Validation of microRNAs as therapeutic targets in hematological malignancies

描述（由申请人提供）：通过靶向信使RNA并导致相应特异性靶蛋白的翻译抑制和下调的DNA寡脱氧核苷酸（ODN）调节癌基因表达长期以来一直是癌症的治疗策略。慢性和急性白血病都被认为适合于这种治疗方法，因为发生了非随机的分子异常，这些异常解除了基因表达的调节并直接促成了白血病的发生。迄今为止，mRNA靶向治疗主要依赖于基于反义或反向互补DNA ODN的方法。然而，当体内给药时，这些分子受到各种限制，这些限制最近通过修饰这些化合物的骨架结构而部分克服。即使如此，ODN用于靶下调的效率总体上仍然较低。最近发现的细胞内源性microRNA（miRs），通过与靶RNA杂交来调节其翻译速率的短RNA序列，为反义DNA寡核苷酸提供了一种合理的替代方案。最近的发现支持了这一概念，即特异性miR水平的改变通过靶癌基因或肿瘤抑制基因表达的失调与恶性转化机制相关。miR提供了作为癌基因或肿瘤抑制基因调控的正常对应物的优点，从而似乎促进相关靶标的延长调节，更重要的是同时靶向参与调控细胞增殖、分化和存活的途径的几个基因。这些结果最近促使设计合成制造的miR在癌症中的潜在治疗应用。在这里，我们建议调查的miR为基础的治疗在体内的小鼠模型中的临床适用性，其中下调特定的miR有助于恶性转化和/或侵略性表型的潜在白血病。我们的研究小组最近发现，miR-29 b通过调节DNA甲基转移酶[DNMT 1、DNMT 3A和DNMT 3B]、DNA超甲基化和基因沉默，在慢性淋巴细胞白血病（CLL）和急性髓细胞白血病（AML）的表观遗传进展的发病机制中具有相关性，而miR-181 a通过调节先天免疫机制中涉及的途径，调节Toll样受体4、IL-18、IL-19、IL-和miR 155在AML细胞系和原代母细胞中的表达。因此，作为原理证明，基于miR的疗法是适用且有效的治疗策略。因此，我们建议使用转基因（CLL）和异种移植（AML）鼠白血病模型对合成的2-OMemiR-29 b和2-OMemiR-181 a进行临床前体内药代动力学（PK）、药效学（PD）和治疗评价，目的是验证药代动力学、药效学和治疗终点。在该项目完成时，我们预计在癌症患者中使用miR 29 b和miR-181进行基于miR的治疗的初始I期研究的开始。

DESCRIPTION (provided by applicant): Modulation of oncogene expression by DNA oligodeoxynucleotides (ODNs) that target messenger RNAs and result in translational inhibition and down-regulation of the corresponding specific target proteins has long been pursued as a therapeutic strategy in cancer. Both chronic and acute leukemia's have been regarded as suitable for this therapeutic approach because of the occurrence of non-random molecular abnormalities that de-regulate gene expression and directly contribute to leukemogenesis. To date mRNA targeted therapies have relied mostly on antisense or reverse complementary DNA ODN-based approaches. When administered in vivo, however, these molecules suffer from a variety of limitations that have recently been partially overcome by modifying the backbone structure of these compounds. Even then, the efficiency of ODNs for target downregulation remains overall low. The recent discovery of cellular endogenous microRNAs (miRs), short RNA sequences that by hybridizing to target RNAs regulate their translation rate, has offered a sound alternative to the antisense DNA oligonucleotides. This concept has been supported by the recent discovery that alterations in the levels of specific miRs are mechanistically relevant to malignant transformation through deregulation of target oncogene or tumor suppressor gene expression. MiRs offer the advantage of being normal counterparts to oncogene or tumor suppressor gene regulation and thereby appear to promote prolonged modulation of the relevant targets and more importantly to target simultaneously several genes involved in pathways regulating cell proliferation, differentiation and survival. These results have recently prompted the design of potential therapeutic applications of synthetically manufactured miRs in cancer. Here, we propose to investigate the clinical applicability of miR-based therapies in-vivo in mouse models where downregulation of specific miRs contributes to malignant transformation and/or aggressive phenotypes of the underlying leukemia. Our group has recently identified relevance of miR-29b in the pathogenesis of epigenetic progression in chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML) through modulation of DNA methyltransferases [DNMT1, DNMT3A and DNMT3B], DNA hypermethylation and gene silencing and miR-181a in tumor suppressor activity by modulating pathways involved in mechanisms of innate immunity, regulating Toll like receptor 4, IL-¿ and miR155 expression in AML cell lines and primary blasts. Therefore, as proof of principle miR-based therapy is an applicable and effective therapeutic strategy. Hence, we propose to perform preclinical in-vivo pharmacokinetic (PK), pharmacodynamic (PD), and therapeutic evaluation of synthetic 2-OMemiR-29b and 2-OMemiR-181a with the goal to validate the pharmacokinetic, pharmacodynamic and therapeutic endpoints, using transgenic (CLL) and xenograft (AML) murine leukemia models. At completion of this project, we anticipate the beginning of initial phase I studies with miR based therapy using miR29b and miR-181 in cancer patients.