Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia.
Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana, Slovenia.
Radiol Oncol. 2022 Aug 14;56(3):326-335. doi: 10.2478/raon-2022-0028.
Nanosecond electric pulses showed promising results in electrochemotherapy, but the underlying mechanisms of action are still unexplored. The aim of this work was to correlate cellular cisplatin amount with cell survival of cells electroporated with nanosecond or standardly used 8 × 100 μs pulses and to investigate the effects of electric pulses on cisplatin structure.
Chinese hamster ovary CHO and mouse melanoma B16F1 cells were exposed to 1 × 200 ns pulse at 12.6 kV/cm or 25 × 400 ns pulses at 3.9 kV/cm, 10 Hz repetition rate or 8 × 100 μs pulses at 1.1 (CHO) or 0.9 (B16F1) kV/cm, 1 Hz repetition rate at three cisplatin concentrations. Cell survival was determined by the clonogenic assay, cellular platinum was measured by inductively coupled plasma mass spectrometry. Effects on the structure of cisplatin were investigated by nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry.
Nanosecond pulses equivalent to 8 × 100 μs pulses were established based on membrane permeabilization and cell survival. Equivalent nanosecond pulses were equally efficient in decreasing the cell survival and accumulating cisplatin intracellularly as 8 × 100 μs pulses after electrochemotherapy. The number of intracellular cisplatin molecules strongly correlates with cell survival for B16F1 cells, but less for CHO cells, implying the possible involvement of other mechanisms in electrochemotherapy. The high-voltage electric pulses did not alter the structure of cisplatin.
Equivalent nanosecond pulses are equally effective in electrochemotherapy as standardly used 8 × 100 μs pulses.
纳秒电脉冲在电化学疗法中显示出良好的效果，但作用机制仍未得到探索。本研究旨在将细胞内顺铂含量与用纳秒或标准使用的 8×100μs 脉冲电穿孔的细胞存活率相关联，并研究电脉冲对顺铂结构的影响。
中国仓鼠卵巢 CHO 和小鼠黑色素瘤 B16F1 细胞分别用 1×200ns 脉冲（12.6kV/cm）或 25×400ns 脉冲（3.9kV/cm，10Hz 重复率），或用 1×1.1（CHO）或 0.9（B16F1）kV/cm、1Hz 重复率的 8×100μs 脉冲在三种顺铂浓度下进行处理。通过集落形成实验测定细胞存活率，通过电感耦合等离子体质谱法测定细胞内铂含量。用核磁共振波谱和高分辨率质谱法研究顺铂结构的变化。
基于细胞膜通透性和细胞存活率，确定了等效的纳秒脉冲。等效的纳秒脉冲与 8×100μs 脉冲在电化学疗法中同样有效地降低细胞存活率并将顺铂积累到细胞内。B16F1 细胞内顺铂分子的数量与细胞存活率密切相关，但在 CHO 细胞中相关性较小，这意味着电化学疗法中可能涉及其他机制。高压电脉冲不会改变顺铂的结构。
等效的纳秒脉冲在电化学疗法中与标准使用的 8×100μs 脉冲同样有效。
