Nanosecond Pulsed Electric Fields Enhance the Anti-tumour Effects of the mTOR Inhibitor Everolimus against Melanoma

Numerical Simulation of Thermal Therapy for Melanoma in Mice

In recent years, the progressively escalating incidence and exceptionally high fatality rate of cutaneous melanoma have drawn the attention of numerous scholars. Magnetic induction hyperthermia, as an efficacious tumor treatment modality, has been promoted and applied in the therapy of some tumors. In this paper, the melanoma atop the mice's heads was chosen as the research subject, and a magnetic induction hyperthermia approach based on Helmholtz coils as the magnetic field excitation was investigated and designed. The influence of the electromagnetic field and thermal field on organisms was addressed through modeling by COMSOL simulation software. The results showed that the maximum values of induced electric field and magnetic induction strength in mouse tumor tissues were 63.1 V/m and 8.5621 mT, respectively, which reached the threshold value of magnetic field strength required for magnetic induction hyperthermia. The maxima of the induced electric field and magnetic induction intensity in brain tissues are, respectively, 35.828 V/m and 8.57 mT. Approximately 93% of the tumor tissue can reach 42 °C, and the maximum temperature is 44.2 °C. Within this temperature range, a large quantity of tumor cells can be successfully induced to undergo apoptosis without harming normal cells, and the therapeutic effect is favorable.

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.

Effects of Nanosecond Pulsed Electric Fields in Cell Vitality, Apoptosis, and Proliferation of TPC-1 Cells

Objective

To evaluate the effects of nanosecond pulsed electric fields (nsPEFs) with different pulse durations in cell vitality, apoptosis, and proliferation of TPC-1 cells, optimize pulse parameters and expand the application range of nsPEFs.

Methods

The pulse duration of 0, 300 ns, 500 ns, and 900 ns is generated with nsPEF generator. CCK-8 was used to investigate the effect of nsPEFs on the viability of TPC-1 cells. Flow cytometry was used to evaluate the apoptosis of TPC-1 after pulse treatment. The effect of nsPEFs on the proliferation ability of TPC-1 cells was detected by 5-ethy-nyl-2′-deoxyuridine. The morphological changes of TPC-1 cells after pulse treatment were observed by transmission electron microscopy.

Results

NsPEFs with 900 ns pulse duration can significantly affect the viability of TPC-1 cells and inhibit the proliferation ability of TPC-1 cells. In addition, nsPEFs can also induce apoptosis of TPC-1 cells.

Conclusion

NsPEFs with longer pulse duration can significantly affect the biological behavior of TPC-1 cells, such as cell viability and proliferation ability, and can also induce cell apoptosis, thereby inhibiting cell growth.

Incorporation of electroendocytosis and nanosecond pulsed electric field in electrochemotherapy of breast cancer cells

The study aimed to evaluate the possibility to perform electrochemotherapy using nanosecond pulsed electric field (nsPEF) and low electric field (LEF) monopolar electrical impulses to alleviate the problems of conventional electroporation. Two types of pulses have been used to treat MCF-7 human breast carcinoma cell line: very low voltage (electric field strength) long trains of short unipolar electric pulses, and low frequencies of extremely intense (40kV/cm), ultra-short (10ns) electric pulses. The electropermeabilization efficiency of the formed endocytotic vesicles was measured using the cloning efficacy test. The cell viability was decreased significantly at a repetition frequency begins from 0.01 Hz by ~35% and reached complete cell loss at 1 Hz of nanosecond pulses for cells treated before with monopolar pulses at 20 V/cm in the presence of BLM with 4 µM concentration. The uptake of non-permeant drugs has been done without plasma membrane permeabilization (classical electroporation), but by endocytosis. Nanosecond electric pulses can disrupt the membrane of endocytotic vesicles and release the cytotoxic drug bleomycin.

Nanosecond pulsed electric fields impair viability and mucin expression in mucinous colorectal carcinoma cell

Nanosecond pulsed electric fields (nsPEFs) are a non-thermal technology that can induce a myriad of biological responses and changes in cellular physiology. nsPEFs have gained significant attention as a novel cancer therapy. However, studies investigating the application of nsPEF in mucinous carcinomas are scarce. In this study, we explored several biological responses in two mucinous colorectal adenocarcinoma cell lines, LS 174T and HT-29, to nsPEF treatment. We determined the overall cell survival and viability rates following nsPEF treatment using CCK-8 and colony formation assays. We measured the intracellular effects of nsPEF treatment by analyzing cell cycle distribution, cell apoptosis and mitochondrial potential. We also analyzed mucin production at both mRNA and protein levels. Our results showed that nsPEF treatment significantly reduced mucinous cell viability in a dose-dependent manner. nsPEF treatment increased cell cycles arrest at G₀/G₁ while the proportion of G₂/M cells gradually decreased. Cell apoptosis increased following nsPEF treatment with a clear loss in mitochondrial membrane potential. Furthermore, the protein expression of functional mucin family members decreased after nsPEF treatment. In conclusion, nsPEF treatment reduced MCRC cell viability, cell proliferation, and mucin protein production while promoted apoptosis. Our work is a pilot study that projects some insights into the potential clinical applications of nsPEFs in treating mucinous colorectal carcinoma.

Activation of Anti-tumor Immune Response by Ablation of HCC with Nanosecond Pulsed Electric Field

Locoregional therapy is playing an increasingly important role in the non-surgical management of hepatocellular carcinoma (HCC). The novel technique of non-thermal electric ablation by nanosecond pulsed electric field has been recognized as a potential locoregional methodology for indicated HCC. This manuscript explores the most recent studies to indicate its unique anti-tumor immune response. The possible immune mechanism, termed as nano-pulse stimulation, was also analyzed.

Effect of Low-Field High-Frequency nsPEFs on the Biological Behaviors of Human A375 Melanoma Cells

OBJECTIVE

To evaluate the effect of low-field high-frequency nanosecond pulsed electric fields (nsPEFs) on multiple biological behaviors of human A375 melanoma cells and to optimize suitable parameters for further study and clinical use.

METHODS

An nsPEF generator was developed to generate appropriate pulses. Cell apoptosis and the cell cycle were evaluated by flow cytometry. The CCK-8 assay was performed to explore the effect of nsPEFs on the viability of A375 melanoma cells. Cell migration was assessed using a Transwell Boyden Chamber. The proliferation of A375 melanoma cells was determined by the cloning efficacy test. Furthermore, the nude mouse tumorigenicity assay was used to detect the effectiveness of nsPEFs in vivo.

RESULTS

The nsPEFs with our tested parameters failed to induce apoptosis of A375 melanoma cells, though nsPEFs with high pulse duration (500 ns) induced necrosis. However, the viability and migration of A375 melanoma cells were significantly inhibited by nsPEFs. nsPEFs also suppressed the proliferation of A375 melanoma cells by restricting cells in G0/G1 phase. Moreover, animal experiments demonstrated that nsPEFs inhibited the growth of melanoma in vivo.

CONCLUSION

Low-field high-frequency nsPEFs failed to induce apoptosis but effectively inhibited the growth of melanoma via affecting other biological behaviors of melanoma cells, such as cell viability, proliferation, and migration.

SIGNIFICANCE

This study investigated the influence of low-field high-frequency nsPEFs on melanoma through evaluating their effects on multiple biological behaviors and is helpful in the treatment of melanoma and other tumors.