FIGURE 4.

Down-regulation of SERCA3 by nifetepimine causes a rise in the cytosolic Ca²⁺ concentration thereby blocking CD4⁺ T cell apoptosis. A, cytosolic Ca²⁺ was measured from control and tumor supernatant (sup)-treated CD4⁺ T cells in the presence and absence of nifetepimine. CD4⁺ T cells were loaded with 5 μm Fura-2AM, and the units of fluorescence, recorded at 510 nm after excitation at 340 and 380 nm, was used to calculate cytosolic Ca²⁺ as described above. B, in a parallel set of experiments, the percent of CD4⁺ T cell viability under the above-mentioned conditions was monitored with time period. C, shown is a Western blot representation for cleaved caspase 9 and 3 in control and MCF-7 supernatant-treated CD4⁺ T cells in the presence and absence of nifetepimine. D, shown is a graphic representation of the percentage of cell death in control and MCF-7 supernatant-treated CD4⁺ T cells in the presence and absence of caspase 9(z-LEHD-FMK)/caspase 3(z-DEVD-FMK)/pan-caspase(z-VAD-FMK) inhibitors. Values are the mean ± S.E. of three independent experiments in each case.