Molecular and biochemical basis of Lymphangioleiomyomatosis

描述（由申请人提供）：肺淋巴管平滑肌瘤病（LAM）是一种缓慢进展的疾病，其特征是肺部囊性破坏和最终呼吸衰竭，每百万女性中有3.4-7.8例受累。在生物化学上，LAM是由多发性硬化症复合体（TSC）的功能丧失引起的，并且似乎需要雷帕霉素复合体1（mTORC 1）信号通路的哺乳动物靶标的激活。尽管使用mTORC 1抑制剂治疗LAM的临床试验结果令人鼓舞，但这些药物受到两个原因的限制：首先，基于雷帕霉素的治疗没有治愈性，因为停止治疗后肿瘤会重新生长;其次，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。为了解决目前尚未满足的临床需求，该项目将研究三个尚未解决的机制问题，长期目标是开发LAM的持久疗法。第一个目标将确定AML和LAM细胞中谷氨酰胺（Gln）代谢的贡献及其在细胞存活中的重要性，因为mTORC 1靶向治疗无法诱导毒性仍然是一个未解决的障碍。该目标将研究这些细胞中Gln代谢的机制，以及通过药理学和shRNA方法在体外和体内靶向AML和LAM细胞生长和存活的新方法。第二个目标是更好地理解mTORC 1通路如何调节LAM中“良性转移”表型所涉及的关键基因的选择性剪接。虽然mRNA剪接是高度调节和普遍的（发生在约95%的人类基因中，并且经常在癌症中失调），但导致失调的机制尚不清楚。利用我们最近完成的磷酸化蛋白质组学筛选的新命中，该目标将研究mTORC 1通路如何调节LAM“良性转移”表型中涉及的关键基因的剪接。最后，第三个目标将确定雌激素如何促进LAM发病机制的关键机制见解，LAM几乎只发生在育龄期女性中。目的是研究雌激素受体信号通过ERK-Fra 1-ZEB通路的作用，在mTORC 1超活化的背景下，调节LAM细胞的存活，迁移和侵袭。除了解决LAM生物学的基本问题之外，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，已经提出了动物研究，以将细胞生物学发现转化为相关的体内模型。总之，非常需要更好地了解LAM的生物学，并且期望成功完成拟议工作将通过鉴定新的生物标志物以及可以特异性消除TSC和LAM患者中异常细胞生长，迁移和肿瘤形成的新型药物来影响LAM治疗。

DESCRIPTION (provided by applicant): 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 project 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.