Comparative Study of Nanosecond Electric Fields In Vitro and In Vivo on Hepatocellular Carcinoma Indicate Macrophage Infiltration Contribute to Tumor Ablation In Vivo

Abstract

Background and AimRecurrence and metastasis are associated with poor prognosis in hepatocellular carcinoma even in the patients who have undergone radical resection. Therefore, effective treatment is urgently needed for improvement of patients' survival. Previously, we reported that nanosecond pulse electric fields (nsPEFs) can ablate melanoma by induction of apoptosis and inhibition of angiogenesis. This study aims to investigate the in vivo ablation strategy by comparing the dose effect of nanosecond electric fields in vitro and in vivo on hepatocellular carcinoma.Materials and MethodsFour hepatocellular carcinoma cell lines HepG2, SMMC7721, Hep1-6, and HCCLM3 were pulsed to test the anti-proliferation and anti-migration ability of 100 ns nsPEFs in vitro. The animal model of human subdermal xenograft HCCLM3 cells into BALB/c nude mouse was used to test the anti-tumor growth and macrophage infiltration in vivo.Results In vitro assays showed anti-tumor effect of nsPEFs is dose-dependant. But the in vivo study showed the strategy of low dose and multiple treatments is superior to high dose single treatment. The macrophages infiltration significantly increased in the tumors which were treated by multiple low dose nsPEFs.ConclusionThe low dose multiple nsPEFs application is more efficient than high dose single treatment in inhibiting the tumor volume in vivo, which is quite different from the dose-effect relationship in vitro. Beside the electric field strength, the macrophage involvement must be considered to account for effect variability and toxicology in vivo.

Reaction Chemistry Generated by Nanosecond Pulsed Dielectric Barrier Discharge Treatment is Responsible for the Tumor Eradication in the B16 Melanoma Mouse Model

“…Use of the glycerol/NaHC0 3 gel should not significantly affect the penetration of the nsPEF or, as we also show (Figure ), affect the temperature generation, thereby strengthening the conclusion that the killing is primarily due to ROS/RNS and radicals. This conclusion does not refute other studies reporting nsPEF as a successful treatment for melanoma but only that the nsPEF associated with the generation of nsP DBD is not sufficient. Interestingly, a recent study showed when a μsPEF was applied in addition to plasma treatment, an enhanced antibacterial effect was observed .…”

“…The effective selectivity of the cancer cells to ROS‐induced death has been attributed their higher metabolic rate which makes them significantly more susceptible to oxidative stress when compared to normal cells . The effective killing of cancer cells using nsP electric field treatment has also been attributed to the stimulation of apoptosis, pyknosis, and DNA fragmentation both in vitro and in vivo. Studies report nsPEF treatment can be used to ablate melanoma, with evidence of destruction of the tumor blood supply and complete remission after nsPEF treatment.…”

The Effect of Nanosecond Pulsed Electric Field on Hepatic Veins—A Mid-Term Investigation

“…In addition, previous studies have shown that nsPEF has extensive biological effects in colon cancer [26][27], ovarian cancer [28][29], oral cancer [30][31][32], pancreatic cancer [33], and brosarcoma [34]. In addition to inducing tumour cell apoptosis, nsPEF modulates tumour cell proliferation, invasion and metastasis, the tumour microenvironment, angiogenesis, and other tumour characteristics [35][36][37][38][39][40].…”

Nano-pulse stimulation (NPS) ablate tumors and inhibit lung metastasis on both canine spontaneous osteosarcoma and murine transplanted hepatocellular carcinoma with high metastatic potential

“…Nanosecond pulsed electric field (nsPEF) ablation originated from high voltage power technology and it showed potential in loco-regional tumor ablation [ 1 ]. NsPEF ablates tumors with ultra-short pulses by altering electrical conductivity and permeability of the tumor cell membrane, causing cell apoptosis [ 2 , 3 ]. Recently its potential in stimulating immune reaction was also reported [ 4 , 5 , 6 ].…”