Investigation of cell viability regulation by calcium electroporation

Abstract

Electroporation is a method, developed in order to deliver exogenous biocompounds (anticancer drugs, nucleic acids, proteins, etc.) to cells and tissues, which are mostly designed for cancer treatment purposes. The synergistic effect of electroporation and chemotherapeutic agents has been widely studied for cancer cell treatment both in vitro and in vivo. An alternative to chemotherapeutic drugs can be Ca2+ ions which are universal signal messengers that regulate a multitude of cellular functions (exocytosis, metabolism, gene expression, cell cycle, etc.). However, overthreshold Ca2+ concentrations are toxic to the cells. After calcium electrotransfer cell death is induced due to sudden increase in the amount of Ca2+ which can further lead to ATP depletion, ROS production, membrane lipid alterations, membrane pore opening and/or other processes. Thus, artificially induced increase in intracellular calcium ion concentration can be exploited to significantly facilitate cancerous cell death as well as reduce tumour growth. In this research we have analyzed Chinese hamster ovary cell viability and metabolic activity by using different calcium concentrations (0 – 5 mM) and different number of 1200 V/cm electric field strength and 100 μs duration pulses (1 – 4 HV). Our results show that during electroporation cell viability decreases as calcium concentration is increased. Thus, using electroporation in combination with calcium ions, depending on parameters, we are getting 20 - 100 % cell death. Similarly, the cell metabolic activity decreases with increasing calcium concentration (after 30 min, 12 h and 24 h).[...]