Stroma-mediated clonal evolution in Multiple Myeloma

描述(申请人提供)：多发性骨髓瘤(MM)是一种骨髓中具有特定定位的浆细胞疾病。最近对包括多发性骨髓瘤在内的几种恶性肿瘤的研究表明，随着时间的推移，在疾病发展的不同阶段，在诊断时克隆内结构的异质性。多发性骨髓瘤中克隆潮的存在代表了骨髓瘤进化生物学中的一种新范式，它将彻底改变目前多发性骨髓瘤发生和发展的模型，并可能具有深远的治疗意义。然而，支持骨髓间充质基质细胞(MSCs)在MM和其他恶性肿瘤的克隆性进化中的作用尚未被阐明。虽然许多调节肿瘤进展的因素是肿瘤细胞自主的，但它们不足以诱导进展和转移，需要一个允许的微环境才能出现坦率的恶性肿瘤。在这笔赠款中，我们重点关注骨髓间充质干细胞作为多发性骨髓瘤克隆进化的关键调节因子，使疾病进展期间能够更快地传播和产生耐药性。我们的主要假设是，在多发性骨髓瘤进展过程中，骨髓间充质干细胞是导致肿瘤扩散和耐药的克隆进化的不可或缺的调节者。我们将从三个具体目标来考察这一点。具体目标1将阐明在多发性骨髓瘤进展过程中发生在骨髓间充质干细胞中的一系列分子事件，并探索这些事件与肿瘤克隆进化的协同机制。疾病进展不同阶段(从MGUS到MM)的MM患者样本将被用来确定与肿瘤克隆多样化相关或推动肿瘤克隆多样化的MSCs中发生的分子变化。具体目标2将确定骨髓间充质干细胞在导致疾病进展的多发性骨髓瘤克隆进化中的作用。这一目标的假设是，MSCs为MM中的肿瘤进展提供特定克隆的选择性优势。我们将使用体内跟踪通过荧光团区分的克隆，其中克隆亚群可以被分子顺序询问，以跟踪在对MSCs中放松调控的特定基因的丧失或功能获得的研究中，出现为“胜利者”或“失败者”MM克隆的细胞的传记。我们的假设是，在大剂量化疗后，MSCs中发生的特定分子变化允许MM侵袭性耐药亚克隆的生长。在这个目标中，我们将使用体外和体内模型系统来确定在MM干细胞移植中使用高剂量化疗后MSCs中发生的分子变化，并研究这反过来如何在MM的克隆进化和耐药性中发挥作用。这项拨款的重点是使用创新和多样化的方法来了解MSCs在MM的克隆进化中的作用。我们结合患者样本和小鼠模型来研究，在高通量无偏方法中，MSCs在诱导肿瘤生长、克隆异质性和耐药性方面的作用。

DESCRIPTION (provided by applicant): Multiple Myeloma (MM) is a disease of plasma cells with specific localization in the bone marrow. Recent studies in several malignancies including MM have shown intraclonal architectural heterogeneity at diagnosis and at different stages of disease progression over time. The presence of "clonal tides" in MM represent a novel paradigm in myeloma evolutionary biology which will revolutionize the current modeling of MM tumorigenesis and progression and are likely to have profound therapeutic implications. However, the role of the supporting bone marrow niche, specifically mesenchymal stromal cells (MSCs) in the clonal evolution of MM and other malignancies has not been previously elucidated. Although many factors regulating tumor progression are tumor cell autonomous, they are insufficient to induce progression and metastasis, and a permissive microenvironment is required for frank malignancy to emerge. In this grant, we focus on MSCs as critical regulators of clonal evolution in MM that allows for more rapid dissemination and drug resistance during disease progression. Our overarching hypothesis is that MSCs are integral regulators of clonal evolution in MM inducing both tumor dissemination and drug resistance during progression. We will examine this in 3 Specific Aims. Specific Aim 1 will elucidate sequential molecular events that occur in MSCs during MM progression and explore mechanisms of cooperativity of these events with tumor clonal evolution. MM patient samples at different stages of disease progression (MGUS to MM) will be used to determine molecular changes that occur in MSCs that correlate with, or drive tumor clonal diversification. Specific Aim 2 will determine the role of MSCs in clonal evolution in MM that leads to disease progression. The hypothesis of this aim is that MSCs confer selective advantage of specific clones for tumor progression in MM. We will use in vivo tracking of clones distinguished by fluorophores, where clonal subsets can be molecularly interrogated sequentially to track the biography of cells that emerge as "winner" or "loser" MM clones in response to loss-of or gain-of-function studies of specific genes deregulated in MSCs. Specific Aim 3 will investigate the role of the MSCs in the regulation of drug resistance in MM. Our hypothesis is that specific molecular changes that occur in MSCs after high-dose chemotherapy allow outgrowth of aggressive drug-resistant subclones of MM. In this aim, we will use in vitro and in vivo model systems to determine molecular changes that occur in MSCs after high dose chemotherapy used in stem cell transplant in MM and investigate how this in turn plays a role in clonal evolution and drug resistance in MM. This grant is focused on using innovative and diverse methods to understand the role of MSCs in clonal evolution in MM. We combine patient samples with mouse models to examine, in high-throughput unbiased methods, the role of MSCs in inducing tumor growth, clonal heterogeneity and drug resistance.