without any change in HNF4alpha (proposed co-factor for HNF1alpha). While carcinogenicin Barrett's esophagus, our group has recently demonstrated that Muc 4 acts as a noveltumor suppressor gene in the colon. Therefore, we hypothesized that deoxycholate, knownto be carcinogenic in the colon, may have a role in modulation of CDX2 and MUC4 levelsin colon. Methods: For these studies, we used the human CRC cell line, HT29. We treatedwith two doses of sodium deoxycholate of 50μM and 500μM for 45 minutes. We evaluatedexpression of Muc 4, CDX 2 along with Muc 4 transcription factors HNF1alpha and HNF4al-pha by immunoblots and PCR analysis using standard protocols. To demonstrate the roleof Muc4, we created MUC4 shRNA stable construct in HT29 cell. Results: As demonstratedin the table, deoxycholate caused a dose dependent reduction in Muc 4 levels leading tocorresponding suppression in CDX2 levels. In order to confirm the Muc 4—CDX2 link, weevaluated the Muc4 ShRNA knockdowns and noted a 50% reduction (p=0.05%) in CDX2expression. Deoxycholate—->HNF4alpha—->MUC4—->CDX2 Conclusions: We provide,herein, the first evidence that CDX 2 downregulation is related to deoxycholate/Muc 4expression. Importantly, given that deoxycholate preferentially targets the right colon, thismay provide a mechanism for the more dramatic CDX2 loss noted in right colon.

There was no change in the expression of HNF1alpha.

S1674

Interaction of RNA Binding Protein HuR With Survivin and p53 mRNAElizabeth Tsu-Ying Chang, James Donahue, Jian-Ying Wang, Richard Battafarano

Survivin is a member of the Inhibitor of Apoptosis (IAP) family and functions to promotecell division and to inhibit apoptosis. It is constitutively overexpressed in a variety of tumors,but in normal cells its expression is tightly regulated and highly cell cycle-dependent.Although numerous transcriptional regulators of survivin have been identified, post-transcrip-tional control of this important protein is largely unknown. HuR is an RNA-binding proteinthat binds to the 3' untranslated region (UTR) of labile mRNAs bearing AU-rich elements.This interaction tends to promote mRNA stabilization and enhance protein translation.Previous work from our group has shown that HuR could bind and stabilize the nascentmRNAs of both the X-linked Inhibitor of Apoptosis Protein (XIAP), another IAP familymember, and p53, a negative transcriptional regulator of survivin. Given the divergentfunctions of IAP family proteins and p53, we sought to determine if HuR binds survivinmRNA and how this affects survivin expression in the presence of p53. Methods: Studieswere conducted in normal human esophageal mucosal cells. Binding of HuR to survivinmRNA was examined by biotinylated RNA pull-down and RNP-IP assays. Levels of proteinexpression were measured by Western blot. mRNA levels were measured by real time PCR.HuR function was examined by overexpression using an adenovirus vector. p53 expressionwas silenced using siRNA. Survivin mRNA stability was determined by measuring its halflife. Results: Both biotinylated RNA pull-down and RNP-IP assays revealed direct bindingof HuR to the 3' UTR of survivin mRNA. The specificity of this interaction was demonstratedby fragmentation analysis of the survivin 3' UTR, showing that HuR binding was restrictedto a 288 bp fragment. Overexpression of HuR led to a decrease in both survivin proteinand mRNA levels as well as an increase in p53 protein level. When p53 expression wassilenced prior to HuR overexpression, however, survivin protein expression was increased.This increase in survivin overexpression was associated with an increase in survivin mRNAstability. Conclusion: HuR binds to the 3' UTR of survivin mRNA and enhances its stability.Under normal conditions with intact p53, HuR overexpression results in decreased survivinexpression secondary to the negative transcriptional regulation of survivin by p53. In theabsence of p53, HuR overexpression results in increased survivin mRNA stability and proteinexpression. These findings may provide an additional explanation for the increased survivinexpression observed in cancer cells that have lost p53 expression.

S1675

TLR4 Does Not Influence Myeloid-Derived Suppressor Cell ChemotaxisTowards MCP-1 In VitroManmish S. Bawa, Donna-Marie McCafferty

Leukocyte biology plays a critical role in inflammation and cancer in chronic conditionssuch as inflammatory bowel disease. Recently, a protumorigenic cell type known as themyeloid-derived suppressor cell (MDSC, Gr1+CD11b+) with various immunosuppressiveand pro-angiogenic functions has been described. We have developed an interleukin-10and toll-like receptor 4 double deficient (IL-10-/- TLR4-/-) model that has a significantlyincreased incidence of adenocarcinoma than the interleukin-10 knockout mouse (IL-10-/-:12%, IL-10-/-TLR4-/-: 50%) at three months of age. Our previous data show that MDSClevels are increased in the colon (IL-10-/-: 4.4±1.3%, IL-10-/-TLR4-/-: 8.8±1.2%) in theabsence of TLR4 in this model as determined via flow cytometry analysis of colonic laminapropria cells. Monocyte chemoattractant protein-1 (MCP-1), prostaglandin E2 (PGE2) andinterleukin-1β (IL-1β) have been identified in literature as molecules critical to the recruit-ment of MDSC In Vivo. The aim for this study was identify MDSC chemoattractants In Vitroand determine whether MDSC chemotaxis is modulated by TLR4. Interestingly, in IL-10-/-mice TLR4mRNA expression is decreased in areas of mucosal hyperplasia (polyps) (0.38±0.1)where tumors and MDSC are found relative to the distal colon (0.86±0.2) of the same mice(n=7). In Vitro chemotaxis assays were conducted using 8μm pore transwell chambers with2.5x10^5 MDSC isolated via percoll gradient density centrifugation of bone marrow in theupper chamber and control or chemoattractant solutions in the lower chamber. Following3 hours of incubation at 37*C, migrant cells were cytospun onto slides and labeled withrat anti-mouse Gr1 and CD11b antibodies to determine the number of MDSC. Chemotaxisdose response data were generated for MCP-1 (0.125 - 0.8μg/ml), PGE2 (3 - 300ng/ml)and IL-1β (1 - 1000ng/ml). No chemotaxis was observed toward PGE2 or IL-1β at any

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concentration. MCP-1 increased MDSC chemotaxis in a dose dependant manner with a peaklevel at 0.1 μg/ml. MDSC chemotaxis responses to MCP-1 were comparable in cells isolatedfrom IL-10-/- (749.6 ± 35 cells at 0.1 μg/ml) and IL-10-/-TLR4-/- (718.3 ± 72.5 cells at 0.1μg/ml vs 300 cells in controls) mice at all doses. MCP-1 mRNA expression in the colonwas elevated in IL-10-/- (0.3 ± 0.06) and IL-10-/-TLR4-/- (0.183 ± 0.03) mice (n=3) relativeto WT (0.097 ± 0.03) but not significantly different in the presence/absence of TLR4. Ourdata show that MCP-1 is a direct chemoattractant for MDSC In Vitro however PGE2 andIL-1β are not. TLR4 expression on MDSC does not influence chemotaxis towards MCP-1.

S1676

Transgenic Overexpression of TGFβ1 Does Not Affect Development of SmallIntestinal Adenomas in APCΔ580 MiceAdam Yakovich, Bo Jiang, Jianguo Du, John Barnard

Introduction: Transforming growth factor β1 (TGFβ1) is a critical regulator of gastrointestinalhomeostasis. In some cell types, TGFβ1 is a tumor suppressor during early oncogenesis;however, in advanced disease it is associated with increased invasiveness and metastasis. Tofurther define the role for TGFβ1 during intestinal oncogenesis, transgenic mice that overex-press constitutively active, villin promoter-driven TGFβ1 specifically in the small intestinewere mated with Apc Delta 580 mice. ApcΔ580 mice harbor a germline mutant Apc allelethat results in multiple small intestinal adenomas. Methods: TGFβ1 overexpressing mice(vil-TGFβ1) were mated with Apc Delta 580 (ApcΔ580), both strains were on the C57BL/6 background. At 16 weeks of age, adenoma multiplicity and size were assessed in theproximal, middle, and distal portions of the small intestine in both ApcΔ580 and vil-TGFβ1-ApcΔ580 mice. Results: Small intestinal villi in mice overexpressing TGFβ1 were shorterand wider than control villi and the lamina propria was infiltrated with myofibroblasticcells. TGFβ1 overexpression increased small intestinal length from 34 cm to 38 cm (p<0.05),an effect we have described previously. Adenoma multiplicity and size were similar betweenvil-TGFβ1-ApcΔ580 and ApcΔ580 groups, even when adjusting for intestinal length. Vil-TGFβ1-ApcΔ580 mice (n=8) had an average of 81 (± 12 SE) adenomas while ApcΔ580mice (n=13) had an average of 89 (± 7 SE) adenomas (p = NS). Adenoma distribution alongthe length of the small intestine was also similar. The average adenoma size was also notstatistically significantly different (1.5 mm vs 1.6 mm) in vil-TGFβ1-ApcΔ580 and ApcΔ580mice respectively. Conclusions: In mice analyzed to date, overexpression of constitutivelyactive TGFβ1 in the small intestinal epithelium of mice does not affect development ofademonas arising from inactivation in the Apc tumor suppressor gene.

S1677

Over-Expression of the Chromosome 11 Mucins is Associated With CIMP andBRAF Mutation in Colorectal CancerMichael D. Walsh, Daniel D. Buchanan, Sally- Ann Pearson, Rhiannon J. Walters, DianeM. McKeone, Mark Clendenning, John Hopper, Mark A. Jenkins, Graham G. Giles, DallasEnglish, Christophe Rosty, Michael A. McGuckin, Joanne P. Young

Mucinous differentiation has been shown to be associated with methylator phenotype (CIMP)in colorectal cancer (CRC). Mucinous differentiation is also associated with the presence ofmicrosatellite instability (MSI). The mucinous phenotype derives from abundant expressionof the colonic goblet cell mucin, MUC2, and de novo expression of gastric foveolar mucin,MUC5AC. Other groups have shown that CRCs which have little or no MUC2 and MUC5ACexpression frequently show evidence of epigenetic silencing of these genes via methylation.We sought to investigate the expression levels of MUC2, MUC5AC and another gastricmucin, MUC6, all of which are encoded for by genes lying in a cluster located on chromosome11p15.5. Patients enrolled prospectively in the Melbourne Collaborative Cohort Study werefollowed for up to 19 years for the development of cancers including colorectal cancer. 675incident CRC from 664 individuals (355 males, 309 females, mean age 67.9 ± 7.9 yr) weretested for CIMP status, MLH1 methylation, and somatic V600E BRAF and codons 12 and13 KRAS mutations, MSI and expression of MUC2, MUC5AC and MUC6. MUC2 over-expression was observed in 32% CRCs overall, and de novo MUC5AC and MUC6 expressionin 33% and 38% CRCs respectively. Co-expression of two or more of the mucins in tumorswas commonly seen. Expression of MUC2 and MUC5AC was strongly associated with CIMPstatus (p<0.001) and MLH1 methylation (p<0.001). Additionally, MUC2, MUC5AC andMUC6 expression was associated with the presence of the somatic V600E BRAF mutation(p<0.001) and proximal location (p<0.001). Over-expression was observed in tumors withand without mucinous differentiation, and was also associated with MSI, poor differentiation,lymphocytic response and increased T stage (all p<0.001), but not lymph node involvement,venous invasion, or infiltrating tumor margins. There were inverse association betweenMUC5AC expression and p53 over-expression (p=0.01), and MUC2 over-expression andcodons 12/13 KRAS mutations (p=0.04). CRCs from females were also more likely to over-express MUC5AC (p=0.03). The over-expression of secreted mucins MUC2, MUC5AC andMUC6 in CIMP positive CRCs is paradoxical since the mucin genes are known to beepigenetically silenced by methylation. The data suggest that, in CIMP positive tumors, theCpG islands of the promoters in these mucin genes are preferentially spared frommethylationand that methylation may silence elements which normally repress mucin gene expression,permitting over-expression of MUC2 and de novo expression of gastric type mucins MUC5ACand MUC6.

S1678

Butyrate's Anti-Colon Cancer Properties are Mediated by MicroRNAsTien Dong, Shien Hu, Eugene B. Chang

[Background] Previous epidemiological studies have shown that dietary fiber may have aprotective effect against colorectal cancer. However, the exact mechanism is still unclear.One possibility in which fiber can affect carcinogenesis is through butyrate, a short chainfatty acid with anti-cancer properties produced by the fermentation of dietary fiber. However,little research has been done to describe the effects of butyrate on microRNAs (miRNAs),

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swhich are small regulatory molecules involved in such pathways as tumorigenesis andmetastasis. Therefore the purpose of our study is to elicit this novel connection betweenbutyrate and miRNAs. [Methods] HCT116 (human cancerous colonic epithelial) and IEC18(noncancerous intestinal epithelial) cells were cultured with or without butyrate. MiRNAchanges were surveyed using a microarray from Exiqon and confirmed using quantitativePCR (qPCR). An In Vivo study was performed comparing wild-type C57Bl/6 mice fed on ahigh fiber diet of 6% pectin to mice fed on a control diet, assaying for miRNAs. qPCR wasperformed using the NCode Kit (Invitrogen). Western blot was used to analyze p21. WST-1 assay was used to measure cell proliferation. [Results] We have identified that the miRNAprofile of butyrate-treated cancerous cells greatly differ from treated-noncancerous cells.Butyrate increased 26 miRNAs (including 3 clusters) and decreased 18 miRNAs (including5 clusters) in HCT116 cells, and increased 9 miRNAs (including 2 clusters) and decreased4 miRNAs (including 1 cluster) in IEC18 cells. Interestingly, the clusters that were increased(ex. mir-194-215) tended to be tumor suppressor-like and the clusters that were decreased(ex. mir-25-106b, mir-17-92a, etc.) tended to be oncogenic-like in characteristic. From ourIn Vivo study, the data shows that mice fed on a high fiber diet have a significant decreasein the mir-25-106b cluster in the cecum, proximal, and distal colon, with the largest decreaseat the cecum, an area with the highest rate of fermentation and highest concentration ofbutyrate. Western blot and qPCR results on p21, a known tumor suppressor and a targetof the mir-25-106b cluster, suggests that the decrease in the mir-25-106b cluster contributesto butyrate's anti-cancer effects. We further showed through the WST-1 assay that butyratedecreases cell proliferation in HCT116 cells and not in IEC18 cells. [Conclusion] Butyratechanges miRNAs and their targets in a manner that reflects butyrate's anti-cancer effects.This implies that miRNAs are a novel pathway in which butyrate may affect tumorigenesis,and that butyrate-modifiable miRNAs can be good targets for future anti-cancer therapies.

S1679

Loss of Interleukin-4 Receptor α Function Drives Initiation, but NotProgression, of Azoxymethane-Induced Colorectal Carcinogenesis in BALB/CMiceNicola Ingram, Sarah L. Perry, Nigel Scott, Louise Coletta, Mark Hull

We have previously demonstrated that genetic deletion of interleukin-4 receptor α (IL-4Rα)in BALB/c mice leads to an increase in azoxymethane (AOM)-induced aberrant crypt focus(ACF) multiplicity. Therefore, we tested the hypothesis that absence of IL-4Rα signallingalso promotes adenoma growth and development in AOM-induced colorectal carcinogenesis.BALB/c IL-4Rα-/- and IL-4Rα+/+ mice (wild-type) were injected twice with 10 mg/kg AOM,for methylene blue stained ACF counting at 6 weeks or with 6 injections, for tumourphenotype analysis at 32 weeks. Lymphocyte (CD4+, CD8+, CD25+ and FoxP3+) andmyeloid-derived suppressor cell (CD11b+, GR-1+; MDSC) splenocyte populations wereanalysed by flow cytometry. Blood cell populations were measured using a Vet abc bloodanalyser. Loss of IL-4Rα signalling was associated with an increase in ACF multiplicity(median 8.5 [IQR 7.25-12; n=8]) compared with wild-type mice (median 3 [IQR 1-3.5; n=9], p=0.007 Mann Whitney U-test) confirming our previous observation of an anti-neoplasticrole of IL-4Rα signalling in AOM-induced tumour initiation. At 32 weeks, the number ofACFs detected in AOM-treated IL-4Rα-/- mice (median 8 [IQR 6-10]; n=16) remained higherthan wild-type mice (median 3 [IQR 2-7]; n=19, p=0.0017). However, loss of IL-4Rαsignalling did not promote macroscopic tumour development (incidence = 25%, meannumber per tumour-bearing mouse = 2 tumours/colon ) compared with wild-type animals(incidence = 26.3%, mean = 1.4 tumours/colon). All tumours apart from one case of milddysplasia were adenomas that exhibited severe dysplasia. Adenomas were only detected infemale mice. Adenomas were smaller in IL-4Rα-/- mice (mean [SD] 2.3 [1.0] mm) comparedwith wild-type tumours (3.7 [1.3] mm; p = 0.06). There was no significant difference inroutine haematological parameters between IL-4Rα-/- mice and wild-type animals at bothtime points. However, there was an increase in CD4+ and FoxP3+ splenocytes (but notMDSCs) in IL-4Rα-/- mice compared with wild-type animals at 32 weeks after AOM treatment.IL-4Rα signalling has stage-specific roles during AOM-induced colorectal carcinogenesis inBALB/c mice. Although absence of IL-4Rα signalling promotes initiation, it does not appearto be protective for progression to adenoma and may even have a pro-tumorigenic roleduring adenoma growth. Smaller tumour size in IL-4Rα-/- mice is associated with an increasein splenic regulatory T cells.

S1680

Mechanism of Expression Alterations of Keratins and Vimentin in IntestinalTumor Cell Lines During Epithelial-Mesenchymal TransitionKoksun Looi

Background: Epithelial-mesenchymal transition (EMT) in human intestinal tumor progressionis associated with the up-regulation of the intermediate filament protein vimentin and thedown-regulation of keratins. In normal and tumor intestinal epithelial cells, the major keratinintermediate filament proteins are keratins 8 (K8) and 18 (K18). K8 and K18 are obligateheteropolymers such that lack of expression of one of the two keratins (e.g., due to mutation)results in proteasomal degradation of the partner protein. Absence of K8 in mice results incolonic hyperplasia and a Th-2 type colitis. The mechanism(s) of changes in keratin andvimentin expression during EMT are not known. Aim: We tested the hypothesis that someintestinal tumor cell lines gain vimentin expression but lose their keratin expression. If so,such cell lines provide useful model systems to study the mechanism of some of the observedmolecular changes that occur during EMT. Methods: Keratin and vimentin protein andmRNA levels were examined in the rodent intestinal cell lines CT26 and IEC6 and in theliver cell lines BNL CL.2 and NMuLi, and compared with the corresponding normal tissueexpression. Proteasomal protein degradation was assessed using the inhibitor MG132. DNAmethylation and the presence of keratin mutations were assessed in K8 and K18 at thegenomic and mRNA levels. Results: Both CT26 and IEC6 cells, but not the remaining celllines tested, have no detectable K8 or K18 protein but have high levels of vimentin. InCT26 cells, MG132 stabilized K18 protein expression but not K8 thereby suggesting therelative absence of K8 mRNA relative to K18. Estimation of K8 and K18 mRNA by qPCRshowed significantly lower levels of K8 mRNA relative to K18 which were also supported

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by the measurement of mRNA half lives of K8 and K18. The findings or relative K18 versusK8 stability were confirmed by transfection of individual wild-type K8 or K18 into CT26cells. Several DNA mutations were also identified, none of which results in a truncatedprotein, which provide a potential explanation for the observed changes in RNA stability.Assessment of DNA methylation did not show significant changes between CT26 and thecontrol cells. Conclusion: Although the CT26 and IEC cell lines are classified as intestinalepithelial cell lines, they appear to be highly transformed based on the lack of keratinexpression and the abundant new expression of vimentin. The EMT-related loss of keratinexpression is due, at least in part, to changes in K8 and K18 at the post-transcriptionalrather than translational level. Similar findings may also occur in human epithelial tumorsthat undergo EMT.

S1681

Expression of Intestinal MUC17 Membrane-Bound Mucin in Inflammatory andNeoplastic Diseases of the ColonSenapati Shantibhusan, Samuel B. Ho, Poonam Sharma, Srustidhar Das, SubhankarChakraborty, Sukhwinder Kaur, Silvia C. Resta, Brandon S. Kandarian, Surinder K. Batra

Background/Aims: Membrane-bound mucins are expressed on intestinal epithelial surfacesand play a role in cytoprotection, anti-apoptosis, cellular restitution and signaling of externalstimuli. The membrane-bound mucin MUC17 is highly expressed in intestinal and colonicepithelia, but the relationship of the expression of this protein to diseases of the colon havenot been described. The aim of this study was to determine the cellular location andexpression of MUC17 core mucin protein in specimens of normal, inflamed and neoplasticcolon. Methods: A polyclonal antibody recognizing a MUC17 tandem repeat amino acidsequence (anti-MUC17tr) was used for immunoblotting and immunohistochemistry. Colonicbiopsy and surgical resection specimens were studied, and included normal (n=12), ulcerativecolitis (n=25), ischemic colitis (n=7), hyperplastic (n=8), adenomatous (n=44), and invasivecancer (n=10) specimens. A semi-quantitative scoring system was used to measure MUC17expression. MUC17 protein and RNA expression was determined in colon cancer cell lines(HT-29, LS174T, SW480, HCT-15, LoVo, LS-180, COLO-205 and WiDr). Results: Anti-MUC17tr recognizes a high MW 500 kDa band on colonic cellular lysates and was highlyexpressed on surface and crypt colon columnar cells. MUC17tr immunoreactivity was local-ized to the supranuclear and diffuse cytoplasmic area of columnar cells. The apical membraneand glycocalyx of most columnar cells did not express MUC17. Goblet cell expression wasabsent. MUC17 expression in normal colon (6.67 ± 0.86) was significantly greater thanspecimens of ulcerative colitis (1.56 ± 0.55; p<0.01) and severe ischemic colitis (1.57±1.13;p<0.01). In severe colitis sparse staining in the regenerating surface columnar cells waspresent, with no differences in specimens with dysplasia. Similarly, MUC17 expression wasdecreased in hyperplastic (1.25±0.8; p<0.01), tubular (2.9±1; p=0.01) and tubulovillousadenomas (0.9±0.4; p<0.01), and invasive cancers (1.4±0.5; p<0.01). MUC17tr expressionwas focal and supranuclear in adenomas and cancer. Confirming a reduction of MUC17gene expression in cancer was the finding that MUC17 protein and RNA were only detectedin 2/8 colon cancer cell lines, LS174T and LS-180. Conclusions: These results indicate thatthe potential protective effects of this membrane-bound mucin are primarily or secondarilydiminished in inflammatory and neoplastic conditions. Decreased MUC17 expression occursat the earliest stages of dysregulated colonocyte growth. Further research is needed todetermine if decreased MUC17 expression plays a role in increased susceptibility to inflam-matory damage and cancer susceptibility.

S1682

Β-Spectrin, ELF is Reactive Against the Monoclonal Antibody, MAb DAS-1,That Recognizes Pre-Malignant Conditions of the Gastrointestinal (GI) Tract.Xin Geng, Lopa Mishra, Kiron M. Das

Background: The mAb Das-1 (also known as 7E12H12) is a novel monoclonal antibodythat was developed against a membrane associated colon epithelial protein (CEP) of Mr200K. In the first trimester fetal tissue, CEP is expressed in the entire GI tract epitheliumand liver (hepatoblast) but from the 2nd trimester onward and after birth, it is detectedonly in the colon and biliary epithelium but not in any other parts of the GI tract. However,it reappears in a number of pre-malignant conditions such as Barrett's epithelium (BE),gastric intestinal metaplasia (GIM) associated with gastric cancer and small intestinal adenomaincluding carcinomas arising from these organs. In BE, CEP is detected with 90-100%sensitivity and specificity. CEP is also present in LS180 colon cancer cells. The structureand function of CEP has been unknown. AIM: In this communication, we report purificationof CEP to homogeneity and its further characterization. Results: CEP is localized in plasmamembrane as shown by confocal microscopy and is released outside the cells. Serum freemedium from LS180 cells was concentrated, subjected to molecular sieve followed byProFACT Proteomics technology Sera FileTM separation platform that exploits the structuraland spatial distribution in elastomedic polyelectrolyte libraries. Final purification of CEPwas accomplished by immunoaffinity chromatography using mAb Das-1 and then analyzedby Mass Spec (LTQ, Thermo Fisher Scientific). Mass Spec yielded a peptide (DK23, 23aaresidues) that demonstrated 95% homology to β-spectrin, ELF. The reactivity of mAb Das-1 to β-spectrin was confirmed against pure β-spectrin by an ELISA and also by using apolyclonal anti-ELF, β-spectrin antibody against CEP by ELISA and Western blot (Table1). The reactivity of mAb Das-1 to purified β-spectrin, ELF could be partially blocked bythe specific peptide DK23.Conclusion: β-spectrin family of cytoskeletal proteins are involvedin regulation of signal transduction by functioning as adaptor molecules. Further characteriza-tion of the CEP related β-spectrin, a stem cell adaptor protein which has been implicatedin various gastrointestinal cancers, and the intriguing oncofetal expression of CEP may helpin the understanding of pre-cancerous stages and oncogenesis in the GI tract.Table 1 ELISA data-OD values