Abstract: Objective To investigate the effect of Na⁺/Ca²⁺ exchanger inhibitors SN-6 and calcium channel blocker verapamil on potassium-stimulated expression of aldosterone synthase in adrenocortical carcinoma cell line NCI-H295R(H295R). Methods H295R cells were treated in different groups, including control group, K⁺ (15 mmol/L) treated group, verapamil (10 μmol/L) group, SN-6 (10 μmol/L) group, combination of K⁺/verapamil treated group, combination of K⁺/SN-6 treated group, combination of K⁺/verapamil and SN-6 treated group. Real-time PCR was used to detect the mRNA expression of aldosterone synthetase (CYP11B2), and FLIPR Calcium 6 was used to detect the intracellular calcium ion level. Results Compared with the control group, K⁺ stimulated CYP11B2 mRNA expression. Both SN-6 and verapamil decreased K⁺ induced CYP11B2 mRNA expression(P＜0.01). Compared with the K⁺+SN-6 treated group, the K⁺,SN-6 and verapamil treated group all significantly inhibited CYP11B2 mRNA expression (P＜0.001). Both of SN-6 and verapamil significantly reduced the intracellular calcium level stimulated by K⁺ (P＜0.0001). Conclusions Both SN-6 and verapamil inhibit K⁺-induced expression of aldosterone synthase in adrenocortical carcinoma H295R cells. The inhibitory effect is more significant when treated by the combination of verapamil and SN6.

Key words: SN-6, verapamil, NCI-H295R cell, intracellular calcium, CYP11B2