Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada.
Department of Medical Biophysics, University of Toronto, Toronto, Canada.
Blood Cancer Discov. 2023 May 1;4(3):180-207. doi: 10.1158/2643-3230.BCD-22-0086.
Acute myeloid leukemia (AML) is fueled by leukemic stem cells (LSC) whose determinants are challenging to discern from hematopoietic stem cells (HSC) or uncover by approaches focused on general cell properties. We have identified a set of RNA-binding proteins (RBP) selectively enriched in human AML LSCs. Using an in vivo two-step CRISPR-Cas9 screen to assay stem cell functionality, we found 32 RBPs essential for LSCs in MLL-AF9;NrasG12D AML. Loss-of-function approaches targeting key hit RBP ELAVL1 compromised LSC-driven in vivo leukemic reconstitution, and selectively depleted primitive malignant versus healthy cells. Integrative multiomics revealed differentiation, splicing, and mitochondrial metabolism as key features defining the leukemic ELAVL1-mRNA interactome with mitochondrial import protein, TOMM34, being a direct ELAVL1-stabilized target whose repression impairs AML propagation. Altogether, using a stem cell-adapted in vivo CRISPR screen, this work demonstrates pervasive reliance on RBPs as regulators of LSCs and highlights their potential as therapeutic targets in AML.
LSC-targeted therapies remain a significant unmet need in AML. We developed a stem-cell-adapted in vivo CRISPR screen to identify key LSC drivers. We uncover widespread RNA-binding protein dependencies in LSCs, including ELAVL1, which we identify as a novel therapeutic vulnerability through its regulation of mitochondrial metabolism. This article is highlighted in the In This Issue feature, p. 171.
急性髓系白血病（AML）是由白血病干细胞（LSC）驱动的，其决定因素难以从造血干细胞（HSC）中辨别，也难以通过专注于一般细胞特性的方法揭示。我们已经鉴定出一组在人 AML LSC 中选择性富集的 RNA 结合蛋白（RBP）。使用体内两步 CRISPR-Cas9 筛选来检测干细胞功能，我们发现 32 个 RBP 在 MLL-AF9；NRASG12D AML 中对 LSC 是必需的。针对关键命中 RBP ELAVL1 的功能丧失方法会损害 LSC 驱动的体内白血病重建，并选择性地耗尽原始恶性细胞与健康细胞。综合多组学揭示了分化、剪接和线粒体代谢是定义白血病 ELAVL1-mRNA 相互作用组的关键特征，线粒体导入蛋白 TOMM34 是 ELAVL1 直接稳定的靶标，其抑制会损害 AML 的增殖。总之，使用适应于干细胞的体内 CRISPR 筛选，这项工作证明了 RBPs 作为 LSC 调节剂的普遍依赖性，并强调了它们作为 AML 治疗靶点的潜力。
LSC 靶向疗法仍然是 AML 中未满足的重大需求。我们开发了一种适应于干细胞的体内 CRISPR 筛选方法来识别关键的 LSC 驱动因素。我们在 LSCs 中发现了广泛的 RNA 结合蛋白依赖性，包括 ELAVL1，我们通过其对线粒体代谢的调节将其鉴定为一种新的治疗弱点。本文在本期特色文章中得到了强调，第 171 页。
