Caveolin-1 mediates the expression and localization of cathepsin B, pro-urokinase plasminogen activator and their cell-surface receptors in human colorectal carcinoma cells
Caveolin-1 mediates the expression and localization of cathepsin B, pro-urokinase plasminogen activator and their cell-surface receptors in human colorectal carcinoma cells
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DOI：
10.1242/jcs.02278
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发表时间：
2005-04-01
影响因子：
4
通讯作者：
Sloane, BF
中科院分区：
文献类型：
--
作者：
Cavallo-Medved, D;Mai, JX;Sloane, BF
组织蛋白酶B和尿激酶原纤溶酶原激活物（pro-uPA）定位于HCT 116人结直肠癌细胞的小窝，这是由活性K-RAS介导的联合。本研究利用反义caveolin-1（AScav-1）基因构建稳定的HCT 116细胞系，观察caveolin-1对cathepsin B和pro-uPA及其细胞表面受体p11和uPA受体（uPAR）表达和定位的影响。通过免疫印迹和胃蛋白酶激活酶原测定，AS-cav-1 HCT 116细胞分泌的组织蛋白酶原B少于对照（空载体）细胞。在AS-cav-1 HCT 116细胞中，uPA原的表达和分泌也明显下调。在AScav-1 HCT 116细胞中，组织蛋白酶B和pro-uPA在小窝中的定位减少，并且与对照细胞相比，这些细胞表达较少的总的和小窝相关的p11和uPAR。以前的研究表明，uPAR与小窝蛋白-1和β 1-整合素形成复合物，我们在这里表明，下调小窝蛋白-1也抑制了β 1-整合素的定位到这些细胞的小窝。最后，下调HCT 116细胞中的小窝蛋白-1抑制细胞外基质蛋白IV胶原的降解和这些细胞通过Matrigel的侵袭。基于这些结果，我们假设小窝蛋白-1影响组织蛋白酶B和pro-uPA及其受体的表达和定位，从而介导与结肠癌细胞侵袭相关的细胞表面蛋白水解事件。
Cathepsin B and pro-urokinase plasminogen activator (pro-uPA) localize to the caveolae of HCT 116 human colorectal carcinoma cells, an association mediated by active K-RAS. In this study, we established a stable HCT 116 cell line with a gene encoding antisense caveolin-1 (AScav-1) to examine the effects of caveolin-1, the main structural protein of caveolae, on the expression and localization of cathepsin B and pro-uPA, and their cellsurface receptors p11 and uPA receptor (uPAR), respectively. AS-cav-1 HCT 116 cells secreted less procathepsin B than control (empty vector) cells as measured by inummoblotting and pepsin activation of the proenzyme. Expression and secretion of pro-uPA was also downregulated in AS-cav-1 HCT 116 cells. Localization of cathepsin B and pro-uPA to caveolae was reduced in AScav-1 HCT 116 cells, and these cells expressed less total and caveolae-associated p11 and uPAR compared with control cells. Previous studies have shown that uPAR forms a complex with caveolin-1 and beta 1-integrin, and we here show that downregulation of caveolin-1 also suppressed the localization of beta 1-integrin to caveolae of these cells. Finally, downregulation of caveolin-1 in HCT 116 cells inhibited degradation of the extracellular matrix protein collagen IV and the invasion of these cells through Matrigel. Based on these results, we hypothesize that caveolin-1 affects the expression and localization of cathepsin B and pro-uPA, and their receptors, thereby mediating cell-surface proteolytic events associated with invasion of colon cancer cells.