1. RNA binding protein IGF2BP1 synergizes with ETV6-RUNX1 to drive oncogenic signaling in B-cell Acute Lymphoblastic Leukemia
- Author
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Sharma, Gunjan, Tran, Tiffany M, Bansal, Ishu, Beg, Mohammad Sabique, Bhardwaj, Ruchi, Bassi, Jaspal, Tan, Yuande, Jaiswal, Amit Kumar, Tso, Christine, Jain, Ayushi, Singh, Jay, Chattopadhyay, Parthaprasad, Singh, Archna, Chopra, Anita, Bakhshi, Sameer, Casero, David, Rao, Dinesh S, and Palanichamy, Jayanth Kumar
- Subjects
Biomedical and Clinical Sciences ,Clinical Sciences ,Pediatric Cancer ,Human Genome ,Rare Diseases ,Cancer ,Hematology ,Pediatric ,Genetics ,Biotechnology ,Stem Cell Research ,Aetiology ,2.1 Biological and endogenous factors ,Animals ,Mice ,Core Binding Factor Alpha 2 Subunit ,Mice ,Knockout ,Phosphatidylinositol 3-Kinases ,Precursor B-Cell Lymphoblastic Leukemia-Lymphoma ,Precursor Cell Lymphoblastic Leukemia-Lymphoma ,ETS Translocation Variant 6 Protein ,RNA binding protein ,Leukemia ,ETV6::RUNX1 translocation ,B-ALL ,NF kappa B ,PI3K pathways ,NFκB ,Oncology and carcinogenesis - Abstract
BackgroundAcute lymphoblastic leukemia (ALL) is the most common pediatric hematological malignancy, with ETV6::RUNX1 being the most prevalent translocation whose exact pathogenesis remains unclear. IGF2BP1 (Insulin-like Growth Factor 2 Binding Protein 1) is an oncofetal RNA binding protein seen to be specifically overexpressed in ETV6::RUNX1 positive B-ALL. In this study, we have studied the mechanistic role of IGF2BP1 in leukemogenesis and its synergism with the ETV6::RUNX1 fusion protein.MethodsGene expression was analyzed from patient bone marrow RNA using Real Time RT-qPCR. Knockout cell lines were created using CRISPR-Cas9 based lentiviral vectors. RNA-Seq and RNA Immunoprecipitation sequencing (RIP-Seq) after IGF2BP1 pulldown were performed using the Illumina platform. Mouse experiments were done by retroviral overexpression of donor HSCs followed by lethal irradiation of recipients using a bone marrow transplant model.ResultsWe observed specific overexpression of IGF2BP1 in ETV6::RUNX1 positive patients in an Indian cohort of pediatric ALL (n=167) with a positive correlation with prednisolone resistance. IGF2BP1 expression was essential for tumor cell survival in multiple ETV6::RUNX1 positive B-ALL cell lines. Integrated analysis of transcriptome sequencing after IGF2BP1 knockout and RIP-Seq after IGF2BP1 pulldown in Reh cell line revealed that IGF2BP1 targets encompass multiple pro-oncogenic signalling pathways including TNFα/NFκB and PI3K-Akt pathways. These pathways were also dysregulated in primary ETV6::RUNX1 positive B-ALL patient samples from our center as well as in public B-ALL patient datasets. IGF2BP1 showed binding and stabilization of the ETV6::RUNX1 fusion transcript itself. This positive feedback loop led to constitutive dysregulation of several oncogenic pathways. Enforced co-expression of ETV6::RUNX1 and IGF2BP1 in mouse bone marrow resulted in marrow hypercellularity which was characterized by multi-lineage progenitor expansion and strong Ki67 positivity. This pre-leukemic phenotype confirmed their synergism in-vivo. Clonal expansion of cells overexpressing both ETV6::RUNX1 and IGF2BP1 was clearly observed. These mice also developed splenomegaly indicating extramedullary hematopoiesis.ConclusionOur data suggest a combined impact of the ETV6::RUNX1 fusion protein and RNA binding protein, IGF2BP1 in activating multiple oncogenic pathways in B-ALL which makes IGF2BP1 and these pathways as attractive therapeutic targets and biomarkers.
- Published
- 2023