Acute myeloid leukemia (AML) is an aggressive blood disorder characterized by rapid growth of poorly differentiated myeloid cells. Gain-of-function mutations in isocitrate dehydrogenases (IDHs) are detected in ~20% of AML and ~80% of secondary gliomas. Mutant IDH1/2 isoenzymes acquire neomorphic activity to produce 2-hydroxyglutarate (2-HG) oncometabolite, resulting in hypermethylated DNA and histones, altered gene expression, and blocked differentiation of hematopoietic progenitors. Here, we presented preclinical development of LY3410738, an oral, dual IDH1/2 inhibitor with potential to penetrate the blood-brain barrier. LY3410738 covalently inhibited mutated-IDH1/2, reduced 2-HG levels at low nanomolar concentrations in human AML and glioma models, and demonstrated efficacy in AML patient-derived xenografts (PDXs) in vivo, inducing myeloid differentiation. LY3410738 retained in vitro activity in cancer models with acquired secondary IDH1/2 mutations conferring resistance to ivosidenib and enasidenib. LY3410738 synergized and was well tolerated with standard-of-care regimens such as cytarabine, azacitidine, venetoclax, or midostaurin in IDH1/2-mutated AML PDXs.
Nathan A Brooks, Anna Skwarska, V. Salama et al.· Blood Cancer Discovery· 0 citations
Acute myeloid leukemia (AML) persistence and relapse are sustained by leukemia-propagating cells, yet the molecular programs supporting their expansion during disease evolution remain incompletely understood. Using serial patient-derived xenotransplantation, we establish a longitudinal model in which leukemia-initiating capacity progressively increases. Integrated single-cell transcriptomics and multi-omics profiling reveal a predominantly non-genetic trajectory that follows a conserved pattern across models and is associated with coordinated changes across epigenetic, transcriptional, and proteomic layers. Ribosome profiling and rRNA 2'-O-methylation analyses further support a stage-specific increase in translational activity with ribosome remodeling in advanced xenografts. A pharmacological screen of 3,247 compounds uncovers a limited set of vulnerabilities that consistently emerge during disease progression, including CRBN-dependent degradation of GSPT1 (CC-885) and IAP antagonism (AZD5582). In vivo validation shows that both agents markedly reduce leukemic burden, impair leukemia propagation, and enhance cytarabine activity in patient-derived xenograft (PDX) models. Together, these findings show that leukemic propagation is driven by a non-genetic remodeling program, providing a framework to prioritize and test stage-specific therapeutic strategies in AML.
Clément Larrue, Paolo Angelino, Sarah Mouche et al.· Cell Reports Medicine· 0 citations
Acute myeloid leukemia (AML) is an aggressive blood cancer characterized by high rates of relapse and poor outcomes, especially in elderly or unfit patients, who cannot tolerate intensive chemotherapy. While the BCL2 inhibitor venetoclax has improved initial responses in this high-risk population, relapses remain nearly universal, highlighting the need for novel therapeutic strategies. Here, we identify the RNA-binding protein PTBP1 as a critical dependency in AML. PTBP1 depletion impairs leukemic growth in vitro and in vivo, and is associated with widespread splicing alterations and global disruption of protein synthesis. Integrative transcriptomic and iCLIP analyses reveal that PTBP1 orchestrates a splicing program centered on Rho GTPase signaling, with CDC42 as a key downstream effector. Mechanistically, PTBP1 loss triggers a splicing switch from CDC42-v1 to CDC42-v2, leading to reduced GTPase activity and impaired protein synthesis. Pharmacological inhibition of CDC42 selectively induces cytotoxicity in AML cells, while sparing healthy hematopoietic cells. Importantly, CDC42 inhibition markedly enhances venetoclax anti-leukemic efficacy. These findings establish PTBP1 as a critical regulator of AML cell fitness and identify a clinically actionable therapeutic combination that exploits AML dependency on PTBP1-CDC42 signaling to enhance the efficacy of venetoclax-based regimens.
