The role of miRNA15a and 16-1 in Multiple Myeloma

描述(申请人提供)：多发性骨髓瘤(MM)是第二种最常见的血液系统恶性肿瘤，它仍然是不可治愈的，中位生存期为3-5年。正常浆细胞发生的变化导致恶性MM细胞增殖的一个可能的解释是表观遗传变化，例如微RNA(MiRNAs)的调节。在这项研究中，我们选择关注miR-15a和-16-1在MM进展中的作用。miR-15a和-16-1存在于13q14染色体上的一个簇中，超过50%的MM患者通常缺失miR-15a和-16-1。最近的研究表明，在MM细胞中miR-15a和-16-1的表达很低。然而，缺乏对这些miRNAs调节肿瘤进展和扩散的机制，以及这些miRNAs如何调节肿瘤克隆和BM微环境之间的相互作用的更好的了解。我们假设miR-15a和-16-1是MM中肿瘤进展和扩散的关键调节因子，通过发生在MM克隆中的调控及其与骨髓微环境的相互作用。在特定的目标1中，我们将研究miR-15a/-16-1簇在MM克隆中作为肿瘤抑制因子在疾病进展中的作用。这将使用多发性骨髓瘤进展过程中患者的样本，并通过多发性骨髓瘤和DLEU2/miR15a/16-1基因敲除小鼠的转基因小鼠模型进行。在目标2中，我们将确定miR-15-a/16-1簇在骨髓环境中MM细胞和间充质细胞相互作用中的作用。在这里，我们将研究MM克隆与间充质干细胞/基质细胞的相互作用是否通过在外体中转移miRNA来实现。最后，在目标3中，我们确定了miR15a/16-1在MM细胞扩散和耐药性中的作用。在这里，我们将研究miR15a/16-1在调节MM细胞体外和体内转移和侵袭中的作用。我们还将确定miR15a/16-1在调节MM细胞对Bortezomib和地塞米松等治疗剂的敏感性/耐药性方面的作用。这些研究将导致miR-15a/-16-1作为预后标志物在临床上的应用。此外，可用于临床试验的前miRNA模拟物的开发可能会导致MM治疗的范式转变，并可能允许基于特定miRNA表达的个体化治疗。因此，这项建议很可能对MM患者具有重要的治疗和预后应用。

DESCRIPTION (provided by applicant): Multiple Myeloma (MM) is the second most prevalent hematological malignancy and it remains incurable, with a median survival of 3-5 years. One possible explanation for the changes that occur in normal plasma cells that lead to proliferation into malignant MM cells is epigenetic alterations, such as the regulation of micro-RNA (miRNAs). miRNAs have recently been shown to be involved in the pathogenesis of MM. In this grant, we chose to focus on the role of miR-15a and -16-1 in the progression of MM. miR-15a and -16-1 are present in a cluster located at chromosome 13q14, which is commonly deleted in over 50% of patients with MM. We have recently shown that the expression of miR-15a and -16-1 is low in MM cells. However, what is lacking is a better understanding of the mechanisms by which these miRNAs regulate tumor progression and dissemination, and how these miRNAs regulate interactions between the tumor clone and the BM microenvironment. We hypothesize that miR-15a and -16-1 are critical regulators of tumor progression and dissemination in MM, through regulations that occur in the MM clone and its interaction with the BM microenvironment. In Specific aim 1, we will examine the role of the miR-15a/-16-1 cluster as tumor suppressors in the MM clone during disease progression. This will be performed using samples from patients during MM progression, and through transgenic mouse models of MM and DLEU2/miR15a/16-1 knockout mice. In Aim 2, we will determine the role of the miR-15-a/16-1 cluster on the interaction of MM cells and mesenchymal cells in the BM milieu. Here, we will examine whether the interaction of the MM clone and the mesenchymal stem cells/stromal cells is through transfer of miRNA in exosomes. Finally, in Aim 3, we determine the role of miR15a/16-1 on cell dissemination and drug-resistance in MM. Here, we will examine the role of miR15a/16-1 in the regulation of cell metastasis and invasion in MM in vitro and in vivo. We will also determine the role of miR15a/16-1 in regulating sensitivity/resistance of MM cells to therapeutic agents such as bortezomib and dexamethasone. These studies will lead to the application of miR-15a/-16-1 as prognostic markers clinically used in practice. In addition, the development of pre-miRNA mimetics that can be used in clinical trials for patients may lead to a paradigm shift in the treatment of MM, and may allow individualized therapy based on the presence of specific miRNA expression. Therefore, this proposal will likely have significant therapeutic and prognostic applications for patients with MM.