Identification of a STAT5 Target Gene, Dpf3, Provides Novel Insights in Chronic Lymphocytic Leukemia

STAT5 controls essential cellular functions and is encoded by two genes, Stat5a and Stat5b. To provide insight to the mechanisms linking hematologic malignancy to STAT5 activation/regulation of target genes, we identified STAT5 target genes and focused on Dpf3 gene, which encodes for an epigenetic factor. Dpf3 expression was induced upon IL-3 stimulation in Ba/F3 cells, while strong binding of both STAT5a and STAT5b was detected in its promoter. Reduced expression of Dpf3 was detected in Ba/F3 cells with Stat5a and Stat5b knock-down, suggesting that this gene is positively regulated by STAT5, upon IL-3 stimulation. Furthermore, this gene was significantly up-regulated in CLL patients, where DPF3 gene/protein up-regulation and strong STAT5 binding to the DPF3 promoter, correlated with increased STAT5 activation, mainly in non-malignant myeloid cells (granulocytes). Our findings provide insights in the STAT5 dependent transcriptional regulation of Dpf3, and demonstrate for the first time increased STAT5 activation in granulocytes of CLL patients. Novel routes of investigation are opened to facilitate the understanding of the role of STAT5 activation in the communication between non-malignant myeloid and malignant B-cells, and the functions of STAT5 target genes networks in CLL biology

Cluster-Randomized Trial of Thrombolysis Implementation Support in Metropolitan and Regional Australian Stroke Centers: Lessons for Individual and Systems Behavior Change

Background: Intravenous thrombolytic therapy (IVT) with tissue plasminogen activator for acute ischemic stroke is underutilized in many parts of the world. Randomized trials to test the effectiveness of thrombolysis implementation strategies are limited. Methods and Results: This study aimed to test the effectiveness of a multicomponent, multidisciplinary tissue plasminogen activator implementation package in increasing the proportion of thrombolyzed cases while maintaining accepted benchmarks for low rates of intracranial hemorrhage and high rates of functional outcomes at 3 months. A cluster randomized controlled trial of 20 hospitals in the early stages of thrombolysis implementation across 3 Australian states was undertaken. Monitoring of IVT rates during the baseline period allowed hospitals (the unit of randomization) to be grouped into 3 baseline IVT strata—very low rates (0% to ≤4.0%); low rates (>4.0% to ≤10.0%); and moderate rates (>10.0%). Hospitals were randomized to an implementation package (experimental group) or usual care (control group) using a 1:1 ratio. The 16-month intervention was based on behavioral theory and analysis of the steps, roles, and barriers to rapid assessment for thrombolysis eligibility and involved comprehensive strategies addressing individual and system-level change. The primary outcome was the difference in tissue plasminogen activator proportions between the 2 groups postintervention. The absolute difference in postintervention IVT rates between intervention and control hospitals adjusted for baseline IVT rate and stratum was not significant (primary outcome rate difference=1.1% (95% CI −1.5% to 3.7%; P=0.38). Rates of intracranial hemorrhage remained below international benchmarks. Conclusions: The implementation package resulted in no significant change in tissue plasminogen activator implementation, suggesting that ongoing support is needed to sustain initial modifications in behavior. Clinical Trial Registration: URL: www.anzctr.org.au Unique identifiers: ACTRN12613000939796 and U1111-1145-6762