GSE127984
STAP-1 is Required for Maintenance of Leukemic Stem Cells in Chronic Myeloid Leukemia.
The family of signal transduction adapter proteins (STAPs) has been reported to be involved in a variety of intracellular signaling and transcriptional molecules. We originally cloned STAP-2 as a c-fms interacting protein and found the effects on chronic myeloid leukemia (CML) leukemogenesis. STAP-2 binds to BCR-ABL, up-regulates BCR-ABL phosphorylation and activates its downstream molecules. In this study, we evaluated the role of STAP-1, another member of the family, in CML pathogenesis. The expression of human STAP-1 is aberrantly upregulated in CML stem cells (LSCs) in patient bone marrow. Using experimental model mice, we revealed that deletion of STAP-1 prolonged survival of CML mice with the induced apoptosis of LSCs. The impaired phosphorylated status of STAT5 by STAP-1 ablation results in downregulation of anti-apoptotic genes, BCL-2 and BCL-xL. Interestingly, transcriptome analyses indicate that STAP-1 affects several signaling pathways related to BCR-ABL, JAK2 as well as PPAR?. This adaptor protein directly binds not only BCR-ABL, also STAT5 proteins, showing synergistic effects of STAP-1 inhibition on the treatment with BCR-ABL or JAK2 tyrosine kinase inhibitor. It is known that the inhibition of BCR-ABL alone cannot eliminate CML LSCs. Our results have identified STAP-1 as a regulator of CML LSCs and support the evidence as a novel therapeutic target for CML cure. Overall design: To gain further understanding of effects of STAP-1, we performed a gene expression analysis using RNA-sequence (RNA-seq), using WT and STAP-1 KO CML LSCs. Putative differentially expressed genes generated by RNA-seq were identified (2 fold change cut-off).