中文摘要：

目的探讨腺瘤性结肠息肉（adenomatous polyposis coli,APC）蛋白截短突变对MDCK细胞中细胞-细胞和细胞-基质之间黏附的影响及机制。方法应用细胞黏附测定实验检验MDCK-N2-APC及MDCK-GFP稳定表达株系的黏附率。相对于对照细胞MDCK-GFP,MDCK-N2-APC细胞为稳定突变株,表达APC蛋白N端449-781氨基酸片段。免疫荧光染色、荧光定量PCR及Western blot测定在细胞黏附过程中发挥重要作用的黏附分子（CD29、E-cadherin）的表达情况。结果与对照细胞相比,N2细胞-基质之间黏附率增加,平均升高约180%,而细胞-细胞间黏附率约下降30%。在MDCK-N2-APC细胞中CD29的表达水平增加,E-cadherin的表达水平降低。结论 APC蛋白在细胞-基质及细胞-细胞间黏附中发挥重要作用。其截短突变片段N2可能通过改变CD29和E-cadherin等黏附分子的表达量来影响细胞黏附,进而影响细胞的侵袭和浸润。

英文摘要：

Objective To explore the impact of mutational adenomatous polyposis coli（APC） on cell-matrix,cell-cell adhesion and the relative mechanism.Methods Cell-matrix and cell-cell adhesion assays were employed to determine the adhesion level of two stable cell lines MDCK-N2-APC and MDCK-GFP.The truncated APC of N2 fragment,which spans residues 449-781,was studied in comparison with control cells including GFP alone.Immunofluorescence staining,RT-PCR analysis and Western blot were applied to check several adhesion molecules which are key roles in cell contact process.Results In contract with control,cell-matrix adhesion was averagely increased to 180% in N2 cells,whereas cell-cell adhesion was reduced by about 30%.Our experiments accordingly indicated that CD29 expression level was enhanced and the expression level of E-cadherin was enervated in N2 cells.And these two molecules all have crucial roles in cell-matrix and cell-cell adhesion.Conclusions Full length APC plays a crucial role in cell-matrix and cell-cell adhesion.Truncated N2-APC may influence cell adhesion through changing the expression level of certain adhesion molecules,such as E-cadherin and CD29.The truncation mutation of APC fragment N2 restrained in the colon cancer cells will alter the cell invasion and migration by affecting cell adhesion and cell-matrix adhesion.