Antitumor Effect and Immune Response of Nanosecond Pulsed Electric Fields in Pancreatic Cancer

Nanosecond pulsed electric field ablation-induced modulation of sphingolipid metabolism is associated with Ly6c2+ mononuclear phagocyte differentiation in liver cancer

Preclinical studies have proven that nanosecond pulsed electric field (nsPEF) ablation can be a safe and effective treatment for humans with unresectable liver cancer that are ineligible for thermal ablation. The concomitant activation of antitumor immunity by nsPEF can also potentially prevent tumor recurrence. However, whether nsPEF exhibits similar efficacy in a clinical setting remains to be investigated. A prospective clinical trial (clinicaltrials.gov identifier: NCT04039747) was conducted to evaluate the safety and efficacy of ultrasound (US)-guided nsPEF ablation in 15 patients with unresectable liver cancer that were ineligible for thermal ablation. We found that nsPEF ablation was safe and produced a 12-month recurrence-free survival (RFS) and local RFS of 60% (9/15) and 86.7% (13/15), respectively, in the enrolled patients. Integrative proteomic and metabolomic analysis showed that sphingolipid metabolism was the most significantly enriched pathway in patient sera after nsPEF without recurrence within 8 months. A similar upregulation of sphingolipid metabolism was observed in the intratumoral mononuclear phagocytes (MNPs), rather than other immune and nonimmune cells, of an nsPEF-treated mouse model. We then demonstrated that lymphocyte antigen 6 complex, locus C2-positive (Ly6c2⁺ ) monocytes first differentiated into Ly6c2⁺ monocyte-derived macrophages with an increase in sphingolipid metabolic activity, and subsequently into Ly6c2⁺ dendritic cells (DCs). Ly6c2⁺ DCs communicated with CD8⁺ T cells and increased the proportions of IFN-γ⁺  CD8⁺ memory T cells after nsPEF, and this finding was subsequently confirmed by depletion of liver Ly6c2⁺ MNPs. In conclusion, nsPEF was a safe and effective treatment for liver cancer. The alteration of sphingolipid metabolism induced by nsPEF was associated with the differentiation of Ly6c2⁺ MNPs, and subsequently induced the formation of memory CD8⁺ T cells with potent antitumor effect.

High-Frequency Nanosecond Bleomycin Electrochemotherapy and its Effects on Changes in the Immune System and Survival

In this work, a time-dependent and time-independent study on bleomycin-based high-frequency nsECT (3.5 kV/cm × 200 pulses) for the elimination of LLC1 tumours in C57BL/6J mice is performed. We show the efficiency of nsECT (200 ns and 700 ns delivered at 1 kHz and 1 MHz) for the elimination of tumours in mice and increase of their survival. The dynamics of the immunomodulatory effects were observed after electrochemotherapy by investigating immune cell populations and antitumour antibodies at different timepoints after the treatment. ECT treatment resulted in an increased percentage of CD4⁺ T, splenic memory B and tumour-associated dendritic cell subsets. Moreover, increased levels of antitumour IgG antibodies after ECT treatment were detected. Based on the time-dependent study results, nsECT treatment upregulated PD 1 expression on splenic CD4⁺ Tr1 cells, increased the expansion of splenic CD8⁺ T, CD4⁺CD8⁺ T, plasma cells and the proportion of tumour-associated pro inflammatory macrophages. The Lin^- population of immune cells that was increased in the spleens and tumour after nsECT was identified. It was shown that nsECT prolonged survival of the treated mice and induced significant changes in the immune system, which shows a promising alliance of nanosecond electrochemotherapy and immunotherapy.

Neutrophil membrane-coated nanoparticles for enhanced nanosecond pulsed electric field treatment of pancreatic cancer

OBJECTIVE

Pancreatic cancer is one of the leading causes of cancer-related deaths worldwide. Poor prognosis and low survival rates have driven the development of novel therapeutic strategies. Nanosecond pulsed electric field has emerged as a novel, minimal invasive and non-thermal treatment for solid tumors. It is of great significance to study the combination therapy of nsPEF and other treatment strategies for pancreatic cancer.

METHODS

We developed neutrophil membrane-wrapped liposomal nanoparticles loaded with gemcitabine (NE/Lip-GEM) and investigated their use as a complementary agent for nsPEF treatment.

RESULTS

Our results showed that neutrophil-mediated delivery of liposomal-gemcitabine (NE/Lip-GEM) efficiently inhibited the growth of pancreatic tumors in mice whose has been treated with incomplete nsPEF ablation.

CONCLUSIONS

The combination of nsPEF and NE/Lip-GEM may be a promising synergistic strategy for pancreatic cancer therapy.

Liquid Biopsy and the Translational Bridge from the TIME to the Clinic

Research and advancing understanding of the tumor immune microenvironment (TIME) is vital to optimize and direct more effective cancer immune therapy. Pre-clinical bench research is vital to better understand the genomic interplay of the TIME and immune therapy responsiveness. However, a vital key to effective translational cancer research is having a bridge of translation to bring that understanding from the bench to the bedside. Without that bridge, research into the TIME will lack an efficient and effective translation into the clinic and cancer treatment decision making. As a clinical oncologist, the purpose of this commentary is to emphasize the importance of researching and improving clinical utility of the bridge, as well as the TIME research itself.

Effect of pulsed field ablation on solid tumor cells and microenvironment

Pulsed field ablation can increase membrane permeability and is an emerging non-thermal ablation. While ablating tumor tissues, electrical pulses not only act on the membrane structure of cells to cause irreversible electroporation, but also convert tumors into an immune active state, increase the permeability of microvessels, inhibit the proliferation of pathological blood vessels, and soften the extracellular matrix thereby inhibiting infiltrative tumor growth. Electrical pulses can alter the tumor microenvironment, making the inhibitory effect on the tumor not limited to short-term killing, but mobilizing the collective immune system to inhibit tumor growth and invasion together.

The Safety and Efficacy of Nanosecond Pulsed Electric Field in Patients With Hepatocellular Carcinoma: A Prospective Phase 1 Clinical Study Protocol

Background

Hepatocellular carcinoma (HCC) is a highly aggressive malignancy. Irreversible electroporation (IRE) is an ablative modality that uses high-voltage electrical pulses to permeabilize the cell membrane leading to cell necrosis. Unlike traditional thermal ablation, IRE is hardly affected by the “heat-sink” effect and can prevent damage of the adjacent vital structures. Nanosecond pulsed electric field (nsPEF) is a new IRE technique using ultra-short pulses (nanosecond duration), can not only penetrate the cell membranes, but also act on the organelles. Sufficient preclinical researches have shown that nsPEF can eliminate HCC without damaging vital organs, and elicit potent anti-tumor immune response.

Objective

This is the first clinical study to evaluate feasibility, efficacy, and safety of nsPEF for the treatment of HCC, where thermal ablation is unsuitable due to proximity to critical structures.

Methods and analysis

We will conduct an open-labeled, single-arm, prospective, multicenter, and objective performance criteria trial. One hundred and ninety-two patients with HCC, in which the tumor is located immediately (<0.5 cm) adjacent to the portal vein, hepatic veins, bile duct, gastrointestinal tract, or diaphragm, will be enrolled among 4 academic medical centers. The primary outcomes are the rate of complete ablation at 1 month and adverse events. Secondary outcomes include technical success, technique efficacy, nsPEF procedural characteristics, local tumor progression, and local progression-free survival.

Ethics and dissemination

The trial will be conducted according to the ethical principles of the Declaration of Helsinki and has been approved by the ethics committee of all participating centers. The results of this study will be published in peer-reviewed scientific journals and presented at relevant academic conferences.

Conclusions

This study is the Phase 1 clinical trial to evaluate the efficacy and safety of nsPEF in patients with HCC at high-risk locations where thermal ablation is contra-indicated. The results may expand the options and offer an alternative therapy for HCC.

Clinical Trial Registration

ClinicalTrials.gov, identifier NCT04309747.

The Synergistic Role of Irreversible Electroporation and Chemotherapy for Locally Advanced Pancreatic Cancer

Irreversible electroporation (IRE) is a local ablative technique used in conjunction with chemotherapy to treat locally advanced pancreatic cancer (LAPC). The combination of IRE and chemotherapy has showed increased overall survival when compared to chemotherapy alone, pointing towards a possible facilitating effect of IRE on chemotherapeutic drug action and delivery. This review aims to present current chemotherapeutic regimens for LAPC and their co-implementation with IRE, with an emphasis on possible molecular augmentative mechanisms of drug delivery and action. Moreover, the potentiating mechanism of IRE on immunotherapy, M1 oncolytic virus and dendritic cell (DC)-based treatments is briefly explored. Investigating the synergistic effect of IRE on currently established treatment regimens as well as newer ones, may present exciting new possibilities for future studies seeking to improve current LAPC treatment algorithms.

Electroporation and Immunotherapy-Unleashing the Abscopal Effect

Simple Summary

Electrochemotherapy and irreversible electroporation are primarily used for treating patients with cutaneous and subcutaneous tumors and pancreatic cancer, respectively. Increasing numbers of studies have shown that the treatments may elicit an immune response in addition to eliminating the tumor cells. The purpose of this review is to give an in-depth introduction to the electroporation-induced immune response and the local and peripheral immune systems, and to describe the various studies investigating the combination of electroporation and immunotherapy. The review may help guide and inspire the design of future clinical trials investigating the potential synergy of electroporation and immunotherapy in cancer treatment.

Abstract

The discovery of electroporation in 1968 has led to the development of electrochemotherapy (ECT) and irreversible electroporation (IRE). ECT and IRE have been established as treatments of cutaneous and subcutaneous tumors and locally advanced pancreatic cancer, respectively. Interestingly, the treatment modalities have been shown to elicit immunogenic cell death, which in turn can induce an immune response towards the tumor cells. With the dawn of the immunotherapy era, the potential of combining ECT and IRE with immunotherapy has led to the launch of numerous studies. Data from the first clinical trials are promising, and new combination regimes might change the way we treat tumors characterized by low immunogenicity and high levels of immunosuppression, such as melanoma and pancreatic cancer. In this review we will give an introduction to ECT and IRE and discuss the impact on the immune system. Additionally, we will present the results of clinical and preclinical trials, investigating the combination of electroporation modalities and immunotherapy.

Exploration of Novel Pathways Underlying Irreversible Electroporation Induced Anti-Tumor Immunity in Pancreatic Cancer

Advancements in medical sciences and technologies have significantly improved the survival of many cancers; however, pancreatic cancer remains a deadly diagnosis. This malignancy is often diagnosed late in the disease when metastases have already occurred. Additionally, the location of the pancreas near vital organs limits surgical candidacy, the tumor's immunosuppressive environment limits immunotherapy success, and it is highly resistant to radiation and chemotherapy. Hence, clinicians and patients alike need a treatment paradigm that reduces primary tumor burden, activates systemic anti-tumor immunity, and reverses the local immunosuppressive microenvironment to eventually clear distant metastases. Irreversible electroporation (IRE), a novel non-thermal tumor ablation technique, applies high-voltage ultra-short pulses to permeabilize targeted cell membranes and induce cell death. Progression with IRE technology and an array of research studies have shown that beyond tumor debulking, IRE can induce anti-tumor immune responses possibly through tumor neo-antigen release. However, the success of IRE treatment (i.e. full ablation and tumor recurrence) is variable. We believe that IRE treatment induces IFNγ expression, which then modulates immune checkpoint molecules and thus leads to tumor recurrence. This indicates a co-therapeutic use of IRE and immune checkpoint inhibitors as a promising treatment for pancreatic cancer patients. Here, we review the well-defined and speculated pathways involved in the immunostimulatory effects of IRE treatment for pancreatic cancer, as well as the regulatory pathways that may negate these anti-tumor responses. By defining these underlying mechanisms, future studies may identify improvements to systemic immune system engagement following local tumor ablation with IRE and beyond.

The investigation of Pulse-Modulated GSM-900 MHz electromagnetic field effects on the electrochemotherapy mechanisms in vivo

Electrochemotherapy (ECT) as a tumor treatment modality is approved for cutaneous and subcutaneous tumors. The purpose of the present study was to examine the effect of 900 MHz radiofrequency (RF) pulse-modulated by 217 Hz EMFs similar to those emitted by mobile phones on the mechanisms of ECT in vivo including: tumor hypoxia and immune system response, and on tumor volume.4 T1 cells were injected subcutaneously into the right flank of Balb/c mice. The mice were exposed to RF fields at specific absorption rate (SAR) 2 W/kg for 10 min/day and then treated with ECT. Two protocols of ECT were used: ((70 V/cm-5 kHz) and 70 V/cm-4 kHz)). Tumor hypoxia was analyzed through HIF-1α immuonohistochemistry assay. Interleukin 4 (IL-4) and IFN-γ levels were estimated by enzyme-linked immunosorbent assay (ELISA) technique to evaluate immune system response. Also, tumors volume changes were measured for 24 days following the treatment. The results showed that pulse-modulated RF fields could increase hypoxia induced by ECT, significantly (about 13% in ECT (70 V/cm-5 kHz) and 11% in ECT (70 V/cm-4 kHz)). However, these fields did not have significant effect on immune system response (the levels of IL-4 and IFN-γ) and tumor volume changes induced by ECT. Our results indicated that pulse-modulated RF fields could not affect tumor volume changes in ECT with the frequency of 5 kHz and voltage of 70 V/cm efficacy in vivo. However, investigating the role of other environmental intervening factors on this protocol of ECT is recommended in further studies.

Immunomodulatory Effect of Irreversible Electroporation Alone and Its Cooperating With Immunotherapy in Pancreatic Cancer

Emerging studies have showed irreversible electroporation (IRE) focused on pancreatic cancer (PC). However, the effects of IRE treatment on the immune response of PC remain unknown. Moreover, there are few studies on the therapeutic effect of IRE combining with immunotherapy on PC. Thus, we review recent advances in our understanding of IRE alone and its working with immunotherapy towards the immune response of PC, discussing potential opportunities for exploring future treatment strategies.