The combination of Ca2+ ions and electroporation has gained attention as potential alternative to electrochemotherapy. Ca2+ is an important component of the cell membrane repair system and its presence directly influences the dynamics of the pore cycle after electroporation which can be exploited for cancer therapies. Here, the influence of Ca2+ concentration is investigated on small molecule electrotransfer and release of Calcein from 4T1, MX-1, B16F10, U87 cancer cells after cell exposure to microsecond electric pulses. Moreover, we investigated simultaneous molecule electrotransfer and intracellular calcium ion influx when media was supplemented with different Ca2+ concentrations. Results show that increased concentrations of calcium ions reduce the electrotransfer of small molecules to different lines of cancer cells as well as the release of Calcein. These effects are related with an enhanced membrane repair mechanism. Overall, we show that the efficiency of molecular electrotransfer can be controlled by regulating Ca2+ concentration in the electroporation medium. For the first time, the cause of cancer cell death in vitro from 1 mM CaCl2 concentrations is related to the irreversible loss of Ca2+ homeostasis after cell electroporation. Our findings provide fundamental insight on the mechanisms of Ca2+ electroporation that might lead to improved therapeutic outcomes.
Keywords: Calcein release; Calcium; Calcium uptake; Cell death; Electroporation; Fluorescence imaging; Membrane resealing; Molecular uptake.
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