Breast cancer is the second-leading cause of cancer-related deaths in women, but the details of how it begins remain elusive. Increasing evidence supports the association of aggressive triple-negative (TN) breast cancer with heightened expression of the Polycomb group protein Enhancer of Zeste Homolog 2 (EZH2) and increased tumorinitiating cells (TICs). However, mechanistic links between EZH2 and TICs are unclear, and direct demonstration of a tumorigenic function of EZH2 in vivo is lacking. Here, we identify an unrecognized EZH2/NOTCH1 axis that controls breast TICs in TN breast carcinomas. EZH2 overexpression increases NOTCH1 expression and signaling, and inhibition of NOTCH1 activity prevents EZH2-mediated stem cell expansion in nontumorigenic breast cells. We uncover a unique role of EZH2 in activating, rather than repressing, NOTCH1 signaling through binding to the NOTCH1 promoter in TN breast cancer cells. EZH2 binding is independent of its catalytic histone H3 lysine 27 methyltransferase activity and of the Polycomb Repressive Complex 2 but corresponds instead to transcriptional activation marks. In vivo, EZH2 knockdown decreases the onset and volume of xenografts derived from TN breast TICs. Conversely, transgenic EZH2 overexpression accelerates mammary tumor initiation and increases NOTCH1 activation in mouse mammary tumor virus-neu mice. Consonant with these findings, in clinical samples, high levels of EZH2 are significantly associated with activated NOTCH1 protein and increased TICs in TN invasive carcinomas. These data reveal a functional and mechanistic link between EZH2 levels, NOTCH1 signaling activation, and TICs, and provide previously unidentified evidence that EZH2 enhances breast cancer initiation.

Regulation of the activity of the proinflammatory cytokine IL-1 is complex, involving transcriptional and translational control, precursor processing, a receptor antagonist (IL-1ra), and a decoy receptor. Here we report that the soluble form of the IL-1 receptor accessory protein (AcP) increases the affinity of binding of human IL-1alpha and IL-1beta to the soluble human type II IL-1 receptor by approximately 100-fold, while leaving unaltered the low binding affinity of IL-1ra. Soluble AcP is present in normal human serum at an average concentration greater than 300 ng/ml. These findings suggest that the soluble form of IL-1R AcP contributes to the antagonism of IL-1 action by the type II decoy receptor, adding another layer of complexity to the regulation of IL-1 action.

OBJECTIVE Children who require chronic mechanical ventilation via tracheostomy are medically complex and require prolonged hospitalization, placing a heavy burden on caregivers and hospital systems. We developed an interdisciplinary Ventilator Care Program to relieve this burden, through improved communication and standardized care. We hypothesized that a standardized team approach to the discharge of tracheostomy- and ventilator-dependent children would decrease length of stay (LOS), reduce patient costs, and improve safety. METHODS We used process mapping to standardize the discharge process for children requiring chronic ventilation. Interventions included developing education materials, a Chronic Ventilation Road Map for caregivers, utilization of the electronic medical record to track discharge readiness, team-based care coordination, and timely case management to arrange home nursing. We aimed to decrease overall and pediatric respiratory care unit LOS as the primary outcomes. We also analyzed secondary outcomes (mortality, emergency department visits, unplanned readmissions), and per-patient hospital costs during 2-year “preintervention” and “postintervention” periods (n = 18 and 30, respectively). RESULTS Patient demographics were not different between groups. As compared with the preintervention cohort, the overall LOS decreased 42% (P = .002). Pediatric respiratory care unit LOS decreased 56% (P = .001). As a result, unplanned readmissions, emergency department visits, and mortality were not increased. Direct costs per hospitalization were decreased by an average of 43% (P = .01). CONCLUSIONS Although LOS remained high, a standardized discharge process for chronically ventilated children by an interdisciplinary Ventilator Care Program team resulted in decreased LOS and costs without a negative impact on patient safety.

Simulation training can be incorporated into discharge training for families of children requiring LTMV. Rehearsal of emergency management in a simulated clinical setting increases caregiver confidence to assume care for their ventilator-dependent child.