prostaglandin e-2 increases intestinal epithelial permeability in vitro
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rostaglandin E-2 increases intestinal epithelialermeability in vitroikael Petrosyan MD, Yigit Guner MD, Catherine Hunter MD,ikunj Chokshi MD, Monica Williams,
effrey Upperman MD, FACS, Anatoly Grishin PhD,enri R Ford MD, FACShildrens Hospital Los Angeles, Los Angeles, CA
NTRODUCTION: Necrotizing enterocolitis (NEC) is character-zed by loss of intestinal epithelial barrier integrity. Sustained upregu-ation of cyclooxygenase 2 (COX-2) and various prostanoids haveeen linked to the pathogenesis of epithelial injury seen in NEC.ne of the most important prostanoids in the gut is prostaglandin-2 (PGE-2). We hypothesize that high levels of PGE-2 contribute to
he development of gut barrier failure in NEC by causing intestinalpithelial injury, and/or by altering epithelial permeability.
ETHODS: Caco-2 cells were grown as polarized monolayers onollagen-coated membranes in bicameral chambers and exposed toarious concentrations (2-50 microg/ml) of exogenous PGE-2.ransepithelial electrical resistance (TEER), an indicator of epithelialonolayer integrity, was measured at various time points (1-5 min)
sing a voltammeter. Apoptosis was assayed with TUNEL stain.
ESULTS: At concentrations normally found in inflamed tissues inivo (1-50 microg/ml), PGE2 caused a dose-dependent and time-ependent decrease in TEER in Caco-2 monolayers ( Table). De-rease in TEER was significantly faster with higher concentrations ofGE-2 (p�0.005). The decrease in TEER was long-lasting, but re-urned to baseline within 24 h after removal of PGE2. PGE-2 alonead no effect on enterocyte apoptosis.
GE-2 �g/ml% TEERat 30 s
% TEER at 1min
% TEER at2 min
% TEER at5 min
1 95 81 65 512 91 79 54 495 88 77 55 530 89 78 53 515 87 45 (p�0.005) 44 440 85 49 (p�0.005) 46 45
ONCLUSIONS: Addition of PGE2 to Caco-2 monolayers in-uces profound and long-lasting disruption of epithelial barrier func-ion, as evidenced by a decrease in TEER. PGE-2 alone does notnduce epithelial apoptosis. These results suggest that PGE-2 maylay a role in gut barrier failure seen in NEC by increasing paracel-
ular permeability through disruption of tight junctions.
ilencing of heat shock factor 1: A potentialherapeutic strategy for pancreatic cancerikas Dudeja MD, Rohit Chugh MD, Steve Skube,umi Yokoyama PhD, Daniel Borja-Cacho MD, Paul Zwolak MD,ara B Antonoff MD, Rajinder Dawara PhD,
elwyn M Vickers MD, FACS, Ashok K Saluja PhDniversity of Minnesota, Minneapolis, MN
NTRODUCTION: Heat Shock Factor 1 (HSF1) is a transcription
actor for Heat Shock Proteins (HSP70, HSP27), multiple drug tS212008 by the American College of Surgeons
ublished by Elsevier Inc.
esistance genes and other survival proteins. We have previously dem-nstrated that HSP70 is overexpressed in pancreatic cancer cells sug-esting that HSF1 is overactive in pancreatic cancer cells. We hypoth-size that silencing HSF1 expression should induce apoptosis inancreatic cancer cells.
ETHODS: HSF1 expression was reduced in MiaPaCa-2 andanc-1 pancreatic cancer lines by treatment with HSF1 siRNA. Twonique sequences of HSF1 siRNA were used to rule out any off-arget effects of siRNA. Cells treated with non-silencing siRNA se-uence (sequence with no homology to any gene) were used as con-rol. Cell viability (MTT assay) and apoptosis (annexin V staining,aspase 3 and 9) were measured.
ESULTS: Inhibition of HSF1 expression in MiaPaCa-2 andanc-1 reduced the viability at 48h and 72h of treatment (viabilityalues [mean�SEM] expressed as % of control. 48h: Panc17.2�4.3, MiaPaCa-2 61.0�3.9, 72h: Panc1 49.2�3.4, MiaPaCa-21.2�8.8). Similar results were obtained with the other HSF1iRNA sequence used. The cell death was associated with markednnexin positivity and activation of caspase 3 and 9 starting at 24h.
ONCLUSIONS: Silencing of HSF1 expression activates caspaseependent apoptotic cell death in pancreatic cancer cells. Implica-ion: Targeting HSF1 has a therapeutic potential in the treatment ofancreatic cancer and holds a great promise as a potential candidateor the drug development. This approach offers the advantage ofbility to target multiple genes involved in resistance to apoptosis,ell death and conventional chemotherapy.
isplatin retains high-mobility group box 1HMGB1) intranuclearly and protects againstepatic ischemia reperfusion (I/R) injury
on S Cardinal MD, Pinhua Pan MD, Rajeev Dhupar MD,ohn Klune BS, Sung Cho MD, David A Geller MD, FACS,llan Tsung MDniversity of Pittsburgh Medical Center, Pittsburgh, PA
NTRODUCTION: The nuclear protein HMGB1 activates inflam-atory pathways upon release from ischemic cells. We have previ-
usly shown neutralizing antibodies to HMGB1 protect against in-lammation and organ injuryfollowing liver I/R. Platinatinghemotherapeutics induce DNA cross links which effectively seques-er HMGB1 in the nucleus. The purpose of this study was to test theypothesis that cisplatin may protect against hepatic IR by prevent-
ng the release of HMGB1.
ETHODS: In vitro, primary hepatocytes were exposed to hypoxia1% O2) or treatment with hydrogen peroxide (H2O2) in the pres-nce or absence of cisplatin. Immunoblotting and immunofluores-ent staining for HMGB1 were performed. In vivo, partial warmepatic I/R was performed on C57BL/6 mice after 12 hour pretreat-ent with either NSS or cisplatin. Serum and tissue samples were
nalyzed for enzyme, protein and inflammatory mediator levels.
ESULTS: Oxidative stress (hypoxia or H2O2 treatment) inducedhe nucleocytoplasmic shuttling and release of HMGB1 from cul-
ured hepatocytes. Cisplatin abrogated this effect and resulted in theISSN 1072-7515/08/$34.00