探讨S100A6蛋白对细胞中β-catenin水平的影响及可能机制。用表达S100A6及其siRNA的重组腺病毒AdS100A6和AdsiS100A6处理人骨肉瘤细胞系143B,Western blot分析处理前后细胞中β-catenin水平的变化;再以人胚肾细胞HEK293为研究对象,通过免疫共沉淀(co-immunoprecipitation,Co-IP)联合Western blot检测S100A6与Wnt经典信号通路主要成员β-catenin、糖原合酶激酶-3β(GSK-3β)、散乱蛋白(Dishevelled,DVL)和轴蛋白(Axin)之间的相互作用。结果:1)AdS100A6作用48h后,143B细胞中β-catenin水平较实验对照组(AdGFP组)增加了64%(P〈0.01),而AdsiS100A6处理的细胞中β-catenin较AdGFP组减少了20.2%(P〈0.05),AdGFP组与空白组之间的差异无统计学意义;2)在S100A6抗体的沉淀物中,检测到β-catenin、GSK-3β和DVL,而无Axin检出;3)β-catenin、GSK-3β和DVL的抗体沉淀物中,均有S100A6检出,而Axin抗体的沉淀物中无S100A6检出。结论:S100A6能够上调人骨肉瘤细胞系143B中的β-catenin水平;并与β-catenin、GSK-3β和DVL之间存在直接相互作用;S100A6与这三个分子之间的直接相互作用可能抑制了β-catenin的降解,使之在胞浆内聚集,水平升高。这可能是S100A6上调β-catenin的部分机制。
The purpose is to analyze the effect of S100A6 on β-catenin and its possible molecular mechanisms.The recombinant adenovirus AdS100A6,AdsiS100A6 and AdGFP were used to infect human osteosarcoma cell line 143B respectively,then Western blot was used to detect cytoplasmic β-catenin levels.Adβ-catenin,pCMV-DVL-Myc,pCMV-Axin-Myc,pcDNA-GSK-3β-HA,pHAHA-S100A6 and pGST-S100A6 were used to infect or transfect or cotransfected HEK293 respectively,then co-immunoprecipitation and Western blot were used to investigate the interactions between S100A6 and β-catenin/GSK-3β/DVL/Axin.Results: 1) Compared with the control group(143B infected with AdGFP),the cytoplasmic β-catenin levels of S100A6 group(143B infected with AdS100A6) and siS100A6 group(143B infected with AdsiS100A6) increased by 64%(P〈0.01) and decreased by 20.2%(P〈0.05),respectively;there was no difference between control group and blank group;2) β-catenin,GSK-3β and DVL were found in the precipitate of S100A6 antibody,but no Axin was found in it;3) S100A6 was found in precipitates of β-catenin antibody,GSK-3β antibody and DVL antibody,but not in precipitate of Axin antibody.The results suggest that S100A6 can upregulate the β-catenin level of human osteosarcoma cell line 143B and that there are direct interactions between S100A6 and β-catenin/GSK-3β/DVL.The interactions maybe inhibit the degradation of β-catenin and therefore increase its cytoplasmic level.