GLP-2 Delays But Does Not Prevent the Onset of Necrotizing Enterocolitis in Preterm Pigs

OBJECTIVES: Necrotizing enterocolitis (NEC) is complex disease thought to occur as a result of an immaturity of the gastrointestinal tract of preterm infants. Intestinal dysfunction induced by total parental nutrition (TPN) may increase the risk for NEC upon introduction of enteral feeding. We hypothesized that the intestinal trophic and anti-inflammatory actions previously ascribed to the gut hormone, glucagon-like peptide-2 (GLP-2), would reduce the incidence of NEC when given in combination with TPN in preterm piglets. METHODS: Preterm, newborn piglets were nourished by TPN and infused continuously with either human GLP-2 (100 μg · kg(−1) · day(−1)) or control saline for 2 days (n = 12/group). On day 3, TPN was discontinued and pigs were given orogastric formula feeding every 3 hours, and continued GLP-2 or control treatment until the onset of clinical signs of NEC for an additional 96 hours and tissue was collected for molecular and histological endpoints. RESULTS: GLP-2 treatment delayed the onset of NEC but was unable to prevent a high NEC incidence (~70%) and severity that occurred in both groups. GLP-2–treated pigs had less histological injury and increased proximal intestinal weight and mucosal villus height, but not crypt depth or Ki-67–positive cells. Inflammatory markers of intestinal myeloperoxidase were unchanged and serum amyloid A levels were higher in GLP-2–treated pigs. CONCLUSIONS: GLP-2 did not prevent NEC and a proinflammatory response despite some reduction in mucosal injury and increased trophic effect

RON (<i>MST1R</i>) and HGFL (<i>MST1</i>) Co-Overexpression Supports Breast Tumorigenesis through Autocrine and Paracrine Cellular Crosstalk

Background: Aberrant RON signaling is present in numerous cancers including breast cancer. Evidence suggests that the ligand, hepatocyte growth factor-like (HGFL), is also overexpressed in breast cancer. RON (MST1R) and HGFL (MST1) genes are located on human chromosome 3 and mouse chromosome 9 respectively and are found near each other in both species. Based on co-expression patterns, we posited that RON and HGFL are co-regulated and that coordinate upregulation drives aggressive tumorigenesis. Methods: Mouse models were used to establish the functional significance of RON and HGFL co-overexpression on the activation of tumor cells and tumor-associated macrophages in breast cancer. TCGA and METABRIC gene expression and alteration data were used to query the relationships between MST1R and MST1 in breast cancer. Results: In tumor models, physiologic sources of HGFL modestly improve Arginase-1+ (M2) macrophage recruitment to the tumor proper. Tumor-cell produced HGFL functions in autocrine to sustain tumor cell RON activation and MAPK-dependent secretion of chemotactic factors and in paracrine to activate RON on macrophages and to promote breast cancer stem cell self-renewal. In silico analyses support that RON and HGFL are co-expressed across virtually all cancer types including breast cancer and that common genomic alterations do not appear to be drivers of RON/HGFL co-overexpression. Conclusions: Co-overexpression of RON and HGFL in breast cancer cells (augmented by physiologic sources of HGFL) promotes tumorigenesis through autocrine-mediated RON activation/RON-dependent secretome changes and paracrine activation of macrophage RON to promote breast cancer stem cell self-renewal