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PURPOSE - Pyruvate kinase muscle isoenzyme 2 (PKM2) is a key enzyme in aerobic glycolysis and is thought to contribute to cancer cell metabolic reprogramming. The aim of this study was to evaluate PKM2 immunohistochemical expression as a potential prognostic biomarker in pancreatic ductal adenocarcinoma (PDAC).
METHODS - A tissue microarray was constructed using surgical specimens for 115 patients who underwent resections for PDAC, stained with PKM2 antibody, and scored for expression level. Statistical analyses were performed to investigate the association between PKM2 and patient survival, tumor stage, tumor grade, surgical margin status, lymph node ratio, perineural invasion status, or the use of adjuvant chemotherapy.
RESULTS - Fifty-three percent of tumors had positive PKM2 expression, and 47 % of tumors had negative PKM2 expression. PKM2 expression was associated with overall survival (HR 0.56, p = 0.007) and CA 19-9 levels (p = 0.035), but was not associated with tumor stage, tumor grade, surgical margin status, lymph node ratio, perineural invasion, or adjuvant chemotherapy use.
CONCLUSIONS - PKM2 expression is associated with overall survival in PDAC. Further studies are warranted to validate the value of PKM2 as a prognostic biomarker and to examine the potential utility of PKM2 in predicting treatment response, as well as a potential therapeutic target in PDAC.
Glucocorticoids signal through the glucocorticoid receptor (GR) and are administered clinically for a variety of situations, including inflammatory disorders, specific cancers, rheumatoid arthritis, and organ/tissue transplantation. However, glucocorticoid therapy is also associated with additional complications, including steroid-induced diabetes. We hypothesized that modification of the steroid backbone is one strategy to enhance the therapeutic potential of GR activation. Toward this goal, two commercially unavailable, thiobenzothiazole-containing derivatives of hydrocortisone (termed MS4 and MS6) were examined using 832/13 rat insulinoma cells as well as rodent and human islets. We found that MS4 had transrepression properties but lacked transactivation ability, whereas MS6 retained both transactivation and transrepression activities. In addition, MS4 and MS6 both displayed anti-inflammatory activity. Furthermore, MS4 displayed reduced impact on islet β-cell function in both rodent and human islets. Similar to dexamethasone, MS6 promoted adipocyte development in vitro, whereas MS4 did not. Moreover, neither MS4 nor MS6 activated the Pck1 (Pepck) gene in primary rat hepatocytes. We conclude that modification of the functional groups attached to the D-ring of the hydrocortisone steroid molecule produces compounds with altered structure-function GR agonist activity with decreased impact on insulin secretion and reduced adipogenic potential but with preservation of anti-inflammatory activity.
© 2015 by The American Society for Biochemistry and Molecular Biology, Inc.
BACKGROUND - Clostridium difficile infection (CDI) can cause severe disease and death, especially in older adults. A better understanding of risk factors for adverse outcomes is needed. This study tests the hypotheses that infection with specific ribotypes and presence of stool toxins independently associate with severity and constructs predictive models of adverse outcomes.
METHODS - Cases of non-recurrent CDI were prospectively included after positive stool tests for toxins A and/or B by enzyme immunoassay (EIA) or tcdB by polymerase chain reaction. Outcomes included severe CDI (intensive care unit admission, colectomy, or death attributable to CDI within 30 days of diagnosis) and 30-day all-cause mortality. Adjusted models were developed to test hypotheses and predict outcomes.
RESULTS - In total, 1144 cases were included. The toxin EIA was positive in 37.2% and 35.6% of patients were of age >65 years. One of the 137 unique ribotypes was ribotype 027 (16.2%). Detectable stool toxin did not associate with outcomes. Adjusting for covariates, including age, Ribotype 027 was a significant predictor of severe CDI (90 cases; odds ratio [OR], 1.73; 95% confidence interval [CI], 1.03-2.89; P = .037) and mortality (89 cases; OR, 2.02; 95% CI, 1.19-3.43; P = .009). Concurrent antibiotic use associated with both outcomes. Both multivariable predictive models had excellent performance (area under the curve >0.8).
CONCLUSIONS - Detection of stool toxin A and/or B by EIA does not predict severe CDI or mortality. Infection with ribotype 027 independently predicts severe CDI and mortality. Use of concurrent antibiotics is a potentially modifiable risk factor for severe CDI.
Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.
Loss of parietal cells initiates the development of spasmolytic polypeptide-expressing metaplasia (SPEM), a precancerous lesion in stomach. CD44 variant (CD44v) that enhances the ability to defend against reactive oxygen species (ROS) in epithelial cells is expressed de novo in SPEM of K19-Wnt1/C2mE mice, a transgenic model of gastric tumorigenesis, and is required for the efficient development of SPEM and gastric tumor in these animals. The role of ROS and its downstream signaling in CD44-dependent gastric tumorigenesis has remained unknown, however. With the use of the K19-Wnt1/C2mE mouse, we now show that parietal cells in the inflamed stomach are highly sensitive to oxidative stress and manifest activation of p38(MAPK) signaling by ROS. Oral treatment with the antioxidant ascorbic acid or genetic ablation of the Ink4a/Arf locus, a major downstream target of ROS-p38(MAPK) signaling, inhibited parietal cell loss and the subsequent gastric tumorigenesis. Our results indicate that signaling activated by oxidative stress in parietal cells plays a key role in CD44-dependent gastric tumorigenesis. .
©2015 American Association for Cancer Research.
Notch signaling largely determines intestinal epithelial cell fate. High Notch activity drives progenitors toward absorptive enterocytes by repressing secretory differentiation programs, whereas low Notch permits secretory cell assignment. Myeloid translocation gene-related 1 (MTGR1) is a transcriptional corepressor in the myeloid translocation gene/Eight-Twenty-One family. Given that Mtgr1(-/-) mice have a dramatic reduction of intestinal epithelial secretory cells, we hypothesized that MTGR1 is a key repressor of Notch signaling. In support of this, transcriptome analysis of laser capture microdissected Mtgr1(-/-) intestinal crypts revealed Notch activation, and secretory markers Mucin2, Chromogranin A, and Growth factor-independent 1 (Gfi1) were down-regulated in Mtgr1(-/-) whole intestines and Mtgr1(-/-) enteroids. We demonstrate that MTGR1 is in a complex with Suppressor of Hairless Homolog, a key Notch effector, and represses Notch-induced Hairy/Enhancer of Split 1 activity. Moreover, pharmacologic Notch inhibition using a γ-secretase inhibitor (GSI) rescued the hyperproliferative baseline phenotype in the Mtgr1(-/-) intestine and increased production of goblet and enteroendocrine lineages in Mtgr1(-/-) mice. GSI increased Paneth cell production in wild-type mice but failed to do so in Mtgr1(-/-) mice. We determined that MTGR1 can interact with GFI1, a transcriptional corepressor required for Paneth cell differentiation, and repress GFI1 targets. Overall, the data suggest that MTGR1, a transcriptional corepressor well characterized in hematopoiesis, plays a critical role in intestinal lineage allocation.
Thomsen-Friedenreich (TF) antigen belongs to the mucin-type tumor-associated carbohydrate antigen. Notably, TF antigen is overexpressed in colorectal cancer (CRC) but is rarely expressed in normal colonic tissue. Increased TF antigen expression is associated with tumor invasion and metastasis. In this study, we sought to validate a novel nanobeacon for imaging TF-associated CRC in a preclinical animal model. We developed and characterized the nanobeacon for use with fluorescence colonoscopy. In vivo imaging was performed on an orthotopic rat model of CRC. Both white light and fluorescence colonoscopy methods were utilized to establish the ratio-imaging index for the probe. The nanobeacon exhibited specificity for TF-associated cancer. Fluorescence colonoscopy using the probe can detect lesions at the stage which is not readily confirmed by conventional visualization methods. Further, the probe can report the dynamic change of TF expression as tumor regresses during chemotherapy. Data from this study suggests that fluorescence colonoscopy can improve early CRC detection. Supplemented by the established ratio-imaging index, the probe can be used not only for early detection, but also for reporting tumor response during chemotherapy. Furthermore, since the data obtained through in vivo imaging confirmed that the probe was not absorbed by the colonic mucosa, no registered toxicity is associated with this nanobeacon. Taken together, these data demonstrate the potential of this novel probe for imaging TF antigen as a biomarker for the early detection and prediction of the progression of CRC at the molecular level.
© 2014 UICC.
Uncontrolled glycemia is a hallmark of diabetes mellitus and promotes morbidities like neuropathy, nephropathy, and retinopathy. With the increasing prevalence of diabetes, both immune-mediated type 1 and obesity-linked type 2, studies aimed at delineating diabetes pathophysiology and therapeutic mechanisms are of critical importance. The β-cells of the pancreatic islets of Langerhans are responsible for appropriately secreting insulin in response to elevated blood glucose concentrations. In addition to glucose and other nutrients, the β-cells are also stimulated by specific hormones, termed incretins, which are secreted from the gut in response to a meal and act on β-cell receptors that increase the production of intracellular cyclic adenosine monophosphate (cAMP). Decreased β-cell function, mass, and incretin responsiveness are well-understood to contribute to the pathophysiology of type 2 diabetes, and are also being increasingly linked with type 1 diabetes. The present mouse islet isolation and cAMP determination protocol can be a tool to help delineate mechanisms promoting disease progression and therapeutic interventions, particularly those that are mediated by the incretin receptors or related receptors that act through modulation of intracellular cAMP production. While only cAMP measurements will be described, the described islet isolation protocol creates a clean preparation that also allows for many other downstream applications, including glucose stimulated insulin secretion, [3(H)]-thymidine incorporation, protein abundance, and mRNA expression.
We identified acyl-coenzyme A-binding protein (ACBP) as part of a proteomic signature predicting the risk of having lung cancer. Because ACBP is known to regulate β-oxidation, which in turn controls cellular proliferation, we hypothesized that ACBP contributes to regulation of cellular proliferation and survival of non-small cell lung cancer (NSCLC) by modulating β-oxidation. We used matrix-assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS) and immunohistochemistry (IHC) to confirm the tissue localization of ABCP in pre-invasive and invasive NSCLCs. We correlated ACBP gene expression levels in NSCLCs with clinical outcomes. In loss-of-function studies, we tested the effect of the downregulation of ACBP on cellular proliferation and apoptosis in normal bronchial and NSCLC cell lines. Using tritiated-palmitate ((3)H-palmitate), we measured β-oxidation levels and tested the effect of etomoxir, a β-oxidation inhibitor, on proliferation and apoptosis. MALDI-IMS and IHC analysis confirmed that ACBP is overexpressed in pre-invasive and invasive lung cancers. High ACBP gene expression levels in NSCLCs correlated with worse survival (HR = 1.73). We observed a 40% decrease in β-oxidation and concordant decreases in proliferation and increases in apoptosis in ACBP-depleted NSCLC cells as compared with bronchial airway epithelial cells. Inhibition of β-oxidation by etomoxir in ACBP-overexpressing cells produced dose-dependent decrease in proliferation and increase in apoptosis (P = 0.01 and P < 0.001, respectively). These data suggest a role for ACBP in controlling lung cancer progression by regulating β-oxidation.
©2014 American Association for Cancer Research.
IMPORTANCE - Long-term patency of human saphenous veins (HSVs) used as autologous conduits for coronary artery bypass grafting (CABG) procedures remains limited because of vein graft failure (VGF). Vein graft failure has been reported to be as high as 45% at 12 to 18 months after surgery and leads to additional surgery, myocardial infarction, recurrent angina, and death. Preparation of HSVs before implantation leads to conduit injury, which may promote VGF.
OBJECTIVES - To investigate whether pressure distension during vein graft preparation leads to endothelial injury and intimal thickening and whether limiting intraluminal pressure during pressure distension by using a pressure release valve (PRV) preserves endothelial function and prevents neointima thickening.
DESIGN, SETTING, AND PARTICIPANTS - Segments of HSVs were collected in a university hospital from 13 patients undergoing CABG procedures immediately after harvest (unmanipulated [UM]), after pressure distension (after distension [AD]), and after typical intraoperative surgical graft preparation (after manipulation [AM]). Porcine saphenous veins (PSVs) from 7 healthy research animals were subjected to manual pressure distension with or without an in-line PRV that prevents pressures of 140 mm Hg or greater. Endothelial function of the HSVs and PSVs was determined in a muscle bath, endothelial integrity was assessed, and intimal thickening in PSVs was evaluated after 14 days in organ culture.
MAIN OUTCOMES AND MEASURES - Endothelial function was measured in force, converted to stress, and defined as the percentage relaxation of maximal phenylephrine-induced contraction. Endothelial integrity was assessed by immunohistologic examination. Neointimal thickness was measured by histomorphometric analysis.
RESULTS - Pressure distension of HSVs led to decreased mean (SEM) endothelial-dependent relaxation (5.3% [2.3%] for AD patients vs 13.7% [2.5%] for UM patients; P < .05) and denudation. In the AM group, the function of the conduits was further decreased (-3.2% [3.2%]; P < .05). Distension of the PSVs led to reduced endothelial-dependent relaxation (7.6% [4.4%] vs 61.9% [10.2%] in the control group; P < .05), denudation, and enhanced intimal thickening (15.0 [1.4] µm vs 2.2 [0.8] µm in the control group; P < .05). Distension with the PRV preserved endothelial-dependent relaxation (50.3% [9.6%]; P = .32 vs control), prevented denudation, and reduced intimal thickening (3.4 [0.8] µm; P = .56 vs controls) in PSVs.
CONCLUSIONS AND RELEVANCE - Use of a PRV during graft preparation limits intraluminal pressure generated by manual distension, preserves endothelial integrity, and reduces intimal hyperplasia. Integration of this simple device may contribute to improved long-term vein graft patency.
INTRODUCTION - Small-cell lung cancer (SCLC) is the most aggressive subtype of lung cancer, with no early detection strategy or targeted therapy currently available. We hypothesized that difference gel electrophoresis (DIGE) may identify membrane-associated proteins (MAPs) specific to SCLC, advance our understanding of SCLC biology, and discover new biomarkers of SCLC.
METHODS - MAP lysates were prepared from three SCLCs, three non-small-cell lung cancers, and three immortalized normal bronchial epithelial cell lines and coanalyzed by DIGE. Subsequent protein identification was performed by mass spectrometry. Proteins were submitted to Ingenuity Pathway Analysis. Candidate biomarkers were validated by Western blotting (WB) and immunohistochemistry (IHC).
RESULTS - Principal component analysis on the global DIGE data set demonstrated that the four replicates derived from each of the nine cell lines clustered closely, as did samples within the same histological group. One hundred thirty-seven proteins were differentially expressed in SCLC compared with non-small-cell lung cancer and immortalized normal bronchial epithelial cells. These proteins were overrepresented in cellular/tissue morphology networks. Dihydropyrimidinase-related protein 2, guanine nucleotide-binding protein alpha-q, laminin receptor 1, pontin, and stathmin 1 were selected as candidate biomarkers among MAPs overexpressed in SCLC. Overexpression of all candidates but RSSA in SCLC was verified by WB and/or IHC on tissue microarrays. These proteins were significantly associated with SCLC histology and survival in univariables analyses.
CONCLUSION - DIGE analysis of a membrane-associated subproteome discovered overexpression of dihydropyrimidinase-related protein 2, guanine nucleotide-binding protein alpha-q, RUVB1, and stathmin 1 in SCLC. Results were verified by WB and/or IHC in primary tumors, suggesting that investigating their functional relevance in SCLC progression is warranted. Association with survival requires further validation in larger clinical data sets.