Menge, K. | bioRxiv Science

bioRxiv2025

The activation of TP53 pathway is a therapeutic vulnerability in NUP98::KDM5A+ pediatric AML

NUP98::KDM5A-rearranged pediatric acute myeloid leukemia (AML) is a rare, infancy-predominant entity with dismal outcome and no targeted therapeutic options. Given its suspected fetal origin, we hypothesized that leukemic maintenance depends on developmentally restricted vulnerabilities embedded within fetal hematopoietic programs. Using matched fetal and adult hematopoietic stem and progenitor cell models, we integrated transcriptomic and proteomic profiling with CRISPR-Cas9 screenings to define ontogeny-specific dependencies in NUP98::KDM5A leukemia. Fetal-derived NUP98::KDM5A leukemias exhibited greater in vivo aggressiveness, and retained fetal transcriptional signatures compared with adult counterparts. A comparative CRISPR-Cas9 screen using a library targeting fetal gene programs, conducted in both fetal- and adult-derived NUP98::KDM5A leukemias, identified the AAA ATPase TRIP13 as a selective and essential dependency in the fetal context. Mechanistically, TRIP13 physically interacted with the TP53 phosphatase PPM1D/WIP1, resulting in suppression of TP53 activation. Genetic ablation of Trip13, or pharmacologic inhibition using DCZ0415, a small-molecule inhibitor targeting TRIP13, reactivated TP53, induced G2/M arrest and mitochondrial apoptosis, and depleted leukemic cells in vitro; these effects were fully rescued by TP53 loss. In competitive transplantation assays, Trip13 ablation significantly impaired leukemic fitness in vivo. Together, these findings define a developmentally restricted TRIP13-PPM1D-TP53 survival axis in NUP98::KDM5A AML and provide mechanistic proof-of-concept that reactivation of the TP53 signaling pathway via TRIP13 inhibition represents a therapeutically targetable vulnerability in this high-risk pediatric leukemia. Visual abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=121 SRC="FIGDIR/small/675580v4_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@143d103org.highwire.dtl.DTLVardef@14f3225org.highwire.dtl.DTLVardef@655541org.highwire.dtl.DTLVardef@c021ae_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2020

iPSC culture expansion selects against putatively actionable mutations in the mitochondrial genome

While human induced pluripotent stem cells (iPSCs) offer fascinating prospects for research and clinics, evaluating their genomic stability before applications is of utmost importance. During reprogramming, clonal hiPSC lines derived from the same parental cell population were observed to harbor different mitochondrial DNA (mtDNA) variants and variant heteroplasmy levels. It is unknown to date to which extent this unequal segregation of heteroplasmies between cells arises from mosaicism in the parental cell population, selection on mutated mtDNA molecules on the cellular or organelle level, genetic drift during reduction of mtDNA during reprogramming (genetic bottleneck), or de novo mutations. We analyzed mtDNA variants in 26 clonal iPSC lines by mtDNA sequencing. We did not observe a strong bottleneck or any selection for cells with specific mtDNA variants (clonal eliteness) during reprogramming. iPSC culture expansion, however, selects against putatively actionable mutations in the mitochondrial genome that may affect mitochondrial function and cell metabolism. In contrast, heteroplasmy levels of neutral variants remained stable or increased within clonal iPSC lines during culture expansion. Interestingly, the mtDNA copy number per cell got transiently reduced during targeted differentiation of iPSCs into cardiomyocytes, but mtDNA heteroplasmy levels were not affected. Altogether, our results point towards a scenario in which intra-cellular selection on mtDNA during culture expansion, but not during reprogramming or differentiation, pivotally shapes the mutational landscape of the mitochondrial genome in iPSCs. Other mechanisms such as inter-cellular selection, genetic bottleneck, and genetic drift exert minor impact.

genomics↗