Fig. 4.

ATP-induced store-operated Ca²⁺ entry (SOCE) and extracellular Ca²⁺ influx in normal and lung cancer cells. A: representative traces showing changes in [Ca²⁺]_cyt in normal and lung cancer cells treated with 100 μM ATP in the absence of extracellular Ca²⁺ and subsequent [Ca²⁺]_cyt changes during and after application of 1.8 mM extracellular Ca²⁺. B: summarized data (means ± SE) showing the amplitude of increase in [Ca²⁺]_cyt induced by 1.8 mM extracellular Ca²⁺ after application of 100 μM ATP in the absence of extracellular Ca²⁺ (n = 5, *P < 0.05 vs. Normal). C: representative traces showing changes in [Ca²⁺]_cyt in normal and lung cancer cells before, during, and after application of 10 μM cyclopiazonic acid (CPA, an inhibitor of SERCA) and subsequent [Ca²⁺]_cyt changes during and after application of 1.8 mM extracellular Ca²⁺. D: representative traces showing changes in [Ca²⁺]_cyt in normal and lung cancer cells before, during, and after application of 10 μM CPA and subsequent [Ca²⁺]_cyt changes during and after application of 100 μM ATP in 1.8 mM extracellular Ca²⁺. E: representative traces showing changes in [Ca²⁺]_cyt in normal and lung cancer cells before, during, and after application of 10 μM CPA and subsequent [Ca²⁺]_cyt changes during and after application of 100 μM ATP in 1.8 mM extracellular Ca²⁺ during treatment with 1 μM TNP-ATP (P2XR blocker). F: overlaid curves of C, D, and E. G: summarized data (means ± SE) showing the amplitude of second peak of [Ca²⁺]_cyt increases in normal and lung cancer cells induced by 1.8 mM extracellular Ca²⁺ or 1.8 mM extracellular Ca²⁺ plus 100 μM ATP after the application of 10 μM CPA, and amplitude of second peak of [Ca²⁺]_cyt increases in normal and lung cancer cells induced by 1.8 mM extracellular Ca²⁺ plus 100 μM ATP after the application of 10 μM CPA during TNP-ATP treatment (n = 3–10, *P < 0.05 vs. Control, ^#P < 0.05 vs. Normal).