Irreversible electroporation augments β-glucan induced trained innate immunity for the treatment of pancreatic ductal adenocarcinoma

Leveraging the Immunological Impacts of Irreversible Electroporation as a New Frontier for Cancer Therapy

Irreversible electroporation (IRE) is a nonthermally mediated tissue ablation modality that makes use of short pulsed electric fields to destroy cancerous lesions in situ. In the past two decades, IRE has established itself not only as an effective means to ablate small, unresectable tumor masses but also as a tool particularly qualified to modulate the tumor microenvironment in a way that dismantles pathways of cancer immunosuppression and permits the development of a systemic antitumor immune response. However, despite its immune-stimulating tendencies, for most cancers conventional IRE alone is insufficient to establish an immune response robust enough to fully eliminate disseminated disease and prevent recurrence. Here, we describe the current understanding of the histological and immunological effects of IRE, as well as recent efforts to optimize IRE parameters and develop rational combination therapies to increase the efficacy of the resulting immune response.

Breaking the immune desert: Strategies for overcoming the immunological challenges of pancreatic cancer

Pancreatic cancer is characterised by its highly aggressive nature and extremely poor prognosis, with a uniquely complex tumour immune microenvironment that manifests as a prototypical "immune desert." This immune-desert phenotype primarily arises from the inherently low immunogenicity of the tumour, the formation of a dense fibrotic stroma, severe deficiency in immune cell infiltration, and profound immunosuppressive effects of the metabolic landscape. Specifically, dysregulated tryptophan metabolism, such as indoleamine 2,3-dioxygenase (IDO)-mediated catabolism, and excessive lactate accumulation contribute to impaired T-cell functionality. Collectively, these factors severely limit the efficacy of current immunotherapy strategies, particularly those based on immune checkpoint inhibitors, which have demonstrated significantly lower clinical response rates in pancreatic cancer than in other malignancies. In response to these therapeutic challenges, this review explores integrated treatment strategies that combine metabolic reprogramming, tumour microenvironment remodelling, and next-generation immune checkpoint blockades, such as LAG-3, TIM-3, and VISTA. These emerging approaches hold substantial promise for clinical application. For example, targeting key metabolic pathways, including glycolysis (Warburg effect) and glutamine metabolism, may help restore T-cell activity by alleviating metabolic stress within the tumour milieu. Additionally, localised administration of immune stimulators such as interleukin-12 (IL-12) and CD40 agonists may enhance immune cell infiltration and promote tumour-specific immune activation. Future research should prioritise large-scale, multicentre clinical trials to validate the therapeutic efficacy of these innovative strategies, aiming to achieve meaningful breakthroughs in pancreatic cancer immunotherapy and significantly improve long-term survival and clinical outcomes in affected patients.

Targeting Splenic Myeloid Cells with Nanobiologics to Prevent Postablative Pancreatic Cancer Recurrence via Inducing Antitumor Peripheral Trained Immunity

Minimally invasive irreversible electroporation ablation shows promise for pancreatic cancer (PCa), but the high recurrence and metastasis rates pose a therapeutic challenge for loco-regional ablation treatment. Immunotherapy holds promise for preventing tumor recurrence, however, its efficacy against PCa remains limited. Here, using a preclinical model of PCa, it is identified that tumor development dramatically restructures the splenic immune landscape characterized by increased frequency of myeloid cells. Further, nanobiologics with high affinity for splenic myeloid cells using erythrocyte membrane fused with apoA1-modified liposomes are presented. Biocompatible CaCO3 nanoparticles are incorporated to serve as a release reservoir of immunomodulatory therapeutics (muramyl dipeptide, MDP). The nanobiologics, MDCa@RBC-Alipo, induce antitumor-trained immunity by epigenetically and metabolically rewiring splenic myeloid cells, thereby overcoming the immunosuppressive tumor microenvironment in residual PCa following irreversible electroporation ablation. This approach enhances the therapeutic efficacy of aPD-L1 and significantly inhibits tumor recurrence and hemorrhagic ascites development. The trafficking of MDP directly to the spleen highlights a previously uncharacterized pathway for inducing peripheral trained immunity, thereby presenting a novel therapeutic approach for locally advanced PCa treatment.

Irreversible Electroporation and Beta-Glucan-Induced Trained Innate Immunity for Treatment of Pancreatic Ductal Adenocarcinoma: A Phase II Study

BACKGROUND

Irreversible electroporation (IRE) has augmented the effects of certain immunotherapies in pancreatic ductal adenocarcinoma (PDA). Yeast-derived particulate beta-glucan induces trained innate immunity and successfully reduced murine pancreatic cancer burden. This is a phase II study to test the hypothesis that IRE may augment beta-glucan-induced trained immunity in patients with PDA.

STUDY DESIGN

In this phase II clinical trial (NCT03080974), surgical ablative IRE was performed on clinical stage III PDA followed by oral beta-glucan administration for 12 months or until disease recurrence. Peripheral blood was taken preoperative, 14 days, and every 3 months and was evaluated by mass cytometry and compared with patients who received IRE alone.

RESULTS

Thirty consecutive patients with preoperative clinical stage III PDA were treated with IRE and then initiated on oral beta-glucan postoperatively were compared with 20 patients treated with IRE alone. There were no dose-limiting toxicities with oral beta-glucan, and compliance with therapy was 96% in all patients. Seven patients (23%) developed grade 3 or 4 treatment-related adverse events at 90 days; none required a dose modification of oral beta-glucan. A median disease-free interval (DFI) was 18 months (range 6 to 48 months), with a median overall survival (OS) of 32.5 months (range 4 to 53 months). At 12 months post-IRE, immunophenotyping was demonstrated a significant effect with improvement in the IRE-beta-glucan-treated group. This also resulted in a significant decrease on naive CD4 and CD8 T cells with increased CD4 and CD8 terminal effector cells in the IRE-beta-glucan-treated group, which correlated with a significant improvement in DFI and OS (p = 0.001).

CONCLUSIONS

Combined beta-glucan with IRE-ablated PDA tumor cells elicited a potent trained response and augmented antitumor functionality at 12 months post-IRE, which translated into an improved DFI and OS.

Exploring the Potential of Medicinal Mushroom β-Glucans as a Natural Frontier in Prostate Cancer Treatment

The global increase in cancer cases, particularly prostate cancer, poses a significant health challenge worldwide. Conventional treatments such as surgery, radiation therapy, hormone therapy, chemotherapy, and immunotherapy offer valuable options but are associated with limitations and potential side effects. As a result, there is growing interest in complementary therapies, including natural compounds such as β-glucans, derived from sources such as yeast and mushrooms. In this review, we explored the potential therapeutic role of medicinal mushrooms β-glucan in prostate cancer treatment. β-glucans has demonstrated anti-cancer properties in preclinical studies, including inhibition of proliferation, induction of apoptosis, and modulation of immune responses. Studies in prostate cancer cell lines and animal models have shown promising results, with β-glucan inhibiting tumor growth, inducing DNA damage, and regulating tumor markers such as p53 and prostate specific antigen. β-glucans acts through various pathways, including stimulation of dendritic cells, modulation of cytokine secretion, suppression of myeloid-derived suppressor cells, and enhancement of immune responses. Moreover, β-glucans exhibits anti-androgenic and immune-modulatory effects, making it a promising candidate for prostate cancer treatment. In this study, we also focused on the mechanism of action of β-glucans through various pathways including tumor cell death by oxidative stress created through ROS generation and autophagy. Although preclinical studies support the potential therapeutic efficacy of medicinal mushrooms β-glucans, further research is needed to elucidate its clinical utility and safety in human trials.

Myeloid activation clears ascites and reveals IL27-dependent regression of metastatic ovarian cancer

Patients with metastatic ovarian cancer (OvCa) have a 5-year survival rate of <30% due to the persisting dissemination of chemoresistant cells in the peritoneal fluid and the immunosuppressive microenvironment in the peritoneal cavity. Here, we report that intraperitoneal administration of β-glucan and IFNγ (BI) induced robust tumor regression in clinically relevant models of metastatic OvCa. BI induced tumor regression by controlling fluid tumor burden and activating localized antitumor immunity. β-glucan alone cleared ascites and eliminated fluid tumor cells by inducing intraperitoneal clotting in the fluid and Dectin-1-Syk-dependent NETosis in the omentum. In omentum tumors, BI expanded a novel subset of immunostimulatory IL27+ macrophages and neutralizing IL27 impaired BI efficacy in vivo. Moreover, BI directly induced IL27 secretion in macrophages where single agent treatment did not. Finally, BI extended mouse survival in a chemoresistant model and significantly improved chemotherapy response in a chemo-sensitive model. In summary, we propose a new therapeutic strategy for the treatment of metastatic OvCa.

B cell c-Maf signaling promotes tumor progression in animal models of pancreatic cancer and melanoma

BACKGROUND

The role of B cells in antitumor immunity remains controversial, with studies suggesting the protumor and antitumor activity. This controversy may be due to the heterogeneity in B cell populations, as the balance among the subtypes may impact tumor progression. The immunosuppressive regulatory B cells (Breg) release interleukin 10 (IL-10) but only represent a minor population. Additionally, tumor-specific antibodies (Abs) also exhibit antitumor and protumor functions dependent on the Ab isotype. Transcription factor c-Maf has been suggested to contribute to the regulation of IL-10 in Breg, but the role of B cell c-Maf signaling in antitumor immunity and regulating Ab responses remains unknown.

METHODS

Conditional B cell c-Maf knockout (KO) and control mice were used to establish a KPC pancreatic cancer model and B16.F10 melanoma model. Tumor progression was evaluated. B cell and T cell phenotypes were determined by flow cytometry, mass cytometry, and cytokine/chemokine profiling. Differentially expressed genes in B cells were examined by using RNA sequencing (RNA-seq). Peripheral blood samples were collected from healthy donors and patients with melanoma for B cell phenotyping.

RESULTS

Compared with B cells from the spleen and lymph nodes (LN), B cells in the pancreas exhibited significantly less follicular phenotype and higher IL-10 production in naïve mice. c-Maf deficiency resulted in a significant reduction of CD9+ IL-10-producing Breg in the pancreas. Pancreatic ductal adenocarcinoma (PDAC) progression resulted in the accumulation of circulating B cells with the follicular phenotype and less IL-10 production in the pancreas. Notably, B cell c-Maf deficiency delayed PDAC tumor progression and resulted in proinflammatory B cells. Further, tumor volume reduction and increased effective T cells in the tumor-draining LN were observed in B cell c-Maf KO mice in the B16.F10 melanoma model. RNA-seq analysis of isolated B cells revealed that B cell c-Maf signaling modulates immunoglobulin-associated genes and tumor-specific Ab production. We furthermore demonstrated c-Maf-positive B cell subsets and an increase of IL-10-producing B cells after incubation with IL-4 and CD40L in the peripheral blood of patients with melanoma.

CONCLUSION

Our study highlights that B cell c-Maf signaling drives tumor progression through the modulation of Breg, inflammatory responses, and tumor-specific Ab responses.

β-glucan: a potent adjuvant in immunotherapy for digestive tract tumors

The immunotherapy for gastrointestinal tumors, as a significant research direction in the field of oncology treatment in recent years, has garnered extensive attention due to its potential therapeutic efficacy and promising clinical application prospects. Recent advances in immunotherapy notwithstanding, challenges persist, such as side effects, the complexity of the tumor immune microenvironment, variable patient responses, and drug resistance. Consequently, there is a pressing need to explore novel adjunctive therapeutic modalities. β-glucan, an immunomodulatory agent, has exhibited promising anti-tumor efficacy in preclinical studies involving colorectal cancer, pancreatic cancer, and gastric cancer, while also mitigating the adverse reactions associated with chemotherapy and enhancing patients' quality of life. However, further clinical and fundamental research is warranted to comprehensively evaluate its therapeutic potential and underlying biological mechanisms. In the future, β-glucan holds promise as an adjunctive treatment for gastrointestinal tumors, potentially bringing significant benefits to patients.

Trained immunity inducers in cancer immunotherapy

While most of the cancer immunotherapy strategies engage adaptive immunity, especially tumor-associated T cells, the small fraction of responding patients and types of cancers amenable, and the possibility of severe adverse effects limit its usage. More effective and general interventions are urgently needed. Recently, a de facto innate immune memory, termed 'trained immunity', has become a new research focal point, and promises to be a powerful tool for achieving long-term therapeutic benefits against cancers. Trained immunity-inducing agents such as BCG and fungal glucan have been shown to be able to avert the suppressive tumor microenvironment (TME), enhance T cell responses, and eventually lead to tumor regression. Here, we review the current understating of trained immunity induction and highlight the critical roles of emergency granulopoiesis, interferon γ and tissue-specific induction. Preclinical and clinical studies that have exploited trained immunity inducers for cancer immunotherapy are summarized, and repurposed trained immunity inducers from other fields are proposed. We also outline the challenges and opportunities for trained immunity in future cancer immunotherapies. We envisage that more effective cancer vaccines will combine the induction of trained immunity with T cell therapies.

Intraperitoneal activation of myeloid cells clears ascites and reveals IL27-dependent regression of metastatic ovarian cancer

Patients with metastatic ovarian cancer (OvCa) have a 5-year survival rate of less than 30% due to persisting dissemination of chemoresistant cells in the peritoneal fluid and the immunosuppressive microenvironment in the peritoneal cavity. Here, we report that intraperitoneal administration of β-glucan and IFNγ (BI) induced robust tumor regression in clinically relevant models of metastatic OvCa. BI induced tumor regression by controlling fluid tumor burden and activating localized antitumor immunity. β-glucan alone cleared ascites and eliminated fluid tumor cells by inducing intraperitoneal clotting in the fluid and Dectin-1-Syk-dependent NETosis in the omentum. In omentum tumors, BI expanded a novel subset of immunostimulatory IL27+ macrophages and neutralizing IL27 impaired BI efficacy in vivo. Moreover, BI directly induced IL27 secretion in macrophages where single agent treatment did not. Finally, BI extended mouse survival in a chemoresistant model and significantly improved chemotherapy response in a chemo-sensitive model. In summary, we propose a new therapeutic strategy for the treatment of metastatic OvCa.

The Induction of Combined Hyperthermal Ablation Effect of Irreversible Electroporation with Polydopamine Nanoparticle-Coated Electrodes

Irreversible electroporation (IRE) is a prominent non-thermal ablation method widely employed in clinical settings for the focal ablation therapy of solid tumors. Utilizing high-voltage, short-duration electric pulses, IRE induces perforation defects in the cell membrane, leading to apoptotic cell death. Despite the promise of irreversible electroporation (IRE) in clinical applications, it faces challenges concerning the coverage of target tissues for ablation, particularly when compared to other thermal ablation therapies such as radiofrequency ablation, microwave ablation, and cryoablation. This study aims to investigate the induced hyperthermal effect of IRE by applying a polydopamine nanoparticle (Dopa NP) coating on the electrode. We hypothesize that the induced hyperthermal effect enhances the therapeutic efficacy of IRE for cancer ablation. First, we observed the hyperthermal effect of IRE using Dopa NP-coated electrodes in hydrogel phantom models and then moved to in vivo models. In particular, in in vivo animal studies, the IRE treatment of rabbit hepatic lobes with Dopa NP-coated electrodes exhibited a two-fold higher increase in temperature (ΔT) compared to non-coated electrodes. Through a comprehensive analysis, we found that IRE treatment with Dopa NP-coated electrodes displayed the typical histological signatures of hyperthermal ablation, including the disruption of the hepatic cord and lobular structure, as well as the infiltration of erythrocytes. These findings unequivocally highlight the combined efficacy of IRE with Dopa NPs for electroporation and the hyperthermal ablation of target cancer tissues.