O011 Investigating the effect of supraphysiological levels of calcium on irreversible electroporation (IRE) of pancreatic cancer cell lines

Abstract Introduction Pancreatic cancer remains difficult to treat with a 5-year survival of 2%. Loco-regional therapies are being introduced such as Irreversible Electroporation (IRE); a non-thermal ablative therapy thought to cause cell death by increasing the cell membrane potential resulting in the formation of aqueous pores, leading to cell death. Mitochondrial changes have previously been reported to be a key driver of apoptosis and calcium has been implicated in this process. We aimed to study the influence of calcium in combination with IRE in pancreatic cancer. Methods Immortalised pancreatic cancer cell line, PANC-1, and pancreatic cancer patient-derived xenograft cells (PDX 185) were exposed to calcium (Ca2+) and IRE monotherapy and in combination. Cells were trypsinised and electroporated in 4mm cuvettes with a BTX generator (Harvard Apparatus). Cell proliferation and viability were analysed, and depolarised mitochondria were evaluated by TMRE and analysed using flow cytometry. Results IRE combined with calcium was more cytotoxic compared to monotherapy with cell proliferation assays demonstrating a statistically significant reduction in proliferation (p<0.0001) across both cell lines. Interestingly, mitochondrial membrane potential analyses demonstrated a depolarising effect only in cells exposed to both calcium and IRE suggesting a mitochondrial mediated effect in cell death in these groups. Conclusion Calcium in combination with IRE may act to potentiate cell death through depolarisation of the mitochondrial membrane. Future work will involve understanding the impact of IRE in combination with calcium in 3D models, allowing the evaluation of molecular cell death mechanisms.