The transcriptional regulatory circuit as a driver and therapeutic target in CML blast crisis

Patients with blast crisis in chronic myeloid leukemia (CML) exhibit an extremely poor prognosis, with median survival of only a few months and limited therapeutic options. Dysregulated transcriptional regulation plays a pivotal role in driving blast crisis progression. In this study, we performed histone modification and transcriptomic high-throughput sequencing on bone marrow cells derived from chronic and blast-phase CML patients, identifying a CML blast-specific transcriptional regulatory circuit comprising MEF2C, MYB, MEIS1, and ZEB2. These transcription factors (TFs) form protein complexes that co-bind to shared enhancers or promoters, reciprocally enhancing each others transcriptional activity and that of their downstream targets. Mechanistically, this circuit synergistically reprograms chromatin accessibility and transcriptional landscapes in blast cells, parallel activation of purine metabolism and Rho GTPase signaling pathways which exhibit functional crosstalk. Functional validation demonstrated that silencing components of this circuit or its downstream core targets significantly suppressed CML blast progression in vitro and in vivo. Notably, mebendazole (MBZ), a clinically approved inhibitor targeting MYB protein stability, recapitulated these inhibitory effects. Our findings establish the MEF2C-MYB-MEIS1-ZEB2 transcriptional circuit as a central driver of CML blast crisis and position MBZ as a high-potential translational strategy for targeting this lethal phase of the disease. Key PointsO_LIMEF2C, MYB, MEIS1, and ZEB2 form the CML blast-crisis transcriptional circuit, synergistically reprogramming chromatin and transcription. C_LIO_LIMebendazole inhibits CML blast progression by impairing the circuit, offering a rapid translational strategy for this lethal phase. C_LI