SRS389 - Bypassing hENT1-mediated resistance: irreversible electroporation drives gemcitabine sensitization in pancreatic ductal adenocarcinoma

Abstract Introduction Gemcitabine resistance in pancreatic ductal adenocarcinoma (PDAC) is associated with low expression of hENT1; a key membrane transporter for drug uptake. This study investigates whether irreversible electroporation (IRE)— a technique that disrupts cell membranes via electrical pulses— can enhance gemcitabine uptake and cytotoxicity in resistant PANC-1 pancreatic cancer cells. Methods PANC-1 cells in 2D/3D cultures were treated with IRE (IC50: 985 V/cm and 1575 V/cm, 30 pulses, 0.01 millisecond duration, 1 second interval) followed by culture with Gemcitabine for 24 h (1–100 µM). After drug removal, cells were incubated for 48 h. Metabolic activity and viability were assessed using MTT/PrestoBlue/Toxilight assays and compared to control and monotherapies (IRE and Gemcitabine alone). Liquid chromatography mass spectrometry (LCMS) quantified intracellular gemcitabine concentrations. Results IRE alone reduced metabolic activity to 64.01% in 2D cultures and Gemcitabine monotherapy had negligible effect. Combining IRE with gemcitabine further suppressed metabolic activity across all Gemcitabine concentrations; 1 µM (48.33% P = 0.049), 10 µM (40.95%, P = 0.007), 50 µM (44.68%, P = 0.016), and 100 µM (49.65%, P = 0.009). There was no Gemcitabine dose-dependent variation (ANOVA P = 0.35). This response was reproducible in 3D spheroids and correlated with a 54.7% increase in intracellular gemcitabine when combined with IRE. Combining treatments did not effect cell viability indicating a cytostatic rather than cytotoxic effect. Conclusions IRE enhances gemcitabine uptake and induces a cytostatic response in resistant PDAC cells, likely bypassing hENT1-mediated resistance. This indicates a translational potential for combining IRE with Gemcitabine in a sub-group of patients displaying chemo-resistance due to low hENT1 expression.