannose-Sensitive-Hemagglutinin (PA-MSHA): An Overview of Positive and Negative Effects

Cancer is a leading cause of death worldwide, for which finding the optimal therapy remains an ongoing challenge. Drug resistance, toxic side effects, and a lack of specificity pose significant difficulties in traditional cancer treatments, leading to suboptimal clinical outcomes and high mortality rates among cancer patients. The need for alternative therapies is crucial, especially for those resistant to conventional methods like chemotherapy and radiotherapy or for patients where surgery is not possible. Over the past decade, a novel approach known as bacteria-mediated cancer therapy has emerged, offering potential solutions to the limitations of conventional treatments. An increasing number of in vitro and in vivo studies suggest that the subtype of highly virulent Pseudomonas aeruginosa bacterium called Pseudomonas aeruginosa mannose-sensitive-hemagglutinin (PA-MSHA) can successfully inhibit the progression of various cancer types, such as breast, lung, and bladder cancer, as well as hepatocellular carcinoma. PA-MSHA inhibits the growth and proliferation of tumor cells and induces their apoptosis. Proposed mechanisms of action include cell-cycle arrest and activation of pro-apoptotic pathways regulated by caspase-9 and caspase-3. Moreover, clinical studies have shown that PA-MSHA improved the effectiveness of chemotherapy and promoted the activation of the immune response in cancer patients without causing severe side effects. Reported adverse reactions were fever, skin irritation, and pain, attributed to the overactivation of the immune response. This review aims to summarize the current knowledge obtained from in vitro, in vivo, and clinical studies available at PubMed, Google Scholar, and ClinicalTrials.gov regarding the use of PA-MSHA in cancer treatment in order to further elucidate its pharmacological and toxicological properties.

Therapeutic potential of Pseudomonas aeruginosa-mannose sensitive hemagglutinin (PA-MSHA) in cancer treatment

Pseudomonas aeruginosa is a Gram-negative bacteria and it has been demonstrated that immunization with the outer membrane proteins of the microbe produces most of the relevant human antibodies. The peritrichous P. aeruginosa strain with MSHA fimbriae (PA-MSHA strain) has been found to be effective in the inhibition of growth and proliferation of different types of cancer cells. Furthermore, it has been revealed that PA-MSHA exhibits cytotoxicity because of the presence of MSHA and therefore it possesses anti-carcinogenic ability against different types of human cancer cell lines including, gastric, breast, hepatocarcinoma and nasopharyngeal cells. Studies have revealed that PA-MSHA exhibits therapeutic potential against cancer growth by induction of apoptosis, arrest of cell cycle, activating NF-κB/TLR5 pathway, etc. In China, PA-MSHA injections have been approved for the treatment of malignant tumor patients from very long back. The present review article demonstrates the therapeutic potential of PA-MSHA against various types of human cancers and explains the underlying mechanism.

Efficacy of anti-programmed cell death protein 1 monoclonal antibody combined with bevacizumab and/or Pseudomonas aeruginosa injection in transplanted tumor of mouse forestomach carcinoma cell gastric cancer in mice and its mechanism in regulating tumor immune microenvironment

Tumor immunotherapy represented by programmed cell death protein 1 (PD-1) inhibitors is considered as the most promising cancer treatment method and has been widely used in the treatment of advanced gastric cancer (GC). However, the effective rate of PD-1 inhibitor monotherapy is low. In this study, we constructed a transplanted tumor model in GC mice by inoculating mouse forestomach carcinoma cell (MFC) GC cells into 615 mice. Interventions were conducted with normal saline, anti-PD-1 monoclonal antibody (mAb), bevacizumab, Pseudomonas aeruginosa-mannose-sensitive hemagglutinin (PA-MSHA), anti-PD-1 mAb combined with bevacizumab, anti-PD-1 mAb combined with PA-MSHA, bevacizumab combined with PA-MSHA, anti-PD-1 mAb combined with bevacizumab and PA-MSHA, respectively. The tumor growth curves were drawn. TUNEL assay, western blotting, and immunohistochemistry were used to detect tumor proliferation and apoptosis. Flow cytometry and ELISA were used to detect the expression of tumor infiltrating lymphocytes and cytokines. This study found that anti-PD-1 mAb alone could not significantly inhibit the growth of transplanted tumors in mice. Anti-PD-1 mAb combined with bevacizumab, anti-PD-1 mAb combined with PA-MSHA, anti-PD-1 mAb combined with bevacizumab and PA-MSHA could all significantly inhibit tumor growth in mice, and the combination of three drugs presented the highest tumor inhibition rate. Anti-PD-1 mAb combined with bevacizumab and PA-MSHA could significantly upregulate the number of Th1-type cells, CD8 + T cells, and Type I tumor-associated macrophages (TAMs), while downregulate the number of Th2-type cells, myeloid-derived suppressor cells, regulatory T cells, and Type II TAMs. Therefore, we conclude that anti-PD-1 mAb combined with bevacizumab and/or PA-MSHA has a synergistic effect. Bevacizumab and PA-MSHA can transform the tumor immunosuppressive microenvironment into a supportive immune microenvironment, thus maximizing the antitumor effect of anti-PD-1 mAb.

Regulatory effect of Pseudomonas aeruginosa mannose-sensitive hemagglutinin on inflammation and immune function in percutaneous nephrolithotomy patients with upper urinary tract calculi complicated with infection

Objective

To study the effect of an injection of Pseudomonas aeruginosa mannose-sensitive hemagglutinin (PA-MSHA) on inflammation and immune function in patients with upper urinary tract calculi complicated by infection who have undergone percutaneous nephrolithotomy.

Methods

We retrospectively recorded the clinical data of patients with upper urinary tract calculi complicated by infection who have undergone Percutaneous nephrolithotomy(PCNL) in the Department of Urology, 2nd Affiliation Hospital of Kunming Medical University, from March to December 2021. Clinical data include general condition, laboratory index, CT, postoperative body temperature, heart rate, respiration, SIRS, sepsis, etc. Patients were divided into treated and control groups according to whether they had received a preoperative PA-MSHA injection. The two groups were compared for indices of inflammation and complications of infection after PCNL. Pre- and post-operative lymphocyte subsets and immunoglobulin changes were compared.

Results

115 patients were included in the study, including 43 in the treatment group and 72 in the control group. After Propensity Score Matching, 90 patients were divided into treatment (n=35) and control (n=55) groups. The postoperative inflammation index was higher in the treatment group than in the control group (P<0.05). The incidence of postoperative SIRS was higher in the treatment group than control (P<0.05). There were no cases of sepsis in either group. The double-positive T cells lymphocyte subsets were higher in the treatment group than in the control group ((P<0.05). Pre- and post-operative changes in immune function: total T lymphocyte count reduced, NK and NKT cell count increased in the control group, double-positive T cell count increased in the treatment group, IgG, IgA, IgM, complement C3 and C4 count reduced in both groups post-operatively.

Conclusion

This study found that patients with upper urinary tract calculi and infection treated with antibiotic-based PA-MSHA before percutaneous nephrolithotomy had an increased inflammatory response after surgery, which may play a role in the prevention and treatment of sepsis. The percentage of double-positive T cells in the peripheral blood was increased after PA-MSHA treatment, which may have an immunomodulatory and protective effect in PCNL patients with stones complicated by infection.

Neoadjuvant Pseudomonas aeruginosa mannose-sensitive hemagglutinin (PA-MSHA) and chemotherapy versus placebo plus chemotherapy in patients with HER2-negative breast cancer: a randomized, controlled, double-blind trial

Background

According to preclinical experiments, Pseudomonas aeruginosa mannose-sensitive hemagglutinin (PA-MSHA) exerts antiproliferative effects against breast cancer cells. It has been approved by the State Food and Drug Administration in China for complementary cancer treatment, and its safety has been confirmed in previous clinical trials. The present randomized, controlled, double-blind clinical trial was conducted to investigate the efficacy and safety of neoadjuvant PA-MSHA and placebo with chemotherapy in patients with human epidermal growth factor receptor 2 (HER2)-negative breast cancer.

Methods

Eligible patients aged 18 years or older with previously untreated HER2-negative stage II-III breast cancer were enrolled and randomly assigned at a 1:1 ratio to receive neoadjuvant chemotherapy with PA-MSHA or a placebo. The Response Evaluation Criteria in Solid Tumors (RECIST) was used to assess clinical response every 2 cycles. The primary endpoint was the objective response rate (ORR) based on the clinical response following neoadjuvant chemotherapy.

Results

A total of 75 patients were randomly assigned to either the PA-MSHA group (37 patients) or the control group (38 patients). The ORR was found to be significantly higher in the PA-MSHA group compared with the control group [86.5% versus 60.5%; rate difference 26.0; 95% confidence interval (CI): 5.9-43.5%; P=0.011]. The pathological complete response (pCR) and survival outcomes did not differ significantly between the 2 groups. Patients with immune-related adverse events (irAEs) appeared to benefit from the PA-MSHA treatment, with greater disease-free, relapse-free, and overall survival. The application of PA-MSHA to neoadjuvant chemotherapy did not increase the incidence of severe adverse events. Moreover, the addition of PA-MSHA increased serum interferon-γ levels and the percentage of peripheral blood T cells, CD8+/CD4+ T cells, CD8+CD28+ T cells, and natural killer (NK) cells, and decreased serum interleukin 4 levels.

Conclusions

The addition of PA-MSHA to neoadjuvant chemotherapy is an effective alternative regimen for HER2-negative breast cancer. Patients with irAEs caused by PA-MSHA may obtain more benefits from this treatment.

Trial Registration

Chinese Clinical Trial Registry ChiCTR-TRC-10000794.

Fisetin, a Potent Anticancer Flavonol Exhibiting Cytotoxic Activity against Neoplastic Malignant Cells and Cancerous Conditions: A Scoping, Comprehensive Review

Diet plays a crucial role in homeostasis maintenance. Plants and spices containing flavonoids have been widely used in traditional medicine for thousands of years. Flavonols present in our diet may prevent cancer initiation, promotion and progression by modulating important enzymes and receptors in signal transduction pathways related to proliferation, differentiation, apoptosis, inflammation, angiogenesis, metastasis and reversal of multidrug resistance. The anticancer activity of fisetin has been widely documented in numerous in vitro and in vivo studies. This review summarizes the worldwide, evidence-based research on the activity of fisetin toward various types of cancerous conditions, while describing the chemopreventive and therapeutic effects, molecular targets and mechanisms that contribute to the observed anticancer activity of fisetin. In addition, this review synthesized the results from preclinical studies on the use of fisetin as an anticancer agent. Based on the available literature, it might be suggested that fisetin has a bioactive potential to become a complementary drug in the prevention and treatment of cancerous conditions. However, more in-depth research is required to validate current data, so that this compound or its derivatives can enter the clinical trial phase.

Pseudomonas aeruginosa in Cancer Therapy: Current Knowledge, Challenges and Future Perspectives

Drug resistance, undesirable toxicity and lack of selectivity are the major challenges of conventional cancer therapies, which cause poor clinical outcomes and high mortality in many cancer patients. Development of alternative cancer therapeutics are highly required for the patients who are resistant to the conventional cancer therapies, including radiotherapy and chemotherapy. The success of a new cancer therapy depends on its high specificity to cancer cells and low toxicity to normal cells. Utilization of bacteria has emerged as a promising strategy for cancer treatment. Attenuated or genetically modified bacteria were used to inhibit tumor growth, modulate host immunity, or deliver anti-tumor agents. The bacteria-derived immunotoxins were capable of destructing tumors with high specificity. These bacteria-based strategies for cancer treatment have shown potent anti-tumor effects both in vivo and in vitro, and some of them have proceeded to clinical trials. Pseudomonas aeruginosa, a Gram-negative bacterial pathogen, is one of the common bacteria used in development of bacteria-based cancer therapy, particularly known for the Pseudomonas exotoxin A-based immunotoxins, which have shown remarkable anti-tumor efficacy and specificity. This review concisely summarizes the current knowledge regarding the utilization of P. aeruginosa in cancer treatment, and discusses the challenges and future perspectives of the P. aeruginosa-based therapeutic strategies.

An HDAC9-associated immune-related signature predicts bladder cancer prognosis

Background

The close relationship between histone deacetylase 9 (HDAC9) and immunity has attracted attention. We constructed an immune signature for HDAC9, a vital epigenetic modification, to predict the survival status and treatment benefits in bladder cancer (BC).

Methods

An exhaustive analysis of HDAC9 and immunology via the tumor and immune system interaction database (TISIDB) was performed, and an immune prognostic risk signature was developed based on genes enriched in the top five immune-related pathways under high HDAC9 status. Comprehensive analysis of survival curves and Cox regression were used to estimate the effectiveness of the risk signature. The relationship between immunological characteristics and the risk score was evaluated, and the mechanisms were also explored.

Results

In the TISIDB, HDAC9 was closely related to various immunological characteristics. The risk signature was obtained based on genes related to prognosis enriched in the top five immune-related pathways under high HDAC9 status. The survival rate of the high-risk BC patients was poor. The risk score was closely related to multiple immunological characteristics, drug sensitivity, immunotherapy benefits and biofunctions.

Conclusion

An immune-related prognostic signature established for HDAC9 expression status could independently predict the prognosis of BC patients. The use of this signature could help clinicians make personalized treatment decisions.

Rapamycin-induced M2 macrophage autophagy promotes the migration and invasion of bladder cancer cells via increased IL-10 secretion

Intrduction:

Rapamycin is an mTOR inhibitor and a prominent inducer of autophagy in cancer cells and tumor interstitial cells. Macrophages are the primary type of immune cells observed in the tumor microenvironment and serve varying roles in the progression of cancer by polarizing into distinct phenotypes. However, whether rapamycin-induced macrophage autophagy influences bladder cancer remains unclear.

Methods:

THP-1 cells were successfully polarized into M1 or M2 macrophages, which were identified by detecting CD86 (M1) or CD206 (M2) expressions using flow cytometry and measuring M1/M2-related mRNA expressions using reverse transcription-quantitative PCR. Rapamycin was employed for inducing autophagy, and then the influences of enhanced autophagic M1 and M2 macrophages on migration and invasion of bladder cancer cells were confirmed by wound healing and Transwell assay in the co-culture model. Furthermore, the gene and protein expressions of IL-10 and the underlying role are still unclear.

Results:

Rapamycin significantly increased autophagy levels in M1 and M2 macrophages, while only autophagy-enhanced M2 macrophages facilitated the migration and invasion of bladder cancer cells. Furthermore, rapamycin increased IL-10 secretion from M2 macrophages, which mediated the effects of M2 macrophages on migration and invasion of bladder cancer.

Conclusion:

Rapamycin induces M2 macrophage autophagy and promotes the migration and invasion of bladder cancer by increasing IL-10 secretion, suggesting that M2 macrophage autophagy is an underlying target of rapamycin in treating bladder cancer.

Immune escape mechanisms and immunotherapy of urothelial bladder cancer

BACKGROUND AND AIM

Urothelial bladder cancer (UBC) is a common malignant tumor of the urogenital system with a high rate of recurrence. Due to the sophisticated and largely unexplored mechanisms of tumorigenesis of UBC, the classical therapeutic approaches including transurethral resection and radical cystectomy combined with chemotherapy have remained unchanged for decades. However, with increasingly in-depth understanding of the microenvironment and the composition of tumor-infiltrating lymphocytes of UBC, novel immunotherapeutic strategies have been developed. Bacillus Calmette-Guerin (BCG) therapy, immune checkpoint blockades, adoptive T cell immunotherapy, dendritic cell (DC) vaccines, etc., have all been intensively investigated as immunotherapies for UBC. This review will discuss the recent progress in immune escape mechanisms and immunotherapy of UBC.

METHODS

Based on a comprehensive search of the PubMed and ClinicalTrials.gov database, this review included the literature reporting the immune escape mechanisms of UBC and clinical trials assessing the effect of immunotherapeutic strategies on tumor or immune cells in UBC patients published in English between 1999 and 2020.

RESULTS

Immune surveillance, immune balance, and immune escape are the three major processes that occur during UBC tumorigenesis. First, the role of immunosuppressive cells, immunosuppressive molecules, immunosuppressive signaling molecules, and DCs in tumor microenvironment is introduced elaborately in the immune escape mechanisms of UBC section. In addition, recent progress of immunotherapies including BCG, checkpoint inhibitors, cytokines, adoptive T cell immunotherapy, DCs, and macrophages on UBC patients are summarized in detail. Finally, the need to explore the mechanisms, molecular characteristics and immune landscape during UBC tumorigenesis and development of novel and robust immunotherapies for UBC are also proposed and discussed.

CONCLUSION

At present, BCG and immune checkpoint blockades have been approved by the US Food and Drug Administration for the treatment of UBC patients and have achieved encouraging therapeutic results, expanding the traditional chemotherapy and surgery-based treatment for UBC.

RELEVANCE FOR PATIENTS

Immunotherapy has achieved desirable results in the treatment of UBC, which not only improve the overall survival but also reduce the recurrence rate and the occurrence of treatment-related adverse events of UBC patients. In addition, the indicators to predict the effectiveness and novel therapy strategies, such as combination regimen of checkpoint inhibitor with checkpoint inhibitor or chemotherapy, should be further studied.

A novel immune-related gene pair prognostic signature for predicting overall survival in bladder cancer

Background

Bladder cancer (BC) is the ninth most common malignant tumor. We constructed a risk signature using immune-related gene pairs (IRGPs) to predict the prognosis of BC patients.

Methods

The mRNA transcriptome, simple nucleotide variation and clinical data of BC patients were downloaded from The Cancer Genome Atlas (TCGA) database (TCGA-BLCA). The mRNA transcriptome and clinical data were also extracted from Gene Expression Omnibus (GEO) datasets (GSE31684). A risk signature was built based on the IRGPs. The ability of the signature to predict prognosis was analyzed with survival curves and Cox regression. The relationships between immunological parameters [immune cell infiltration, immune checkpoints, tumor microenvironment (TME) and tumor mutation burden (TMB)] and the risk score were investigated. Finally, gene set enrichment analysis (GSEA) was used to explore molecular mechanisms underlying the risk score.

Results

The risk signature utilized 30 selected IRGPs. The prognosis of the high-risk group was significantly worse than that of the low-risk group. We used the GSE31684 dataset to validate the signature. Close relationships were found between the risk score and immunological parameters. Finally, GSEA showed that gene sets related to the extracellular matrix (ECM), stromal cells and epithelial-mesenchymal transition (EMT) were enriched in the high-risk group. In the low-risk group, we found a number of immune-related pathways in the enriched pathways and biofunctions.

Conclusions

We used a new tool, IRGPs, to build a risk signature to predict the prognosis of BC. By evaluating immune parameters and molecular mechanisms, we gained a better understanding of the mechanisms underlying the risk signature. This signature can also be used as a tool to predict the effect of immunotherapy in patients with BC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08486-0.

Topical Application of Pseudomonas aeruginosa-Mannose Sensitive Hemagglutinin (PA-MSHA) for Refractory Lymphatic Leakage Following Lymphadenectomy in Patients with Gynecological Malignancies

PURPOSE

To observe the feasibility and efficacy of Pseudomonas aeruginosa-mannose sensitive hemagglutinin (PA-MSHA) in refractory lymphatic leakage following lymphadenectomy among patients with gynecological cancers.

PATIENTS AND METHODS

Ten cases with post-operative massive lymphatic leakage were collected, in which patients failed to respond to conservative treatment. Topical PA-MSHA injection of a single dose (2mL) was performed through drainage tube or transvaginal catheter into pelvic or peritoneal cavity. Drainage volumes and side effects were recorded.

RESULTS

The incidence of refractory lymphatic leakage following pelvic and para-aortic lymphadenectomy was 2.44% (10/409). All ten patients (100%) had quick recovery and were discharged within 72 hours. Among them, one patient (10%) experienced fever and six patients (60%) experienced abdominal pain, one of which was moderate and relieved by routine analgesic treatment. During 11 (6-38) months of follow-up time, no long-term side effect was observed.

CONCLUSION

Topical injection of PA-MSHA of a single dose appears a feasible and effective treatment for refractory post-operative lymphatic leakage.

Profiles of tumor-infiltrating immune cells and prognostic genes associated with the microenvironment of bladder cancer

The immune microenvironment in bladder cancer (BC) and its significance still remain poorly understood. The present work aims to investigate tumor-infiltrating immune cells (TIICs) and prognostic genes associated with the tumor microenvironment (TME) of BC. The immune and stromal scores of BC samples from The Cancer Genome Atlas database were downloaded from the ESTIMATE website. Based on these scores, BC samples were assigned to the high and low score groups and 429 intersecting differentially expressed genes were identified. Functional enrichment analysis further revealed that these genes dramatically participated in the immune-related biological processes and signaling pathways. Two TME-related genes, angiotensin II receptor type 2 (AGTR2) and sclerostin domain containing 1 (SOSTDC1), were identified to establish an immune-related risk model using Cox regression analyses. Intriguingly, patients with high-risk scores had poor outcomes (p < 0.001). The areas under the curve for the risk model in predicting 3- and 5-year survival rates were 0.692 and 0.707, respectively. Kaplan-Meier survival analysis showed that the expression of AGTR2 and SOSTDC1 significantly correlated with the overall survival of BC patients. Additionally, 22 TIICs in the BC microenvironment were analyzed with the CIBERSORT algorithm. This study indicated that the effective components of TME affected the clinical outcomes of BC patients and might provide a basis for the development of new immunotherapies for BC patients.

A review on the role of M2 macrophages in bladder cancer; pathophysiology and targeting

Tumor-associated macrophages (TAMs) which are often referred to as immunosuppressive cells (M2 macrophage), constitute a subset of tumor microenvironment cells and affect tumor progression in solid tumors. Recently, these cells have gained remarkable importance as therapeutic candidates for solid tumors. In bladder cancer, major studies have focused on evaluating TAMs in response to Bacillus Calmette-Guerin (BCG) therapy. M2 macrophages may directly impact the BCG-induced immune responses against tumor in bladder cancer. They are the main inhibitors of the tumor microenvironment that promotes growth and metastasis of the tumor. However, the clinical significance of M2 macrophages in bladder cancer is controversial. In this review, we will discuss the clinical significance of M2 macrophages in prognosis of bladder cancer as well as worth of their potential targeting in bladder cancer treatment. In the following, we will introduce important factors resulting in M2 macrophage promotion and also experimental therapeutic agents that may cause the inhibition of bladder cancer tumor growth.

Bladder cancer, a unique model to understand cancer immunity and develop immunotherapy approaches

With the mechanistic understanding of immune checkpoints and success in checkpoint blockade using antibodies for the treatment of certain cancers, immunotherapy has become one of the hottest areas in cancer research, with promise of long‐lasting therapeutic effect. Currently, however, only a proportion of cancers have a good response to checkpoint inhibition immunotherapy. Better understanding of the cancer response and resistance mechanisms is essential to fully explore the potential of immunotherapy to cure the majority of cancers. Bladder cancer, one of the most common and aggressive malignant diseases, has been successfully treated both at early and advanced stages by different immunotherapeutic approaches, bacillus Calmette–Guérin (BCG) intravesical instillation and anti‐PD‐1/PD‐L1 immune checkpoint blockade, respectively. Therefore, it provides a good model to investigate cancer immune response mechanisms and to improve the efficiency of immunotherapy. Here, we review bladder cancer immunotherapy with equal weight on BCG and anti‐PD‐1/PD‐L1 therapies and demonstrate why and how bladder cancer can be used as a model to study the predictors and mechanisms of cancer immune response and shine light on further development of immunotherapy approaches and response predictive biomarkers to improve immunotherapy of bladder cancer and other malignancies. We review the success of BCG and anti‐PD‐1/PD‐L1 treatment of bladder cancer, the underlying mechanisms and the therapeutic response predictors, including the limits to our knowledge. We then highlight briefly the adaptation of immunotherapy approaches and predictors developed in other cancers for bladder cancer therapy. Finally, we explore the potential of using bladder cancer as a model to investigate cancer immune response mechanisms and new therapeutic approaches, which may be translated into immunotherapy of other human cancers. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Molecular Repolarisation of Tumour-Associated Macrophages

The tumour microenvironment (TME) is composed of extracellular matrix and non-mutated cells supporting tumour growth and development. Tumour-associated macrophages (TAMs) are among the most abundant immune cells in the TME and are responsible for the onset of a smouldering inflammation. TAMs play a pivotal role in oncogenic processes as tumour proliferation, angiogenesis and metastasis, and they provide a barrier against the cytotoxic effector function of T lymphocytes and natural killer (NK) cells. However, TAMs are highly plastic cells that can adopt either pro- or anti-inflammatory roles in response to environmental cues. Consequently, TAMs represent an attractive target to recalibrate immune responses in the TME. Initial TAM-targeted strategies, such as macrophage depletion or disruption of TAM recruitment, have shown beneficial effects in preclinical models and clinical trials. Alternatively, reprogramming TAMs towards a proinflammatory and tumouricidal phenotype has become an attractive strategy in immunotherapy. This work summarises the molecular wheelwork of macrophage biology and presents an overview of molecular strategies to repolarise TAMs in immunotherapy.

Lumbrokinase/paclitaxel nanoparticle complex: potential therapeutic applications in bladder cancer

Background

Lumbrokinase (LK) is an enzyme complex with antithrombotic, antioxidant, antitumor, and immunomodulatory effects. It has been extensively studied and used in clinical anti-tumor therapy. However, its half-life is short, its bioavailability is low, and its toxicity and side effects are great, which greatly limit its clinical application. Therefore, LK is often combined with other drugs (such as immune agents, hormones, or Chinese herbal medicine) to reduce its dosage and side effects and to improve its anti-tumor effects.

Methods and results

Here, we described an LK/paclitaxel (PTX) nanocarrier based on poly(ethylene glycol)-b-(poly(ethylenediamine l-glutamate)-g-poly(ε-benzyoxycarbonyl-l-lysine)-r-poly(l-lysine)) (PEG-b-(PELG-g-(PZLL-r-PLL))). In the present study, LK and PTX were loaded by electrostatic and/or hydrophobic effects under mild conditions, thereby increasing the half-life and bioavailability of the drugs via the sustained release and enhancement of tumor site enrichment by the LK/PTX/PEG-b-(PELG-g-(PZLL-r-PLL)) complex through passive targeting. In this study, using bladder cancer cells (J82 cells) and rat bladder cancer model as the object, the structure of the nanocarrier, the relationship between drugs composition and antitumor properties were systematically studied.

Conclusion

We propose that the block copolymer PEG-b-(PELG-g-(PZLL-r-PLL)) may function as a potent nanocarrier for augmenting anti-bladder cancer pharmacotherapy, with unprecedented clinical benefits.