The MSHA strain of Pseudomonas aeruginosa (PA-MSHA) inhibits gastric carcinoma progression by inducing M1 macrophage polarization

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.

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.

Tumour-associated macrophages in gastric cancer: From function and mechanism to application

BACKGROUND

Gastric cancer (GC) is a malignant tumour, with high morbidity and mortality rates worldwide. The occurrence and development of GC is a complex process involving genetic changes in tumour cells and the influence of the surrounding tumour microenvironment (TME). Accumulative evidence shows that tumour-associated macrophages (TAMs) play a vital role in GC, acting as plentiful and active infiltrating inflammatory cells in the TME.

MAIN BODY

In this review, the different functions and mechanisms of TAMs in GC progression, including the conversion of phenotypic subtypes; promotion of tumour proliferation, invasion and migration; induction of chemoresistance; promotion of angiogenesis; modulation of immunosuppression; reprogramming of metabolism; and interaction with the microbial community are summarised. Although the role of TAMs in GC remains controversial in clinical settings, clarifying their significance in the treatment selection and prognostic prediction of GC could support optimising TAM-centred clinicaltherapy.

CONCLUSION

In summary, we reviewed the the phenotypic polarisation, function and molecular mechanism of TAMs and their potential applications in the treatment selection and prognostic prediction of GC.

PA-MSHA induces inflamed tumor microenvironment and sensitizes tumor to anti-PD-1 therapy

A low response rate to immune checkpoint inhibitor (ICI) therapy has impeded its clinical use. As reported previously, an inflamed tumor microenvironment (TME) was directly correlated with patients' response to immune checkpoint blockade (ICB). Thus, restoring the cytotoxic effect of immune cells in the TME is a promising way to improve the efficacy of ICB and overcome primary resistance to immunotherapy. The effect of Pseudomonas aeruginosa mannose-sensitive-hemagglutinin (PA-MSHA) in facilitating T cell activation was determined in vitro and in vivo. Subsets of immune cells were analyzed by flow cytometry. Proteomics was carried out to comprehensively analyze the discriminated cellular kinases and transcription factors. The combinational efficacy of PA-MSHA and αPD-1 therapy was studied in vivo. In this study we demonstrated that PA-MSHA, which is a clinically used immune adjuvant, effectively induced the anti-tumor immune response and suppressed the growth of non-small cell lung cancer (NSCLC) cells. PA-MSHA showed great potential to sensitize refractory "cold" tumors to immunotherapy. It effectively enhanced macrophage M1 polarization and induced T cell activation. In vivo, in combination with αPD-1, PA-MSHA suppressed tumor growth and prolonged the survival time of allograft model mice. These results indicate that PA-MSHA is a potent agent to stimulate immune cells infiltration into the TME and consequently induces inflammation in tumors. The combination of PA-MSHA with αPD-1 is a potential strategy to enhance the clinical response rate to ICI therapy.

Inflammation-targeted nanomedicine against brain cancer: From design strategies to future developments

Brain cancer is an aggressive type of cancer with poor prognosis. While the immune system protects against cancer in the early stages, the tumor exploits the healing arm of inflammatory reactions to accelerate its growth and spread. Various immune cells penetrate the developing tumor region, establishing a pro-inflammatory tumor milieu. Additionally, tumor cells may release chemokines and cytokines to attract immune cells and promote cancer growth. Inflammation and its associated mechanisms in the progression of cancer have been extensively studied in the majority of solid tumors, especially brain tumors. However, treatment of the malignant brain cancer is hindered by several obstacles, such as the blood-brain barrier, transportation inside the brain interstitium, inflammatory mediators that promote tumor growth and invasiveness, complications in administering therapies to tumor cells specifically, the highly invasive nature of gliomas, and the resistance to drugs. To resolve these obstacles, nanomedicine could be a potential strategy that has facilitated advancements in diagnosing and treating brain cancer. Due to the numerous benefits provided by their small size and other features, nanoparticles have been a prominent focus of research in the drug-delivery field. The purpose of this article is to discuss the role of inflammatory mediators and signaling pathways in brain cancer as well as the recent advances in understanding the nano-carrier approaches for enhancing drug delivery to the brain in the treatment of brain cancer.

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.

NF-κB in Cancer Immunity: Friend or Foe?

The emergence of immunotherapies has definitely proven the tight relationship between malignant and immune cells, its impact on cancer outcome and its therapeutic potential. In this context, it is undoubtedly critical to decipher the transcriptional regulation of these complex interactions. Following early observations demonstrating the roles of NF-κB in cancer initiation and progression, a series of studies converge to establish NF-κB as a master regulator of immune responses to cancer. Importantly, NF-κB is a family of transcriptional activators and repressors that can act at different stages of cancer immunity. In this review, we provide an overview of the selective cell-intrinsic contributions of NF-κB to the distinct cell types that compose the tumor immune environment. We also propose a new view of NF-κB targeting drugs as a new class of immunotherapies for cancer.

Enhancing antibody-dependent cellular phagocytosis by Re-education of tumor-associated macrophages with resiquimod-encapsulated liposomes

Tumor-associated macrophages (TAMs) exist in nearly all tumors, and form a major part of the tumor microenvironment. TAMs are divided into two groups: tumor-suppressing M1 type and tumor-promoting M2 type. Most TAMs are educated by the tumor cells to become M2 type, which support tumor growth and make immunotherapy ineffective. Antibody-dependent cellular phagocytosis (ADCP) is an important mechanism for antibody cancer therapy, and this mechanism is dependent on TAMs. In this study, we found that the M1 type macrophages elicit a more efficient ADCP response than the M2 type, which was confirmed by three tumor cell lines, Raji, A431, and SKBR3, along with their corresponding therapeutic antibody Rituximab, anti-EGFR mouse monoclonal antibody (clone 528), and Trastuzumab, respectively. Resiquimod (R848), an immune system activating agent, has been shown to stimulate the M1 type macrophages, and re-educate the TAMs from M2 type to M1 type. By treating TAMs with R848, the ADCP response increased significantly in vitro and in in vivo mouse xenograft models. R848 encapsulated liposomes (R848-LPs) not only accumulated efficiently in the tumor tissues, but also distributed in the TAMs. Synergizing the R848-LPs with the anti-EGFR mouse monoclonal antibody (clone 528) significantly inhibited WiDr-tumor growth in vivo. Our study also revealed that the TAM-targeted delivery of R848 is able to re-educate the TAMs to M1 type, enhance the ADCP effect of the antibodies, and hence, enhance the anti-tumor effect of the therapeutic antibodies.

Tumor-Associated Macrophages: Protumoral Macrophages in Inflammatory Tumor Microenvironment

Tumor microenvironment consists of malignant and non-malignant cells. The interaction of these dynamic and different cells is responsible for tumor progression at different levels. The non-malignant cells in TME contain cells such as tumor-associated macrophages (TAMs), cancer associated fibroblasts, pericytes, adipocytes, T cells, B cells, myeloid-derived suppressor cells (MDSCs), tumor-associated neutrophils (TANs), dendritic cells (DCs) and Vascular endothelial cells. TAMs are abundant in most human and murine cancers and their presence are associated with poor prognosis. The major event in tumor microenvironment is macrophage polarization into tumor-suppressive M1 or tumor-promoting M2 types. Although much evidence suggests that TAMS are primarily M2-like macrophages, the mechanism responsible for polarization into M1 and M2 macrophages remain unclear. TAM contributes cancer cell motility, invasion, metastases and angiogenesis. The relationship between TAM and tumor cells lead to used them as a diagnostic marker, therapeutic target and prognosis of cancer. This review presents the origin, polarization, role of TAMs in inflammation, metastasis, immune evasion and angiogenesis as well as they can be used as therapeutic target in variety of cancer cells. It is obvious that additional substantial and preclinical research is needed to support the effectiveness and applicability of this new and promising strategy for cancer treatment.

Tumor-Associated Macrophages (TAMs): A Critical Activator In Ovarian Cancer Metastasis

Tumor-associated macrophages (TAMs) that appear in every stage of cancer progression are usually tumor-promoting cells and are present abundantly in the tumor-associated microenvironment. In ovarian cancer, the overall and intratumoral M1/M2 ratio is a relatively efficient TAM parameter for predicting the prognosis of patients, especially for serous tissue type cancer. TAMs exhibit immunological checkpoint modulators, such as the B7 family and programmed death-ligand 1 (PD-L1), and play a key role in the development, metastasis and invasion of ovarian cancer, but the underlying mechanism is barely understood. Ovarian cancer is a severe gynecological malignancy with high mortality. Ovarian cancer-associated death can primarily be attributed to cancer metastasis. The majority of patients are diagnosed with wide dissemination in the peritoneum and omentum, limiting the effectiveness of surgery and chemotherapy. In addition, unlike other well-documented cancers, metastasis through vasculature is not a usual dissemination pathway in ovarian cancer. This review sheds light on TAMs and the main process and mechanism of ovarian cancer metastasis.

Nanoparticles Targeting Macrophages as Potential Clinical Therapeutic Agents Against Cancer and Inflammation

With the development of nanotechnology, significant progress has been made in the design, and manufacture of nanoparticles (NPs) for use in clinical treatments. Recent increases in our understanding of the central role of macrophages in the context of inflammation and cancer have reinvigorated interest in macrophages as drug targets. Macrophages play an integral role in maintaining the steady state of the immune system and are involved in cancer and inflammation processes. Thus, NPs tailored to accurately target macrophages have the potential to transform disease treatment. Herein, we first present a brief background information of NPs as drug carriers, including but not limited to the types of nanomaterials, their biological properties and their advantages in clinical application. Then, macrophage effector mechanisms and recent NPs-based strategies aimed at targeting macrophages by eliminating or re-educating macrophages in inflammation and cancer are summarized. Additionally, the development of nanocarriers targeting macrophages for disease diagnosis is also discussed. Finally, the significance of macrophage-targeting nanomedicine is highlighted, with the goal of facilitating future clinical translation.

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.

Redirecting tumor-associated macrophages to become tumoricidal effectors as a novel strategy for cancer therapy

Cancer research in recent decades has highlighted the potential influence of the tumor microenvironment on the progression and metastasis of most known cancer types. Within the established microenvironment, tumor-associated macrophages (TAMs) are one of the most abundant and crucial non-neoplastic cell types. The polarization of macrophages into tumor-suppressive M1 or tumor-promoting M2 types is a fundamental event in the establishment of the tumor microenvironment. Although ample evidence indicates that TAMs are primarily M2 polarized, the mechanisms responsible for the regulation and maintenance of M1 and M2 polarization imbalance remain unclear. The manipulation of this critical axis through three main approaches may provide new strategies for cancer therapy - (I) specific interference with M2-like TAM survival or inhibiting their signaling cascades, (II) repression of macrophage recruitment to tumors, and (III) repolarization of tumor-promoting M2-like TAMs to a tumoricidal M1-like phenotype. This review summarizes current strategies for cancer intervention via manipulation of macrophage polarization, with particular focus on composition of the tumor microenvironment and its influence on cancer progression and metastasis. It is clear that additional fundamental and preclinical research is required to confirm the efficacy and practicality of this novel and promising strategy for treating cancer.

Pseudomonas aeruginosa-mannose-sensitive hemagglutinin inhibits pancreatic cancer cell proliferation and induces apoptosis via the EGFR pathway and caspase signaling

Pseudomonas aeruginosa-mannose-sensitive hemagglutinin (PA-MSHA) has demonstrated efficacy against several solid tumors. In this study, we found that PA-MSHA inhibited the proliferation of PANC-1 and SW1990 pancreatic cancer cells, but had no obvious effects on HPDE6-C7 normal human pancreatic duct epithelial cells. Electron microscopy revealed the presence of apoptotic bodies and intracellular vacuole formation in PA-MSHA-treated pancreatic cancer cells. Flow cytometric analysis indicated the rate of apoptosis correlated with the PA-MSHA concentration. We observed a decrease in cell fractions in G0/G1 and G2/M phases, and an increase in the fraction in S phase (p < 0.01). PA-MSHA thus caused cell cycle arrest. Increasing concentrations of PA-MSHA did not alter total levels of EGFR, AKT or ERK, but levels of the corresponding phosphoproteins decreased. PA-MSHA also reduced tumor volume in a xenograft mouse model of pancreatic cancer (p < 0.01). Furthermore, caspase-3 levels decreased while the levels of cleaved caspase-3 increased (p < 0.01). These data suggest that by blocking cell cycle progression, PA-MSHA induces apoptosis and inhibits tumor growth. PA-MSHA-mediated inhibition of EGFR signaling and activation of the caspase pathway may play an important role in the induction of apoptosis in pancreatic cancer cells.

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

BACKGROUND

The aim of the present study was to investigate effects of Pseudomonas aeruginosa-mannose-sensitive hemagglutinin (PA-MSHA) on the inhibition of the proliferation of bladder cancer cell lines and to further define its functional mechanisms.

METHODS

A rat model of bladder tumor was induced by intravesical N-methyl-N nitrosourea. The dynamic growth of tumor was measured by whole-body fluorescent imaging system. Morphological analysis was observed by hematoxylin-eosin staining and microscopic examination. The expression of Caspase 3 and E-Ca were detected by immunohistochemistry technique. Macrophages were separated by flow cytometry. The expression of cytokines was measured by qRT-PCR and western blot. Apoptosis ability was conducted by means of annexin V and propidium iodide. The abilities of invasion and migration were determined by transwell migration assay and scratch assay.

RESULTS

PA-MSHA and PA-MSHA + Fisetin groups inhibited the growth of tumor and increased the ratio of M1/M2. For one thing, PA-MSHA suppressed the invasive ability of the bladder tumor cell and promoted bladder tumor cell apoptosis. For another, it facilitated the expression of M1 cytokines and reduced expression of M2 cytokines. Furthermore, treated with PA-MSHA, mouse M1 phagocytosis rates were higher than that of M2 macrophages for bladder cancer lines.

CONCLUSIONS

The data revealed that PA-MSHA might promote apoptosis and inhibit proliferation, invasion and migration of mouse bladder cancer cells by inducing M1 polarization.