Comparative study of nanosecond electric fields in vitro and in vivo on hepatocellular carcinoma indicate macrophage infiltration contribute to tumor ablation in vivo.
OBJECTIVE
Recurrence 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.


METHODS
Four 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.


CONCLUSIONS
The 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.
Key Lab of Combined Multi-organ Transplantation, Ministry of Public Health, The Department of Hepatobiliary and Pancreatic Surgery. The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China.
Xinhua
X
Chen
Key Lab of Combined Multi-organ Transplantation, Ministry of Public Health, The Department of Hepatobiliary and Pancreatic Surgery. The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China.
Shengyong
S
Yin
Key Lab of Combined Multi-organ Transplantation, Ministry of Public Health, The Department of Hepatobiliary and Pancreatic Surgery. The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China.
Chen
C
Hu
The Department of Pharmacy, Shandong Traditional Chinese Medicine University, Jinan, Shandong Province, China.
Xinmei
X
Chen
Colleges of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, Zhejiang Province, China.
Kai
K
Jiang
Colleges of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, Zhejiang Province, China.
Shuming
S
Ye
Key Lab of Combined Multi-organ Transplantation, Ministry of Public Health, The Department of Hepatobiliary and Pancreatic Surgery. The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China.
Xiaowen
X
Feng
Xinjiang Nanosecond Pulse Technology Institute, Urumqi, Xinjiang, China.
Shifeng
S
Fan
Key Lab of Combined Multi-organ Transplantation, Ministry of Public Health, The Department of Hepatobiliary and Pancreatic Surgery. The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China.
Haiyang
H
Xie
Key Lab of Combined Multi-organ Transplantation, Ministry of Public Health, The Department of Hepatobiliary and Pancreatic Surgery. The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China.
Lin
L
Zhou
Key Lab of Combined Multi-organ Transplantation, Ministry of Public Health, The Department of Hepatobiliary and Pancreatic Surgery. The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China.
Shusen
S
Zheng
D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis / Q000528:radiation effects; D006528:Carcinoma, Hepatocellular / Q000276:immunology* / Q000532:radiotherapy*; D045744:Cell Line, Tumor; D004599:Electric Stimulation Therapy / Q000379:methods*; D006801:Humans; D008113:Liver Neoplasms / Q000276:immunology* / Q000532:radiotherapy*; D008262:Macrophage Activation / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000532:radiotherapy