Irreversible electroporation reverses resistance to immune checkpoint blockade in pancreatic cancer

Potential targets for synergistic bipolar irreversible electroporation in tumor suppression through transcriptomics and proteomics analysis

Previous studies have demonstrated that synergistic bipolar irreversible electroporation (SBIRE) is a promising non-thermal tumor ablation technique that effectively targets tumors without causing muscle contractions. Despite its clinical potential, the mechanistic understanding of SBIRE's tumor-suppressive effects remains underexplored. This study aims to identify potential molecular targets for SBIRE-mediated tumor suppression through comprehensive transcriptomics and proteomics analyses. Mice were selected as subjects for the creation of tumor models by the subcutaneous tumor-bearing method. Following the SBIRE intervention, tumor surveillance and pathological investigations were carried out. A comprehensive investigation was conducted using RNA sequencing-based transcriptomics and label-free quantitative proteomics to examine normal and SBIRE treated tumor samples. Differentially expressed genes (DEGs) and crucial signaling pathways were found using bioinformatics analysis. Western blot (WB), immunohistochemistry (IHC), and quantitative real-time PCR (qRT-PCR) were used to validate potentially associated genes. The results demonstrate that a substantial reduction in tumor size was achieved following SBIRE treatment. A total of 86 genes exhibited differential expression in tumors, with 84 genes showing upregulation and 2 genes showing downregulation. According to bioinformatics research, these DEGs were involved in a wide variety of biological activities, such as cell adhesion, positive regulation of tumor necrosis factor production, and immune system process. Beside major enrichment pathways like Efferocytosis, Endocytosis, PPAR signaling pathway and Metabolic pathways. The upregulation of WDFY family member 4 (WDFY4), Thrombospondin 1(THBS1), Pentraxin 3 (PTX3), Superoxide dismutase 3 (SOD3) and Glutathione peroxidase 3 (GPX3) genes were confirmed. These insights into the molecular underpinnings of SBIRE offer a novel therapeutic strategy for enhancing tumor suppression and improving clinical outcomes in cancer treatment.

Co-inhibition of RAGE and TLR4 sensitizes pancreatic cancer to irreversible electroporation in mice by disrupting autophagy

Irreversible electroporation (IRE) is a local ablative treatment for patients with pancreatic cancer. During the IRE procedure, high-intensity electric pulses are released intratumorally to disrupt plasma membranes and induce cell death. Since the intensity of the pulsed electric field (PEF) can be decreased by the tumor microenvironment, some cancer cells are subjected to a sublethal PEF and may survive to cause tumor recurrence later. Autophagy activation induced by anticancer therapies is known to promote treatment resistance. In this study, we investigated whether autophagy is activated in residual cancer cells after IRE and assessed the roles it plays during tumor recurrence. Subcutaneous KPC-A548 or Panc02 murine pancreatic cancer cell line xenograft mouse models were established; once the tumors reached 7 mm in one dimension, the tumor-bearing mice were subjected to IRE. For in vitro sublethal PEF treatment, the pancreatic cancer cell suspension was in direct contact with the electrodes and pulsed at room temperature. We showed that autophagy was activated in surviving residual cells, as evidenced by increased expression of LC3 and p62. Suppression of autophagy with hydroxychloroquine (60 mg/kg, daily intraperitoneal injection) markedly increased the efficacy of IRE. We demonstrated that autophagy activation can be attributed to increased expression of high-mobility group box 1 (HMGB1); co-inhibition of two HMGB1 receptors, receptor for advanced glycosylation end products (RAGE) and Toll-like receptor 4 (TLR4), suppressed autophagy activation by upregulating the PI3K/AKT/p70 ribosomal S6 protein kinase (p70S6K) axis and sensitized pancreatic cancer cells to PEF. We prepared a polymeric micelle formulation (M-R/T) encapsulating inhibitors of both RAGE and TLR4. The combination of IRE and M-R/T (equivalent to RAGE inhibitor at 10.4 mg/kg and TLR4 inhibitor at 5.7 mg/kg, intravenous or intraperitoneal injection every other day) significantly promoted tumor apoptosis, suppressed cell cycle progression, and prolonged animal survival in pancreatic tumor models. This study suggests that disruption of HMGB1-mediated autophagy with nanomedicine is a promising strategy to enhance the response of pancreatic cancer to IRE.

Transient Lymphatic Remodeling Follows Sub-Ablative High-Frequency Irreversible Electroporation Therapy in a 4T1 Murine Model

High-frequency irreversible electroporation (H-FIRE) is a minimally invasive local ablation therapy known to activate the adaptive immune system and reprogram the tumor microenvironment. Its predecessor, irreversible electroporation (IRE), transiently increases microvascular density and immune cell infiltration within the surviving non-ablated and non-necrotic tumor region, also known as the viable tumor region. However, the impact of pulse electric field therapies on lymphatic vessels, crucial for T-cell fate and maturation, remains unclear. This study investigates how sub-ablative H-FIRE (SA-HFIRE) affects lymphatic and blood microvascular remodeling in the 4T1 mammary mouse model. We conducted a temporal and spatial analysis to evaluate vascular changes in the viable tumor, peritumoral fat pad, and tumor-draining lymph node post-treatment. Histological examination showed a transient increase in blood vessel density on Day 1 post-treatment, followed by a spike in lymphatic vessel density in the viable tumor region on Day 3 post-treatment, increased lymphatic vessel density in the peripheral fat pad, and minimal remodeling of the tumor-draining lymph node within 3 days following treatment. Gene expression analysis indicated elevated levels of CCL21 and CXCL2 on Day 1 post-treatment, while VEGFA and VEGFC did not appear to contribute to vascular remodeling. Likewise, CCL21 protein content in tumor-draining axillary lymph nodes correlated with gene expression data from the viable tumor region. These findings suggest a dynamic shift in lymphatic and blood microvascular structures post-SA-HFIRE, potentially enhancing the adaptive immune response through CCL21-mediated lymphatic homing and subsequent lymph node microvascular remodeling. Future work will assess the immune and transport function of the microvasculature to inform experiments aimed at the application of adjuvant therapies during scenarios of tumor partial ablation.

Irreversible electroporation combined with PD-L1/IL-6 dual blockade promotes anti-tumor immunity via cDC2/CD4+T cell axis in MHC-I deficient pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a "cold" solid tumor with frequent Major Histocompatibility Complex I (MHC-I) deficiency, thereby making it resistant to type-1-conventional dendritic cell (cDC1)-CD8+T cell mediated anti-tumor immunity. Current studies have demonstrated the emerging compensatory role of MHC-II-mediated antigen presentation and CD4+T cell activation in anti-tumor immunity against MHC-I-deficient tumors. However, the underlying mechanism of the compensatory immune response by CD4+T cells in cancer ablation therapy remains to be elucidate. In clinical samples and murine models, we observed that irreversible electroporation (IRE) ablation therapy promoted immune infiltration and the conversion of CD4+T cells into anti-tumor IFN-γ+Th1 cells and Th17 cells in MHC-I low-expressed PDAC using scRNA-seq and flow-cytometry analyses. Furthermore, we found that PD-L1 blockade predominantly enhanced the activation of CD11b+CD103-type-2 conventional dendritic cells (cDC2s) and their antigen presentation to CD4+T cells after ablation, stimulating the anti-tumor immune response through the tumor antigen-specific IFN-γ+Th1-NK cell axis. Elevated plasma levels of IL-6 in pancreatic cancer patients receiving ablation therapy are significant indicators for impaired prognosis. IL-6 and PD-L1 dual blockade could significantly augment the ratio of IFN-γ+Th1 in CD4+T cells to boost the anti-tumor immunity of NK cells, leading to prolonged survival of mouse bearing pancreatic cancer. Collectively, we have elucidated that PD-L1 blockade activates the cDC2-CD4+T cell axis after IRE therapy, thereby playing a pivotal compensatory anti-tumor role in MHC-I low-expressed pancreatic cancer. Moreover, a combination strategy involving dual-target blockade of PD-L1/IL-6 along with ablation therapy could emerge as a novel therapeutic approach for MHC-I deficient tumors.

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.

Recent Advances and Challenges in the Treatment of Advanced Pancreatic Cancer: An Update on Completed and Ongoing Clinical Trials

Pancreatic cancer is a deadly disease with a low survival rate, particularly in its advanced stages. Advanced pancreatic cancer remains a major clinical challenge due to limited treatment options. Surgical resection may not always be feasible, and traditional chemotherapy often shows restricted effectiveness. As a result, researchers are exploring a multifaceted therapeutic approach targeting the genetic and molecular drivers of the disease. A combination of molecular profiling and targeted therapies are being investigated to improve outcomes and address the shortcomings of traditional treatments. The focus of this review is to provide a summary of current and completed clinical trials for the treatment of advanced pancreatic cancer. This includes adagrasib (a KRAS inhibitor), olaparib (a PARP inhibitor for BRCA mutations), APG-1387 (an IAP antagonist), minnelide (an anti-stromal agent), arimastat (an MMP inhibitor), MK-0646 (an IGF1R inhibitor), sirolimus (an mTOR inhibitor), and metabolic inhibitors. These agents are being evaluated both as standalone treatments and in combination with standard therapy. Furthermore, we have summarized novel approaches such as cancer vaccines and ablation techniques as emerging strategies in the treatment of advanced pancreatic cancer. We have also examined the challenges in treating advanced pancreatic cancer and the factors contributing to therapeutic failure, which may offer valuable insights for developing more effective treatment strategies and innovative drug designs.

Advancements in the application of ablative therapy and its combination with immunotherapy in anti-cancer therapy

Cancer is a significant health issue impacting humans. Currently, systemic therapies such as chemotherapy have significantly increased the life expectancy of cancer patients. However, some patients are unable to endure systemic treatment due to its significant adverse effects, leading to an increased focus on local therapies including radiation and ablation therapy. Ablation therapy is a precise, low-toxicity, and minimally invasive localized therapy that is increasingly acknowledged by clinicians and cancer patients. Many cancer patients have benefited from it, with some achieving full recovery. Currently, numerous studies have shown that ablation therapy is effective due to its ability to kill cancer cells efficiently and activate the body's anti-cancer immunity. It can also convert "cold cancers" into "hot cancers" and enhance the effectiveness of immunotherapy when used in combination. In this article, we categorize ablation therapy into thermal ablation, cryoablation, photodynamic therapy (PDT), irreversible electroporation (IRE), etc. Thermal ablation is further divided into Radiofrequency ablation (RFA), microwave ablation (WMA), high-frequency focused ultrasound (HIFU), photothermal therapy (PTT), magnetic heat therapy (MHT), etc. We systematically review the most recent advancements in these ablation therapies that are either currently used in clinic or are anticipated to be used in clinic. Then, we also review the latest development of various ablative therapies combined with immunotherapy, and its future development. CLINICAL RELEVANCE STATEMENT: Ablation therapy, an invasive localized treatment, offers an alternative to systemic therapies for cancer patients who cannot tolerate their adverse effects. Its ability to kill cancer cells efficiently and activate anti-cancer immunity. This article reviews recent advancements in ablation therapies, including thermal, cryoablation, PDT, and IRE, and their potential clinical applications, both standalone and in combination with immunotherapy.

Oral Microalgae-Based Biosystem to Enhance Irreversible Electroporation Immunotherapy in Hepatocellular Carcinoma

Irreversible electroporation (IRE) is a novel local tumor ablation technique that can potentially stimulate immune responses. However, IRE alone cannot effectively activate the immune system or prevent distant metastases. Therefore, this study utilized the biocompatibility of Chlorella vulgaris (C. vulgaris) and polydopamine (PDA) adhesive properties to encapsulate a PD-1 inhibitor (PI). The PDA coating protects the drug from degradation by stomach acid and enhances its intestinal absorption. This carrier demonstrates excellent in vivo drug release control and biodistribution, significantly increasing the oral bioavailability of PI. Combining IRE with this natural carrier significantly improves the therapeutic efficacy, which increases the local drug concentration and activates the immune system. This system demonstrates significantly improved therapeutic efficacy against local tumors compared with PI or IRE alone and significantly reduces PI-associated side effects. A convenient oral delivery system is developed using this readily available natural micro-carrier that not only improves the therapeutic effect of IRE but also mitigates its adverse effects, indicating significant potential for clinical applications. This discovery offers a new strategy for hepatocellular carcinoma treatment with the potential to improve patient outcomes.

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.

Systemic immunomodulation by irreversible electroporation versus stereotactic ablative body radiotherapy in locally advanced pancreatic cancer: the CROSSFIRE trial

BACKGROUND

Irreversible electroporation (IRE) and stereotactic ablative body radiotherapy (SABR) are cytoreductive therapies for locally advanced pancreatic cancer (LAPC). Both may signify immunogenic cell death. We aimed to compare systemic immune responses between the treatments.

METHODS

As part of the randomized phase II CROSSFIRE trial (NCT02791503), comparing the oncological efficacy of IRE to SABR in patients with LAPC, pre- and post-treatment (2 weeks and 3 months) peripheral blood samples were collected. Frequency and activation status of lymphocytic and myeloid subsets were determined using flow cytometry. T cell responses to pancreatic cancer associated with Wilms tumor-1 (WT-1) and survivin tumor antigens were determined by interferon-γ enzyme-linked immunospot assay.

RESULTS

In total, 20 IRE and 20 SABR-treated participants were analyzed (20 men; median age 65 (IQR 55-70)). IRE induced immediate decreases in systemic regulatory T cell (Treg) and conventional type-1 dendritic cell rates, coinciding with CD4+/CD8+ T cell activation by upregulation of PD-1, which was associated with improved overall survival (OS). SABR similarly induced immediate CD4+/CD8+ T cell activation by upregulation of Ki67 and CD25 but resulted in asynchronously delayed Treg downregulation. SABR also induced a durable increase in CD4+ EM T cells, associated with improved OS. Ablation-induced WT-1 or survivin-specific T cell responses were observed in 9/16 (56%) immune competent participants (IRE n=5, SABR n=4) and were associated with longer OS.

CONCLUSION

Distinct immune stimulatory responses associated with improved OS, suggest that SABR might benefit from combined Treg depletion strategies while IRE could benefit from PD-1 checkpoint inhibition.

TRIAL REGISTRATION NUMBER

The trial was registered on clinical trials.gov (NCT02791503).

Foundational insights for theranostic applications of magnetoelectric nanoparticles

Reviewing emerging biomedical applications of MagnetoElectric NanoParticles (MENPs), this paper presents basic physics considerations to help understand the possibility of future theranostic applications. Currently emerging applications include wireless non-surgical neural modulation and recording, functional brain mapping, high-specificity cell electroporation for targeted cancer therapies, targeted drug delivery, early screening and diagnostics, and others. Using an ab initio analysis, each application is discussed from the perspective of its fundamental limitations. Furthermore, the review identifies the most eminent challenges and offers potential engineering solutions on the pathway to implement each application and combine the therapeutic and diagnostic capabilities of the nanoparticles.

Pancreatic cancer: failures and hopes-a review of new promising treatment approaches

Pancreatic cancer is a challenging disease with limited treatment options and a high mortality rate. Just few therapy advances have been made in recent years. Tumor microenvironment, immunosuppressive features and mutational status represent important obstacles in the improvement of survival outcomes. Up to now, first-line therapy did achieve a median overall survival of less than 12 months and this discouraging data lead clinicians all over the world to focus their efforts on various fields of investigation: 1) sequential cycling of different systemic therapy in order to overcome mechanisms of resistance; 2) discovery of new predictive bio-markers, in order to target specific patient population; 3) combination treatment, in order to modulate the tumor microenvironment of pancreatic cancer; 4) new modalities of the delivery of drugs in order to pass the physical barrier of desmoplasia and tumor stroma. This review shows future directions of treatment strategies in advanced pancreatic cancer through a deep analysis of these recent macro areas of research.

Enhancing pancreatic cancer treatment: the role of H101 oncolytic virus in irreversible electroporation

Background

Irreversible Electroporation (IRE) offers a promising treatment for pancreatic cancer by using high-voltage pulses to kill tumor cells. But variations in tumor size and shape can lead to uneven electric fields, causing some cells to undergo only reversible electroporation (RE) and survive. However, RE can temporarily increase the permeability of the cell membrane, allowing small molecules to enter. H101 virus is an oncolytic adenovirus with deleted E1B-55kD and E3 regions that selectively targets and kills tumor cells. This study aimed to investigate whether the H101 oncolytic virus can serve as a supplementary therapeutic approach to kill tumors combined with RE.

Methods

We first explored how RE and the H101 oncolytic virus, both individually and together, affected tumor cell proliferation and migration in cellular experiments. Subsequent in vitro studies further assessed the effects of different treatments on tumor growth. To understand the mechanisms of pathway changes in tumors from different treatment groups, we analyzed tumor samples from each group using bulk RNA sequencing (bulk RNA-seq) and single-cell RNA sequencing (scRNA-seq). Additional biochemical techniques were used to validate key molecular changes.

Results

The combination of RE with the H101 oncolytic virus effectively inhibited pancreatic cancer cell proliferation and migration. Experiments using mouse subcutaneous tumor models confirmed that the combination therapy significantly reduced tumor growth. Further analysis bulk RNA-seq and scRNA-seq revealed that this combined approach activates the JNK-MAPK pathway, inducing apoptosis and enhancing therapeutic effects.

Conclusions

This combination boosts therapeutic effectiveness by activating the JNK-MAPK pathway and promoting tumor cell apoptosis. These findings suggest that the H101 oncolytic virus could serve as a valuable adjunct to improve the efficacy of IRE treatment.

Irreversible electroporation combined with anti-programmed cell death protein 1 therapy promotes tumor antigen-specific CD8+ T cell response

BACKGROUND

Irreversible electroporation (IRE) is a novel local tumor ablation approach with the potential to activate the host's immune system. However, this approach is insufficient to prevent cancer progression, and complementary approaches are required for effective immunotherapy.

AIM

To assess the immunomodulatory effects and mechanism of IRE combined anti-programmed cell death protein 1 (PD-1) treatment in subcutaneous pancreatic cancer models.

METHODS

C57BL-6 tumor-bearing mice were randomly divided into four groups: Control group; IRE group; anti-PD-1 group; and IRE + anti-PD-1 group. Tumor-infiltrating T, B, and natural killer cell levels and plasma concentrations of T helper type 1 cytokines (interleukin-2, interferon-γ, and tumor necrosis factor-α) were evaluated. Real-time PCR was used to determine the expression of CD8 (marker of CD8+ T cells) in tumor tissues of the mice of all groups at different points of time. The growth curves of tumors were drawn.

RESULTS

The results demonstrated that the IRE + anti-PD-1 group exhibited significantly higher percentages of T lymphocyte infiltration, including CD4+ and CD8+ T cells compared with the control group. Additionally, the IRE + anti-PD-1 group showed increased infiltration of natural killer and B cells, elevated cytokine levels, and higher CD8 mRNA expression. Tumor volume was significantly reduced in the IRE + anti-PD-1 group, indicating a more pronounced therapeutic effect.

CONCLUSION

The combination of IRE and anti-PD-1 therapy promotes CD8+ T cell immunity responses, leading to a more effective reduction in tumor volume and improved therapeutic outcomes, which provides a new direction for ablation and immunotherapy of pancreatic cancer.

A preliminary follow-up study on irreversible electroporation therapy in older patients with prostate cancer

BACKGROUND

Prostate cancer is a prevalent condition among older males, with radical prostatectomy being the standard treatment. However, this procedure can inevitably impact urinary and sexual functions. Irreversible electroporation represents an innovative therapeutic approach that employs high-voltage electrical pulses to selectively eradicate tumor cells, potentially preserving vital normal tissue.

MATERIALS AND METHODS

This follow-up study included 11 older prostate cancer patients who underwent IRE therapy from November 2021 to December 2023. The cohort was aged 66-77 years with a median preoperative PSA of 9.46 ng/mL. Based on the EAU risk groups classification, patients were divided into low (n = 4), intermediate (n = 6), and high-risk (n = 1) groups. Follow-up exams were conducted every 3 to 6 months to assess PSA levels, imaging, and urinary/sexual function.

RESULTS

Postoperatively, there was a significant decline in PSA levels across all patients, with a mean nadir of 0.78 ng/mL. The cumulative clinically significant prostate cancer recurrence rate was 27.3% at 30 months. Complications included urinary issues in 3 patients (27.3%), urethral pain in 2 patients (18.2%), and sexual dysfunction in 1 patient (9.1%).

CONCLUSION

This study suggests that IRE therapy is a safe and effective treatment option for older prostate cancer patients, with promising results in preserving urinary and sexual functions. However, the recurrence rate is higher than historical controls, indicating the need for further research to optimize treatment outcomes.

Enhancing CAR-T cell therapy against solid tumor by drug-free triboelectric immunotherapy

Chimeric antigen receptor (CAR) T cell therapy is a highly effective immunotherapy for hematological tumors, but its efficacy against most solid tumors remains challenging. Herein, a novel synergistic combination therapy of drug-free triboelectric immunotherapy and CAR-T cell therapy against solid tumor was proposed. A triboelectric nanogenerator (TENG) that can generate pulsed direct-current by coupling triboelectrification effect and electrostatic breakdown effect was fabricated. The TENG can generate up to 30 pulse direct-current peaks with peak current output ≈35 μA in a single sliding to power the triboelectric immunotherapy. The pulsed direct-current stimulation induced immunogenic cell death of tumor cells (survival rate of 35.9 %), which promoted dendritic cells maturation, accelerated the process of antigen presentation to CAR-T cells and enhanced the systemic adaptive immune response. Furthermore, triboelectric immunotherapy promoted M1-like macrophage polarization, reduced regulatory T cells differentiation and reprogrammed the tumor immunosuppressive microenvironment, which ultimately enhanced the efficacy of CAR-T cells to eradicate nearly 60 % of NALM6 solid tumor mass. Notably, considering that triboelectric immunotherapy is a safe and effective drug-free antitumor strategy, the combined therapy did not increase the burden of double-medication on patients.

Pulsed field ablation in medicine: irreversible electroporation and electropermeabilization theory and applications

BACKGROUND

Focal ablation techniques are integral in the surgical intervention of diseased tissue, where it is necessary to minimize damage to the surrounding parenchyma and critical structures. Irreversible electroporation (IRE) and high-frequency IRE (H-FIRE), colloquially called pulsed-field ablation (PFA), utilize high-amplitude, low-energy pulsed electric fields (PEFs) to nonthermally ablate soft tissue. PEFs induce cell death through permeabilization of the cellular membrane, leading to loss of homeostasis. The unique nonthermal nature of PFA allows for selective cell death while minimally affecting surrounding proteinaceous structures, permitting treatment near sensitive anatomy where thermal ablation or surgical resection is contraindicated. Further, PFA is being used to treat tissue when tumor margins are not expected after surgical resection, termed margin accentuation. This review explores both the theoretical foundations of PFA, detailing how PEFs induce cell membrane destabilization and selective tissue ablation, the outcomes following treatment, and its clinical implications across oncology and cardiology.

CONCLUSIONS

Clinical experience is still progressing, but reports have demonstrated that PFA reduces complications often seen with thermal ablation techniques. Mounting oncology data also support that PFA produces a robust immune response that may prevent local recurrences and attenuate metastatic disease. Despite promising outcomes, challenges such as optimizing field delivery and addressing variations in tissue response require further investigation. Future directions include refining PFA protocols and expanding its application to other therapeutic areas like benign tissue hyperplasia and chronic bronchitis.

Calcium electroporation induces stress response through upregulation of HSP27, HSP70, aspartate β-hydroxylase, and CD133 in human colon cancer cells

BACKGROUND

Electroporation (EP) leverages electric pulses to permeabilize cell membranes, enabling the delivery of therapeutic agents like calcium in cancer treatment. Calcium electroporation (CaEP) induces a rapid influx of calcium ions, disrupting cellular calcium homeostasis and triggering cell death pathways. This study aims to compare the cellular responses between microsecond (µsEP) and nanosecond (nsEP) electroporation, particularly in terms of oxidative stress, immune response activation, and cancer stem cell (CSC) viability in drug-resistant (LoVo Dx) and non-resistant (LoVo) colorectal cancer cell lines.

RESULTS

Both µsEP and nsEP, particularly when combined with Ca2+, significantly reduced the viability of cancer cells, with nsEP showing greater efficacy. Reactive oxygen species (ROS) levels increased 5-fold in malignant cells following nsEP, correlating with decreased ATP production and mitochondrial dysfunction. Nanosecond CaEP (nsCaEP) also induced significant expression of aspartate-β-hydroxylase (ASPH), a protein linked to calcium homeostasis and tumor progression. Moreover, nsEP led to heightened expression of heat shock proteins (HSP27/70), indicating potential immune activation. Interestingly, nsEP without calcium drastically reduced the expression of CD133, a marker for CSCs, while the addition of Ca2+ preserved CD133 expression. The expression of death effector domain-containing DNA binding protein (DEDD), associated with apoptosis, was significantly elevated in treated cancer cells, especially in the nucleus after nsCaEP.

CONCLUSIONS

The study confirms that nsEP is more effective than µsEP in disrupting cancer cell viability, enhancing oxidative stress, and triggering immune responses, likely through HSP overexpression and ROS generation. nsEP also appears to reduce CSC viability, offering a promising therapeutic approach. However, preserving CD133 expression in the presence of calcium suggests complex interactions that require further investigation. These findings highlight the potential of nsCaEP as an innovative strategy for targeting both cancer cells and CSCs, potentially improving treatment outcomes in colorectal cancer. Further studies are needed to explore the exact cell death mechanisms and optimize protocols for clinical applications.

Toward Large Ablations With Single-Needle High-Frequency Irreversible Electroporation In Vivo

Irreversible electroporation (IRE) is a minimally thermal tissue ablation modality used to treat solid tumors adjacent to critical structures. Widespread clinical adoption of IRE has been limited due to complicated anesthetic management requirements and technical demands associated with placing multiple needle electrodes in anatomically challenging environments. High-frequency irreversible electroporation (H-FIRE) delivered using a novel single-insertion bipolar probe system could potentially overcome these limitations, but ablation volumes have remained small using this approach. While H-FIRE is minimally thermal in mode of action, high voltages or multiple pulse trains can lead to unwanted Joule heating. In this work, we improve the H-FIRE waveform design to increase the safe operating voltage using a single-insertion bipolar probe before electrical arcing occurs. By uniformly increasing interphase () and interpulse () delays, we achieved higher maximum operating voltages for all pulse lengths. Additionally, increasing pulse length led to higher operating voltages up to a certain delay length (25 μs), after which shorter pulses enabled higher voltages. We then delivered novel H-FIRE waveforms via an actively cooled single-insertion bipolar probe in swine liver in vivo to determine the upper limits to ablation volume possible using a single-needle H-FIRE device. Ablations up to 4.62 0.12 cm x 1.83 0.05 cm were generated in 5 minutes without a requirement for cardiac synchronization during treatment. Ablations were minimally thermal, easily visualized with ultrasound, and stimulated an immune response 24 hours post H-FIRE delivery. These data suggest H-FIRE can rapidly produce clinically relevant, minimally thermal ablations with a more user-friendly electrode design.

Role of the Receptor for Advanced Glycation End Products (RAGE) and Its Ligands in Inflammatory Responses

Since its discovery in 1992, the receptor for advanced glycation end products (RAGE) has emerged as a key receptor in many pathological conditions, especially in inflammatory conditions. RAGE is expressed by most, if not all, immune cells and can be activated by many ligands. One characteristic of RAGE is that its ligands are structurally very diverse and belong to different classes of molecules, making RAGE a promiscuous receptor. Many of RAGE ligands are damaged associated molecular patterns (DAMPs) that are released by cells under inflammatory conditions. Although RAGE has been at the center of a lot of research in the past three decades, a clear understanding of the mechanisms of RAGE activation by its ligands is still missing. In this review, we summarize the current knowledge of the role of RAGE and its ligands in inflammation.

Advances in irreversible electroporation for prostate cancer

Irreversible electroporation is a nonthermal ablation technique that uses a high-voltage electric current to create nanosized pores in the cell membrane of a malignant tumor, thus resulting in cell death. In recent years, an increasing number of clinical studies have shown that irreversible electroporation is a safe and effective treatment for prostate cancer. We describe the progress of irreversible electroporation in prostate cancer in recent years in terms of its mechanism of action, clinical studies, advantages and disadvantages and summarize the gaps in existing studies and directions for future research.

How to Use Macrophages Against Cancer

Numerous studies have demonstrated the significant influence of immune cells on cancer development and treatment. This study specifically examines tumor-associated macrophages (TAMs), detailing their characteristics and roles in tumorigenesis and analyzing the impact of the ratio of TAM subtypes on patient survival and prognosis. It is established that TAMs interact with immunotherapy, radiotherapy, and chemotherapy, thereby influencing the efficacy of these treatments. Emerging therapies are explored, such as the use of nanoparticles (NPs) for drug delivery to target TAMs and modify the tumor microenvironment (TME). Additionally, novel anticancer strategies like the use of chimeric antigen receptor macrophages (CAR-Ms) show promising results. Investigations into the training of macrophages using magnetic fields, plasma stimulation, and electroporation are also discussed. Finally, this study presents prospects for the combination of TAM-based therapies for enhanced cancer treatment outcomes.

Pembrolizumab followed by irreversible electroporation of a liver metastasis in pancreatic cancer patients

Preclinical studies suggest that irreversible electroporation (IRE) increases the effect of immune checkpoint inhibition in pancreatic cancer (PC). Patients with PC received PD-1 inhibitor pembrolizumab and, on day 10, percutaneous IRE of a liver metastasis. Blood samples were analyzed for immune cell subsets and inflammation related proteins. mRNA expression profiling was done in sequential biopsies. Treatment was safe, but the trial was terminated early. The response rate in eight patients was 0% and tumor growth was exponential. A drop in circulating plasmacytoid dendritic cells and a rise in several cytokines and proteins, especially PD-1, after immunotherapy was observed. In liver metastases, immune stimulatory genes were upregulated and immune suppressive genes were downregulated after pembrolizumab, while markers of effector T cells were unchanged. Treatment was safe but showed no efficacy in PC. Immunotherapy induced an immune permissive tumor microenvironment but with no increase in effector cells.

Acoustic Controllable Spatiotemporal Cell Micro-oscillation for Noninvasive Intracellular Drug Delivery

Intracellular cargo delivery is crucial for drug evaluation, nanomedicine development, and gene therapy, in which high efficiency while maintaining cell viability is needed for downstream analysis. Here, an acoustic-mediated precise drug delivering mechanism is proposed by directly modulating cell micro-oscillation mode and membrane permeability. Through phase shifting keying-based spatiotemporal acoustic tweezers, controllable oscillating cell arrays can be achieved in shaking potentials. At the same time, continually oscillating radiation force and fluid shear stress exerted on cells effectively disturbs cellular membrane mobility and enhances permeability, thereby facilitating nanodrug entrance. In experiments, cell oscillation is tunable in frequency (10-2 to 102 Hz), shaking direction, amplitude (0 to quarter acoustic wavelength), and speed. Doxorubicin is actively delivered across cellular membranes and accumulates in inner cells, with a concentration more than 8 times that of the control group. Moreover, there is no obvious compromise in cell activity during oscillation, exhibiting excellent biocompatibility. This "dancing acoustic waves" scheme introduces a new dimension of cell manipulation in both space and time domains and an effective drug delivering strategy, offering advantages of flexibility, gentleness, and high throughput. It may advance related fields like nanobiological research, drug and nanomedicine development, and medical treatment.

A novel simple suture method for establishing an orthotopic pancreatic cancer mouse model: a comparative study with two conventional methods

OBJECTIVE

This study aims to evaluate the efficacy of a novel simple suture method in establishing an optimal animal model for preclinical research in pancreatic cancer.

METHODS

To establish a novel simple suture method, the tumor fragment was placed on the tail of the pancreas and securely wrapped into the pancreas, and compared with two conventional methods: the cell injection method and the tumor fragment embedding method. Subsequently, emission tomography/computed tomography scanning, gross anatomy observation, hematoxylin and eosin staining, and immunohistochemistry staining were performed to assess the effectiveness of these methods.

RESULTS

The emission tomography/computed tomography scanning and anatomical examinations confirmed the successful construction of orthotopic pancreatic cancer models using all three methods. Histopathological analysis of the orthotopic masses and metastatic lesions revealed malignant transformation with tumor infiltration into normal tissue. Comparative analysis demonstrated that the cell injection method was easy to perform but resulted in poor uniformity of tumor size and had high costs. The tumor fragment embedding method exhibited excellent uniformity of tumor size, with the highest tumor growth rates and a greater pancreatic impairment. In contrast, the novel simple suture method featured a relatively simple surgical procedure, slower growth rates, good uniformity of tumor size, and minimal pancreatic impairment.

CONCLUSION

The novel simple suture method is the optimal protocol for establishing an orthotopic pancreatic cancer mouse model, providing a robust foundation for preclinical studies on pancreatic cancer.

Prospects of Synergy: Local Interventions and CAR T Cell Therapy in Solid Tumors

Chimeric antigen receptor T cell therapy has been established in the treatment of various B cell malignancies. However, translating this therapeutic effect to treat solid tumors has been challenging because of their inter-tumoral as well as intratumoral heterogeneity and immunosuppressive microenvironment. Local interventions, such as surgery, radiotherapy, local ablation, and locoregional drug delivery, can enhance chimeric antigen receptor T cell therapy in solid tumors by improving tumor infiltration and reducing systemic toxicities. Additionally, ablation and radiotherapy have proven to (re-)activate systemic immune responses via abscopal effects and reprogram the tumor microenvironment on a physical, cellular, and chemical level. This review highlights the potential synergy of the combined approaches to overcome barriers of chimeric antigen receptor T cell therapy and summarizes recent studies that may pave the way for new treatment regimens.

Probiotics functionalized with a gallium-polyphenol network modulate the intratumor microbiota and promote anti-tumor immune responses in pancreatic cancer

The intratumor microbiome imbalance in pancreatic cancer promotes a tolerogenic immune response and triggers immunotherapy resistance. Here we show that Lactobacillus rhamnosus GG probiotics, outfitted with a gallium-polyphenol network (LGG@Ga-poly), bolster immunotherapy in pancreatic cancer by modulating microbiota-immune interactions. Upon oral administration, LGG@Ga-poly targets pancreatic tumors specifically, and selectively eradicates tumor-promoting Proteobacteria and microbiota-derived lipopolysaccharides through a gallium-facilitated disruption of bacterial iron respiration. This elimination of intratumor microbiota impedes the activation of tumoral Toll-like receptors, thus reducing immunosuppressive PD-L1 and interleukin-1β expression by tumor cells, diminishing immunotolerant myeloid populations, and improving the infiltration of cytotoxic T lymphocytes in tumors. Moreover, LGG@Ga-poly hampers pancreatic tumor growth in both preventive and therapeutic contexts, and amplifies the antitumor efficacy of immune checkpoint blockade in preclinical cancer models in female mice. Overall, we offer evidence that thoughtfully designed biomaterials targeting intratumor microbiota can efficaciously augment immunotherapy for the challenging pancreatic cancer.

Tissue Ablation: Applications and Perspectives

Tissue ablation techniques have emerged as a critical component of modern medical practice and biomedical research, offering versatile solutions for treating various diseases and disorders. Percutaneous ablation is minimally invasive and offers numerous advantages over traditional surgery, such as shorter recovery times, reduced hospital stays, and decreased healthcare costs. Intra-procedural imaging during ablation also allows precise visualization of the treated tissue while minimizing injury to the surrounding normal tissues, reducing the risk of complications. Here, the mechanisms of tissue ablation and innovative energy delivery systems are explored, highlighting recent advancements that have reshaped the landscape of clinical practice. Current clinical challenges related to tissue ablation are also discussed, underlining unmet clinical needs for more advanced material-based approaches to improve the delivery of energy and pharmacology-based therapeutics.

Dendritic cell vaccination combined with irreversible electroporation for treating pancreatic cancer-a narrative review

Background and Objective

Pancreatic ductal adenocarcinoma (PDAC) is 3rd most lethal cancer in the USA leading to a median survival of six months and less than 5% 5-year overall survival (OS). As the only potentially curative treatment, surgical resection is not suitable for up to 90% of the patients with PDAC due to late diagnosis. Highly fibrotic PDAC with an immunosuppressive tumor microenvironment restricts cytotoxic T lymphocyte (CTL) infiltration and functions causing limited success with systemic therapies like dendritic cell (DC)-based immunotherapy. In this study, we investigated the potential benefits of irreversible electroporation (IRE) ablation therapy in combination with DC vaccine therapy against PDAC.

Methods

We performed a literature search to identify studies focused on DC vaccine therapy and IRE ablation to boost therapeutic response against PDAC indexed in PubMed, Web of Science, and Scopus until February 20th, 2023.

Key Content and Findings

IRE ablation destructs tumor structure while preserving extracellular matrix and blood vessels facilitating local inflammation. The studies demonstrated IRE ablation reduces tumor fibrosis and promotes CTL tumor infiltration to PDAC tumors in addition to boosting immune response in rodent models. The administration of the DC vaccine following IRE ablation synergistically enhances therapeutic response and extends OS rates compared to the use of DC vaccination or IRE alone. Moreover, the implementation of data-driven approaches further allows dynamic and longitudinal monitoring of therapeutic response and OS following IRE plus DC vaccine immunoablation.

Conclusions

The combination of IRE ablation and DC vaccine immunotherapy is a potent strategy to enhance the therapeutic outcomes in patients with PDAC.

Spontaneous Overactivation of Xenopus Frog Eggs Triggers Necrotic Cell Death

The excessive activation of frog eggs, referred to as overactivation, can be initiated by strong oxidative stress, leading to expedited calcium-dependent non-apoptotic cell death. Overactivation also occurs spontaneously, albeit at a low frequency, in natural populations of spawned frog eggs. Currently, the cytological and biochemical events of the spontaneous process have not been characterized. In the present study, we demonstrate that the spontaneous overactivation of Xenopus frog eggs, similarly to oxidative stress- and mechanical stress-induced overactivation, is characterized by the fast and irreversible contraction of the egg's cortical layer, an increase in egg size, the depletion of intracellular ATP, a drastic increase in the intracellular ADP/ATP ratio, and the degradation of M phase-specific cyclin B2. These events manifest in eggs in the absence of caspase activation within one hour of triggering overactivation. Importantly, substantial amounts of ATP and ADP leak from the overactivated eggs, indicating that plasma membrane integrity is compromised in these cells. The rupture of the plasma membrane and acute depletion of intracellular ATP explicitly define necrotic cell death. Finally, we report that egg overactivation can occur in the frog's genital tract. Our data suggest that mechanical stress may be a key factor promoting egg overactivation during oviposition in frogs.

MRI-guided stereotactic ablative body radiotherapy versus CT-guided percutaneous irreversible electroporation for locally advanced pancreatic cancer (CROSSFIRE): a single-centre, open-label, randomised phase 2 trial

BACKGROUND

Pancreatic ductal adenocarcinoma is an aggressive disease with a dismal prognosis. Stage III locally advanced pancreatic cancer is considered unresectable and current palliative chemotherapy regimens only modestly improve survival. Guidelines suggest chemoradiation or stereotactic ablative body radiotherapy (SABR) could be beneficial in certain circumstances. Other local treatments such as irreversible electroporation could enhance patient outcomes by extending survival while preserving quality of life. We aimed to compare the efficacy and safety of MRI-guided SABR versus CT-guided percutaneous irreversible electroporation following standard FOLFIRINOX chemotherapy.

METHODS

CROSSFIRE was an open-label, randomised phase 2 superiority trial conducted at the Amsterdam University Medical Centre (Amsterdam, Netherlands). Eligible patients were aged 18 years or older with confirmed histological and radiological stage III locally advanced pancreatic cancer. The maximum tumour diameter was 5 cm and patients had to be pretreated with three to eight cycles of FOLFIRINOX. Patients were randomly assigned (1:1) to MRI-guided SABR (five fractions of 8 Gy delivered on non-consecutive days) or CT-guided percutaneous irreversible electroporation using a computer-generated variable block randomisation model. The primary endpoint was overall survival from randomisation, assessed in the intention-to-treat population. Safety was assessed in the per-protocol population. A prespecified interim futility analysis was done after inclusion of half the original sample size, with a conditional probability of less than 0·2 resulting in halting of the study. The trial was registered at ClinicalTrials.gov, NCT02791503.

FINDINGS

Between May 1, 2016, and March 31, 2022, 68 patients were enrolled and randomly assigned to SABR (n=34) or irreversible electroporation (n=34), of whom 64 were treated according to protocol. Of the 68 participants, 36 (53%) were male and 32 (47%) were female, with a median age of 65 years (IQR 57-70). Median overall survival from randomisation was 16·1 months (95% CI 12·1-19·4) in the SABR group versus 12·5 months (10·9-17·0) in the irreversible electroporation group (hazard ratio [HR] 1·39 [95% CI 0·84-2·30]; p=0·21). The conditional probability to demonstrate superiority of either technique was 0·13; patient accrual was therefore stopped early for futility. 20 (63%) of 32 patients in the SABR group versus 19 (59%) of 32 patients in the irreversible electroporation group had adverse events (p=0·8) and five (16%) patients in the SABR group versus eight (25%) in the irreversible electroporation group had grade 3-5 adverse events (p=0·35). The most common grade 3-4 adverse events were cholangitis (two [6%] in the SABR group vs one [3%] in the irreversible electroporation group), abdominal pain (one [3%] vs two [6%]), and pancreatitis (none vs two [6%]). One (3%) patient in the SABR group and one (3%) in the irreversible electroporation group died from a treatment-related adverse event.

INTERPRETATION

CROSSFIRE did not identify a difference in overall survival or incidence of adverse events between MRI-guided SABR and CT-guided percutaneous irreversible electroporation after FOLFIRINOX. Future studies should further assess the added value of local ablative treatment over chemotherapy alone.

FUNDING

Adessium Foundation, AngioDynamics.

Irreversible electroporation promotes a pro-inflammatory tumor microenvironment and anti-tumor immunity in a mouse pancreatic cancer model

Pancreatic cancer is a significant cause of cancer-related mortality and often presents with limited treatment options. Pancreatic tumors are also notorious for their immunosuppressive microenvironment. Irreversible electroporation (IRE) is a non-thermal tumor ablation modality that employs high-voltage microsecond pulses to transiently permeabilize cell membranes, ultimately inducing cell death. However, the understanding of IRE's impact beyond the initiation of focal cell death in tumor tissue remains limited. In this study, we demonstrate that IRE triggers a unique mix of cell death pathways and orchestrates a shift in the local tumor microenvironment driven, in part, by reducing the myeloid-derived suppressor cell (MDSC) and regulatory T cell populations and increasing cytotoxic T lymphocytes and neutrophils. We further show that IRE drives induce cell cycle arrest at the G0/G1 phase in vitro and promote inflammatory cell death pathways consistent with pyroptosis and programmed necrosis in vivo. IRE-treated mice exhibited a substantial extension in progression-free survival. However, within a span of 14 days, the tumor immune cell populations reverted to their pre-treatment composition, which resulted in an attenuation of the systemic immune response targeting contralateral tumors and ultimately resulting in tumor regrowth. Mechanistically, we show that IRE augments IFN- γ signaling, resulting in the up-regulation of the PD-L1 checkpoint in pancreatic cancer cells. Together, these findings shed light on potential mechanisms of tumor regrowth following IRE treatment and offer insights into co-therapeutic targets to improve treatment strategies.

Irreversible Electroporation-Induced Inflammation Facilitates Neutrophil-Mediated Drug Delivery to Enhance Pancreatic Cancer Therapy

Pancreatic cancer is a deadly disease with a five-year overall survival rate of around 11%. Chemotherapy is a cornerstone in the treatment of this malignancy, but the intratumoral delivery of chemotherapy drugs is impaired by the highly fibrotic tumor-associated stroma. Irreversible electroporation (IRE) is an ablative technique for treating locally advanced pancreatic cancer. During a typical IRE procedure, high-intensity electric pulses are released to kill tumor cells through the irreversible disruption of the cytoplasm membranes. IRE also induces rapid tumor infiltration by neutrophils and offers an opportunity for neutrophil-mediated drug delivery. We herein showed that the IRE-induced neutrophil trafficking was facilitated by the upregulation of neutrophil chemotaxis and migration as well as the release of several chemoattractants. Doxorubicin-loaded bovine serum albumin nanoparticles were prepared and loaded into neutrophils at a ratio of 9.9 ± 1.2 to 11.7 ± 2.0 pg of doxorubicin per cell. The resultant formulation (NP@NEs) efficiently accumulated in the IRE-treated KPC-A377 murine pancreatic tumors with an uptake value of 10.7 ± 1.5 (percent of injected dose per gram of tissue, abbreviated as %ID/g) at 48 h after intravenous injection. In both Panc02 and KPC-A377 murine pancreatic tumor models, the combination of IRE + NP@NEs inhibited tumor growth more effectively than either monotherapy. The tumors treated with the combination also exhibited the lowest frequency of Ki67+ proliferating cells and the highest abundance of terminal deoxynucleotidyl transferase dUTP nick end labeling+ (TUNEL+) apoptotic cells among the experiment groups. Minimal treatment-associated toxicity was observed. Our findings suggest that neutrophil-mediated delivery of chemotherapy drugs is a useful tool to enhance the response of pancreatic cancer to IRE.

Optimal Irreversible Electroporation Combined with Nano-Enabled Immunomodulatory to Boost Systemic Antitumor Immunity

In this work, we proposed nµPEF, a novel pulse configuration combining nanosecond and microsecond pulses (nµPEF), to enhance tumor ablation in irreversible electroporation (IRE) for oncological therapy. nµPEF demonstrated improved efficacy in inducing immunogenic cell death, positioning it as a potential candidate for next-generation ablative therapy. However, the immune response elicited by nµPEF alone was insufficient to effectively suppress distant tumors. To address this limitation, we developed PPR@CM-PD1, a genetically engineered nanovesicle. PPR@CM-PD1 employed a polyethylene glycol-polylactic acid-glycolic acid (PEG-PLGA) nanoparticle encapsulating the immune adjuvant imiquimod and coated with a genetically engineered cell membrane expressing programmed cell death protein 1 (PD1). This design allowed PPR@CM-PD1 to target both the innate immune system through toll-like receptor 7 (TLR7) agonism and the adaptive immune system through programmed cell death protein 1/programmed cell death-ligand 1 (PD1/PDL1) checkpoint blockade. In turn, nµPEF facilitated intratumoral infiltration of PPR@CM-PD1 by modulating the tumor stroma. The combination of nµPEF and PPR@CM-PD1 generated a potent and systemic antitumor immune response, resulting in remarkable suppression of both nµPEF-treated and untreated distant tumors (abscopal effects). This interdisciplinary approach presents a promising perspective for oncotherapy and holds great potential for future clinical applications.

Pulsed Electric Field Ablation versus Radiofrequency Thermal Ablation in Murine Breast Cancer Models: Anticancer Immune Stimulation, Tumor Response, and Abscopal Effects

PURPOSE

To compare the immune response and survival after size-matched radiofrequency (RF) ablation and a proprietary form of pulsed electric field (PEF) ablation in murine tumors.

MATERIAL AND METHODS

Orthotopically inoculated EMT6 or 4T1 murine tumors received sham, RF ablation, or PEF ablation. 4T1 tumor ablations included subgroups with intraperitoneal checkpoint inhibition immunotherapy (αPD-1). Blood was collected for cytokine profiling and flow cytometry. Tumor size was measured and survival was monitored. Tumor samples were processed for histology, immunohistochemistry, flow cytometry, and cytokine profiling. Lungs were collected from 4T1-bearing mice for hematoxylin and eosin histology to assess metastatic spread and abscopal effect induced by ablation.

RESULTS

PEF elicited distinct immunomodulatory effects, with clear differences in serum and tumor cytokine profiles compared with RF ablation, including intratumoral downregulation of vascular endothelial growth factor, hypoxia-inducible factor 1α, c-MET, interleukin-10, Ki67, and tumor necrosis factor-α (all P < .05). PEF increased innate immune activation, with enhanced recruitment of dendritic cells, M1 macrophages, and natural killer cells coupled with a reduction in M2 macrophages and myeloid-derived suppressor cells (all P < .05). Concurrently, PEF strengthened adaptive immunity compared with RF ablation, characterized by increased antigen-specific T cells and decreased regulatory T cells (all P < .05). PEF stalled tumor growth and increased survival at the end of the study (≥4× versus RFA). Finally, PEF promoted an abscopal effect of clearing metastases in the lungs, which was stronger in combination with αPD-1 than with PEF alone.

CONCLUSIONS

The proprietary form of PEF used in this study evoked a preferential immunostimulatory profile versus RF ablation thermal ablation in mice, with implications for enhancing the therapeutic effectiveness of checkpoint inhibition immunotherapy for immunotherapy-unresponsive tumors.

Successful immunotherapy with PD-1 Iinhibitor for advanced pancreatic cancer: report of two cases and review of literature

Pancreatic cancer is a highly malignant tumor, and most patients are diagnosed at an advanced stage. Unfortunately, due to the immunosuppressive tumor microenvironment of pancreatic cancer, the benefits of immunotherapy for patients with advanced pancreatic cancer are still unclear. Here, we present two cases of advanced pancreatic cancer being controlled by immunotherapy, with pathological diagnoses of ductal adenocarcinoma and acinar cell carcinoma, respectively. Next-generation sequencing (NGS) of both patients is high tumor mutation burden (tumor mutation burden-High) and microsatellite stable. The patient with pancreatic ductal adenocarcinoma was diagnosed as a locally advanced disease (stage III). She received irreversible electroporation, used the programmed death receptor-1 (PD-1) inhibitor (pembrolizumab) combined with chemotherapy (S-1), and then used only the PD-1 inhibitor as a maintenance treatment. As a result, the patient's lesion was significantly reduced, with a partial response time of up to 31 months. The patient with acinar cell carcinoma was diagnosed as a metastatic disease (stage IV), next-generation sequencing revealed mutations in SMAD4 and KMT2D, and two chemotherapy regimens were used unsuccessfully. Then, the combination of chemotherapy with PD-1 (tislelizumab) and vascular endothelial growth factor/vascular endothelial growth factor receptor (anlotinib) inhibitors were used, and the lesions of the patient were significantly reduced, and the progression-free survival after immunotherapy was 19 months. In advanced pancreatic cancer, a prognosis of this magnitude is rare. Our cases reveal the potential of immunotherapy as a cornerstone treatment in the management of advanced pancreatic cancer.

Potent induction of antitumor immunity by combining cryo-thermal ablation with immune checkpoint inhibitors in hepatocellular carcinoma

BACKGROUND

The low response rate of immune checkpoint inhibitors (ICIs) prompts the exploration of novel combination therapies for patients with hepatocellular carcinoma (HCC). Here, we aimed to examine the efficiency and potential mechanism of cryo-thermal ablation (Cryo-A) combined with anti-programmed death protein 1 (αPD1) and/or cytotoxic T-lymphocyte antigen 4 (αCTLA4) inhibitors in a murine hepatoma model.

METHOD

Immunocompetent C57BL/6 mice inoculated with unilateral or bilateral H22 hepatic tumour cells were treated with Cryo-A and/or ICIs (αPD1 and/or αCTLA4). Flow cytometry, immunohistochemistry, ELISpot assay, time-of-flight cytometry, tumour rechallenging, and T-cell depletion assay were used to assess the dynamic changes of immune cell subsets following therapy.

RESULTS

We found Cryo-A resulted in immunogenic cell death of tumour cells, activation of dendritic cells, and enhancement of antitumor immunity. Cryo-A alone was insufficient to extend survival, combining Cryo-A with αPD1 and αCTLA4 further modulated the tumour microenvironment, inducing a durable antitumor immune response by tumour-reactive CD8+ T cells and significantly prolonged survival. Time-of-flight cytometry (CyTOF) data revealed that combination therapies reshaped the tumour microenvironment by the increase of intratumoral CD8+ T cells expressed higher levels of cytotoxic markers and immune checkpoint molecules, and by downregulation of intratumoral granulocytes. The combination also resulted in the eradication of remote unablated tumours (abscopal effect).

CONCLUSIONS

These findings suggested that Cryo-A turned HCC from "cold" tumours to "hot" tumours and the combination of Cryo-A with αPD1 and αCTLA4 may be a promising approach to improve the prognosis of HCC.

Threatment Strategies for Recurrent Hepatocellular Carcinoma Patients: Ablation and its Combination Patterns

With the development of guidance technology and ablation equipment, ablative procedures have emerged as important loco-regional alternatives to surgical resection for recurrent hepatocellular carcinoma (rHCC) patients. Currently, ablation modalities used in clinical practice mainly include radiofrequency ablation (RFA), microwave ablation (MWA), laser ablation (LA), cryoablation (CRA), high-intensity focused ultrasound (HIFU), and irreversible electroporation (IRE). Accumulated comparative data of ablation versus surgical resection reveal noninferior responses and outcomes but superior adverse effects. Moreover, studies demonstrate that ablation may serve as an excellent procedure for rHCC given its exact minimal invasiveness and immune modulation. We focus on the current status of ablation in clinical practice for rHCC and discuss new research in the field, including ablation combined with these other modalities, such as targeted therapy and immunotherapy.

Irreversible Electroporation of the Hepatobiliary System: Current Utilization and Future Avenues

Liver cancer remains a leading cause of cancer-related deaths worldwide despite numerous advances in treatment. While surgical resection remains the gold standard for curative treatment, it is only possible for a minority of patients. Thermal ablation is an effective option for the treatment of smaller tumors; however, its use is limited to tumors that are not located in proximity to sensitive structures due to the heat sink effect and the potential of thermal damage. Irreversible electroporation (IRE) is a non-thermal ablative modality that can deliver targeted treatment and the effective destruction of tumors that are in close proximity to or even surrounding vascular or biliary ducts with minimal damage to these structures. IRE produces short pulses of high-frequency energy which opens pores in the lipid bilayer of cells leading to apoptosis and cell death. IRE has been utilized clinically for over a decade in the treatment of liver cancers with multiple studies documenting an acceptable safety profile and high efficacy rates.

Investigation of integrated time nanosecond pulse irreversible electroporation against spontaneous equine melanoma

Introduction

Integrated time nanosecond pulse irreversible electroporation (INSPIRE) is a novel tumor ablation modality that employs high voltage, alternating polarity waveforms to induce cell death in a well-defined volume while sparing the underlying tissue. This study aimed to demonstrate the in vivo efficacy of INSPIRE against spontaneous melanoma in standing, awake horses.

Methods

A custom applicator and a pulse generation system were utilized in a pilot study to treat horses presenting with spontaneous melanoma. INSPIRE treatments were administered to 32 tumors across 6 horses and an additional 13 tumors were followed to act as untreated controls. Tumors were tracked over a 43-85 day period following a single INSPIRE treatment. Pulse widths of 500ns and 2000ns with voltages between 1000 V and 2000 V were investigated to determine the effect of these variables on treatment outcomes.

Results

Treatments administered at the lowest voltage (1000 V) reduced tumor volumes by 11 to 15%. Higher voltage (2000 V) treatments reduced tumor volumes by 84 to 88% and eliminated 33% and 80% of tumors when 500 ns and 2000 ns pulses were administered, respectively.

Discussion

Promising results were achieved without the use of chemotherapeutics, the use of general anesthesia, or the need for surgical resection in regions which are challenging to keep sterile. This novel therapeutic approach has the potential to expand the role of pulsed electric fields in veterinary patients, especially when general anesthesia is contraindicated, and warrants future studies to demonstrate the efficacy of INSPIRE as a solid tumor treatment.

Inflammasome Activation and IL-1β Release Triggered by Nanosecond Pulsed Electric Fields in Murine Innate Immune Cells and Skin

Although electric field-induced cell membrane permeabilization (electroporation) is used in a wide range of clinical applications from cancer therapy to cardiac ablation, the cellular- and molecular-level details of the processes that determine the success or failure of these treatments are poorly understood. Nanosecond pulsed electric field (nsPEF)-based tumor therapies are known to have an immune component, but whether and how immune cells sense the electroporative damage and respond to it have not been demonstrated. Damage- and pathogen-associated stresses drive inflammation via activation of cytosolic multiprotein platforms known as inflammasomes. The assembly of inflammasome complexes triggers caspase-1-dependent secretion of IL-1β and in many settings a form of cell death called pyroptosis. In this study we tested the hypothesis that the nsPEF damage is sensed intracellularly by the NLRP3 inflammasome. We found that 200-ns PEFs induced aggregation of the inflammasome adaptor protein ASC, activation of caspase-1, and triggered IL-1β release in multiple innate immune cell types (J774A.1 macrophages, bone marrow-derived macrophages, and dendritic cells) and in vivo in mouse skin. Efflux of potassium from the permeabilized cell plasma membrane was partially responsible for nsPEF-induced inflammasome activation. Based on results from experiments using both the NRLP3-specific inhibitor MCC950 and NLRP3 knockout cells, we propose that the damage created by nsPEFs generates a set of stimuli for the inflammasome and that more than one sensor can drive IL-1β release in response to electrical pulse stimulation. This study shows, to our knowledge, for the first time, that PEFs activate the inflammasome, suggesting that this pathway alarms the immune system after treatment.

Local ablative therapies and the effect on antitumor immune responses in pancreatic cancer - A review

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease, projected to rank as the second most prevalent cause of cancer-related mortality by 2030. Despite significant progress in advances in surgical techniques and chemotherapy protocols, the overall survival (OS) remains to be less than 10 % for all stages combined. In recent years, local ablative techniques have been introduced and utilized as additional therapeutic approaches for locally advanced pancreatic cancer (LAPC), with promising results with respect to local tumor control and OS. In addition to successful cytoreduction, there is emerging evidence that local ablation induces antitumor immune activity that could prevent or even treat distant metastatic tumors. The enhancement of antitumor immune responses could potentially make ablative therapy a therapeutic option for the treatment of metastatic PDAC. In this review, we summarize current ablative techniques used in the management of LAPC and their impact on systemic immune responses.

Irreversible electroporation: Beyond the limits of tumor ablation

Irreversible Electroporation (IRE) is a non-thermal tumor ablation technique. High-voltage electrical pulses are applied between pairs of electrodes inserted around and/or inside a tumor. The generated electric current induces the creation of nanopores in the cell membrane, triggering apoptosis. As a result, IRE can be safely used in areas near delicate vascular structures where other thermal ablation methods are contraindicated. Currently, IRE has demonstrated to be a successful ablation technique for pancreatic, renal, and liver tumors and is widely used as a focal therapeutic option for prostate cancer. The need for specific anesthetic management and accurate parallel placement of multiple electrodes entails a high level of complexity and great expertise from the interventional team is required. Nevertheless, IRE is a very promising technique with a remarkable systemic immunological capability and may impact on distant metastases (abscopal effect).

Amplifying T cell-mediated antitumor immune responses in nonsmall cell lung cancer through photodynamic therapy and anti-PD1

Photodynamic therapy (PDT) is nowadays widely employed in cancer treatment. We sought to assess the efficacy of combining PDT with anti-programmed cell death protein 1 (PD1) and to investigate the associated mechanisms in nonsmall cell lung cancer (NSCLC). We established a xenograft tumor model in C57BL/6J mice using Lewis lung carcinoma (LLC) cells, recorded tumor growth, and quantified reactive oxygen species (ROS) levels using a ROS detection kit. Pathological changes were assessed through H&E staining, while immunofluorescence (IF) was used to determine the expression of CD8 and Foxp3. Transcriptomic analysis was conducted, analyzing differential expressed genes (DEGs) among control, PDT, and PDT combined with anti-PD1 (PDT+anti-PD1) groups. Functional enrichment analysis via Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) was performed. The Cancer Genome Atlas (TCGA) database was utilized to analyze the expression of aminolevulinate synthase gene (ALAS2), integrin alpha10 (ITGA10), ATP1A2, a disintegrin and metalloprotease 12 (ADAM12), and Lox1 in lung adenocarcinoma and adjacent tissues, with concurrent immune infiltration analysis. Quantitative real-time polymerase chain reaction and western blot were employed to measure mRNA and protein expression levels. Treatment with PDT combined with anti-PD1 significantly inhibited tumor growth and increased the number of CD8+ cells while decreasing Foxp3+ cells. Immune infiltration results presented ALAS2, ADAM12, and ITGA10 were associated with various types of T cells or macrophages. Additionally, the expression levels of EGFR, ERK, and PI3K/Akt were suppressed after PDT with anti-PD1 treatment. Our findings collectively suggest that PDT combined with anti-PD1 treatment could enhance the infiltration of CD8+ T cells, suppressing tumor growth, and this effect was associated with ALAS2, ITGA10, and ADAM12. The underlying mechanism might be linked to EGFR, ERK, and PI3K/Akt signaling. Overall, this study provides valuable insights into the application of PDT combined with anti-PD1 treatment in NSCLC.

Scheduled dosage regimen by irreversible electroporation of loaded erythrocytes for cancer treatment

Precise control of cargo release is essential but still a great challenge for any drug delivery system. Irreversible electroporation (IRE), utilizing short high-voltage pulsed electric fields to destabilize the biological membrane, has been recently approved as a non-thermal technique for tumor ablation without destroying the integrity of adjacent collagenous structures. Due to the electro-permeating membrane ability, IRE might also have great potential to realize the controlled drug release in response to various input IRE parameters, which were tested in a red blood cell (RBC) model in this work. According to the mathematical simulation model of a round biconcave disc-like cell based on RBC shape and dielectric characteristics, the permeability and the pore density of the RBC membrane were found to quantitatively depend on the pulse parameters. To further provide solid experimental evidence, indocyanine green (ICG) and doxorubicin (DOX) were both loaded inside RBCs (RBC@DOX&ICG) and the drug release rates were found to be tailorable by microsecond pulsed electric field (μsPEF). In addition, μsPEF could effectively modulate the tumor stroma to augment therapy efficacy by increasing micro-vessel density and permeability, softening extracellular matrix, and alleviating tumor hypoxia. Benefiting from these advantages, this IRE-responsive RBC@DOX&ICG achieved a remarkably synergistic anti-cancer effect by the combination of μsPEF and chemotherapy in the tumor-bearing mice model, with the survival time increasing above 90 days without tumor burden. Given that IRE is easily adaptable to different plasma membrane-based vehicles for delivering diverse drugs, this approach could offer a general applicability for cancer treatment.

Present and future of metal nanoparticles in tumor ablation therapy

Cancer is an important factor affecting the quality of human life as well as causing death. Tumor ablation therapy is a minimally invasive local treatment modality with unique advantages in treating tumors that are difficult to remove surgically. However, due to its physical and chemical characteristics and the limitation of equipment technology, ablation therapy cannot completely kill all tumor tissues and cells at one time; moreover, it inevitably damages some normal tissues in the surrounding area during the ablation process. Therefore, this technology cannot be the first-line treatment for tumors at present. Metal nanoparticles themselves have good thermal and electrical conductivity and unique optical and magnetic properties. The combination of metal nanoparticles with tumor ablation technology, on the one hand, can enhance the killing and inhibiting effect of ablation technology on tumors by expanding the ablation range; on the other hand, the ablation technology changes the physicochemical microenvironment such as temperature, electric field, optics, oxygen content and pH in tumor tissues. It helps to stimulate the degree of local drug release of nanoparticles and increase the local content of anti-tumor drugs, thus forming a synergistic therapeutic effect with tumor ablation. Recent studies have found that some specific ablation methods will stimulate the body's immune response while physically killing tumor tissues, generating a large number of immune cells to cause secondary killing of tumor tissues and cells, and with the assistance of metal nanoparticles loaded with immune drugs, the effect of this anti-tumor immunotherapy can be further enhanced. Therefore, the combination of metal nanoparticles and ablative therapy has broad research potential. This review covers common metallic nanoparticles used for ablative therapy and discusses in detail their characteristics, mechanisms of action, potential challenges, and prospects in the field of ablation.

The Role of Immune Checkpoint Inhibitors in Metastatic Pancreatic Cancer: Current State and Outlook

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest tumors, characterized by its aggressive tumor biology and poor prognosis. While immune checkpoint inhibitors (ICIs) play a major part in the treatment algorithm of various solid tumors, there is still no evidence of clinical benefit from ICI in patients with metastatic PDAC (mPDAC). This might be due to several reasons, such as the inherent low immunogenicity of pancreatic cancer, the dense stroma-rich tumor microenvironment that precludes an efficient migration of antitumoral effector T cells to the cancer cells, and the increased proportion of immunosuppressive immune cells, such as regulatory T cells (Tregs), cancer-associated fibroblasts (CAFs), and myeloid-derived suppressor cells (MDSCs), facilitating tumor growth and invasion. In this review, we provide an overview of the current state of ICIs in mPDAC, report on the biological rationale to implement ICIs into the treatment strategy of pancreatic cancer, and discuss preclinical studies and clinical trials in this field. Additionally, we shed light on the challenges of implementing ICIs into the treatment strategy of PDAC and discuss potential future directions.