Lai L C, Erbas H, Lennard T W, Peaston R T
Department of Clinical Biochemistry, Freeman Group of Hospitals NHS Trust, Newcastle upon Tyne, UK.
Int J Cancer. 1996 Jun 11;66(6):743-6. doi: 10.1002/(SICI)1097-0215(19960611)66:6<743::AID-IJC6>3.0.CO;2-#.
Prostate-specific antigen (PSA) is a 33 kDa serine protease which is produced by many different tissues in the body and has been shown to be present in low concentrations in breast milk and in about 30% of breast cancers. The presence of PSA in breast cancers is associated with the presence of steroid-hormone receptors and may be a favourable prognostic indicator. In this study, PSA immunoreactivity was measured in breast cyst fluid obtained from women with palpable breast cysts which is the most common benign breast disease. PSA was found to be present in very low concentrations in breast cyst fluid. In an attempt to understand the possible role of PSA in the breast, the effect of PSA on growth of the hormone-dependent MCF-7 and hormone-independent MDA-MB-231 human breast cancer cell lines was studied. In addition, the effect of PSA on oestrone sulphatase activity and oestrogen 17-oxidoreductase activity in these cell lines was investigated. PSA, in low concentrations, was found to inhibit MCF-7 cell growth and to stimulate the conversion of oestradiol to the less potent oestrogen oestrone in this cell line. PSA had no effect on the MDA-MB-231 cell line. Our findings suggest that PSA may act as a negative growth regulator in hormone-dependent breast cancers.
前列腺特异性抗原（PSA）是一种33千道尔顿的丝氨酸蛋白酶，由体内多种不同组织产生，已证实在母乳中以及约30%的乳腺癌中以低浓度存在。乳腺癌中PSA的存在与类固醇激素受体的存在相关，可能是一个良好的预后指标。在本研究中，对从患有可触及乳腺囊肿（这是最常见的良性乳腺疾病）的女性获取的乳腺囊肿液中的PSA免疫反应性进行了检测。发现PSA在乳腺囊肿液中的浓度非常低。为了试图了解PSA在乳腺中的可能作用，研究了PSA对激素依赖性MCF - 7和激素非依赖性MDA - MB - 231人乳腺癌细胞系生长的影响。此外，还研究了PSA对这些细胞系中雌酮硫酸酯酶活性和雌激素17 - 氧化还原酶活性的影响。发现低浓度的PSA可抑制MCF - 7细胞生长，并在该细胞系中刺激雌二醇转化为活性较低的雌激素雌酮。PSA对MDA - MB - 231细胞系没有影响。我们的研究结果表明，PSA可能在激素依赖性乳腺癌中充当负生长调节因子。
