Cell morphology impact on the set-up of electroporation protocols for in-suspension and adhered breast cancer cells

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.

KEYWORDS:

• Attached cells
• electric field threshold
• electropermeabilization
• finite element modelling
• hybrid electrode
• membrane thickness

Acknowledgments

Authors thank M.Sc. José Hugo Zepeda and M.Sc. Juan Carlos Osorio Trujillo for their technical support, Dr. Damijan Miklavčič and Dr. Bor Kos for their critical review and comments on this work. C. E. Vera-Tizatl (CVU: 708156) and A. L. Vera-Tizatl (CVU: 388502) thank the National Council for Science and Technology (CONACYT, Mexico) for the scholarship granted. Authors appreciate the funding for project: ERAnet-EMHE 200022, CYTED-DITECROD-218RT0545 and Proyecto IV-8 call Amexcid-Auci 2018-2020.

Additional information

Funding

This work was supported by the ERAnet-EMHE [200022]; Proyecto IV-8 call Amexcid-Auci 2018-2020 [Amexcid 2020]; CYTED-DITECROD [218RT0545].