Thomas L N, Douglas R C, Vessey J P, Gupta R, Fontaine D, Norman R W, Thompson I M, Troyer D A, Rittmaster R S, Lazier C B
Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada.
J Urol. 2003 Nov;170(5):2019-25. doi: 10.1097/01.ju.0000091804.20183.81.
In the prostate testosterone is converted to the more potent androgen dihydrotestosterone by the enzymes 5alpha-reductase (5alphaR) types 1 (5alphaR1) and 2 (5alphaR2). Since 5alphaR2 is the dominant prostatic enzyme, the 5alphaR2 selective inhibitor finasteride has been widely used to treat benign prostatic hyperplasia (BPH). However, inhibition of both 5alphaR enzymes provides a greater decrease in serum dihydrotestosterone. We developed a specific antibody to 5alphaR1 and assessed expression in BPH and prostate cancer (pCa) tissue. The presence of this isoenzyme in localized prostate cancer would provide a rationale for assessing the efficacy of dual inhibition for prostate cancer prevention.
A polyclonal antibody to 5alphaR1 was developed and validated using 5alphaR1 and 5alphaR2 transfected COS-1 cells. A total of 26 BPH and 53 pCa specimens were assessed for 5alphaR1 protein expression using immunocytochemical methods. Also, 29 BPH and 37 pCa specimens were assayed for 5alphaR1 and 5alphaR2 enzyme activity.
Specificity of the 5alphaR1 antibody was confirmed using transfected COS-1 cells. Cells transfected with 5alphaR1 showed specific staining in immunocytochemistry experiments and on Western blotting of cell lysates the expected 24 kDa band was observed. High intensity immunoreactivity for 5alphaR1 was observed in the tumor epithelium of 28% of pCa specimens. No high intensity epithelial staining was observed in BPH specimens. In 19% of pCa and 7% of BPH specimens 5alphaR1 enzyme activity was detected.
The presence of increased 5alphaR1 in some prostatic malignancies suggests that it is worthwhile to investigate the use of a dual 5alphaR inhibitor to prevent or treat early stage prostate cancer.
在前列腺中，睾酮通过1型（5αR1）和2型（5αR2）5α - 还原酶（5αR）转化为活性更强的雄激素双氢睾酮。由于5αR2是前列腺中的主要酶，5αR2选择性抑制剂非那雄胺已被广泛用于治疗良性前列腺增生（BPH）。然而，抑制两种5αR酶可使血清双氢睾酮水平有更大幅度的降低。我们研发了一种针对5αR1的特异性抗体，并评估其在BPH和前列腺癌（pCa）组织中的表达。局部前列腺癌中这种同工酶的存在将为评估双重抑制预防前列腺癌的疗效提供理论依据。
研发了一种针对5αR1的多克隆抗体，并使用转染了5αR1和5αR2的COS - 1细胞进行验证。使用免疫细胞化学方法对总共26个BPH标本和53个pCa标本进行5αR1蛋白表达评估。此外，对29个BPH标本和37个pCa标本进行5αR1和5αR2酶活性检测。
使用转染的COS - 1细胞证实了5αR1抗体的特异性。转染了5αR1的细胞在免疫细胞化学实验中显示出特异性染色，并且在细胞裂解物的蛋白质印迹分析中观察到预期的24 kDa条带。在28%的pCa标本的肿瘤上皮中观察到5αR1的高强度免疫反应性。在BPH标本中未观察到高强度上皮染色。在19%的pCa标本和7%的BPH标本中检测到5αR1酶活性。
一些前列腺恶性肿瘤中5αR1增加，这表明研究使用双重5αR抑制剂预防或治疗早期前列腺癌是值得的。
