RT Journal Article T1 CDK6 as a key regulator of hematopoietic and leukemic stem cell activation A1 Scheicher, Ruth A1 Hoelbl-Kovacic, Andrea A1 Bellutti, Florian A1 Tigan, Anca-Sarmiza A1 Prchal-Murphy, Michaela A1 Heller, Gerwin A1 Schneckenleithner, Christine A1 Salazar Roa, María A1 Zochbauer-Muller, Sabine A1 Zuber, Johannes A1 Malumbres, Marcos A1 Kollmann, Karoline A1 Sexl, Veronika AB The cyclin-dependent kinase 6 (CDK6) and CDK4 have redundant functions in reg- ulating cell-cycle progression. We describe a novel role for CDK6 in hematopoietic and leukemic stem cells (hematopoietic stem cells [HSCs] and leukemic stem cells [LSCs]) that exceeds its function as a cell-cycle regulator. Although hematopoiesis appears normal under steady-state conditions, Cdk62/2 HSCs do not efficiently repopulate upon competitive transplantation, and Cdk6-deficient mice are significantly more sus- ceptible to 5-fluorouracil treatment. We find that activation of HSCs requires CDK6, which interferes with the transcription of key regulators, including Egr1. Transcrip- tional profiling of HSCs is consistent with the central role of Egr1. The impaired repopulation capacity extends to BCR-ABLp2101 LSCs. Transplantation with BCR- ABLp2101–infected bone marrow from Cdk62/2 mice fails to induce disease, although recipient mice do harbor LSCs. Egr1 knock-down in Cdk62/2 BCR-ABLp2101 LSKs significantly enhances the potential to form colonies, underlining the importance of the CDK6-Egr1 axis. Our findings define CDK6 as an important regulator of stem cell activation and an essential component of a transcriptional complex that suppresses Egr1 in HSCs and LSCs. PB The American Society of Hematology SN 0006-4971 YR 2015 FD 2015 LK https://hdl.handle.net/20.500.14352/97337 UL https://hdl.handle.net/20.500.14352/97337 LA eng NO Ruth Scheicher, Andrea Hoelbl-Kovacic, Florian Bellutti, Anca-Sarmiza Tigan, Michaela Prchal-Murphy, Gerwin Heller, Christine Schneckenleithner, María Salazar-Roa, Sabine Zöchbauer-Müller, Johannes Zuber, Marcos Malumbres, Karoline Kollmann, Veronika Sexl; CDK6 as a key regulator of hematopoietic and leukemic stem cell activation. Blood 2015; 125 (1): 90–101. doi: https://doi.org/10.1182/blood-2014-06-584417 NO Austrian Science Foundation DS Docta Complutense RD 18 abr 2025