Integrated Dependency and Primary-Patient Profiling Prioritize Nucleotide-Synthesis Vulnerabilities in High-Risk B-ALL
Relapsed B-cell acute lymphoblastic leukemia (B-ALL) remains difficult to treat, yet the space of therapeutic hypotheses is crowded with lineage markers, recurrent fusions, and poorly prioritized dependencies. We asked a narrower question: which noncanonical genes and pathways remain compelling therapeutic liabilities after integrating cell-line dependency data with primary-patient subtype and relapse information? We combined DepMap 24Q2 CRISPR knockout and expression profiles across 32 B-lymphoblastic leukemia/lymphoma models with two public patient cohorts: the DFCI 16-001 pediatric ALL RNA-seq cohort with molecular subtype calls and a paired diagnosis/relapse pediatric B-precursor ALL cohort. Rather than identifying a single dominant target, the analysis converged on a pathway-level program centered on de novo pyrimidine synthesis and connected one-carbon/purine support. UMPS, CAD, DHODH, ATIC, MTHFD1, and FPGS remained the most coherent axis after primary-cohort integration. Pathway-level scoring placed TCF3-PBX1 B-ALL near the top of the combined nucleotide program and highlighted KMT2A-rearranged disease as a strong pyrimidine-focused comparison subtype. Exploratory pharmacology using the public PRISM repurposing screen showed broad activity of the antifolate trimetrexate in annotated B-ALL lines, whereas the public release lacked a clean DHODH inhibitor. These results prioritize nucleotide-synthesis stress, rather than a single receptor or transcription factor, as the most defensible near-term therapeutic hypothesis for high-risk B-ALL and nominate antifolate-versus-pyrimidine-blockade experiments in TCF3-PBX1 and KMT2A-rearranged models as the next concrete step.