Pathophysiology of Adult T-cell Leukemia/Lymphoma

T细胞白血病和淋巴瘤是临床上对常规化疗耐药的侵袭性癌症。 治疗方案和迫切需要新的治疗方法。这项建议研究的发病机制。 这些血液肿瘤和直接受益于退伍军人的健康，通过促进有针对性的发展 治疗，以及对这些耐药癌症的精确医学。我们实验室一直在研究T细胞 从两条主要致癌途径的角度看肿瘤：LIM结构域-2(LMO2)途径 IL2RG/JAK1/3/STAT5细胞因子信号通路。LMO2是最频繁解除管制的 T细胞急性淋巴细胞白血病中的癌基因。LMO2编码一个18 kDa的小蛋白，它是一个大的 调节关键靶基因转录的多亚单位蛋白复合体。我们一直在剖析 Lmo2基因S增强表达诱导T-ALL的机制及发现关键的白血病前期 LMO2促进的表型有分化停滞和自我更新增强等。这个 IL2RG/JAK1/3/STAT5通路是淋巴细胞发育和功能所必需的途径 研究发现，在成熟和未成熟的T细胞肿瘤中，这一途径的功能获得都是常见的。在……里面 最近令人兴奋的数据，我们的LMO2和JAK3的工作已经收敛在有趣的发现。突变与基因 表达分析表明，LMO2过表达和JAK3激活突变是一致的 成熟和未成熟的T细胞肿瘤。结果提示，这两条途径协同作用诱导T- 细胞转化。有趣的是，LMO2在双阴性T细胞前体细胞中的强制表达诱导 高度渗透性T细胞白血病，但双重阳性的祖细胞不会发展成白血病。同样，强制执行 结构性活性突变体JAK3的表达本身并不会导致疾病。我们假设T细胞 如果这两个途径被一致激活，就可能发生向白血病或淋巴瘤的转化。 在这项建议中，我们将研究这种协作性的机制基础，以便T细胞白血病和 淋巴瘤可能是更好的治疗靶点。在目标1中，我们将研究两者之间的协同性 Lmo2和JAK3癌基因在我们的Lmo2转基因中的骨髓转导和移植 老鼠模型。在目标2中，我们将分析IL2RG/JAK1/3/STAT5通路中的信号转导。 Lmo2转基因小鼠诱发的白血病和淋巴瘤。在目标3中，我们将测试JAK抑制剂的使用 抗原发人类T细胞肿瘤，并分析与化疗和LMO2基因敲除的协同作用。这个 AIMS将为开发新的生物标记物和新的治疗方法奠定基础 基于LMO2和IL2RG/JAK1/3/STAT5通路。

T-cell leukemias and lymphomas are clinically aggressive cancers resistant to conventional chemotherapy regimens and in desperate need for novel therapeutic approaches. This proposal studies the pathogenesis of these hematologic neoplasms and directly benefits Veterans' health by advancing the development of targeted therapy, and precision medicine for these treatment-resistant cancers. Our laboratory has been studying T-cell neoplasms from the perspective of two major oncogenic pathways: the LIM domain Only-2 (LMO2) pathway and the IL2RG/JAK1/3/STAT5 cytokine signaling pathway. LMO2 is one of the most frequently deregulated oncogenes in T-cell acute lymphoblastic leukemia. LMO2 encodes a small 18 kDa protein that is part of a large multisubunit protein complex that regulates the transcription of key target genes. We have been dissecting the mechanism by which LMO2's enforced expression induces T-ALL and have discovered key pre-leukemic phenotypes enforced by LMO2 like differentiation arrest and enhanced self-renewal. The IL2RG/JAK1/3/STAT5 pathway is required for the development and function of lymphocytes and our lab discovered that gain of function in this pathway is common in both mature and immature T-cell neoplasms. In recent exciting data, our LMO2 and JAK3 work has converged in intriguing findings. Mutational and gene expression analyses show that LMO2 overexpression and JAK3 activating mutations are concordant hits in both mature and immature T-cell neoplasms. The results imply that these two pathways cooperate to induce T- cell transformation. Interestingly, enforced expression of LMO2 in double negative T-cell progenitors induces highly penetrant T-cell leukemias but double positive progenitors do not develop leukemia. Similarly, enforced expression of constitutively active mutant JAK3 does not induce disease on its own. We hypothesize that T-cell transformation into leukemia or lymphomas may manifest if these two pathways were concordantly activated. In this proposal, we will investigate the mechanistic basis of this cooperativity so that T-cell leukemias and lymphomas may be better targeted therapeutically. In Aim 1, we will investigate the cooperativity between LMO2 and JAK3 oncogenes using bone marrow transduction and transplantation in our Lmo2 transgenic mouse model. In Aim 2, we will analyze signal transduction within the IL2RG/JAK1/3/STAT5 pathway in leukemias and lymphomas induced in Lmo2 transgenic mice. In Aim 3, we will test the use of JAK inhibitors against primary human T-cell neoplasms and analyze synergy with chemotherapy and LMO2 knockdown. The Aims will establish a foundation for the development of novel biomarkers and novel therapeutic approaches based on LMO2 and IL2RG/JAK1/3/STAT5 pathways.