Biology subjects

Pikman, Y.

Publications and source records attributed to Pikman, Y..

8 recordsLinked to original sources

bioRxiv2026

Altered immune and treatment response gene expression signatures among poverty-exposed children with B-ALL

Children diagnosed with cancer typically receive standardized treatment regimens. Despite highly protocolized care, children living in poverty experience a greater risk of cancer relapse and higher mortality compared to their more affluent peers.1,2 Acute lymphoblastic leukemia (ALL) is the most prevalent childhood cancer, and children with ALL exposed to poverty are more likely to experience early relapse.3 Using single-cell RNA sequencing to analyze leukemic blasts and their microenvironment at diagnosis we found that poverty-exposed patients with standard-risk B-ALL exhibit transcriptional signatures of steroid resistance at time of diagnosis. Additionally, we observe increased expression of inflammatory signatures in myeloid cells and reduced effector signatures in CD8+ T-cells in children with B-ALL living in poverty. Further investigation of the mechanisms underlying these associations may identify opportunities for risk-adapted therapeutic strategies to improve disease outcomes in pediatric ALL.

cancer biology↗

bioRxiv2025

Comparative analysis of plasma and bone marrow nutrient levels in pediatric B-ALL patients

Nutrient availability in the tumor microenvironment is a key determinant of cancer progression and therapeutic response, yet the physiological nutrient environment for most cancers is poorly understood. In this study, we investigated nutrient levels in pediatric B-cell acute lymphoblastic leukemia (B-ALL) patients across different subtypes undergoing chemotherapy, focusing on both bone marrow and circulation. Our analysis revealed distinct differences in nutrient profiles between leukemic and healthy plasma and among B-ALL subtypes, with hyperdiploid B-ALL exhibiting pronounced alterations in arginine and asymmetric dimethylarginine metabolism. Bone marrow and blood plasma exhibited largely similar metabolite profiles, even after chemotherapy, indicating these environments are metabolically comparable. Comparisons with renal cell carcinoma and non-small cell lung cancer highlighted a unique enrichment of tricarboxylic acid cycle intermediates in the circulation of B-ALL patients. These findings provide a comprehensive view of nutrient dynamics in pediatric B-ALL and identify metabolic alterations that could guide biomarker discovery and new therapeutic strategies.

cancer biology↗

bioRxiv2025

Multi-selective RAS(ON) Inhibition Targets Oncogenic RAS Mutations and Overcomes RAS/MAPK-Mediated Resistance to FLT3 and BCL2 Inhibitors in Acute Myeloid Leukemia

Aberrant activation of the RAS/MAPK signaling limits the clinical efficacy of several targeted therapies in acute myeloid leukemia (AML). In FLT3-mutant AML, the selection of clones harboring heterogeneous RAS mutations drives resistance to FLT3 inhibitors (FLT3i). RAS activation is also associated with resistance to other AML targeted therapies, including the BCL2 inhibitor venetoclax. Despite the critical need to inhibit RAS/MAPK signaling in AML, no targeted therapies have demonstrated clinical benefit in RAS-driven AML. To address this unmet need, we investigated the preclinical activity of RMC-7977, a multi-selective inhibitor of GTP-bound active [RAS(ON)] isoforms of mutant and wild-type RAS in AML models. RMC-7977 exhibited potent antiproliferative and pro-apoptotic activity across AML cell lines with MAPK-activating signaling mutations. In cell line models with acquired FLT3i resistance due to secondary RAS mutations, treatment with RMC-7977 restored sensitivity to FLT3i. Similarly, RMC-7977 effectively reversed resistance to venetoclax in RAS-addicted cell line models with both RAS wild-type and mutant genetic backgrounds. In murine patient-derived xenograft models of RAS-mutant AML, RMC-7977 was well tolerated and significantly suppressed leukemic burden in combination with gilteritinib or venetoclax. Our findings strongly support clinical investigation of broad-spectrum RAS(ON) inhibition in AML to treat and potentially prevent drug resistance due to activated RAS signaling.

cancer biology↗

bioRxiv2025

A structure-based tool to interpret the significance of kinase mutations in clinical next generation sequencing in cancer

IntroductionClinical workflows to analyze variants of unknown significance (VUSs) found in clinical next generation sequencing (NGS) are labor intensive, requiring manual analysis of published data for each variant. There is a strong need for tools and resources that provide a consistent way to analyze variants. With the explosion of clinical NGS data and the concurrent availability of protein structures through the Protein Data Bank and protein models through programs such as AlphaFold, there exists an unprecedented opportunity to use structural information to help standardize NGS analysis with the overall goal of advancing personalized cancer therapy. MethodsUsing the Catalogue of Somatic Mutations in Cancer (COSMIC), the largest curated database of clinical cancer mutations, we mapped thousands of missense mutations in the kinase and juxtamembrane (JM) domains of 48 receptor tyrosine kinases (RTKs) onto structurally aligned kinase structures, then clustered known activating mutations along with VUSs based on proximity in three-dimensional structure. Using cell-based models we illustrate that our resource can be used to identify activating mutations and provide insight into mechanisms of kinase activation and regulation. ResultsWe provide a database of structurally aligned and functionally annotated mutations that can be used as a tool to evaluate kinase VUSs based on their structural alignment with known activating mutations. The tool can be accessed through a user-friendly website in which one can input a kinase mutation of interest, and the system will output a list of structurally analogous mutations in other kinases, as well as their functional annotations. DiscussionWe expect our database to be an important addition to the current tools and resources used to analyze clinical NGS, with important clinical implications to guide recommendations for personalized cancer therapy.

cancer biology↗

bioRxiv2024

CEBPA repression by MECOM blocks differentiation to drive aggressive leukemias

Acute myeloid leukemias (AMLs) have an overall poor prognosis with many high-risk cases co-opting stem cell gene regulatory programs, yet the mechanisms through which this occurs remain poorly understood. Increased expression of the stem cell transcription factor, MECOM, underlies one key driver mechanism in largely incurable AMLs. How MECOM results in such aggressive AML phenotypes remains unknown. To address existing experimental limitations, we engineered and applied targeted protein degradation with functional genomic readouts to demonstrate that MECOM promotes malignant stem cell-like states by directly repressing pro-differentiation gene regulatory programs. Remarkably and unexpectedly, a single node in this network, a MECOM-bound cis-regulatory element located 42 kb downstream of the myeloid differentiation regulator CEBPA, is both necessary and sufficient for maintaining MECOM-driven leukemias. Importantly, targeted activation of this regulatory element promotes differentiation of these aggressive AMLs and reduces leukemia burden in vivo, suggesting a broadly applicable differentiation-based approach for improving therapy.

cancer biology↗

bioRxiv2024

Targeting DLK1 improves survival in patient-derived xenograft models of myeloid leukemia associated with Down syndrome

Children with Down syndrome have a markedly increased risk of developing myeloid leukemia (ML-DS). Although having an excellent prognosis, 10-20% develop relapsed or refractory disease with poor survival, highlighting the need for new targeted approaches. The pathogenesis of ML-DS is tightly linked to fetal hematopoiesis and mutations in GATA1, generating the truncated GATA1short(s) isoform. We identified Delta-like non-canonical Notch ligand 1 (DLK1) as a direct GATA1s target. DLK1, a paternally imprinted transmembrane protein, is highly expressed in fetal liver CD34 cells but absent in adult hematopoiesis, making it an attractive immunotherapeutic target. Chromatin profiling revealed GATA1s occupancy at a distal enhancer within the DLK1-DIO3 locus, driving aberrant DLK1 upregulation in ML-DS. Functional studies demonstrated that DLK1 is a leukemia dependency, as its genetic ablation impaired proliferation and engraftment, induced apoptosis, and altered Notch and {beta}-catenin signaling. Therapeutically, a DLK1-directed antibody-drug conjugate (DLK1-ADC) induced selective cytotoxicity, abrogated colony formation, and significantly prolonged survival in refractory ML-DS PDX models, achieving durable remissions at higher doses. These findings establish DLK1 as a leukemia-specific vulnerability and provide preclinical proof-of-concept for DLK1-targeted therapies in ML-DS and other leukemias with fetal-like expression programs. Key PointsO_LIDLK1 is a GATA1s-driven leukemia dependency in ML-DS, linking fetal hematopoietic programs to leukemic stemness and refractory disease. C_LIO_LITherapeutic targeting of DLK1 with an antibody-drug conjugate selectively eradicates leukemia cells and prolongs survival in ML-DS PDX models C_LI

cancer biology↗

bioRxiv2020

Single-cell analysis reveals mechanisms of plasticity of leukemia initiating cells

Leukemia initiating cells (LICs) fuel leukemic growth and spark relapse. Previously thought to be primitive and rare, the LIC state may actually be heterogeneous and dynamic, enabling evasion of therapies. Here, we use single-cell transcriptomics to track LIC multipotency within the cellular ontogeny of MLL-rearranged B-lymphoblastic leukemia (MLL-r B-ALL). Although we identify rare transcriptionally and phenotypically primitive LICs, we also observe LICs emerging from more differentiated populations with the capability to replenish the full leukemic cellular diversity. We find that activation of MYC-driven oxidative phosphorylation controls this process of facultative state conversion in LICs.

cancer biology↗

bioRxiv2020

Targeting serine hydroxymethyltransferases 1 and 2 for T-cell acute lymphoblastic leukemia therapy.

Despite progress in the treatment of acute lymphoblastic leukemia (ALL), T-cell ALL (T-ALL) has limited treatment options particularly in the setting of relapsed/refractory disease. Using an unbiased genome-scale CRISPR-Cas9 screen we sought to identify pathway dependencies for T-ALL which could be harnessed for therapy development. Disruption of the one-carbon folate, purine and pyrimidine pathways scored as the top metabolic pathways required for T-ALL proliferation. We used a recently developed inhibitor of SHMT1 and SHMT2, RZ-2994, to characterize the effect of inhibiting these enzymes of the one-carbon folate pathway in T-ALL and found that T-ALL cell lines were differentially sensitive to RZ-2994, with a S/G2 cell cycle arrest. The effects of SHMT1/2 inhibition were rescued by formate supplementation. Loss of both SHMT1 and SHMT2 was necessary for impaired growth and cell cycle arrest, with suppression of both SHMT1 and SHMT2 impairing leukemia progression in vivo. RZ-2994 decreased leukemia burden in vivo and remained effective in the setting of methotrexate resistance in vitro. This study highlights the significance of the one-carbon folate pathway in T-ALL and supports further development of SHMT inhibitors for treatment of T-ALL and other cancers.

cancer biology↗