TY  - JOUR
AU  - Rahimian, Elahe
AU  - Koochak, Masoud
AU  - Traikov, Sofia
AU  - Schroeder, Michael
AU  - Brilloff, Silke
AU  - Schäfer, Silvia
AU  - Kufrin, Vida
AU  - Küchler, Sandra
AU  - Krüger, Alexander
AU  - Mirtschink, Peter
AU  - Baretton, Gustavo
AU  - Schröck, Evelin
AU  - Schewe, Denis M
AU  - Ball, Claudia
AU  - Bornhäuser, Martin
AU  - Glimm, Hanno
AU  - Bill, Marius
AU  - Wurm, Alexander Arthur
TI  - A quiescence-like/TGF-β1-specific CRISPRi screen reveals drug uptake transporters as secondary targets of kinase inhibitors in AML.
JO  - Drug resistance updates
VL  - 81
SN  - 1368-7646
CY  - Oxford
PB  - Elsevier
M1  - DKFZ-2025-00723
SP  - 101242
PY  - 2025
AB  - Relapse in acute myeloid leukemia (AML) is driven by resistant subclones that survive chemotherapy. It is assumed that these resilient leukemic cells can modify their proliferative behavior by entering a quiescent-like state, similar to healthy hematopoietic stem cells (HSCs). These dormant cells can evade the effects of cytostatic drugs that primarily target actively dividing cells. Although quiescence has been extensively studied in healthy hematopoiesis and various solid cancers, its role in AML has remained unexplored. In this study, we applied an HSC-derived quiescence-associated gene signature to an AML patient cohort and found it to be strongly correlated with poor prognosis and active TGF-β signaling. In vitro treatment with TGF-β1 induces a quiescence-like phenotype, resulting in a G0 shift and reduced sensitivity to cytarabine. To find potential therapeutic targets that prevent AML-associated quiescence and improve response to cytarabine, we conducted a comprehensive CRISPR interference (CRISPRi) screen combined with TGF-β1 stimulation. This approach identified TGFBR1 inhibitors, like vactosertib, as effective agents for preventing the G0 shift in AML cell models. However, pretreatment with vactosertib unexpectedly induced complete resistance to cytarabine. To elucidate the underlying mechanism, we performed a multi-faceted approach combining a second CRISPRi screen, liquid chromatography-tandem mass spectrometry (LC-MS/MS), and in silico analysis. Our findings revealed that TGFBR1 inhibitors unintentionally target the nucleoside transporter SLC29A1 (ENT1), leading to reduced intracellular cytarabine levels. Importantly, we found that this drug interaction is not unique to TGFBR1 inhibitors, but extends to other clinically significant kinase inhibitors, such as the FLT3 inhibitor midostaurin. These findings may have important implications for optimizing combination therapies in AML treatment.
KW  - AML (Other)
KW  - Chemoresistance (Other)
KW  - Kinase inhibitors (Other)
KW  - Nucleoside transporter ENT1 (Other)
KW  - Quiescence (Other)
KW  - TGF-β signaling pathway (Other)
KW  - Vactosertib (Other)
LB  - PUB:(DE-HGF)16
C6  - pmid:40184725
DO  - DOI:10.1016/j.drup.2025.101242
UR  - https://inrepo02.dkfz.de/record/300270
ER  -