Progressive changes in adherens junction structure during intestinal adenoma formation in Apc mutant mice
Progressive changes in adherens junction structure during intestinal adenoma formation in Apc mutant mice
复制标题
DOI：
10.1074/jbc.m103450200
复制
发表时间：
2001-10-19
影响因子：
4.8
通讯作者：
Bertagnolli, MM
中科院分区：
文献类型：
--
作者：
Carothers, AM;Melstrom, KA;Bertagnolli, MM
C57 BL/6 J-Min/+（Min/+）小鼠携带突变型Apc基因，因此是肠道肿瘤发生的重要体内模型。Min/+小鼠发生腺瘤，表现出野生型Apc等位基因（Apc（Min/-））的丢失。以前，我们发现，具有截短的Apc蛋白（Apc（Min/+））的组织学正常的肠上皮细胞在体内迁移比具有野生型Apc（Apc（+/+））或Apc蛋白杂合缺失（Apc（1638 N））的肠上皮细胞更慢。为了进一步研究这种表型，我们通过检查粘附连接的组分来确定Apc（Min）突变对细胞-细胞粘附的影响（A.）。我们观察到Apc（Min/+）肠细胞中E-钙粘蛋白和β-连环蛋白之间的相关性降低。来自Apc（+/+）、Apc（Min/+）和Apc（Min/-）肠组织的蛋白质的亚细胞分级分离揭示了完整的E-钙粘蛋白仅在Apc（Min/+）中的细胞质定位，表明E-钙粘蛋白在这些肠细胞中内化。β-连环蛋白酪氨酸磷酸化在Apc（Min/+）肠细胞中也增加，与其从E-钙粘蛋白的解离一致。此外，Apc（Min/+）肠细胞显示β-连环蛋白和受体蛋白-酪氨酸磷酸酶β/ζ（RPTP β/ζ）之间的关联降低，而Apc（Min/-）细胞显示β-连环蛋白和受体蛋白-酪氨酸磷酸酶γ之间的关联。与Apc（Min/+）肠细胞相反，Apc（Min/-）腺瘤显示相对于Apc（+/+）对照增加的E-钙粘蛋白、β-连环蛋白和α-连环蛋白的表达和缔合。这些数据表明，APC在调节肠内粘附连接结构和功能中起作用。此外，在启动但组织学正常的组织（Apc（Min/+））中发现这些效应定义了肠粘膜中肿瘤发生的前腺瘤阶段。
The C57BL/6J-Min/+ (Min/+) mouse bears a mutant Apc gene and therefore is an important in vivo model of intestinal tumorigenesis. Min/+ mice develop adenomas that exhibit loss of the wild-type Apc allele (Apc(Min/-)). Previously, we found that histologically normal enterocytes bearing a truncated Apc protein (Apc(Min/+)) migrated more slowly in vivo than enterocytes with either wild-type Ape (Apc(+/+)) or with heterozygous loss of Apc protein (Apc(1638N)). To study this phenotype further, we determined the effect of the Apc(Min) mutation upon cell-cell adhesion by examining the components of the adherens junction (A.). We observed a reduced association between E-cadherin and beta -catenin in Apc(Min/+) enterocytes. Subcellular fractionation of proteins from Apc(+/+), Apc(Min/+), and Apc(Min/-) intestinal tissues revealed a cytoplasmic localization of intact E-cadherin only in Apc(Min/+), suggesting E-cadherin internalization in these enterocytes. beta -Catenin tyrosine phosphorylation was also increased in Apc(Min/+) enterocytes, consistent with its dissociation from E-cadherin. Furthermore, Apc(Min/+) enterocytes showed a decreased association between beta -catenin and receptor protein-tyrosine phosphatase beta/zeta (RPTP beta/zeta), and Apc(Min/-) cells demonstrated an association between beta -catenin and receptor protein-tyrosine phosphatase gamma. In contrast to the Apc(Min/+) enterocytes, Apc(Min/-) adenomas displayed increased expression and association of E-cadherin, beta -catenin, and alpha -catenin relative to Apc(+/+) controls. These data show that Apc plays a role in regulating adherens junction structure and function in the intestine. In addition, discovery of these effects in initiated but histologically normal tissue (Apc(Min/+)) defines a pre-adenoma stage of tumorigenesis in the intestinal mucosa.