SMARCC1 controls oncogenic NOTCH1 signaling in T-cell acute lymphoblastic leukemia

Abstract: T cell development and differentiation are tightly regulated through a complex interplay of external signals and conserved signal-directed regulatory networks governing transcriptional programs that enable precise differentiation of precursors into mature CD4+ or CD8+ SP T cells. Dysregulation of these processes can lead to differentiation arrest and leukemic transformation of T cells. Activating mutations in NOTCH1 are highly prevalent in T-ALL and aberrant NOTCH1 signaling is required for maintenance of the leukemogenic state in T-cell progenitors. However, little is known about which interaction partners are essential for oncogenic NOTCH1 signaling and the maintenance of the differentiation blockade. We therefore aimed to identify previously unappreciated molecular dependencies required for NOTCH1-driven T-ALL. To systematically probe members of the NOTCH1-interactome for functionality in maintaining the oncogenic state, we performed an in vitro miR-E-based loss-of-function RNAi screen employing an shRNA-library targeting 340 genes of the NOTCH1-interactome in a murine model of human intracellular NOTCH1-induced T-ALL (Tx17 cell line). To elucidate NOTCH1-specific depletors, the screen was also performed in two murine NOTCH1-negative cell lines, the pro-B-cell line Ba/F3 and the T-cell lymphoma cell line EL4. Using our screening platform, we uncovered SMARCC1, a core member of the SWI/SNF nucleosome remodeling complex, as essential for maintaining NOTCH1-driven T-ALL. We identified that Smarcc1 knockdown in Tx17 cells resulted in a rapid and strong depletion of shRNA-expressing cells. These results were confirmed in the NOTCH1-dependent human T-ALL cell line Jurkat and by probing public data from the depmap portal, revealing a strong SMARCC1-dependency in the two most NOTCH1-dependent cell lines tested, Jurkat and PF-382. Pulldown of human SMARCC1 in Tx17 cells and proteomic analysis revealed binding of most SWI/SNF complex subunits and NOTCH1. Retransplantation of Tx17 cells harboring shSmarcc1 or neutral shRNAs and in vivo shRNA induction led to a significantly decreased spleen infiltration of Tx17 cells transduced with the shSmarcc1 compared to a neutral shRNA. RNA-seq analysis of Smarcc1 depleted cells indicated a differentiation switch from DP to CD4+ SP cells, implicating SMARCC1 as a mediator of NOTCH1-induced differentiation blockade. Collectively, we identified SMARCC1 as a major contributor to oncogenic NOTCH1 signaling and maintenance of the immature differentiation state in T-ALL

Angaben zum Objekt

• Standort: Deutsche Nationalbibliothek Frankfurt am Main
• Umfang: Online-Ressource
• Sprache: Englisch
• Anmerkungen: Universität Freiburg, Dissertation, 2022

Klassifikation und Themen

• Schlagwort: Genexpression ; Signaltransduktion

Beteiligte, Orts- und Zeitangaben

• Ereignis: Veröffentlichung
• (wo): Freiburg
• (wer): Universität
• (wann): 2022
• Urheber: Shoumariyeh, Khalid
• Beteiligte Personen und Organisationen: Miething, Cornelius ; Duyster, Justus ; Flotho, Christian ; Albert-Ludwigs-Universität Freiburg. Medizinische Fakultät

Weitere Informationen

• URN: urn:nbn:de:bsz:25-freidok-2309194
• Rechteinformation: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Letzte Aktualisierung: 15.08.2025, 07:35 MESZ