ABSTRACT In order to establish cancer-type-specific electroporation protocols for breast cancer, electroporation was performed in vitro in two modalities: in-suspension and adhered cells. Electroporation of cell suspensions was carried out through commercial electroporation cuvettes whereas a novel electrode for electroporation of adhered cells was designed and manufactured aimed to preserve cell structure, to provide a closer model to an in vivo scenario, and as a means to visualize the mechanical effects of electroporation on the cell membrane by using scanning electron microscopy. Electroporation protocols and electric field thresholds were predicted in silico and experimentally tuned through propidium iodide uptake and cell viability. Three breast-cancer cell lines (BT-20, MCF-7 and HCC1419) and a non-cancerous cell line (BEAS-2B) were used. Cancerous cells responded differently to electroporation depending on the electric parameters, cell histology, the cell culture modality, and the cell morphology (membrane thickness mainly), which was evaluated trough confocal and transmission electron microscopy. Particularly, it was found that electrochemotherapy may represent a promising alternative as an adjuvant treatment of metastatic breast tumours, and as a neoadjuvant therapy for Her2/neu tumours. Oppositely, triple negative breast tumours may show a high sensitivity to electroporation and therefore, they could be efficiently treated with irreversible electroporation. On the other hand, noncancerous cells demanded the highest voltage in both cell culture modalities in order to be electroporated. Hence, these cells in suspension may provide a reliable, easy-to-perform, low-cost model for the development of electroporation protocols for eradication of healthy tissue around a tumour in a safety margin.

中文翻译：

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细胞形态对悬浮和粘附的乳腺癌细胞电穿孔方案设置的影响

摘要 为了建立针对乳腺癌的癌症类型特异性电穿孔方案，在体外以两种方式进行电穿孔：悬浮细胞和粘附细胞。细胞悬浮液的电穿孔是通过商业电穿孔比色皿进行的，而设计和制造了一种用于粘附细胞电穿孔的新型电极，旨在保护细胞结构，提供更接近体内情况的模型，并作为一种可视化机械效应的手段使用扫描电子显微镜在细胞膜上进行电穿孔。电穿孔协议和电场阈值是在计算机中预测的，并通过碘化丙啶摄取和细胞活力进行实验调整。使用了三种乳腺癌细胞系（BT-20、MCF-7 和 HCC1419）和一种非癌细胞系（BEAS-2B）。根据电参数、细胞组织学、细胞培养方式和细胞形态（主要是膜厚度），癌细胞对电穿孔的反应不同，通过共聚焦和透射电子显微镜对其进行评估。特别是，发现电化学疗法作为转移性乳腺肿瘤的辅助治疗和 Her2/neu 肿瘤的新辅助治疗可能是一种有前景的替代疗法。相反，三阴性乳腺肿瘤可能对电穿孔表现出高度敏感性，因此，它们可以通过不可逆电穿孔进行有效治疗。另一方面，非癌细胞在两种细胞培养方式中都需要最高电压才能进行电穿孔。因此，这些悬浮细胞可以提供可靠、易于执行、