Expression and different polarity of aminopeptidase N in normal human colonic mucosa and colonic tumors.
Expression and different polarity of aminopeptidase N in normal human colonic mucosa and colonic tumors.
复制标题
氨肽酶N在正常人结肠粘膜和结肠肿瘤中的表达和不同极性。
DOI：
10.1002/ijc.2910510312
复制
发表时间：
1992
影响因子：
6.4
通讯作者：
Hamilton,SR
中科院分区：
文献类型：
--
作者：
Quaroni,A;Nichols,BL;Quaroni,E;Hurst,K;Herrera,L;Weiser,MM;Hamilton,SR
使用一组与天然或变性蛋白质反应的单克隆抗体，研究了正常人结肠、结肠息肉和恶性肠肿瘤中刷状缘酶（氨肽酶 N、二肽酶 IV、乳糖酶、麦芽糖酶）的表达和细胞定位。通过间接免疫荧光染色在低温切片上检测酶，或通过凝胶电泳和免疫印迹进行亲和纯化和分析。所有检查的样品中均不存在二肽基肽酶 IV、乳糖酶和麦芽糖酶，而在取自无肠肿瘤的个体的大多数结肠标本的上皮细胞基底膜上检测到氨肽酶 N (APN)。相比之下，APN 经常位于肿瘤、腺瘤和增生性息肉远端大肠粘膜表面上皮的管腔膜上，并且来自遗传性结肠癌综合征家族的成员。 APN 也在结肠肿瘤中表达，在所检查的 3/23 腺瘤和 14/35 腺癌中，它存在于顶端细胞膜位置。肿瘤细胞侵袭性（按“Dukes”︁分期分类）与氨肽酶 N 的表达或细胞位置之间没有发现相关性。组织学上，所有阳性肿瘤均中度或高度分化。这些结果表明，氨肽酶 N 通常在成人结肠中表达，但大肠和小肠的上皮细胞在细胞内分选这种酶并最终将其插入其表面膜的不同方面的方式不同，这一过程可能在癌发生的早期阶段发生改变。
Expression and cellular localization of brush‐border enzymes (aminopeptidase N, dipeptidylpeptidase IV, lactase, maltase) in normal human colon, colonic polyps and malignant intestinal tumors were investigated with a panel of monoclonal antibodies reacting with either native or denatured proteins. The enzymes were detected on cryostat sections by indirect immunofluorescence staining, or affinity‐purified and analyzed by gel electrophoresis and immunoblotting. Dipeptidylpeptidase IV, lactase and maltase were absent from all samples examined, while aminopeptidase N (APN) was detected at the basal membrane of the epithelial cells in most specimens of colon obtained from individuals free of intestinal tumors. In contrast, APN was frequently localized at the luminal membrane of the surface epithelium in large‐intestinal mucosa distal to tumors, adenomas and hyperplastic polyps, and from members of hereditary colon cancer syndrome families. APN was also expressed in colonic tumors, where it was present in an apical cell membrane location in 3/23 adenomas and 14/35 adenocarcinomas examined. No correlation was found between tumor‐cell invasiveness (classified by „Dukes”︁ stage) and expression or cellular location of aminopeptidase N. Histologically, all positive tumors were moderately or well differentiated. These results suggest that aminopeptidase N is normally expressed in adult human colon, but epithelial cells in the large and small intestine differ in their ways of sorting this enzyme intracellularly and eventually inserting it into different aspects of their surface membrane, a process which may be altered at an early stage of carcinogenesis.