An accumulating body of evidence implicates activation of TRPM2, a non-selective, Ca²⁺-permeant cation channel, in cell death (reviewed by Miller, 2006). Channel opening is stimulated by oxidative stress, a feature of numerous disease states. The wide expression profile of TRPM2 renders it a potentially significant therapeutic target in a variety of pathological settings including cardiovascular and neurodegenerative diseases. To examine the role of TRPM2 in cell death, HEK293 cells were stably transfected with a pCINeo/IRES-GFP bicistronic expression vector containing the human TRPM2 gene. Intracellular Ca²⁺ ([Ca²⁺]_i) was measured from fura-2 loaded cells and cell viability was assessed using the MTT assay. In HEK293/hTRPM2 cells H₂O₂ (10-1000μM) stimulated both Ca²⁺ influx (within 10min) and cell death (over 24h) in a concentration-dependent fashion. HEK293/hTRPM2 cells were more susceptible to H₂O₂-mediated cell death compared to untransfected controls, and the latter did not show a rise of [Ca²⁺]_i in response to H₂O₂. A number of compounds are reported to inhibit TRPM2 activation, including poly(ADP-ribose) polymerase (PARP) inhibitors, flufenamic acid (FFA) and N-(p-amylcinnamoyl) anthranilic acid (ACA). FFA (200μM) reduced Ca²⁺ influx in response to 100μM H₂O₂ (to 41±8%, n=4), with no effect on viability at the same [H₂O₂] (24h). ACA (20μM) also attenuated Ca²⁺ influx (to 43±24%, n=4), but again had no effect on viability. PARP inhibitors (PJ34 (1μM), DPQ (10μM) and nicotinamide (1mM)) abolished Ca²⁺ influx and mediated some restorative effects on viability of HEK293/hTRPM2 cells. However, PARP inhibition also offered some protection against cell death in untransfected controls (in which the H₂O₂-stimulated Ca²⁺ influx seen in transfected cells was absent). As a widely expressed channel which permits Ca²⁺ influx in response to oxidative stress, TRPM2 would seem destined for a role in cell death pathways and indeed much evidence points towards this being the case (Miller, 2006). However, our data suggest that although transfection with hTRPM2 sensitises cells to H₂O₂–induced cell death, the underlying mechanism is at least in part Ca²⁺-independent, since blockade of channel opening (as evidenced by suppression of Ca²⁺ influx) did not correlate with protection from cell death. In addition, since PARP inhibition had protective effects in untransfected control cells, part of the mechanism by which PARP inhibitors act to preserve viability of HEK293/hTRPM2 cells may be TRPM2-independent.