Pharmacological Profile of 6,12-Dihydro-3-methoxy-1-benzopyrano[3,4-b][1,4]benzothiazin-6-one, a Novel Human Estrogen Receptor Agonist.
作者:Yves Jacquot、Anny Cleeren、Ioanna Laios、Yan Ma、Athem Boulahdour、Laurent Bermont、Bernard Refouvelet、Gérard Adessi、Guy Leclercq、Alain Xicluna
DOI:10.1248/bpb.25.335
日期:——
Pharmacological studies were carried out to characterize further the endocrinological profile and the binding mode to the estrogen receptor (ER) of 6,12-dihydro-3-methoxy-1-benzopyrano[3,4-b][1,4]benzothiazin-6-one (1). Binding experiments were conducted with highly purified recombinant human estrogen receptors hERα and β. Potent estrogenic activity of compound 1 was assessed by testing its ability to down-regulate ERs and to enhance estrogen receptor element (ERE)-dependent transcription. The latest step of our work dealt with the synthesis of the 9-fluorinated derivative 15 for ionic microscopy experiments to determine the intracellular localization of compound 1. Although 1 failed to compete with [3H]E2 for binding to both ER isoforms, evidence was reported that it interacted with hERα in MCF-7 cells (ER down-regulation/ERE-dependent luciferase induction). Hence, an appropriate conformation of the hormone binding domain, most probably conferred by co-regulators of ER, is required for the onset of an activity of the compound 1. Estrogenic activity was weak but on the order of magnitude of that of coumestrol (slightly weaker). The synthesis of the 9-methoxylated derivative 16 and its pharmacological evaluation led us to propose a binding mode of 1 on hERα. Compound 1 appears to interact with ERα mainly through interactions of its 3-methoxy substituent with the residue His-524 of the hormone binding domain.
为了进一步确定 6,12-二氢-3-甲氧基-1-苯并吡喃并[3,4-b][1,4]苯并噻嗪-6-酮(1)的内分泌特征和与雌激素受体(ER)的结合模式,我们进行了药理研究。化合物 1 的强效雌激素活性是通过测试其下调ERs 和增强雌激素受体元件(ERE)依赖性转录的能力来评估的。虽然化合物 1 未能与 [3H]E2 竞争与两种 ER 异构体的结合,但有证据表明它与 MCF-7 细胞中的 hERα 发生了相互作用(ER 下调/ERE 依赖性荧光素酶诱导)。因此,化合物 1 的活性开始需要激素结合结构域的适当构象,这很可能是由 ER 的协同调节因子赋予的。通过合成 9-甲氧基化衍生物 16 及其药理评估,我们提出了 1 与 hERα 的结合模式。化合物 1 似乎主要通过其 3-甲氧基取代基与激素结合域残基 His-524 的相互作用与 ERα 发生作用。