磷脂酶Cγ1在大肠癌细胞中的信号转导机制  

Signal transduction mechanism of phospholipase Cγ1 in colorectal cancer cells

作　　者：李秀梅[1] 华亮[2] 罗深秋[3] 

机构地区：[1]解放军第458医院全军肝病重点实验室,广州510602 [2]广州市儿童医院中心实验室 [3]南方医科大学细胞生物学教研室

出　　处：《解放军医学杂志》2006年第12期1146-1148,共3页Medical Journal of Chinese People's Liberation Army

摘　　要：目的研究磷脂酶Cγ1(PLCγ1)在大肠癌细胞中的信号转导机制。方法采用凝胶迁移率变动分析(EMSA),免疫细胞化学,酶谱分析及RT-PCR等技术,分析了大肠癌细胞LoVo中,PLCγ1在表皮生长因子(EGF)刺激下对相关信号分子核因子-KappaB(NF-κB)、基质金属蛋白酶-2(MMP-2)和组织金属蛋白酶抑制剂-2(TIMP-2)的活性与表达的影响。结果与对照组相比,EGF处理组胞核阳性率显著增高,从26.91%±2.84%升高至40.83%±4.36%,而2.5μmol/LU73122处理组中胞核的阳性率则降低至12.20%±1.89%。同时,EGF刺激前若以2.5μmol/LU73122预处理,胞核阳性的细胞与只用EGF处理组相比也显著减少,从40.83%±4.36%降至18.21%±1.34%。EMSA结果显示,EGF处理细胞后可以增强NF-κB的活性,而U73122则可部分抑制其活性。RT-PCR结果表明,EGF处理细胞后,PLCγ1和NF-κB对于MMP-2与TIMP-2在mRNA水平的表达无显著影响。酶谱分析结果同时表明EGF处理细胞后,PLCγ1和NF-κB对于MMP-2酶原的表达及激活也无显著影响。结论在大肠癌细胞LoVo中,EGF可作为PLCγ1的上游刺激物,NF-κB作为其下游分子参与PLCγ1作用的发挥,而MMP-2、TIMP-2则不参与PLCγ1信号通路。Objective To investigate signal transduction mechanism of phospholipase Cγ1（PLCγ1） in colorectal cancer cells. Methods Gel electrophoresis mobility shift assay （EMSA）, immunocytochemistry, zymography and RT-PCR were performed to investigate the function of PLCγ1 on nuclear factor-Kappa B （NF-κB）, matrix metalloproteinase-2 （MMP-2） and tissue inhibitor of metalloproteinase-2 （TIMP-2） in LoVo cell. Results Compared with control group, nuclear positive rate of cells treated with epidermal growth factor （EGF） increased significantly （from 26. 91% ±2.84% to 40. 83% ±4. 36%）, while that of cells treated with 2. 5mol/L U73122 decreased to 12. 20%±1.89%. Meanwhile, pretreatment with 2. 5mol/L U73122 before EGF treatment decreased nuclear positive rate of cells from 40. 83% ±4. 36% to 18. 21% ± 1.34%. The results of EMSA further verified that PLCγ1 can regulate the activity of NF-κB. RT PCR results showed that EGF, PLCγ1 or NF-κB had no significant effect on the expression of MMP-2, TIMP-2 at mRNA level. Furthermore, zymography indicated that the activity of MMP-2 did not change dramatically by EGF, PLCγ1 or NF-κB. Conclusion These data suggested that EGF-PLCγ1-NF-κB signaling pathway was operative in LoVo cell, but MMP-2 and TIMP-2 may not be regulated by EGFR- PLCγ1-NF-κB signaling pathway.

关 键 词：磷脂酶Cγ1 信号传导 NF-ΚB 明胶酶A 

分 类 号：R735.3[医药卫生—肿瘤]