Involvement of estrone-3-sulfate transporters in proliferation of hormone-dependent breast cancer cells
Involvement of estrone-3-sulfate transporters in proliferation of hormone-dependent breast cancer cells
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DOI：
10.1124/jpet.104.071522
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发表时间：
2004-12-01
影响因子：
3.5
通讯作者：
Tamai, I
中科院分区：
文献类型：
--
作者：
Nozawa, T;Suzuki, M;Tamai, I
尽管循环中的 3-硫酸雌酮是生物活性雌激素的主要前体，但由于分子的高亲水性，不太可能通过扩散发生穿过质膜的渗透。本研究的目的是阐明特定转运蛋白在向人类乳腺癌衍生的 T-47D 细胞（以雌激素依赖性方式生长）供应 3-硫酸雌酮中的作用。通过向培养基中添加雌酮-3-硫酸盐或雌二醇来增加T-47D细胞的增殖。雌酮-3-硫酸酯的初始摄取速率在动力学上表现出单一可饱和成分，K-m 和 V-max 值分别为 7.6 muM 和 172 pmol/mg 蛋白质/分钟。用Li+、K+或N-甲基葡糖胺(+)替代细胞外Na+对[H-3]雌酮-3-硫酸盐的摄取没有影响。类固醇激素的硫酸盐结合物强烈抑制该摄取，但 17β-葡萄糖醛酸雌二醇则不抑制该摄取。牛磺胆酸盐和磺溴酞抑制吸收，而其他测试的阴离子和阳离子化合物则没有。通过逆转录聚合酶链式反应分析检测到有机阴离子转运多肽 OATP-D 和 OATP-E（它们是 3-硫酸雌酮的候选转运蛋白）的表达，尽管它们在雌激素摄取中的实际参与仍有待澄清。总之，T-47D 细胞对 3-硫酸雌酮的摄取是通过载体介导的运输机制介导的，表明雌激素前体是由雌激素依赖性乳腺癌细胞主动输入的。
Although circulating estrone-3-sulfate is a major precursor of biologically active estrogen, permeation across the plasma membrane is unlikely to occur by diffusion because of the high hydrophilicity of the molecule. The object of this study was to clarify the involvement of specific transporter(s) in the supply of estrone-3-sulfate to human breast cancer-derived T-47D cells, which grow in an estrogen-dependent manner. The proliferation of T-47D cells was increased by the addition of estrone-3-sulfate, or estradiol, to the cultivation medium. The initial uptake rate of estrone-3-sulfate kinetically exhibited a single saturable component, with K-m and V-max values of 7.6 muM and 172 pmol/mg of protein/min, respectively. The replacement of extracellular Na+ with Li+, K+, or N-methylglucamine(+) had no effect on the uptake of [H-3] estrone-3-sulfate. The uptake was strongly inhibited by sulfate conjugates of steroid hormones, but not by estradiol-17beta-glucuronide. Taurocholate and sulfobromophthalein inhibited the uptake, whereas other tested anionic and cationic compounds did not. The expression of organic anion transporting polypeptides, OATP-D and OATP-E, which are candidate transporters of estrone-3-sulfate, was detected by reverse transcription-polymerase chain reaction analysis, although their actual involvement in the uptake of estrogen remains to be clarified. In conclusion, the uptake of estrone-3-sulfate by T-47D cells was mediated by a carrier-mediated transport mechanism, suggesting that the estrogen precursor is actively imported by estrogen-dependent breast cancer cells.