Molecular Mechanisms and Application of Ah Receptor-MicroRNA Interactions

项目总结 芳香烃受体(AhR)最初是作为一种细胞内蛋白被发现的，它与 环境毒物2，3，7，8-四氯二苯并对二恶英(TCDD)及其结构相关性氯化 芳香化合物。近年来，已有研究表明，AhR在结构上与 功能多样的化合物，包括化学保护植物化学物质，如黄酮类、多酚类 和吲哚-3-甲醇。毫不奇怪，这些化合物显示出组织特异性的AhR激动剂和拮抗剂。 活性，并可被归类为选择性AhR调节器(SAhRM)。本实验室以前的研究 已利用SAhRms在治疗疾病方面的潜在应用，以及6-甲基-1，3，8- 三氯二苯并呋喃(MCDF)最初的特征是AhR拮抗剂，但与TCDD一样，MCDF 在雌激素反应的乳腺癌细胞和乳腺肿瘤中显示出抗雌激素活性，MCDF 是一种有效的抗雌激素，通过抑制AhR-雌激素受体(ER)串扰发挥作用。结果： 初步研究表明，AhR激动剂，如TCDD和MCDF，可抑制大量 ER阴性的乳腺癌细胞包括高侵袭性的MDA-MB-231和MDA-MB-468细胞 分类为基底性或三重负性细胞。MCDF还能抑制裸鼠体内肿瘤生长 携带ER阴性细胞作为异种移植。此外，MCDF和TCDD的抗肿瘤活性是 伴随着对两个抗转移microRNAs(MiR)的依赖于AhR的诱导，即miR-335和miR- 205.拟议的研究将进一步探讨分子机制和潜在的临床应用。 MCDF和结构相关SAhRMs用于治疗ER阴性乳腺癌。目标1将专注于 SAHRM诱导miR-335和miR-205的调控以及AhR在抑制增殖中的作用 一组ER阴性乳腺癌细胞系的迁移和侵袭。在目标2中，AhR- 将确定ER阴性乳腺癌细胞对miR-335和miR-205表达的依赖性调节 将识别调控miR表达的二恶英反应元件(DREs)。在……里面 此外，还将研究由AhR-miR-335和AhR-miR-205相互作用调节的基因。目标3将 确认AhR、miR-335和miR-205在裸鼠原位乳腺肿瘤生长调控中的作用 裸鼠使用AhR、miR-335和miR-205表达受调控的细胞系。建议数 研究将首次表征AhR-miR相互作用的分子机制和 SAhRms在ER阴性乳腺癌治疗中的临床应用。

PROJECT SUMMARY The aryl hydrocarbon receptor (AhR) was initially discovered as an intracellular protein that binds to the environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and structurally related chlorinated aromatic compounds. In recent years, it has been demonstrated that the AhR binds with structurally and functionally diverse compounds including chemoprotective phytochemicals such as flavonoids, polyphenolics and indole-3-carbinol. Not surprisingly, these compounds exhibit tissue-specific AhR agonist and antagonist activities and can be classified as selective AhR modulators (SAhRMs). Previous studies in this laboratory have taken advantage of the potential applications of SAhRMs for treatment of diseases, and 6-methyl-1,3,8- trichlorodibenzofuran (MCDF) was initially characterized as an AhR antagonist but, like TCDD, MCDF exhibited antiestrogenic activity in estrogen-responsive breast cancer cells and mammary tumors, and MCDF is a potent antiestrogen that acts through inhibitory AhR-estrogen receptor (ER) crosstalk. Results of preliminary studies now show that AhR agonists such as TCDD and MCDF inhibit growth of a large number of ER-negative breast cancer cells including highly invasive MDA-MB-231 and MDA-MB-468 cells that are classified as basal or triple negative cells. MCDF also inhibits tumor growth in vivo in athymic nude mice bearing ER-negative cells as xenografts. Moreover, the antitumorigenic activity of MCDF and TCDD is accompanied by AhR-dependent induction of two antimetastatic microRNAs (miRs), namely miR-335 and miR- 205. The proposed studies will further investigate the molecular mechanisms and potential clinical applications of MCDF and structurally-related SAhRMs for treatment of ER-negative breast cancer. Aim 1 will focus on SAhRM-induced modulation of miR-335 and miR-205 and the role of the AhR in decreasing the proliferation, migration and invasion of a panel of ER-negative breast cancer cell lines. In Aim 2, the mechanism of AhR- dependent regulation of miR-335 and miR-205 expression will be determined ER-negative breast cancer cell lines and the functional dioxin responsive elements (DREs) regulating miR expression will be identified. In addition, genes regulated by AhR-miR-335 and AhR-miR-205 interactions will also be investigated. Aim 3 will confirm the role of the AhR, miR-335 and miR-205 in regulating orthotopic mammary tumor growth in athymic nude mice using cell lines in which expression of the AhR, miR-335 and miR-205 is regulated. The proposed studies will be the first to characterize the molecular mechanisms of AhR-miR interactions and development of SAhRMs for clinical applications in the treatment of ER-negative breast cancer.