Sonia Chowdhury

Sa1965 Garcinol Interferes With Oncogenic IL1b-STAT3 and Facilitates Tumor Suppressive KLF11-Sin3A to Down-Regulate AKT1 Expression and Cell Growth in Barrett's Epithelium

ESR2 physical interactions. Surprisingly, our preliminary results showed an upregulation in EGFR signals in ERB041 treated ESR2 transfectants. Summary: In AA with adenomas, reductions in ESR2 expression might contribute to higher colon cancer incidence and worse prognosis. The in vitro studies confirmed that ESR2 suppresses colon cancer cell proliferation. We postulate that the antiproliferative effects of ESR2 involve miR-145 dependent, EGFRindependent pathways. Our study suggests that ESR2 down-regulation might play an important role in colon cancer risk and contribute to racial differences in cancer progression.

Tu1218 Prostaglandin E2 Levels Are Not Elevated in Mucinous Pancreatic Cysts

branch duct (n = 20), main duct (n = 4), mixed type (n = 8). LGD was present in 5 patients, MD in 17 patients, HGD in 9 patients, and invasive cancer in 1 patient. HMGA2 protein was detected in the cyst fluid of 30/32 (94%) specimens. Mean HMGA2 concentration (ng/ ml): LGD 0.52 ± 0.40, MD 2.56 ± 2.52, HGD 10.5 ±15.22 (p , 0.05). No HMGA2 was detected in the one sample from IPMNwith invasive cancer. Themean HMGA2 concentration was significantly higher in the HGD group (10.5 ± 15.22 ng/ml) compared to the concentration in the low-risk IPMN group (2.1 ± 2.38 ng/ml, p = 0.03). The ROC for HMGA2 had an area under the curve of 0.74. Conclusions: HMGA2 protein is present in the cyst fluid of IPMN. Significantly higher concentrations of cyst fluid HMGA2 proteins are found in IPMN with HGD as compared to lesions with LGD or MD. Cyst fluid concentration of HMGA2 may thus serve as a biomarker to differentiate patients with high-risk IPMN lesions from patients with low-risk IPMN lesions. Such a biomarker could help guide clinical decision making regarding which patients may benefit from surgical resection of their IPMN. Further investigation of this cyst fluid biomarker on prospectively obtained samples from EUS-FNA is warranted.

388 IL-1β-STAT3 Mediated Up-Regulation of AKT1 Expression in Barrett's Esophagus: A Potential Link Between Inflammation and Carcinogenesis

BACKGROUND AND AIM: We have recently shown that, in addition to AKT1 activation through its phosphorylation, overall increased expression of AKT1 that is observed during neoplastic progression in patients with Barretts also plays a direct role in this injury-induced oncogenesis. Since pro-inflammatory cytokine IL-1β promotes esophageal adenocarcinoma and its downstream effector STAT3 could bind to the core promoter region of AKT1, it is plausible that IL-1β-STAT3-AKT1 could link inflammation to carcinogenesis in Barretts esophagus. The aims of this study were to examine IL-1 β-STAT3 mediated regulation of AKT1 expression and explore the underlying mechanisms in Barretts epithelium. METHODS and RESULTS: Using Barretts epithelial cells, we noted that both IL-1 β and constitutively active STAT3c induced AKT1 promoter activity. Moreover, in a dose and time dependent manner IL-1β increased AKT1 mRNA expression. Similarly, constitutively active STAT3c also increased AKT1 mRNA expression. We also noted that IL-1 β increased cellular p300 levels, a histone acetyl transferase that STAT3 recruits on target promoter chromatin to activate them by acetylating histone H3. We found that while constitutively active STAT3c increased AKT1 promoter activity/expression, there was an increased acetylation of AKT1 promoter (ChIP using anti H3 K18 and 27 antibody) during neoplastic progression in Barretts epithelium. Additionally, both IL-1β and STAT3c partially interfered with repression of AKT1 promoter by anti-inflammatory transcription factor KLF11, a known recruiter of Sin3-HDAC that deacetylates and represses AKT1 promoter. Together, these findings raise a possibility that pro-inflammatory IL-1β, by simultaneously increasing p300 and STAT3 activation could direct p300 onto the AKT1 promoter to hyper acetylate and activate AKT1 promoter. Alternatively, pro-inflammatory IL-1β-pSTAT3 through antagonizing the antiinflammatory KLF11-Sin3-histone deacetylase pathway preserve AKT1 promoter acetylation to activate AKT1 promoter/expression. CONCLUSION: Our observations expose an antagonism between pro-inflammatory IL-1β-STAT3-p300 and anti-inflammatory KLF11-Sin3HDAC pathways in regulating oncogenic AKT1 during neoplastic transformation in Barretts esophagus, providing a potential link between inflammation and carcinogenesis.

407a Oncogenic AKT1 Regulation by Tumor Suppressor KLF11: Implications in Growth Regulation During Neoplastic Transformation in Barrett's Esophagus and Interference by Carcinogenic Bile Acid Dependent Erk2 and PKCa Activation

Pancreatic adenocarcinoma is the fifth leading cause of cancer death, with an abysmal 5year survival rate of less than 5%, due in large part to the high incidence of metastasis. Metastatic invasion represents a complex synergy of cell motility, adhesion, and matrix remodeling. How these multiple processes are coordinated during dissemination is a central focus of tumor cell biology. The small oncogenic G protein Rac1 is a major regulator of cell motility, and it is activated through the action of guanine nucleotide exchange factors (GEFs). A critical GEF in tumor cell biology is the proto-oncogene Vav1, which is ectopically expressed in most pancreatic tumors to cause poor prognosis in patients and enhanced tumor growth In Vitro. Vav1 interacts directly with the large GTPase Dynamin 2 (Dyn2), though the function of this interaction is not known. Importantly, Dyn2 is also markedly upregulated in pancreatic cancer, is a potent activator of metastatic migration, and is required for Rac1-mediated formation of lamellipodia. We have recently found that Dyn2 binds Vav1 directly in pancreatic tumor cells. Therefore, the GOAL of this study was to test if the Dyn2Vav1 interaction could promote the activation of Rac1 and the invasive migration of pancreatic tumor cells. RESULTS: We found that disruption of the Dyn2-Vav1 interaction impairs Rac1 activation and subsequent lamellipodia formation and cell migration, indicating that Dyn2-Vav1 binding regulates tumor cell motility. Surprisingly, RNAi-mediated suppression of Dyn2 or disruption of Dyn2-Vav1 binding results in a dramatic reduction in Vav1 protein stability, resulting in diminished levels of this proto-oncogene and decreased Rac1 activation and migration. Remarkably, this degradative reduction is a result of Vav1 targeted transport to the lysosome, as treatment of these cells with the protease inhibitor chloroquine prevents Vav1 loss, and immunofluorescent cell staining shows a dramatic localization of Vav1 to the lysosomal lumen when it cannot bind Dyn2.CONCLUSION: These findings demonstrate a novel regulatory role for direct Dyn2 binding in Rac1 activation, lamellipod protrusion and cellular migration through the stabilization of Vav1, and demonstrate a potent mechanism by which metastatic migration is upregulated in pancreatic tumor cells. This study was funded by NCI CA104125 to MAM.

Su1051 Dietary Macronutrients Alter Erk2-AKT1-PGE2 Pathway in Barrett's Mucosa: Potential Role During Carcinogenesis in Barrett's Epithelium

Background: No-shows and appointment cancellations are especially salient to gastroenterology. Data shows that the incidence of colorectal cancer is down-trending, which correlates to increased colorectal cancer awareness and increase in the number of per capita screening colonoscopies. Patients lost to follow-up because of a no-show or cancellation (NS/C) might be at a higher risk of developing malignancy because of a missed screening opportunity. If particular patient demographics can be identified that are associated with NS/C, specific interventions can be proposed to capture those patients at possible increased risk. Aim: To determine if certain patient demographics contribute to the NS/C. Methods: A retrosepctive chart review using the Computerized Patient Records System (CPRS) at the Carl T.Hayden VA Medical Center in Phoenix, Arizona analyzed 17 weeks of data regarding NS/C. Data was obtained regarding the patients: age, gender, new vs. follow appointment, type of procedure vs. clinic appointment, reason for appointment, and origin of the appointment, whether within the GI department or through open access primary care consultation. Results: 17 weeks of data were reviewed. A majority were male (92.2%). Ages ranged from 23-88 years and average age was 57.5 years old. 14.8% of patients were younger than 50. More NS/C were for follow-ups (55.8%) rather than new consults (44.2%). There were also more NS/C for colonoscopies (73.8%) than EGDs (24.1%) and paracentesis contributed to only 1.9% of the total. Appointments originating from outside the GI department were more likely to result in NS/C as 73.6% of those appointments originated from the PCP. Only 26.1% of NS/C originated from within the GI department. A specific analysis of coloscopy was made (table) revealing that 265 colonoscopies were performed. 19.3% of the NS/C colonoscopies scheduled for symptomatic complaints (pain, diarrhea, constipation, hematochezia) came from within the GI department while 80.7% came from the patients PCP. This was supported by an overwhelming majority of /C screening and surveillance appointments that also came from outside the GI department (87.1%). Conclusions: This data illustrates that of patients who fail to keep their appointments, they are likely to be older than 50, with asymptomatic complaints, who are referred to the GI department by their PCPs. This is valuable information because patients lost in the NS/C process represent a missed opportunity for possible positive interventions including but not limited to the prevention of colorectal cancer. By identifying these variables, steps can be taken to minimize their contribution to the NS/C rate in the future.

Abstract PR-03: Aspirin mediated downregulation of Warburg kinase AKT1 in patients with Barrett's esophagus: Implications in neoplastic transformation

Background: In patients with Barretts esophagus, chronic reflux injury and inflammation are associated with esophageal adenocarcinoma, one of the most rapidly increasing lethal cancers. Epidemiological and preclinical studies support decreased risk of esophageal adenocarcinoma with NSAID use. Gastroesophageal refluxate contents can promote carcinogenesis in Barretts metaplasia by activating AKT, which up regulates COX-2 expression and prostaglandin biosynthesis. We recently noted that neoplastic transformation in Barretts esophagus is associated with increased AKT expression, particularly isoform AKT1. The AIM of this study is to investigate the effect of NSAID (Aspirin) use in patients with Barretts esophagus on AKT1 expression using frozen tissue from the randomized, phase II trial of aspirin and esomeprazole for esophageal cancer chemoprevention in Barretts esophagus patients and to assess the functional consequences of AKT1 expression in-vitro. Methods and Results: In a subset of patients (12 of 120 patients) with Barretts esophagus who were randomized to placebo, lower dose (81 mg) or higher dose (325 mg) Aspirin for 4 weeks, both PCR and Western blot revealed marked reduction in AKT1 expression in patients who received 325 mg of Aspirin daily compared to patients who received placebo. Our in-vitro experiments support that AKT1 expression is functionally relevant to the process of carcinogenesis in Barretts epithelial cells. Using adenovirus to induce AKT1 expression, we show that increased AKT1 expression increases Barretts epithelial cell growth, facilitates RAS-mediated transformation of pre-neoplastic epithelial cells and promotes colony formation. Since AKT1 is known as Warburg kinase and regulates cellular glucose uptake to support aerobic glycolysis during growth de-regulation and neoplasia, we examined the uptake of fluorescent deoxyglucose analog (2-NBDG) in Barretts epithelial cells transduced with AKT1 adenovirus. At 48 hrs, compared to control, AKT1 overexpression resulted in increased glucose uptake both by metaplastic and neoplastic Barretts epithelial cells. Transcriptional repression of AKT1 abrogated the 2-NBDG uptake by these cells. Finally, we did pathway specific qPCRs and noted that use of Aspirin is associated with altered expression of chromatin remodelers that could down-regulate AKT1 expression. Conclusion: Collectively, our results demonstrate that Aspirin mediated down-regulation of Warburg kinase AKT1 in patients with Barrett?s esophagus is a novel mechanism for the regulation of Barrett?s epithelial cell growth. The in-depth characterization of molecular mechanisms is currently underway. This abstract is also presented as Poster A82. Citation Format: Navtej S. Buttar, Gary W. Falk, Cathrine J. DeMars, Sonia Chowdhury, Ahmed Elebiary, Anamay Sharma, Sidhartha Chaudhry, Nathan R. Foster, Katie L. Allen Ziegler, Yvonne Romero, Norman E. Marcon, Thomas Schnell, Douglas A. Corley, Prateek Sharma, Marcia R. Cruz-Correa, Chin Hur, David E. Fleischer, Amitabh Chak, Kenneth R. DeVault, David S. Weinberg, Gary Della’Zanna, Ellen Richmond, Thomas C. Smyrk, Sumithra Mandrekar, Paul J. Limburg. Aspirin mediated downregulation of Warburg kinase AKT1 in patients with Barretts esophagus: Implications in neoplastic transformation. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr PR-03.