Identification of steroid sulfate transport processes in the human mammary gland
Identification of steroid sulfate transport processes in the human mammary gland
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DOI：
10.1210/jc.2003-030174
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发表时间：
2003-08-01
影响因子：
5.8
通讯作者：
St-Pierre, MV
中科院分区：
文献类型：
--
作者：
Pizzagalli, F;Varga, Z;St-Pierre, MV
循环激素和类固醇前体的局部生物转化都是人类乳腺组织中雌激素的来源。雌酮-3-硫酸酯（E（1）S）是绝经前妇女重要的雌激素形式，硫酸脱氢表雄酮（DHEAS）是主要的肾上腺前体。研究了控制这些阴离子类固醇缀合物递送至乳腺的膜转运系统。用RT-PCR和北方印迹法检测有机阴离子转运多肽（OATP）（溶质载体家族21 A）和有机阴离子转运蛋白（OAT）（溶质载体家族22 A）基因家族的表达。OATP-B（SLC 21 A9）是表达的主要载体; OATP-D（SLC 21 A11）和OATP-E（SLC 21 A12）丰度较低。在正常切片中，OATP-B免疫定位于导管上皮细胞周围的肌上皮。浸润性癌导管上皮细胞呈阳性。在稳定转染的中国仓鼠卵巢细胞中表征了OATP-B。E（1）S亲和常数（K（m））[K（m）= 5 μ mol/L，最大速度（V（max））V（max）= 777 pmol/mg。DHEAS（K（m）= 9 μ mol/L，V（max）= 85 pmol/mg . min）为底物。前列腺素（PG）A（1）和PGA（2）通过使V（max）增加2倍而不改变K（m）来刺激E（1）S和DHEAS的摄取。PGA的作用被亲脂性巯基试剂N-乙基马来酰亚胺选择性阻断，但不被亲水性乙酰氨基-4 '（碘乙酰基）氨基二苯乙烯-2，2'-二磺酸阻断，表明亲电性环戊烯酮与OATP-B的特定半胱氨酸残基之间的相互作用。
Circulating hormones and local biotransformation of steroid precursors are both sources of estrogen in human mammary tissue. Estrone-3-sulfate (E(1)S) is an important estrogenic form in premenopausal women, and dehydroepiandrosterone sulfate (DHEAS) constitutes a major adrenal precursor. Membrane transport systems that govern delivery of these anionic steroid conjugates to the mammary gland were investigated. RNA was screened by RT-PCR and Northern blotting for expression of organic anion transporting polypeptide (OATP) ( solute carrier family 21A) and organic anion transporter ( OAT) ( solute carrier family 22A) gene families. OATP-B (SLC21A9) was the major carrier expressed; OATP-D (SLC21A11) and OATP-E (SLC21A12) were less abundant. In normal sections, OATP-B immunolocalized to the myoepithelium that surrounds the ductal epithelial cells. In invasive carcinoma, ductal epithelial cells were positive. OATP-B was characterized in stable transfected Chinese hamster ovary cells. E(1)S affinity constant (K(m)) [K(m) = 5 mumol/liter, maximum velocity (V(max)) V(max) = 777 pmol/mg . min] and DHEAS (K(m) = 9 mumol/liter, V(max) = 85 pmol/mg . min) were substrates. The prostaglandins (PG) A(1) and PGA(2) stimulated uptake of E(1)S and DHEAS by increasing V(max) 2-fold but not changing K(m). The effect of PGA was selectively blocked by the lipophilic thiol reagent N-ethylmaleimide but not by the hydrophilic acetamido-4'( iodoacetyl) aminostilbene-2,2'-disulfonic acid, suggesting an interaction between the electrophilic cyclopentenone and specific cysteine residues of OATP-B.