Molecular and biochemical basis of Lymphangioleiomyomatosis

摘要 肺淋巴管平滑肌瘤病（LAM）是一种缓慢进展的疾病， 肺的破坏和最终的呼吸衰竭，影响到每百万妇女3.4-7.8人。在生物化学上， LAM是由脑硬化复合体（TSC）功能丧失引起的，似乎需要激活 哺乳动物雷帕霉素靶蛋白复合物1（mTORC 1）信号通路的研究进展。尽管令人鼓舞的临床 从使用mTORC 1抑制剂治疗LAM的试验结果来看，这些药物由于两个原因而受到限制：首先， 基于雷帕霉素的治疗不是治愈性的，因为肿瘤在停止治疗后再生;第二， 长期使用雷帕霉素具有巨大的副作用，包括免疫紊乱和糖尿病。解决 目前，未满足的临床需求，该提案将研究三个未解决的机制问题， 长期目标是开发长效的LAM疗法。第一个目标将决定 在AML和LAM细胞中谷氨酰胺（Gln）代谢及其在细胞存活中的重要性， 诱导毒性的mTORC 1靶向治疗仍然是一个未解决的障碍。这一目标将调查 这些细胞中谷氨酰胺代谢的机制，以及新的方法来靶向的生长和生存， AML和LAM细胞通过药理学和shRNA方法，在体外和体内。第二个目标将 更深入地了解mTORC 1通路如何调节关键基因的选择性剪接 参与LAM中所见的“良性转移”表型。虽然mRNA剪接受到高度调控， 普遍存在的（发生在~95%的人类基因中，并且经常在癌症中失调）， 解除管制是未知的。利用我们最近完成的磷酸化蛋白质组学筛选的新结果， 将研究mTORC 1通路如何调节参与“良性肿瘤”的关键基因的剪接， LAM的“转移”表型。最后，第三个目标将确定关键的机制见解如何雌激素 有助于LAM的发病机制，其几乎仅发生在育龄期的女性中。 本研究的目的是研究雌激素受体信号通过ERK-Fra 1-ZEB通路的作用， mTORC 1过度活化，调节LAM细胞存活、迁移和侵袭。除了解决 LAM生物学的基本问题，这些目标中的每一个都具有临床意义，并且在其中两个目标中， 已经提出了将细胞生物学发现转化为相关的体内模型的研究。最后，我谨指出， 对LAM的生物学有更深入的了解是非常必要的， 拟议工作的完成将通过鉴定新的生物标志物以及 可特异性消除TSC中异常细胞生长、迁移和肿瘤形成的新药， LAM患者。

Abstract Pulmonary Lymphangioleiomyomatosis (LAM) is a slowly progressing disease characterized by cystic destruction of the lungs and eventual respiratory failure, and affects 3.4-7.8 per million women. Biochemically, LAM is caused by loss of function of the Tuberous Sclerosis Complex (TSC) and appears to require activation of the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway. Despite encouraging clinical trial results from the use of mTORC1 inhibitors to treat LAM, these drugs are limited for two reasons: first, rapamycin-based treatments are not curative as tumors regrow following cessation of treatment; and second, long-term rapamycin usage has tremendous side effects including immune disorders and diabetes. To resolve this currently, unmet clinical need, this proposal will investigate three unresolved mechanistic questions, with the long-term goal of developing long-lasting therapies for LAM. The first aim will determine the contribution of glutamine (Gln) metabolism in AML and LAM cells and its importance in cellular survival as inability of mTORC1-targeted therapies to induce toxicity remains an unaddressed hurdle. This aim will investigate the mechanism of Gln metabolism in these cells as well as new approaches to target the growth and survival of AML and LAM cells via pharmacologic and shRNA methods, both in vitro and in vivo. The second aim will garner a greater understanding of how the mTORC1 pathway regulates the alternative splicing of key genes involved in the "benign metastasis" phenotype seen in LAM. While mRNA splicing is highly regulated and pervasive (occurring in ~95% of human genes and frequently deregulated in cancer), the mechanisms causing deregulation are unknown. Using novel hits from a phospho-proteomic screen we recently completed, this aim will investigate how the mTORC1 pathway regulates the splicing of key genes involved in the "benign metastasis" phenotype of LAM. Finally, the third aim will identify key mechanistic insights into how estrogen contributes to the pathogenesis of LAM, which occurs almost exclusively in females during childbearing years. The aim will investigate the role of estrogen receptor signaling via the ERK-Fra1-ZEB pathway, in the context of mTORC1 hyperactivation, in regulating LAM cell survival, migration and invasion. In addition to addressing basic questions of LAM biology, each of these aims has clinical implications, and in two of the aims animal studies have been proposed to translate the cell biology discoveries into relevant in vivo models. In conclusion, there's a great need for greater understanding of the biology of LAM, and the expectations are that successful completion of the proposed work will impact LAM treatment through identification of new biomarkers as well as novel drugs that can specifically eliminate abnormal cell growth, migration and tumor formation in TSC and LAM patients.