Pathophysiology of Adult T-cell leukemia/lymphoma

T细胞急性淋巴细胞性白血病(T-ALL)是一种侵袭性较强的成人癌症。成人T-ALL经常 早期T细胞前体(ETP-ALL)亚型，表现为耐药和高复发风险。 成人T-ALL的人口结构与年轻退伍军人的人口结构相匹配，因此这笔赠款有可能影响 对这些退伍军人的诊断和护理。像许多侵袭性人类白血病和淋巴瘤一样，T-ALL 可以通过细胞毒化疗缓解，但大多数患者会复发。我们从中吸取了教训 我们的研究针对刺激增殖的突变癌基因，如JAK1/3，也诱导了 反应是短暂的。在这些癌症中，高完全缓解率随后是高缓解率 复发的原因是具有造血功能的耐药白血病启动细胞(LIC)的存在。 干细胞样特征。LIC在化疗期间处于休眠状态并存活下来，然后在缓解后扩张- 归纳法。因此，瞄准这类LIC人群是实现治疗的关键。仅限LIM域(LMO2)是 T-ALL中的主要致癌基因，它赋予正常T细胞前体细胞干细胞特征。 靶向LMO2诱导的T-ALL LIC将涉及靶向LMO2复合体。为此，我们有 对LMO2复合体进行生化表征，以了解其结构和功能。在初步数据中，我们 证明LMO2的S致癌功能要求其作为多亚单位大分子复合体的一部分。 LMO2的S直接结合伙伴包括碱性螺旋-环-螺旋蛋白、TAL1或LYL1以及GATA基序 结合蛋白GATA1、GAT2和GAT3。我们发现LMO2的S诱导T-ALL的能力密切相关 在另一种蛋白质LIM结构域结合1(LDB1)上，LMO2结构性结合到该蛋白质上。LDB1有自己的 相互作用伙伴，即单链结合蛋白SSBP1-4。重要的是，LMO2复合体 形成能赋予蛋白质稳定性。在我们的研究过程中，我们观察到了可能掌握关键的 更好地理解Lmo2的S对LIC的诱导，并更好地靶向Lmo2复合体。虽然《伦敦金属2》的S 在小鼠模型中诱导LIC已被广泛研究，但尚未翻译到人类细胞中。 我们假设LIC的特性是由LMO2复合体赋予T细胞前体细胞的。 此外，我们的蛋白质组学研究显示，LMO2复合体中有大量类似的蛋白质，但我们没有 相信它们在功能上是等同的。我们假设不同的类似物具有独特的功能作用。 LMO2复合体，TAL1对LYL1，GATA因子1-3，以及SSBP因子2对3。我们将在一本新的 人体建模系统。最后，我们假设针对LMO2的靶向治疗将涉及对 LMO2复合体。这笔赠款的具体目的将促进我们对LMO2如何发挥作用和 它如何在这些侵袭性白血病中成为靶点。

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive cancer in adult patients. Adult T-ALL is frequently the Early T-cell Precursor (ETP-ALL) subtype that manifests with treatment-resistance and high risk of relapse. The demographic of adult T-ALL matches that of young Veterans so this grant has the potential to impact the diagnosis and care of this Veteran population. Like many aggressive human leukemias and lymphomas, T-ALL can be put into remission by cytotoxic chemotherapy yet the majority of patients relapse. We have learned from our studies that targeted therapies against mutant oncogenes stimulating proliferation, like JAK1/3, also induce responses that are short lived. In these cancers, the high rate of complete remission followed by the high rate of relapse is explained by the presence of treatment-resistant leukemia-initiating cells (LIC) that have hematopoietic stem cell-like features. The LIC lie dormant and survive during chemotherapy and then expand after remission- induction. Hence, targeting this LIC population is crucial to achieving cures. LIM domain Only-2 (LMO2) is a major driver oncogene in T-ALL, where it confers stem cell characteristics upon normal T-cell progenitor cells. Targeting LMO2-induced T-ALL LIC will involve targeting the LMO2 complex. Towards this end, we have biochemically characterized the LMO2 complex to understand its structure and function. In preliminary data, we show that LMO2’s oncogenic function requires it to act as part of a multisubunit macromolecular complex. LMO2’s direct binding partners include the basic helix-loop-helix proteins, TAL1 or LYL1, and the GATA motif binding proteins GATA1, 2, and 3. We discovered that LMO2’s ability to induce T-ALL is exquisitely dependent upon another protein, LIM domain binding 1 (LDB1), to which LMO2 is constitutively bound. LDB1 has its own interaction partners, namely the Single Stranded Binding Proteins SSBP1-4. Importantly, LMO2 complex formation confers protein stability. In the course of our studies, we made observations that could hold the key to better understanding LMO2’s induction of the LIC and to better targeting of the LMO2 complex. Although LMO2’s induction of the LIC in mouse models has been extensively studied, this has not been translated to human cells. We hypothesize that LIC properties are conferred by the LMO2 complex upon T-cell progenitor cells. Furthermore, our proteomic studies reveal a panoply of paralogous proteins in the LMO2 complex but we do not believe they are functionally equivalent. We hypothesize unique functional roles for the various paralogues of the LMO2 complex, TAL1 v. LYL1, GATA factors 1-3, and SSBP factors 2 v. 3. We will investigate this in a novel human modeling system. Lastly, we hypothesize that targeted therapy against LMO2 will involve perturbation of the LMO2 complex. The Specific Aims of this grant will advance our understanding of how LMO2 functions and how it may be targeted in these aggressive leukemias.