Elucidation of Tumor Resistance Mechanisms in Tuberous Sclerosis Complex-Associated Renal Angiomyolipoma for the Design of Novel Nanotherapies

总结 大多数患有多发性硬化症（TSC）的患者发展为良性肾脏肿瘤，称为肾肿瘤。 血管平滑肌脂肪瘤（AML）可导致肾功能不全和自发性危及生命的血管瘤。的 AML的主要疗法是依维莫司，一种具有细胞生长抑制活性的激酶mTOR的雷帕霉素类似物抑制剂， 只能部分缩小肿瘤大小AML随着时间的推移变得稳定，并且肿瘤再生长通常发生在 治疗因副作用而中断。因此，迫切需要阐明 肿瘤耐药性，以开发更有效的治疗方法。 在过去的20多年里，通过实验重现AML的努力都失败了，排除了AML的研究 生物学为了解决这个问题，我们使用了基因工程的患者来源的诱导多能干细胞， 细胞（iPSC）以产生AML类器官。由携带双等位基因失活的iPSC产生的类器官 TSC 2基因座中的突变（即TSC 2-/-）忠实地再现了人类肿瘤的关键解剖学和分子特征。 肾AML（报道于埃尔南德斯JOR等人，Nat Commun. 2021年11月11日;12（1）：6496）。其中一些功能 包括存在共表达平滑肌和黑素细胞标志物的肌黑素细胞AML样细胞， 以及与肾AML共享的信号通路的转录激活。TSC 2-/- AML的移植 类器官进入免疫缺陷啮齿动物的肾脏导致完全血管化的人AML异种移植物， 机理研究和体内药物测试。利用这些新工具，我们发现了潜在的 由p21 CIP 1和BCL-2凋亡调节剂驱动的肿瘤抗性机制，防止AML细胞 由雷帕霉素类似物引起的死亡。我们的体内实验还表明，通过纳米载体的药物递送可以 增加抗肿瘤治疗的功效，同时减少在其它组织中的不期望的作用。的目的 我们的建议是阐明p21 CIP 1和BCL-2蛋白驱动的抗凋亡机制， 组合BCL-2蛋白抑制剂药物和雷帕霉素类似物的新型抗肿瘤疗法，其可以使用 组织靶向纳米颗粒。我们的长期目标是设计疗效更高的AML新疗法 和特异性。中心假设是由p21 CIP 1和BCL-2驱动的抗凋亡机制 凋亡抑制剂维持AML细胞存活，促进肿瘤对雷帕霉素治疗的抗性。我们的三 目的1：探讨p21 CIP 1介导的肾AML肿瘤耐药的抗凋亡机制; 目的2：阐明IGFBP 2在稳定p21 CIP 1促进AML细胞存活中的作用;目的3：研究IGFBP 2在AML细胞中的作用。 BCL-2蛋白通过药理学阻断BH 3结构域相互作用对AML细胞存活的贡献。 总的来说，这些研究将为AML的机制提供急需的见解，并将评估AML的治疗效果。 在AML靶向纳米颗粒中单独或与雷帕霉素类似物组合的BCL-2抑制剂治疗的功效。

Summary A majority of patients with Tuberous Sclerosis Complex (TSC) develop benign kidney tumors known as renal angiomyolipoma (AML) that can cause renal insufficiency and spontaneous life-threatening hemorrhages. The main therapy for AML is everolimus, a rapamycin analog inhibitor of the kinase mTOR with cytostatic activity that only partially reduces tumor size. AMLs become stable over time, and tumor re-growth is often occurs after treatment is interrupted due to side effects. Therefore, there is an urgent need to elucidate mechanisms of tumor resistance for the development of more efficacious therapies. Efforts to recapitulate AML experimentally have failed for the past 20+ years, precluding the study of AML biology. To address this problem, we have used genetically engineered patient-derived induced pluripotent stem cells (iPSCs) to generate AML organoids. Organoids generated from iPSCs carrying biallelic inactivating mutations in the TSC2 locus (i.e. TSC2-/-) faithfully recapitulated key anatomical and molecular features of human kidney AML (reported in Hernandez JOR et al. Nat Commun. 2021 Nov 11;12(1):6496). Some of those features included the presence of myomelanocytic AML-like cells co-expressing smooth muscle and melanocyte markers, and the transcriptional activation of signaling pathways shared with kidney AML. Transplantation of TSC2-/- AML organoids into the kidneys of immunodeficient rodents resulted in fully vascularized human AML xenografts for mechanistic studies and for drug testing testing in vivo. Using these novel tools we identified potential mechanisms of tumor resistance driven by p21CIP1 and by BCL-2 apoptosis modulators, preventing AML cell death induced by rapalogs. Our in vivo experiments also indicated that drug delivery via nanocarriers may increase the efficacy of anti-tumor therapy while reducing undesired effects in other tissues. The objective of this proposal is to elucidate anti-apoptotic mechanisms driven by p21CIP1 and BCL-2 proteins for the development of novel anti-tumor therapies combining BCL-2 protein inhibitor drugs and rapalogs, that can be co-delivered using tissue-targeting nanoparticles. Our long-term goal is to design new therapies for AML with increased efficacy and specificity. The central hypothesis is that antiapoptotic mechanisms driven by p21CIP1 and BCL-2 apoptosis inhibitors sustain AML cell survival promoting tumor resistance to rapalog therapy. Our three aims are: Aim 1: To investigate anti-apoptotic mechanisms of tumor resistance driven by p21CIP1 in renal AML; Aim 2: To elucidate the role of IGFBP2 in stabilizing p21CIP1 promoting AML cell survival; Aim 3: To study the contribution of BCL-2 proteins to AML cell survival through pharmacologic blockage of BH3 domain interaction. Collectively, these studies will provide much needed insight into the mechanisms of AML and will assess the efficacy of BCL-2 inhibitor therapy alone or in combination with rapalogs in AML-targeting nanoparticles.