also had 4-fold higher levels of miR-145 (n= 3, p<0.05). We could not demonstrate any EGFR-ESR2 physical interactions. Surprisingly, our preliminary results showed an upregulation inEGFR signals in ERB041 treated ESR2 transfectants. Summary: In AA with adenomas,reductions in ESR2 expression might contribute to higher colon cancer incidence and worseprognosis. The in vitro studies confirmed that ESR2 suppresses colon cancer cell proliferation.We postulate that the antiproliferative effects of ESR2 involve miR-145 dependent, EGFR-independent pathways. Our study suggests that ESR2 down-regulation might play an impor-tant role in colon cancer risk and contribute to racial differences in cancer progression.

Sa1963

Low Molecular Weight Procyanidins From Grape Seeds Enhance the Impact of5-Fluorouracil Chemotherapy on Colon Cancer CellsKer Y. Cheah, Gordon S. Howarth, Keren A. Bindon, James A. Kennedy, SuzanneMashtoub, Susan E. Bastian

Introduction: Grape seed procyanidins (PC) are flavan-3-ol oligomers and polymers knownfor their biological activity in the gut. Grape seed PCs have been reported to reduce intestinalinjury in rat models of intestinal mucositis [Cheah et al. Cancer Biol Ther (2009)] andulcerative colitis [Cheah et al. Dig Dis Sci (2013)]. We sought to determine the differentialefficacy of purified PC fractions differing in mean degree of polymerization (mDP) onthe viability of colon cancer cells (Caco-2) when combined with 5-Fluorouracil (5-FU)chemotherapy. Methods: Six PC fractions (F1-F6) were isolated from Cabernet Sauvignonseeds at two ripeness stages: pre-veraison unripe (immature) and ripe (mature), utilizingstep gradient, low-pressure chromatography on a Sephadex LH-20 resin. Fractions werecharacterized by phloroglucinolysis and gel permeation chromatography (GPC). The antioxi-dant capacity of the fractions was determined by ferric reducing antioxidant power (FRAP)assay. Fractions were tested on Caco-2 cells, alone and in combination with 5-FU. Cellviability was determined by 3-(4,5-Dimethylthiazol-2yl)-2,5-diphenyl-tetrazolium bromide)(MTT) assay. Statistical significance was assumed at p<0.05. Results: The antioxidant capacityof six fractions was negatively correlated with PC mDP (r2 = -0.81, p<0.05). All isolatedfractions significantly reduced Caco-2 cell viability compared to control (p<0.05), althoughF2 and F3 were the most active fractions (immature F2 = 32%, F3 = 35% and mature F2 =13% and F3 = 17%; percentage of viable cells remaining) on Caco-2 cells. When combinedwith 5-FU, immature seed fractions F1-F3 and mature seed fractions F1-F4 enhanced thegrowth-inhibitory effects of 5-FU by 27-73% and 60-83% (p<0.05; compared to 5-FUcontrol), respectively. Moreover, some fractions were more potent at decreasing viability inCaco-2 cells (p<0.05; immature F2-F3 = 65-68%; mature F2-F4 = 83-87%) compared to5-FU alone (37%). Conclusions: Procyanidin fractions of mDP 2-6 (immature F1-F3 andmature F1 and F4) exhibited synergistic effects on viability of Caco-2 cells when tested incombination with 5-FU. Concomitant use of grape seed PCs and 5-FU chemotherapy couldrepresent a promising new approach for colon cancer chemoprevention.

Sa1964

Gastric Cancer Chemoprevention by Phenethyl Isothiocyanate-Containing Dietin Chemically - but Not Genetically - Induced Gastric Cancer in MiceAnders Øverby, Chun-Mei Zhao, Timothy C. Wang, Atle Bones, Duan Chen

Background/aim: Vegetables containing isothiocyanates (ITCs) such as broccoli, cauliflowerand watercress have been linked epidemiologically to decreased risk of gastric cancer. Theaim of the present study was to demonstrate the chemopreventive effect of the naturallyoccurring aromatic phenethyl ITC (PEITC) in vivo in mouse models of gastric cancer andin vitro using human gastric cancer cell lines. Methods: FVB mice treated with N-nitroso-N-methylurea (MNU, orally for 10 weeks) and transgenic INS-GAS mice with spontaneousgastric cancer were employed. Tumorigenesis was assessed by measurement of tumor sizeusing a point counting method. PEITC-containing diet (5 μmol/g PEITC) was given adlibitum to FVB mice that were either treated with MNU simultaneously or immediately after10-week MNU treatment for 9 months. INS-GAS mice were fed the standard mouse dietwith or without PEITC for 11.5 months (starting at preneoplastic stage, i.e., 4-5 weeks ofage). For the in vitro study, the gastric cancer cell lines Kato-III and MKN74 were used.Cell proliferation was determined with the MTT-assay, while morphology and cell migrationwere analysed using a contrast microscope, cell cycle distribution was analysed with flowcytometry, and the effect of PEITC on microtubules was examined in transfected cells byconfocal microscopy. Results: The PEITC-containing diet was without effect on the bodyweight development in all groups of mice. Both PEITC regimens whether it was administeredprior or subsequent to MNU treatment yielded a significant reduced tumorigenesis in MNU-treated mice, with chemoprevention pre-MNU feeding being more potent than post-MNUfeeding. There was no significant inhibitory effect of PEITC-containing diet on tumorigenesisin INS-GAS mice compared with age-matched INS-GAS mice without PEITC-containingdiet. In vitro studies using Kato-III and MKN74 cells showed that PEITC inhibited cellproliferation in a time- and dose-dependent manner in the concentration range of 1-100μM for 24, 48 and 72 hours, with Kato-III cells being more sensitive to PEITC than MKN74cells. The reduction in cell survival coincided with changes in cell morphology and reducedcell migration. Furthermore, treatment of PEITC for 24 hours led to an accumulation ofcells in G2/M-phase of the cell cycle. Kato-III cells expressing GFP-tagged microtubulesshowed that PEITC induced disruption of microtubules with the subsequent formation ofapoptotic blebs. Conclusions: The present study demonstrates a chemopreventive effect ofPEITC-containing diet in a mouse model of chemically-induced gastric cancer. The anti-cancer effect may involve disruption of microtubules, resulting in cell cycle arrest andapoptosis.

S-341 AGA Abstracts

Sa1965

Garcinol Interferes With Oncogenic IL1b-STAT3 and Facilitates TumorSuppressive KLF11-Sin3A to Down-Regulate AKT1 Expression and CellGrowth in Barrett's EpitheliumAnamay N. Sharma, Sarah Kossak, Sonia Chowdhury, Raghav Chandra, Ishtpreet Singh,Anushka Baruah, Cathrine J. DeMars, Prasad G. Iyer, Raul A. Urrutia, Kenneth K. Wang,Kausilia K. Krishnadath, Navtej Buttar

BACKGROUND: Chronic reflux injury promotes Barrett's metaplasia and adenocarcinoma,one of the most rapidly increasing, highly lethal cancers in Western countries. We havepreviously shown that transcriptional up-regulation of AKT1 expression plays a critical roleduring this neoplasia and is involved in increased cell growth, transformation, colonyformation in-vitro and the growth of tumor implants in-vivo. This regulation is an importantnode on which pro-inflammatory oncogenic IL1b-STAT3 and tumor suppressive KLF11-Sin3a pathways compete to regulate carcinogenesis. AIM: Our goal was to investigate thechemopreventive potential of the naturally occurring compound Garcinol, through interfer-ence with oncogenic IL1b-STAT3 and facilitation of tumor suppressive KLF11-Sin3a path-ways. METHODS AND RESULTS: We treated Barrett's epithelial cells (FLO and SKGT) withGarcinol at baseline and under the conditions of activated IL1b-pSTAT3 or KLF11-Sin3Apathway. We used promoter-reporter luciferase assay, PCR, Western blot and BrDU incorpo-ration. We noted that while IL1b-pSTAT3 increased AKT1 promoter activity and AKT1expression, KLF11-Sin3A decreased them. A 24-hour treatment of Barrett's epithelial cellswith 20uM Garcinol resulted in marked down-regulation of pSTAT3 protein expression andfacilitated KLF11-mediated repression of AKT1 promoter, decreased AKT1 promoter activity,as well as decreased AKT1 mRNA expression. These molecular changes had functionalconsequences as similar treatment with Garcinol resulted in up to 50±1% reduction in cellgrowth compared to control treated cells (p<0.05). CONCLUSIONS: The interference withoncogenic IL1b-STAT3, facilitation of tumor suppressive KLF11-Sin3A, and down-regulationof AKT1 expression, as well as decreased cell growth in-vitro support the chemopreventivepotential of Garcinol. However this agent needs to be tested further in-vivo in pre-clinicaland clinical studies.

Sa1966

Predictors of Right-Sided Polyp Growth in a Veteran PopulationCynthia E. Quainoo, Sonia DeAlwis, Ching-Ho Huang, Vidushi Golla, Michael Haynes,Yasemin Aytaman, Albert Ndzengue, Kathlynn Caguiat, Ayse Aytaman, Manuel Martinez,Garrett Lawlor

INTRODUCTION The clinical implications of right sided colon polyps is gaining interestthough the exact difference of their pathogenesis as compared to left sided colon polypsremains unclear. Thus far, there is suggestion that right sided colon polyps carry increasedrisks of malignant transformation and this may be attributable to both environmental andhost factors. The aim of our study is to better understand the factors which impact the rateof right sided colon polyp growth and pathogenesis. METHODS All patients undergoingtwo colonoscopies at least 12 months apart between 1996 and 2012 with detection andremoval of a polyp on index colonoscopy, were identified using our endoscopic databaseto determine the incidence of polyps and adenomas. We recorded patient age, intervalbetween colonoscopies, gender, race, BMI, HbA1C (>6.5, <6.4), HCV Ab positivity andstatin use (Y/N), folate, Vitamin D use, Aspirin and NSAIDS. Patients were classified accordingto age (<49, 50-59, 60-69, 70-79, > 80yrs). From the endoscopic data, we recorded polyphistology, location, size and prep score. RESULTS Overall, 1056 patients underwent twocolonoscopies at least 12 months apart (median interval 47 months) with removal of polypon initial examination. Considering all patients, there were more right sided polyps amongthe white population (56%) compared to the black population (44.4%, P 0.0056). Statinswere used by 57.9% of patient population; their use was associated with an increasedpercentage of right sided polyps (54.6% versus 46%, P 0.03). Aspirin use was found toincrease the percentage of right sided polyps relative to left sided (56.5% versus 47.4% P0.0219. Finally, Vitamin D supplementation was associated with a trend towards increasedright sided polyps (OR 1.474, P 0.0716, CI 0.9648-2.25). CONCLUSION The pathogenesisand natural history of right -sided polyps appears to differ compared to left -sided polyps,though this mechanism is unclear. Our data suggest that race, statin use, aspirin, and vitaminD supplementation appear to impact right - sided polyp growth independent of age ormedian time between colonoscopies(while also impacting left-sided polyp growth). The effectof medication and non-colorectal disease on polyp growth will increasingly be recognized asdifferential between left and right-sided polyps, owing to their poorly understood, differentmechanisms of growth.

Sa1967

Lipid Profile and Polyp Size in Subjects With Colon AdenomasSandar Linn, Carmen M. Stanca, Gregory Rozansky, Juan Tejada, Philip Xiao, Sury Anand

BACKGROUND: Increased expression of LDL receptor mRNA has been described in coloncancer tissue. Malignant colon tumors are thought to be involved in cholesterol catabolism,and curative surgery would lead to changes in cholesterol levels. We examined the lipidprofile of patients with colonic adenomas. METHODS: Adult patients who underwent poly-pectomy over a one year period were enrolled in this retrospective study. Controls includedpatients coming to the ambulatory clinic during the same period for routine visits. Werecorded demographics, lipid levels, co-morbidities, and statin use in both study and controlgroups; we documented polyp size in patients undergoing polypectomy. Patients withconcomitant colon or other malignancies were excluded. Data were analyzed using SPSS;results are shown as median (range). RESULTS: Ninety-four subjects with colon adenomasand one hundred and thirty controls were enrolled. Fifty-four percent of subjects werewomen and 88% were African American. The median age was 62 (23-94). There were nosignificant differences in terms of age, gender, race, BMI and statin use between the adenomagroup and the controls. Significantly lower LDL-cholesterol levels were identified in theadenoma group (median 54 vs 114; p<0.001) in the absence of statin use. All the other

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sserum lipids had higher levels in the adenoma group compared to controls: total cholesterol(186 vs 146; p<0.001), triglycerides (104 vs 72; p=0.002), and HDL-cholesterol (105 vs45; p=0.075 did not reach statistical significance). An inverse correlation was found betweenthe total cholesterol level and the polyp size (Spearman's r=-0.343; p = 0.047). No statisticallysignificant differences were identified in the serum lipid levels in the adenoma group afterpolypectomy. CONCLUSION: Subjects with colon adenomas have significantly lower LDL-cholesterol levels, and their total cholesterol level inversely correlates with polyp size. Serumlipid levels do not change after polypectomy. Although the cause-effect relationship betweenlipid levels and colon cancer is not clearly defined, changes in the lipid profile seem toprecede the development of colon cancer. This study offers additional insights in the complexrelationship between lipid metabolism and colonic neoplasms.

Sa1968

Mesalamine Exhibits a Protective DNA Damage Response in Normal ColonEpithelial Cells Under Oxidative StressVineeta Khare, Mario Asboth, Christoph Gasche

Background: Ineffective DNA damage response such as cell cycle arrest and DNA repaircontributes to colorectal cancer (CRC). Recently, our lab demonstrated that in colitis andcolitis-associated cancer (CAC) oxidative stress causes DNA double strand breaks (DSB).Pharmacological manipulation of DNA damage response could be a potential mechanismfor chemoprevention in CAC. Mesalamine (5-ASA) is commonly used as an anti-inflammatorycompound in the treatment of UC and improves replication fidelity by activation of areplication checkpoint. Here we examined the effect of 5-ASA on DNA damage and DNArepair in normal colon epithelial cells (and a colorectal cancer cell line as control). Methods:Normal diploid human colon epithelial cells (HCEC-1CT) and HCT116 cells (CRC control)were treated with 5-ASA (5mM; 24h). Proteins implicated in DSB were analyzed by Westernblot using various antibodies for DNA damage response proteins in the nuclear enrichedcellular fraction. To assess the effect of 5-ASA on oxidative stress, cells were treated withH2O2 (100μM, 30 min) in the presence or absence of 5-ASA (5h pretreatment). Nuclearfoci formation by 53BP1 and gamma-H2AX in response to oxidative stress was determinedby immunocytochemistry. BrdU incorporation was measured to assess cell proliferationduring recovery phase (24h). Results: DNA damage sensor proteins MRE11, γ-H2AX, and53BP1 were strongly induced upon 5-ASA treatment in HCEC-1CT. Inversely, such proteinswere highly expressed in HCT116 and were downregulated upon 5-ASA. In HCEC-1CT,5-ASA resulted in diffuse nuclear localization of 53BP1 and γ- H2AX. Oxidative stress,however, resulted in redistribution of these proteins into distinct foci indicative of DNAdamage. Pretreatment with 5-ASA reduced foci formation under oxidative stress. Comparedto untreated HCEC-1CT, cell proliferation was significantly reduced upon H2O2 treatment(3% relative BrdU incorporation), however, 5-ASA pretreatment was protective (45%).HCT116 cells remained proliferative under oxidative stress and 5-ASA pretreatment showedno such effect (80% and 81.5%, respectively). Conclusion: 5-ASA treatment induces DNAdamage response in normal colon epithelial cells and exhibits a protective effect underoxidative stress by induction of a double-strand break repair pathway impeding with CACdevelopment. Advanced dysplastic lesions are rather unlikely to benefit from 5-ASA.

Sa1969

Effects of Neoadjuvant and Adjuvant Therapy for Rectal Cancer on Long TermSurvivalMohan K. Mallipeddi, Paul J. Speicher, Asvin M. Ganapathi, Brian R. Englum, JohnMigaly, Christopher R. Mantyh

Purpose: Pre-operative chemoradiation (C/XRT) for advanced rectal cancers often pathologi-cally downstages tumors and significantly decreases local recurrence. Adjuvant chemotherapyis also recommended for advanced staged rectal cancer to reduce systemic recurrence.However, it is unknown what C/XRT downstaging effect has on overall long term survival.Also it is unclear what effect omission of adjuvant chemotherapy has on overall survival.Methods: Patients with clinical stage III rectal cancer who underwent pre-op C/XRT in 2006were identified from the National Cancer Database (NCDB), which captures cancer sitespecific data from over 1500 centers across the US. Overlapping survival and chemotherapydata only were available for 2006. Patients who underwent resection with curative intentwere included for analysis. Kaplan-Meier survival estimates were used to compare survivalby pathological stage with native stage I patients and complete responders as references.Cox proportional hazards modeling was used to assess the impact of demographic, clinical,and pathological factors on survival as well as the interaction between adjuvant therapy anddegree of neoadjuvant downstaging. Results: There were 818 patients with clinical stage IIIdisease who received neoadjuvant therapy. Pathology revealed 403 ypStageIII patients, 193ypStageII patients, and 186 ypStageI patients, and 36 complete responders (CRs). Overall,231 patients received adjuvant chemotherapy, 25% of ->ypI patients vs 35% of ->ypIIIpatients (p<0.001). Five-year overall survival for all cIII->ypI patients compares favorablyto native stage I disease at 83.3% versus 77.7%, respectively (Hazard Ratio: 0.98, CI: 0.63,p=0.909) (Figure). The subset of the cIII->ypI patients who received adjuvant therapy hadsignificantly better unadjusted survival than native stage I patients (p=0.007). For ->CR,->ypI, ->ypII, and ->ypIII patients receiving adjuvant therapy, 5-year survival was 94.4%,92.8%, 90.5%, and 63.1%, respectively. Among patients who were downstaged to ypI, therewas a trend towards a survival advantage with the addition of adjuvant chemotherapy (HR:0.25, CI: 0.05-1.12, p=0.07), and adjuvant therapy provided a significantly larger survivalbenefit with increasing degree of downstaging (p=0.028). Yet, in the NCDB less than 50%of downstaged cStage III patients through 2011 were receiving adjuvant therapy. Conclusions:Patients with stage III rectal cancer that were downstaged to stage I had equivalent long-term survival compared to native stage I patients. Progressive downstaging by neoadjuvantC/XRT significantly improved survival after adjuvant C/XRT. Unfortunately, a minority ofrectal cancer patients received adjuvant therapy which likely reduced overall survival. Futurework should focus on improving utilization of adjuvant therapy in these patients.

S-342AGA Abstracts

Figure: Kaplan-Meier survival for patients with native stage I and downstaged clinical stageIII rectal cancer. Adj = adjuvant. CR = complete responder.

Sa1970

CD98 As a Ligand for Colitis-Targeted Delivery of NanoparticleBo Xiao, Emilie Viennois, Yuchen Zhang, Saravanan Ayyadurai, Hamed Laroui, DidierMerlin

Background and Aims: Treatment strategies for inflammatory bowel disease (IBD) have beenconstrained by limited therapeutic efficacy and serious adverse effects owing to a lack ofligand for targeted drug delivery to the inflamed colon. Upon inflammation, CD98 expressionis highly elevated in colonic epithelial cells and infiltrating immune cells. To investigatewhether CD98 can be used as a colitis-targeted delivery ligand, we constructed CD98 Fab-bearing quantum dots (QDs)-loaded nanoparticles (Fab'-NPs). Materials and Methods: CD98Fab' was conjugated to the surfaces of QDs-loaded NPs mediated by bi-functional PEGderivative (MAL-PEG-NHS). Next, we evaluated their physicochemical properties (e.g.,hydrodynamic particle size, zeta-potential, emission and absorption properties) in relationto their targeting capacity. We also investigated their targeting capacities to CD98 over-expressed colonic cells using flow cytometry. Finally, we tested their ability to target colitistissue. Results: The resultant Fab'-NPs had desired particle size (~458 nm) with a narrowsize distribution and zeta-potential (approximately +19 mV), low cytotoxicity, and excellentfluorescence properties. Electron microscopy images provided direct evidence for the well-dispersed distribution of QDs within spherical Fab'-NPs. Cellular uptake experiments demon-strated that Fab'-NPs were efficiently internalized into Colon-26 and RAW 264.7 cellsthrough the CD98-mediated endocytosis pathway, and showed that the targeting effect ofCD98 Fab' markedly increased their cellular uptake efficiency compared with control pegy-lated QDs-loaded NPs (PEG-NPs). Furthermore, ex vivo studies showed much more effectiveaccumulation of Fab'-NPs in colitis tissue than that of PEG-NPs. Conclusion: In the contextof IBD therapy, one of the most relevant features of the drug formulation is that they cantargetable deliver therapeutic molecules to specific cells. Our above findings suggest thatactive colitis-targeted delivery can be accomplished using NPs decorated with CD98 antibodybased on the inflammation-dependent over-expression of CD98.

Sa1971

High-Resolution Esophageal Impedance Topography (EIT) Parameters forQuantifying Bolus RetentionZhiyue Lin, Frédéric Nicodème, Chen-Yuan Lin, Benjamin Mogni, Laurel Friesen, Peter J.Kahrilas, John E. Pandolfino

Background and Aim: The multichannel intraluminal impedance (MII) technique allows oneto evaluate bolus transit without radiation. However, the line tracing analysis mode is limitedby low spatial resolution and the higher resolution impedance color contour plot view(CCPV) mode does not provide quantitative analysis of bolus volume on MII data. Thisstudy aimed to develop a new method for quantifying bolus volume clearance using high-resolution esophageal impedance topography (EIT) technique. Methods: The ability of high-resolution EIT parameters to detect bolus volume clearance was validated and tested withconcurrent fluoroscopic imaging and high-resolution impedance manometry (HRIM) studies(barium bolus) in 10 healthy subjects (4 males, mean age 28 years, range 21-47). HRIMdata from each subject were analyzed using a MATLAB program customized for calculatingEIT parameters for each swallow within a region of interest from lower limit of UES toupper limit of EGJ in distance and from onset of swallowing to 12 seconds later or untilcompletion of peristalsis (red dashed rectangle in Figure). The impedance volume definedas the sum of all pixel volumes (i.e., impedance value less than 50% drop from the meanbaseline value to the mean nadir impedance (white curves) multiplied by time interval andby spatial interval) were derived in area 1 prior to the contraction wave-front at 20 mmHgisobaric contour (black solid curves) as Z1 and in area 2 after the contraction as Z2, andpresented as a ratio of Z2 area/Z1 area. Results: A total of 40 thin barium swallows (4 persubject; 2 supine and 2 upright) were analyzed from the 10 subjects with simultaneousfluoroscopic imaging and HRIM data. In 93% (37/40) of swallows, the results from the EITmethod were in agreement with fluoroscopy results with one of three patterns: 1) 25 normalbolus transit, 2) 8 bolus stasis, and 3) 4 retrograde escape or reflux. Three swallows (8%)had slight retention at the transition zone or distal esophagus (Z2/Z1<0.3) identified by EIT,but no retention was detected by videofluoroscopy. There was a strong correlation betweenpercent of bolus area retained in the esophagus detected by fluoroscopic imaging and percentof bolus area retention (Z2/Z1) after swallows with EIT method (r=0.96 for supine and r=0.69 for upright position, p<0.001). Conclusions: There was a strong correlation betweenpercent of areas retained in the esophagus detected by fluoroscopic imaging and the EITmethod and thus, bolus volume retention can be estimated by the Z2/Z1 EIT parameter.Outcome-based prospective studies are needed to clarify whether the Z2/Z1 ratio is a better