目的:探讨5α双氢睾酮(DHT)对前列晾癌LNCaP细胞钙离子移动的影响及其机制。方法:应用Fura-2/AMCa2+荧光探针法结合MiraCal荧光成像系统动态检测DHT刺激以及Ca2+通道阻滞剂干预后LNCaP细胞内钙离子浓度(ECa2+]i)的变化。应用MTT法观察细胞活力,流式细胞仪观察早期细胞凋亡率。结果:DHT浓度为1、10、100和1000nmol/L时,能快速诱导[Ca2+]i升高,在20s~3min升至峰值。细胞外液无Ca2+时,1000nmol/L DHT未能诱导[Ca2+]i升高。细胞膜L-型电压门控Ca2+通道阻滞剂维拉帕米(50μmol/L)、地尔硫革(100μmol/L)或硝苯地平(5mmol/L)37℃孵育细胞5min后,能完全抑制l000nmol/LDHT诱导的[Ca2+]i升高。磷脂酶C抑制刺新霉素(1mmol/L)37℃孵育细胞5min或兰尼定受体阻滞剂普鲁卡因(50mmol/l)37C孵育细胞3Min后,对1000nmol/LDHT诱导的[Ca2+]i升高没有影响。1000nmoL/L DHT作用细胞48h后,与1000nmol/L DHT作用前用维拉帕米预孵细胞相比,细胞光密度(D)值[(0.67±0.10)vs(2.13±0.16))和早期细胞凋亡率[(14.31±2.29)%vs(1.07±0.19)%]差异有统计学意义(P〈0.01)。结论:DHT可快速地、剂量依赖性地诱导LNCaP细胞[Ca2+]i升高;DHT诱导的LNCaP细胞[Ca2+]i的升高是通过细胞外Ca2+经细胞膜L-型电压门控Ca2+通道流入细胞内实现的,细胞内贮钙库未释放Ca2+。DHT诱导的LNCaP细胞[Ca2+]i升高促进细胞凋亡、抑制细胞生长。
Objective:To investigate the effects of 5α- dihydrostestosterone (DHT) on calcium mobilization and growth of prostate cancer cell line LNCaP. Methods: Intracellutar calcium concentration ([Ca2+ ) was assayed by MiraCal Image System using Fura-2/AM as Ca2+ fluorescence probe. Cell viability was observed by MTT assay and apoptosis by flow cytometry. Results: The calcium levels rapidly increased following addition of DHT, with the latency of response only in seconds. DHT at the concentrations of 1, 10, 100 and 1 000 nmol/L increased [Ca2+ ]i from (28±5), (29±5), (28±4) and (28±9) nmol/L to (31±3) (P〉0.05,65±9) (P〈0.01), (193±33) (P〈0. 001) and (208±42) nmol/L (P〈0.001), respectively. The response induced by 1 000 nmol/L DHT was similar to that induced by 100 nmol/L DTH. DHT 1 000 nmol/L did not increase [Ca2+ ]i under extracellular Ca2+ free condition. Blockers of I. type voltage-gated calcium channels, including verapamil (50 μmol/L), dihiazem (100μmol/L) or nifedipine (5 mmol/L) at 37℃ for 5 min prior to stimulation with 1 000 nmol/L DHT, complctely inhibited DHT-induced [Ca2+]i rise. Pre-treatment with inhibitor of phospholipase C such as neomycin sulfate (1 mmol/L) at 37 C for 3 min or inhibitor of ryanodine receptor such as procaine (50 mmol/L) at 37℃ for 3 min had no influence on [Ca2+] rise induced by 1 000 nmol/L DHT. The optical density (D) values and early apoptosis rates of the cells stimulated with 1 000 nmol/L DHT for 48 h were significantly different from those of cells pre-treated with verapamil prior to stimulation with 1 000 nmol/L DHT ([0. 67±0.10] %0 vs [2. 13±0.16] %and [14. 31±2. 29]% vs [1. 07±0. 19]% ,P〈0.01).Conclusion: DHT can induce rapid [Ca2+ ]i rise in LNCaP cells in a concentration-dependent manner. The increase of [Ca2+]i induced by DHT involves L-type voltagc-gated calcium channels, but does not involve release of intracellular Ca2+ stores. The incre