Fig. 2

Selected cells survived by PMCA induction to pump calcium to ECM under glucose deprivation-induced metabolic stress. A Cell viability assay (MTT) of parental and selected cells under glucose deprivation-induced metabolic stress conditions by 2DG and glucose-deprived conditions. B Immunoblot analysis of PMCA, CHOP, PGC1α, caspase-3, and caspase-7 in the parental and selected cells under glucose deprivation-induced metabolic stress conditions at time series. C qRT-PCR of parental and selected cells showing the time-dependent mRNA expression of the PMCA family under glucose deprivation-induced metabolic stress conditions. D Cytosolic free calcium was measured after treatment with calcium channel blockers (nifedipine or verapamil), SERCA (thapsigargin), or PMCA (caloxin 2a1) inhibitor in parental and selected cells under glucose-deprived conditions in early (12 h) and late (48 h) phases. An arrow indicates the addition of high K⁺ depolarization to induce an increase in Ca²⁺ on traces. E Immunoblot analysis of CHOP (ER stress marker) expression after treatment with calcium channel blockers, SERCA, or PMCA inhibitor in selected cells under glucose deprivation-induced metabolic stress conditions at time series. F The values of the plateau (F₃₄₀/F₃₈₀), as the time is 810 s, intracellular Ca²⁺ on MB-231 and MCF-7 cells (left and middle). The values of plateau after treatment with calcium channel blockers (nifedipine or verapamil), SERCA (thapsigargin), or PMCA (caloxin 2a1) inhibitor under glucose-deprived conditions at 48 h in selected cells. G Cell viability assay (MTT) of selected cells after treatment of calcium channel blockers and PMCA inhibitors in selected cells under glucose deprivation-induced metabolic stress conditions (48 h). H, I Immunofluorescence assay for nuclear-translocated PGC1α and PMCA expression in parental or selected cells under glucose deprivation-induced metabolic stress for 48 h. Magnification, × 400. Scale bar, 20 μm. G (−), glucose-deprived condition. Data represent the average of at least three separate independent experiments and presented as means ± SEM. *P < 0.05 vs. parental, **P < 0.01 vs. parental, **P < 0.01 vs. selected G (−), G (+) glucose present, G (−) glucose deprivation