Ca ²⁺ movement induced by deltamethrin in PC3 human prostate cancer cells

This study explored the effect of deltamethrin, a pesticide, on intracellular free Ca ²⁺ concentration ([Ca ²⁺ ]i) in PC3 human prostate cancer cells. Deltamethrin at concentrations between 5 µM and 20 µM evoked [Ca ²⁺ ]i rises in a concentration-dependent manner. This Ca ²⁺ signal was inhibited by 22% by removal of extracellular Ca ²⁺ . Nifedipine, econazole, and SKF96365 also inhibited the Ca ²⁺ signal. Treatment with the endoplasmic reticulum Ca ²⁺ pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) in Ca ²⁺ -free medium nearly abolished deltamethrin-induced [Ca ²⁺ ]i rises. Treatment with deltamethrin also inhibited most of BHQ-induced [Ca ²⁺ ]i rises. Inhibition of phospholipase C (PLC) with U73122 failed to alter deltamethrin-evoked [Ca ²⁺ ]i rises. Deltamethrin killed cells at concentrations of 20-100 µM in a concentration-dependent fashion. Chelation of cytosolic Ca ²⁺ with 1,2-bis (2-aminophenoxy) ethane-N, N, N’, N’-tetraacetic acid/acetoxymethyl ester (BAPTA/AM) did not prevent deltamethrin’s cytotoxicity. Together, in PC3 human prostate cancer cells, deltamethrin induced [Ca ²⁺ ]i rises that involved Ca ²⁺ entry through store-operated Ca ²⁺ channels and PLC-independent Ca ²⁺ release from the endoplasmic reticulum. Deltamethrin induced cytotoxicity in a Ca ²⁺ -independent manner.