Effect of NPC-15199 on Ca2+ levels in renal tubular cells.

In Madin-Darby canine kidney (MDCK) cells, effect of NPC-15199 on intracellular Ca2+ concentration ([Ca2+]i) was investigated by using fura-2. NPC-15199 (100-1000 microM) caused a rapid and sustained increase of [Ca2+]i in a concentration-dependent manner (EC50=500 microM). NPC-15199-induced [Ca2+]i rise was prevented by 70% by removal of extracellular Ca2+, but was not changed by dihydropyridines, verapamil and diltiazem.

Tamoxifen-induced increases in cytoplasmic free Ca2+ levels in human breast cancer cells.

Tamoxifen has been shown to increase cytoplasmic free Ca2+ levels [Ca2+]i in renal tubular cells and bladder cancer cells, and to after Ca2+ signaling in MCF-7 breast cancer cells. The present study examined the effect of tamoxifen on [Ca2+], in ZR-75-1 human breast cancer cells using fura-2 as an indicator. Tamoxifen increased [Ca2+]i at a concentration above 2 microM with an EC50 of 5 microM.