Corey E, Brown L G, Corey M J, Buhler K R, Vessella R L
Department of Urology, School of Medicine, University of Washington, Seattle 98195, USA.
Prostate. 1998 May;35(2):135-43. doi: 10.1002/(sici)1097-0045(19980501)35:2<135::aid-pros7>3.0.co;2-i.
Our objective was to investigate the presence of prostate specific antigen (PSA) and alpha-1-antichymotrypsin (ACT) mRNA and protein in prostate cancer cell lines, and the complexing characteristics of expressed PSA.
RT-PCR, immunohistochemistry, and Western blots were employed. Trypsin treatment of PSA was performed to establish the possible presence of an activatable form of PSA.
ACT mRNA and protein were detected in LNCaP, PC-3, and DU 145 by RT-PCR and by immunohistochemistry, respectively. Only LNCaP cells were positive for PSA mRNA and protein. LNCaP expressed approximately 30% active PSA, approximately 40% putative zymogen form of PSA, and approximately 30% stably inactive PSA.
We have shown that the majority of PSA expressed by LNCaP cells is present in free, noncomplexed forms in the conditioned media. A portion (40%) can be activated by trypsin, while the rest is stably inactive PSA. LNCaP cells may serve as a source of the "unreactive" PSA present in prostate cancer patients' serum.
我们的目的是研究前列腺癌细胞系中前列腺特异性抗原（PSA）和α1-抗糜蛋白酶（ACT）的mRNA及蛋白的存在情况，以及所表达的PSA的复合特性。
采用逆转录聚合酶链反应（RT-PCR）、免疫组织化学和蛋白质免疫印迹法。对PSA进行胰蛋白酶处理以确定是否可能存在可激活形式的PSA。
通过RT-PCR和免疫组织化学分别在LNCaP、PC-3和DU 145细胞中检测到ACT的mRNA和蛋白。仅LNCaP细胞的PSA mRNA和蛋白呈阳性。LNCaP细胞表达约30%的活性PSA、约40%的假定PSA酶原形式和约30%的稳定无活性PSA。
我们已经表明，LNCaP细胞表达的大多数PSA以游离的、非复合形式存在于条件培养基中。一部分（40%）可被胰蛋白酶激活，其余为稳定无活性的PSA。LNCaP细胞可能是前列腺癌患者血清中“无反应性”PSA的来源。
