Activation of store – operated Ca(2+) entry in cisplatin resistant leukemic cells after treatment with photoexcited fullerene C(60) and cisplatin

摘要

Casup2+/sup-regulating system in cancer cells is suggested to be remodulated particularly by reduced store-operated Casup2+/sup entry (SOCE) through plasma membrane in order to maintain moderately reduced cytosolic Casup2+/sup concentration and to avoid apoptosis. The endoplasmic reticulum (ER) Casup2+/sup pool content and the size of SOCE in leukemic wild type (L1210) and resistant to cisplatin (L1210R) cells in control, after treatment with either cisplatin (1 μg/ml) or photoexcited fulleren Csub60/sub (10sup-5/sup M) alone, or their combination were estimated with the use of Indo-1 AM. The SOCE in resistant to cisplatin L1210R cells was found to be lower than in the wild-type cells. After treatment with cisplatin the decrease of thapsigargin (TG)-sensitive ER Casup2+/sup pool with no significant increase of SOCE was observed in L1210 cells, while no changes were detected in L1210R cells. Photoexcitation of intracellular accumulated fullerene Csub60/sub in the visible range of spectrum (410-700 nm) was accompanied by increase of SOCE not only in sensitive, but in resistant cells as well. In resistant L1210R cells treated with photoexcited Csub60/sub essential effect of cisplatin on Casup2+/sup homeostasis became obvious: the size of SOCE proved to be higher than after treatment with photoexcited Csub60/sub alone. The data obtained allow suggesting the influence of photoexcited Csub60/sub not only on Casup2+/sup-regulating system, but on those involved in controlling cisplatin entry into drug resistant cancer cells.