Polyamine biosynthesis is regulated by ornithine decarboxylase (ODC), which is transcriptionally activated by c-Myc. A large library was screened to find molecules that potentiate the ODC inhibitor, difluoromethylornithine (DFMO). Anthranilic acid derivatives were identified as DFMO adjunct agents.
View Article and Find Full Text PDFThe portal venous circulation provides a conduit for pancreatic ductal adenocarcinoma (PDAC) tumor cells to the liver parenchyma sinusoids, a frequent site of metastasis. Turbulent flow in the portal circulation promotes retention of PDAC shed circulating tumor cells (CTC) and myeloid-derived immunosuppressor cells (MDSC). Excessive colony stimulating factor-1 receptor (CSF1R) signaling can induce myeloid differentiation to MDSC and transformation of MDSC to myeloid-derived fibroblasts (M-FB).
View Article and Find Full Text PDFACS Chem Neurosci
February 2021
The melanocortin receptors (MCRs) are important for numerous biological pathways, including feeding behavior and energy homeostasis. In addition to endogenous peptide agonists, this receptor family has two naturally occurring endogenous antagonists, agouti and agouti-related protein (AGRP). At the melanocortin-4 receptor (MC4R), the AGRP ligand functions as an endogenous inverse agonist in the absence of agonist and as a competitive antagonist in the presence of agonist.
View Article and Find Full Text PDFBackground: While inflammation is associated with pancreatic cancer, the underlying mechanisms leading to cancer initiation are still being delineated. Eosinophils may promote or inhibit tumor growth, although the specific role in pancreatic cancer has yet to be determined. Eosinophil-supporting cytokine interleukin-5 and receptor are likely to have a role, but the significance in the pancreatic cancer microenvironment is unknown.
View Article and Find Full Text PDFExternal pancreatic duct stents inserted after resection of pancreatic head tumors provide unique access to pancreatic juice analysis of genetic and metabolic components that may be associated with peri-ampullary tumor progression. For this pilot study, portal venous blood and pancreatic juice samples were collected from 17 patients who underwent pancreaticoduodenectomy for peri-ampullary tumors. Portal vein circulating tumor cells (CTC) were isolated by high-speed fluorescence-activated cell sorting (FACS) and analyzed by quantitative reverse transcription polymerase chain reaction (RT-PCR) for exon 12 mutant gene expression ().
View Article and Find Full Text PDFCirculating tumor cells (CTC) enter the blood from many carcinomas and represent a likely source of metastatic dissemination. In contrast to the peripheral circulation, KRAS mutation- positive CTC thrive in the portal venous blood of patients with pancreatic ductal adenocarcinoma (PDAC). To analyze the essential interactions that contribute to carcinoma CTC growth and immune resistance, portal venous blood was collected during pancreatico-duodenectomy in 41 patients with peri-ampullary pathologies (PDAC = 11; ampullary adenocarcinoma (AA) = 15; distal cholangiocarcinoma (CC) = 6; IPMN = 7; non-malignant pancreatitis = 2).
View Article and Find Full Text PDFBackground. Blatchford and AIMS65 scores were developed to risk stratify patients with upper gastrointestinal bleed (UGIB). We sought to assess the performance of Blatchford and AIMS65 scores in predicting outcomes in elderly patients with nonvariceal UGIB.
View Article and Find Full Text PDFObjectives: Aggressive spread and liver metastases are predominant features of pancreatic ductal adenocarcinoma (PDAC). This study investigates activation of PDAC circulating tumor cells (CTC) and immunosuppression in the portal venous system.
Methods: Portal venous and peripheral blood were collected during pancreaticoduodenectomy from patients with PDAC (n = 21) or other non-PDAC pancreatic conditions (n = 20).
STAT5 proteins are adaptor proteins for histone acetylation enzymes. Histone acetylation at promoter and enhancer chromosomal regions opens the chromatin and allows access of transcription enzymes to specific genes in rapid response cell signals, such as in inflammation. Histone acetylation-mediated gene regulation is involved in expression of 2 key inflammatory response genes: CSF2, encoding granulocyte-macrophage colony stimulating factor (GM-CSF), and PTGS2, encoding prostaglandin synthase 2/cyclooxygenase 2 (PGS2/COX2).
View Article and Find Full Text PDFEfforts involving therapeutic islet cell transplantation have been hampered by limited islet availability and immune rejection. In vitro transdifferentiation of human bone marrow-derived stem (hBMDS) cells into functional insulin-producing cells promises to provide a tissue source for autologous cell transplantation. In this study, we isolated hBMDS cells, developed a single-cell-derived stem cell line, and induced the cells to differentiate into islet-like clusters.
View Article and Find Full Text PDFBackground: Over-diagnosis and treatment of prostate cancer has been a major problem in prostate cancer care and management. Currently the most relevant prognostic factor to predict a patient's risk of death due to prostate cancer is the Gleason score of the biopsied tissue samples. However, pathological analysis is subjective, and the Gleason score is only a qualitative estimate of the cancer malignancy.
View Article and Find Full Text PDFThe melanocortin-4 receptor (MC4R) is a G-protein-coupled receptor (GPCR) that is expressed in the central nervous system and has a role in regulating feeding behavior, obesity, energy homeostasis, male erectile response, and blood pressure. Since the report of the MC4R knockout mouse in 1997, the field has been searching for links between this genetic biomarker and human obesity and type 2 diabetes. More then 80 single nucleotide polymorphisms (SNPs) have been identified from human patients, both obese and nonobese controls.
View Article and Find Full Text PDFThe melanocortin pathway, specifically the melanocortin-4 receptor and the cognate endogenous agonist and antagonist ligands, have been strongly implicated in the regulation of energy homeostasis and satiety. Genetic studies of morbidly obese human patients and normal weight control patients have resulted in the discovery of over 70 human melanocortin-4 receptor (MC4R) polymorphisms observed as both heterozygous and homozygous forms. A number of laboratories have been studying these hMC4R polymorphisms attempting to understand the molecular mechanism(s) that might explain the obese human phenotype.
View Article and Find Full Text PDFBiochem Biophys Res Commun
May 2007
We investigate JAK-STAT5 activation and its relationship to full-length Stat5B (FL-Stat5) and constitutive phosphorylated carboxy-truncated Stat5B (ct-pStat5) in four different strains of mouse. Our electrophoresis mobility shift assays data indicate constitutive phosphorylation of full-length-Stat5 (p<0.001) and DNA binding in NOD but not in B6 mice.
View Article and Find Full Text PDFRegulatory T cells (Treg), characterized as CD4(+)/CD25(+hi) T cells, are critical for sustaining and promoting immune tolerance. Treg are highly dependent on IL-2 and IL-2 signaling to maintain their numbers and function and interruption of this pathway promotes autoimmunity. The transcription factor, Foxp3, is also required for Treg function as defective Foxp3 promotes autoimmunity in both mice and humans.
View Article and Find Full Text PDFThe melanocortin-4 receptor (MC4R) is a G-protein coupled receptor (GPCR) that is expressed in the central nervous system and has a role in regulating energy homeostasis and obesity. Up to a remarkable 6% of morbidly obese adults and children studied possess single nucleotide polymorphisms (SNPs) of the MC4R. Upon stimulation by agonist, the MC4R signals through the intracellular adenylate cyclase signal transduction pathway.
View Article and Find Full Text PDFThe Melanocortin-4 Receptor is a G-protein coupled receptor that has been physiologically linked to participate in the regulation of energy homeostasis. The Melanocortin-4 Receptor is stimulated by endogenous melanocortin agonists derived from the pro-opiomelanocortin gene transcript and antagonized by the endogenous antagonist agouti-related protein. Central administration of melanocortin agonists has been demonstrated to decrease food intake and conversely, treatment with antagonists resulted in increased food intake.
View Article and Find Full Text PDFUnstimulated monocytes of at-risk/type 1 diabetic humans and macrophages of the NOD mouse have markedly elevated autocrine GM-CSF production and persistent STAT5 phosphorylation. We analyzed the relationship between GM-CSF production and persistent STAT5 phosphorylation in NOD macrophages using reciprocal congenic mouse strains containing either diabetes-susceptible NOD (B6.NODC11), or diabetes-resistant C57L (NOD.
View Article and Find Full Text PDFEfforts toward routine islet cell transplantation as a means for reversing type 1 diabetes have been hampered by islet availability as well as allograft rejection. In vitro transdifferentiation of mouse bone marrow (BM)-derived stem (mBMDS) cells into insulin-producing cells could provide an abundant source of autologous cells for this procedure. For this study, we isolated and characterized single cell-derived stem cell lines obtained from mouse BM.
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