Soto A M, Silvia R M, Sonnenschein C
Tufts University Health Science Schools, Department of Anatomy and Cellular Biology, Boston, MA 02111.
J Steroid Biochem Mol Biol. 1992 Dec;43(7):703-12. doi: 10.1016/0960-0760(92)90296-u.
Charcoal-dextran stripped serum/plasma supplemented media specifically inhibit the proliferation of estrogen-sensitive cells in culture conditions; estrogens cancel this effect. Here, we further characterize this phenomenon using human estrogen-sensitive breast cancer MCF7 cells and human serum/plasma. The serum/plasma-borne inhibitory activity (estrocolyone-I) is a non-dialyzable, heat-stable (60 degrees C x 2 h), protease-sensitive macromolecule and it is not extractable by organic solvents. Estrocolyone-I activity is retained after dialysis against 6 M urea or 10-100 mM dithiothreitol; however, simultaneous treatment with 6 M urea and 10-100 mM dithiothreitol completely abolishes its inhibitory activity. The inhibitory effect of serum is not due to serum albumin, nor to estrogen trapping by albumin or by sex hormone-binding globulin. Substantial purification was achieved by a combination of chromatographic techniques (dye-affinity, ion exchange, hydrophobic interaction chromatography). Estrocolyone-I activity seems to be due to a protein of an apparent native Mw of 70-80 kDa and an isoelectric point of 4.5-4.8.
用木炭 - 葡聚糖去除血清/血浆补充的培养基在培养条件下能特异性抑制雌激素敏感细胞的增殖；雌激素可消除这种作用。在此，我们使用人雌激素敏感的乳腺癌MCF7细胞和人血清/血浆进一步表征这一现象。血清/血浆携带的抑制活性（雌激素抑制素 - I）是一种不可透析、热稳定（60℃×2小时）、对蛋白酶敏感的大分子，且不能被有机溶剂提取。在对6M尿素或10 - 100mM二硫苏糖醇进行透析后，雌激素抑制素 - I活性得以保留；然而，同时用6M尿素和10 - 100mM二硫苏糖醇处理会完全消除其抑制活性。血清的抑制作用并非由于血清白蛋白，也不是由于白蛋白或性激素结合球蛋白对雌激素的捕获。通过多种色谱技术（染料亲和、离子交换、疏水相互作用色谱）的组合实现了大量纯化。雌激素抑制素 - I活性似乎归因于一种表观天然分子量为70 - 80kDa且等电点为4.5 - 4.8的蛋白质。
