Nanosecond pulsed electric fields modulate the expression of Fas/CD95 death receptor pathway regulators in U937 and Jurkat Cells

Abstract In this publication, we demonstrate that exposure of Jurkat and U937 cells to nanosecond pulsed electrical fields (nsPEF) can modulate the extrinsic-mediated apoptotic pathway via the Fas/CD95 death receptor. An inherent difference in survival between these two cell lines in response to 10 ns exposures has been previously reported (Jurkat being more sensitive to nsPEF than U937), but the reason for this sensitivity difference remains unknown. We found that exposure of each cell line to 100, 10 ns pulses at 50 kV/cm caused a marked increase in expression of cFLIP (extrinsic apoptosis inhibitor) in U937 and FasL (extrinsic apoptosis activator) in Jurkat, respectively. Measurement of basal expression levels revealed an inherent difference between U937 cells, having a higher expression of cFLIP, and Jurkat cells, having a higher expression of FasL. From these data, we hypothesize that the sensitivity difference between the cells to nsPEF exposure may be directly related to expression of extrinsic apoptotic regulators. To validate this hypothesis, we used siRNA to knockdown cFLAR (coding for cFLIP protein) expression in U937, and FasL expression in Jurkat and challenged them to 100, 10 ns pulses at 150 kV/cm, a typical lethal dose. We observed that U937 survival was reduced nearly 60 % in the knockdown population while Jurkat survival improved ~40 %. These findings support the hypothesis that cell survival following 10 ns pulse exposures depends...
Source: Apoptosis - Category: Molecular Biology Source Type: research