BioProject

In several cancer types, STAT (Signal transducer and activator of transcription) transcription factors are constitutively activated. More...

In several cancer types, STAT (Signal transducer and activator of transcription) transcription factors are constitutively activated. We previously identified a target gene, LPP/miR-28 (LIM domain containing preferred translocation partner in lipoma), induced by constitutive activation of STAT5, but not by transient cytokine-activated STAT5. Here, we demonstrate in transformed hematopoietic cells that binding of both STAT5B and p53 to chromatin is required for transcriptional activity of an alternative LPP/miR-28 promoter. Using a genome-wide approach, we identified 463 genomic positions at promoter regions where STAT5B and p53 are co-localized on the chromatin. At these positions, p53 chromatin binding is dependent on persistent STAT5B activation. The transcriptional activity of selected promoters bound by STAT5B and p53 was significantly changed upon STAT5 or p53 inhibition, and the transcription of these target genes is frequently altered in platelets of myeloproliferative neoplasm patients harboring mutations constitutively activating STAT5. These data suggest that the constitutive STAT5 activation recruits p53 in cancer cells and thereby activates oncogenic transcriptional programs. Overall design: STAT5B and p53 ChIP-chip with or without JAK2 inhibition (ruxolitinib) to inhibit STAT5 phosphorylation and DNA binding. Less...