Christiansen Jason J, Rajasekaran Sigrid A, Moy Peggy, Butch Anthony, Goodglick Lee, Gu Zhennan, Reiter Robert E, Bander Neil H, Rajasekaran Ayyappan K
Department of Pathology and Laboratory Medicine, Room 13-344 CHS, University of California Los Angeles, Los Angeles, CA 90095, USA.
Prostate. 2003 Apr 1;55(1):9-19. doi: 10.1002/pros.10203.
Madin-Darby canine kidney (MDCK) cells are immortalized epithelial cells that have been used extensively as a model system to study intracellular molecular trafficking, polarized expression, and secretion of proteins in various epithelia. In order to determine if MDCK cells might serve as a model to study molecular events within prostate epithelial cells, we have evaluated the polarized distribution of three prostate restricted proteins, PSMA, PSCA, and PSA, in situ, and in MDCK cells.
Using immunofluorescence, confocal microscopy, cell surface biotinylation, antibody internalization, and biochemical assays we evaluated surface expression and secretion of three prostate restricted proteins expressed in MDCK cells. We compared these patterns of expression to results observed within prostatic epithelium.
We demonstrate that PSMA is localized primarily to the apical plasma membrane in both the prostatic epithelium and transfected MDCK cells, whereas PSCA is expressed in a non-polarized fashion. We also show that PSA is secreted predominantly from the apical surface of transfected MDCK cells, consistent with in vivo observations.
Similar patterns of localization among MDCK and prostatic epithelial cells suggest that the mechanisms of polarized sorting within these cell types are conserved. Thus, MDCK cells offer a useful model system to study mechanisms of targeting of these proteins within the prostate.
Madin-Darby犬肾（MDCK）细胞是永生化上皮细胞，已被广泛用作模型系统，以研究各种上皮细胞内的细胞内分子运输、极化表达和蛋白质分泌。为了确定MDCK细胞是否可作为研究前列腺上皮细胞内分子事件的模型，我们评估了三种前列腺限制性蛋白（PSMA、PSCA和PSA）在原位及MDCK细胞中的极化分布。
我们使用免疫荧光、共聚焦显微镜、细胞表面生物素化、抗体内化和生化分析，评估了MDCK细胞中表达的三种前列腺限制性蛋白的表面表达和分泌情况。我们将这些表达模式与在前列腺上皮中观察到的结果进行了比较。
我们证明，PSMA主要定位于前列腺上皮和转染的MDCK细胞的顶端质膜，而PSCA以非极化方式表达。我们还表明，PSA主要从转染的MDCK细胞的顶端表面分泌，这与体内观察结果一致。
MDCK细胞和前列腺上皮细胞之间相似的定位模式表明，这些细胞类型中极化分选的机制是保守的。因此，MDCK细胞为研究这些蛋白质在前列腺内的靶向机制提供了一个有用的模型系统。
