Exploring microRNA degradation in T-cell acute lymphoblastic leukemia

项目总结 基因表达，从DNA到信使RNA(MRNA)再到蛋白质的遗传信息流， 涉及一组名为microRNAs的小RNA的微妙调控。MicroRNAs可以抑制基因 通过与mRNAs结合来表达，并阻止它们被翻译成蛋白质。微RNA 癌细胞中的水平通常与健康细胞中的microRNA水平不同，导致 某些癌症相关基因的差异表达。因此，控制microRNA水平提供了一种 癌症治疗的前景看好的靶点。 最近，我们发现当T细胞急性淋巴细胞白血病(T-ALL)细胞用 地塞米松，一种常用于白血病化疗的糖皮质激素，两种高度相关 而致癌microRNAs(miR-221/222)则被其靶基因(BIM)降解。这真是令人惊讶 因为microRNA通常控制其靶标的水平，但反之亦然。这也是 令人兴奋的是，它代表了一种由mRNAs执行的新兴基因调控模式，并打开了 制定癌症干预策略。 在这个建议中，我们首先旨在了解BIM mRNA是如何触发miR-221/222降解的。我们的 第二个目标是探索miR-221/222的降解如何增强T-ALL细胞在 化疗。在最终目标中，我们将开发一种创新的生化和计算方案来 全局识别T-ALL中不同靶mRNAs中可诱导miRNA降解的序列 病人样本。 总而言之，我们将研究T-ALL中一种新的基因调控机制，在这种机制中，mRNAs 中和microRNA。因为对糖皮质激素的抵抗是T-ALL的严重限制 化疗，阐明耐药的潜在机制可能为改善 目前的治疗干预措施。鉴于我们已经发现了一种潜在的广泛发生 在癌症中，识别可以 降解miRNAs和参与这一过程的蛋白质将有助于开发新的治疗方法来对抗 全部都是。

PROJECT SUMMARY Gene expression, the flow of genetic information from DNA to messenger RNA (mRNA) to protein, involves delicate regulation by a group of small RNAs named microRNAs. MicroRNAs can inhibit gene expression by binding to mRNAs and prevent them from being translated into proteins. MicroRNA levels in cancer cells are usually different from the microRNA levels in healthy cells, leading to differential expression of certain cancer-related genes. Controlling microRNA levels therefore offers a promising target for cancer treatment. Recently, we found that when T-cell acute lymphoblastic leukemia (T-ALL) cells are treated with dexamethasone, a glucocorticoid steroid commonly used in leukemia chemotherapy, two highly related and pro-cancer microRNAs (miR-221/222) are degraded by their target mRNA (BIM). This is surprising because microRNAs usually control the levels of their targets, but not the other way around. This is also exciting because it represents an emerging gene regulation mode carried out by the mRNAs and opens up strategies for cancer intervention. In this proposal, we first aim to understand how BIM mRNA triggers miR-221/222 degradation. Our second aim is to explore how miR-221/222 degradation enhances killing of T-ALL cells during chemotherapy. In the final aim, we will develop an innovative biochemical and computational protocol to globally identify sequences in different target mRNAs that can induce miRNA degradation in T-ALL patient samples. Collectively, our efforts will examine a new mechanism of gene regulation in T-ALL, in which mRNAs counteract microRNAs. Because resistance to glucocorticoid is a serious limitation for T-ALL chemotherapy, elucidating the underlying mechanism of resistance may provide the basis for improving current therapeutic interventions. Given that we have discovered a potentially widespread occurrence of the mRNA-induced microRNA degradation pathway in cancer, identifying the mRNAs that can degrade miRNAs and the proteins involved in this process would help develop new therapies to combat T-ALL.