miRNAs:Safe and effective therapeutic adjuvants for treating drug resistant TNBC

描述（由申请人提供）：大约15-20%的乳腺癌为三阴性乳腺癌（tnbc），表现出侵袭性、明显的转移模式和不良预后，导致不成比例的乳腺癌死亡。尽管早期化疗反应率较高，但仍有60%的tnbc患者出现化疗耐药，导致早期复发和较短的生存期。因此，了解这种耐药性背后的机制对于开发新的、有效的抗癌药物至关重要。最近，我们发现小的非编码rna - mirna在tnbc的药物敏感/耐药介导中起关键作用。通过高通量miRNA抑制剂文库筛选，我们已经确定了miRNA抑制剂，使耐药tnbc对紫杉醇敏感。有趣的是，我们初步的致敏剂mirna在复发转移性TNBC患者血清中的表达水平明显低于其健康兄弟姐妹的血清。此外，使用脂质体或生物相容性的PLGA纳米颗粒为基础的方法，我们发现在临床前小鼠肿瘤模型中，全身递送候选miRNA抑制乳腺癌肺转移而没有任何肝毒性。这些发现使我们假设肿瘤特异性miRNAs以药物特异性方式呈现选择性细胞毒性，这些miRNAs可以作为识别可能从特定药物治疗中获益最多的患者的检测标记物，并且这些miRNAs可能代表治疗tnbc的新治疗工具。我们提出三个具体目标来检验我们的假设。在Aim 1中，我们将验证候选miRNA通过靶向微管相关蛋白（MAPs）使细胞对紫杉醇的反应增敏的假设。在Aim 2中，我们将验证候选miRNA通过靶向DNA损伤监测途径影响紫杉醇反应的假设。在Aim 3中，我们将利用肿瘤异种移植小鼠模型和免疫系统完整的同基因小鼠模型，确定候选mirna在提高紫杉醇治疗耐药TNBC疗效方面的治疗潜力。我们还将测试候选mirna和紫杉醇联合治疗的反应，使用来自治疗敏感和治疗耐药TNBC患者的体外移植体。这项研究的成功完成将为使用miRNA疗法治疗耐药tnbc的新范例奠定基础。最近基于miRNA的临床试验已经开始确立miRNA疗法作为治疗一般疾病特别是癌症的可行方法。由于mirna通过对大量因素的微妙调节发挥作用，并且可以很容易地使用合成寡核苷酸进行操作，因此它们代表了比传统癌症治疗的单一基因或基因产物更有吸引力的靶标，后者通常容易产生耐药性。

DESCRIPTION (provided by applicant): Approximately, 15-20% of all breast cancers account for triple negative breast cancers (TNBCs) that exhibit aggressive, distinct metastatic pattern and poor prognosis resulting in disproportionate number of breast cancer deaths. Despite, a better chemotherapy response rate in early-stages, >60% of patients with TNBCs develop chemoresistance leading to early relapse and shorter survival. Understanding the mechanisms underlying such resistance is therefore crucial for the development of new, efficacious cancer drugs. Recently, we have discovered that small non-coding RNAs-miRNAs play critical roles in mediating drug sensitivity/resistance in TNBCs. Through high-throughput miRNA inhibitor library screens, we have identified miRNA inhibitors that uniquely sensitize drug resistant TNBCs to paclitaxel. Interestingly, our preliminary sensitizer miRNAs are expressed at significantly lower levels in relapsed metastatic TNBC patient sera compared to sera from their healthy siblings. Furthermore, using liposome- or biocompatible PLGA nanoparticle-based approaches, we show that systemic delivery of candidate miRNA suppresses breast cancer lung metastasis without any hepatotoxicity in preclinical mouse tumor models. These findings led us to hypothesize that tumor-specific miRNAs render selective cell cytotoxicity in a drug-specific manner, that these miRNAs may serve as detection markers for identifying patients those who might benefit most from specific drug treatment, and that these miRNAs may represent novel therapeutic tools for the treatment of the TNBCs. We propose three specific aims to test our hypothesis. In Aim 1, we will test the hypothesis that candidate miRNA sensitizes cellular response to taxol by targeting microtubule-associated proteins (MAPs). In Aim 2, we will test the hypothesis that candidate miRNA affects taxol response by targeting DNA damage surveillance pathway. In Aim 3, we will determine the therapeutic potential of candidate miRNAs in improving the efficacy of taxol for treating therapy resistant TNBC using tumor xenograft mouse model and syngeneic mouse model with intact immune system. We will also test the response of candidate miRNAs and taxol combination therapy using ex-vivo explants from therapy sensitive and therapy resistant TNBC patients. Successful completion of this study will set stage for a new paradigm of treating therapy resistant TNBCs using miRNA therapeutics. Recent miRNA-based clinical trials have begun to establish miRNA therapeutics as a feasible approach for treating diseases in general and cancer in particular. Since miRNAs function through subtle regulation of a large numbers of factors, and can be easily manipulated using synthetic oligos, they represent more attractive targets than the single gene or gene product that is the target of conventional cancer treatments, which are typically prone to drug resistance.