Effects of YBX1 on gene expression and translation in acute myeloid leukemia (AML)

YBX1 对急性髓系白血病 (AML) 基因表达和翻译的影响

• 批准号: 453491106
• 负责人: Professor Dr. Florian Heidel
• 金额: --
• 依托单位: Klinik für Hämatologie, Hämostaseologie, Onkologie und Stammzelltransplantation
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/453491106?language=en
• 关键词: Effects; YBX1; gene; expression; translation

Persistence of malignant cells following cytotoxic or targeted therapy is a major determinant of adverse outcome in patients with hematologic cancers. Despite the fact that the majority of patients with acute myeloid leukemia (AML) achieve complete remission after chemotherapy, a large proportion of them relapse as a result of residual malignant cells. After discontinuation of treatment, these persistent clones have a competitive advantage over normal cells in the bone marrow niche leading to re-establishment of the disease. Targeting strategies that specifically reduce competitivity of malignant cells while leaving normal cells unaffected are highly needed. Recently, our group identified the splicing factor YBX1 as a downstream effector of JAK2-kinase and uncovered its function in stabilizing cell signaling. Of note, JAK2-mutated cells are not primarily dependent on YBX1, as indicated by an RNAi-screen. However, inactivation of YBX1 sensitized JAK2-mutated cells to JAK-inhibitor treatment.In contrast, analysis of publicly available CRISPR-Cas9 dependency screening datasets on human cancer cell lines of the Achilles Project (Broad Institute) indicated a pan-cancer dependency for YBX1 which was even more significant in hematopoietic cancers and most pronounced in AML cell lines. These findings indicate a relevant dependency and distinct mechanism in AML. We have validated the dependency of AML cells using an arrayed CRISPR-Cas9 based negative selection screen, which showed a strong dependency on Ybx1 following infection with 4 different sgRNAs. This effect could be confirmed in several AML cell lines and in different in vivo models of AML. Transcriptome analysis following YBX1 inactivation revealed deregulation of genes involved in translation and elongation.According to our proposed working program we will confirm the functional relevance of YBX1 for leukemia stem cells in conditional mouse models. In pre-clinical models of human AML (patient-derived xenograft; PDX) we will specifically assess for cell competition against normal hematopoietic cells, a therapeutically relevant setting in a minimal residual disease situation. This approach will be complemented by testing of pharmacologic compounds which may interfere with YBX1 function. Moreover, we will investigate the mechanistic consequences of YBX1-mediated (post-) transcriptional regulation by polysome profiling and global proteome analysis. Using genome editing approaches in human AML cells, we aim to identify relevant molecules that depend on YBX1 function.In summary, we aim to confirm the relevant dependency of AML cells on YBX1 in pre-clinical models followed by investigation of mechanistic aspects to identify relevant effector molecules. Our experimental approach may therefore facilitate therapeutic targeting of frequently persisting leukemic cells, the source of relapse in AML.

细胞毒性或靶向治疗后恶性细胞的持续存在是血液系统癌症患者不良结局的主要决定因素。尽管大多数急性髓性白血病（AML）患者在化疗后达到完全缓解，但其中很大一部分患者由于残留的恶性细胞而复发。停止治疗后，这些持续性克隆比骨髓生态位中的正常细胞具有竞争优势，导致疾病重新建立。非常需要特异性降低恶性细胞的竞争性同时使正常细胞不受影响的靶向策略。最近，我们的小组确定了剪接因子YBX 1作为JAK 2激酶的下游效应子，并揭示了其在稳定细胞信号传导中的功能。值得注意的是，JAK 2突变的细胞并不主要依赖于YBX 1，如RNAi筛选所示。然而，YBX 1的失活使JAK 2突变细胞对JAK抑制剂治疗敏感，相反，对Achilles Project（Broad Institute）的人类癌细胞系的公开可用的CRISPR-Cas9依赖性筛选数据集的分析表明，YBX 1的泛癌症依赖性在造血系统癌症中甚至更显著，并且在AML细胞系中最明显。这些发现表明AML中存在相关的依赖性和独特的机制。我们已经使用基于阵列CRISPR-Cas9的阴性选择筛选验证了AML细胞的依赖性，其在用4种不同的sgRNA感染后显示出对Ybx 1的强烈依赖性。这种效应可以在几种AML细胞系和不同的AML体内模型中得到证实。YBX 1失活后的转录组分析揭示了参与翻译和延伸的基因的失调。根据我们提出的工作计划，我们将在条件小鼠模型中证实YBX 1与白血病干细胞的功能相关性。在人AML（患者源性异种移植物; PDX）的临床前模型中，我们将专门评估与正常造血细胞的细胞竞争，这是最小残留疾病情况下的治疗相关环境。这种方法将通过测试可能干扰YBX 1功能的药理化合物来补充。此外，我们将调查YBX 1介导的（后）转录调控的机制的后果，通过多核糖体分析和全球蛋白质组分析。在人类AML细胞中使用基因组编辑方法，我们的目标是识别依赖于YBX 1功能的相关分子。总之，我们的目标是在临床前模型中确认AML细胞对YBX 1的相关依赖性，然后研究机制方面以识别相关效应分子。因此，我们的实验方法可能有助于治疗经常持续存在的白血病细胞，AML复发的来源。