HERG钾通道表达与小檗碱的抗肿瘤作用的关系

Correlation of HERG Potassium Channel Expression Level with the Antitumor Activity of Berberine

目的以HERG钾通道为靶点,研究HERG钾通道表达水平与小檗碱的抗肿瘤作用的相关性。方法采用Westernblot检测了HERG钾离子通道在不同肿瘤细胞的表达情况,经过质粒的分离和纯化、基因转染技术、MTT法研究了HERG钾通道的表达与小檗碱杀伤肿瘤细胞作用的关系,同时通过对细胞粘附能力和明胶酶分泌的测定研究了小檗碱对肿瘤细胞粘附和明胶酶分泌的影响。结果HERG通道蛋白在不同肿瘤细胞的表达水平高低不同,在HT29细胞中表达较高,而在A549细胞中基本不表达,在MCF7、MCF7/ADM、Bel7402、PG细胞中表达居中。HERG通道蛋白表达较高的HT29细胞对小檗碱的敏感性比表达较低的A549细胞弱。将herg基因转染入表达较低的A549细胞后,HERG通道蛋白的表达明显增加,而小檗碱的细胞增殖抑制作用明显降低,IC50值是A549亲本细胞的30倍;同时,它还能抑制HT29细胞对Ⅰ型胶原的粘附和HT1080细胞分泌明胶酶MMP9,这种抑制作用呈浓度依赖性。结论小檗碱对肿瘤细胞的杀伤作用可能与HERG通道的表达呈负相关,即HERG表达高,杀伤作用较弱,反之,杀伤作用较强。同时,小檗碱可能通过抑制肿瘤细胞的粘附功能和释放明胶酶的功能而影响肿瘤的侵袭和转移。HERG钾通道可能是与肿瘤化疗相关的分子靶点。

AIM:To study correlation of anticancer effect of berberine with HERG potassium channel expression level.METHOD:Western blot was used to determine HERG expression level in a variety of human cancer cell lines.Gene transfection and MTT assay were applied to examine the change of HERG-related cytotoxicity of berberine.Cell adhesion test and gelatin zymography were used to detect the effect of berberine on invasion and metastasis of cancer cells.RESULT:HERG expression level was highly different in various human cancer cell lines.Among the tested cell lines,the level in HT-29 cells was the highest,and then it decreased in an order of MCF-7,MCF-7/ADM,Bel7402,PG and A549 cells.Inhibition of the proliferation of A549 cells by berberine was more potent as compared to that of HT-29 cells.Furthermore,the inhibition of herg-transfected A549 cells by berberine was significantly decreased as compared to that of A549 or pCDNA3.1-transfected A549 cells.Berberine inhibited the adhesion of HT-29 cells to collagenⅠand decreased MMP-9 secretion from HT-1080 cells in a dose-dependent manner.CONCLUSION: HERG expression level negatively correlated with inhibitory effect on the proliferation of cancer cells by berberine.Highly HERG-expressing cells were less sensitive to berberine than those with much lower HERG protein level.Furthermore,berberine could influence on the invasion and metastatic capacity of cancer cells.HERG potassium channel may be a molecular target of cancer chemotherapy.