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熊果酸激活低分化鼻咽癌细胞氯通道和减小细胞容积

厉冰雪, 滕双凤, 刘振锋, 刘梅, 叶东, 马莲顺, 朱林燕, 王立伟, 陈丽新

暨南大学医学院药理学系；医学院生理学系，广州 510632

摘要

本文旨在研究熊果酸对低分化鼻咽癌细胞氯通道的激活作用，以及熊果酸对其细胞容积的影响。采用膜片钳技术记录熊果酸激活的鼻咽癌细胞(CNE-2Z)全细胞氯电流，应用离子置换、改变细胞外渗透压、氯通道阻断剂等观察熊果酸诱导的氯电流的特性，活细胞动态图像分析技术测量细胞容积变化。结果显示，等渗条件下可记录到CNE-2Z细胞微弱且稳定的背景氯电流，细胞外灌流熊果酸可浓度依赖性(1~100 nmol/L)诱发氯电流的产生，在±80 mV电压钳制下，100 nmol/L熊果酸激活的氯电流的平均电流密度为(78.92 ± 6.39) pA/pF和(−59.86 ± 4.86) pA/pF，该电流具有较明显的外向优势，不表现明显的时间依赖性和电压依赖性失活。该电流翻转电位为(−4.83 ± 0.30) mV，较接近Cl−平衡电位(−0.9 mV)。熊果酸激活的氯通道对不同阴离子的通透性为：Cl− = I− > Br− > 葡萄酸根离子。该电流具有容积敏感性，可被细胞外高渗透压显著抑制；氯通道阻断剂他莫昔芬(tamoxifen)、5-硝基-2-(3-苯丙胺)苯甲酸[(5-nitro-2-(3-phenylpro-pylamino) benzoic acid, NPPB]可抑制该电流。细胞外灌流熊果酸1 h后，细胞容积减小，氯通道阻断剂NPPB可抑制该容积变化。以上结果提示，熊果酸可以激活低分化鼻咽癌细胞的氯通道，使Cl−外流，进而引起细胞容积减小。

关键词： 熊果酸; 低分化鼻咽癌细胞; Cl−; 通道; 膜片钳技术; 细胞容积

分类号：R736.630.22

[Ursolic acid activates chloride channels and decreases cell volume in poorly differentiated nasopharyngeal carcinoma cells.] [Article in Chinese]

LI Bing-Xue, TENG Shuang-Feng, LIU Zhen-Feng, LIU Mei, Ye Dong, MA Lian-Shun, ZHU Lin-Yan, WANG Li-Wei, CHEN Li-Xin

Department of Pharmacology； Department of Physiology, Medical College, Jinan University, Guangzhou 510632, China

Abstract

The present study aimed to investigate the effects of ursolic acid on the chloride channels and cell volume in nasopharyngeal carcinoma cells (CNE-2Z). The whole-cell patch clamp technique was used to detect the current, and cell imaging technique was applied to measure cell volume. The properties of the currents induced by ursolic acid were investigated by changing the extracellular osmotic pressure, replacing the extracellular anions and applying chloride channel blockers. The results showed that, under isotonic conditions, the background current was weak and stable. When perfusing the cells with ursolic acid (100 nmol/L), a large current (-59.86 pA/pF ± 4.86 pA/pF at -80 mV, 78.92 pA/pF ± 6.39 pA/pF at +80 mV) was induced. The chloride current showed outward rectification and negligible time- and voltage-dependent inactivation. The reversal potential (-4.83 mV ± 0.30 mV) of the current was close to the calculated equilibrium potential for Cl(-) (-0.9 mV). The permeabilities of the channel to different anions were ranked in order as follows: Cl(-) = I(-) > Br(-) > gluconate. Hypertonic solutions inhibited the current induced by ursolic acid. The chloride channel blockers, tamoxifen (20 μmol/L) and 5-nitro-2-(3-phenylpro-pylamino) benzoic acid (NPPB, 100 μmol/L), suppressed the current. Furthermore, ursolic acid decreased the cell volume by (11.78 ± 1.20)% in 1 h, and the effect was inhibited by NPPB. These results suggest that ursolic acid can activate chloride channels, resulting in outflow of Cl(-) and decrease of cell volume in nasopharyngeal carcinoma cells.

Key words: Ursolic acid; nasopharyngeal carcinoma cells; chloride channels; patch-clamp techniques; cell volume;

收稿日期：2012-04-13　　录用日期：2012-08-27

通讯作者：王立伟,陈丽新　　E-mail: chenlixinw@sohu.com,wangliweic@sohu.com

引用本文：

厉冰雪, 滕双凤, 刘振锋, 刘梅, 叶东, 马莲顺, 朱林燕, 王立伟, 陈丽新. 熊果酸激活低分化鼻咽癌细胞氯通道和减小细胞容积[J]. 生理学报 2012; 64 (6): 673-680.

LI Bing-Xue, TENG Shuang-Feng, LIU Zhen-Feng, LIU Mei, Ye Dong, MA Lian-Shun, ZHU Lin-Yan, WANG Li-Wei, CHEN Li-Xin. [Ursolic acid activates chloride channels and decreases cell volume in poorly differentiated nasopharyngeal carcinoma cells.] [Article in Chinese]. Acta Physiol Sin 2012; 64 (6): 673-680 (in Chinese with English abstract).