Targeting TRPM2 Channels Impairs Radiation-Induced Cell Cycle Arrest and Fosters Cell Death of T Cell Leukemia Cells in a Bcl-2-Dependent Manner

Figure 1

Ionizing radiation (IR) increases the cation and the Ca²⁺ conductance of the plasma membrane in human Jurkat T cell leukemia cells. (a, b) Current density-voltage relationships (I/V curves, a) and conductance densities (b) of Jurkat cells at different time periods (as indicated) after IR with 0 Gy (control, open circles and bar) or 10 Gy (closed symbols and bars). Currents were recorded in whole-cell voltage-clamp mode with K-gluconate/KCl pipette and NaCl bath solution and elicited by 9 voltage square pulses to voltages between −80 mV and +80 mV (20 mV increments). Conductance densities were calculated for the inward currents as shown by the blue and red line in (a) for control cells and irradiated cells (2–6 h after IR), respectively. (c, d) I/V curves of control (c) and irradiated Jurkat cells (2–6 h after 10 Gy, d) recorded as in (a) with NaCl bath solutions (circles) or after replacement of Na⁺ with Ca²⁺ (squares) or the impermeable cation N-methyl-D-glucamine (NMDG, triangles). (e) Ca²⁺ conductance density of control cells (open bar) and irradiated Jurkat cells (2–6 h after 10 Gy, closed bar). The blue and red line in (c) and (d), respectively, show the voltage range used for calculation of the Ca²⁺ conductance densities. Data are means ± SE, for the 46–49 h values in (a) and for all other data. and indicate and 0.01 as tested by ANOVA (b) and Welch-corrected -test (e), respectively.

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