Intestinal Stem Cell Marker Research Articles

Aging of intestinal stem cells.

SummaryThe intestine is one of the organs that relies on stem cell function for maintaining tissue homeostasis. Recent findings on intestinal aging show that intestinal architecture, such as villus length, crypt size, and cell composition changes in the aged crypts. The correspondent decline in the regenerative capacity of the intestine is mainly due to a decline in intestinal stem cell function upon aging, as the underlying mechanisms of aging intestinal stem cells are beginning to unravel. This review summarizes our current knowledge on stem cell-intrinsic mechanisms of aging of intestinal stem cells and their connection to extrinsic factors, such as niche cells and microbiota and will introduce recent approaches to attenuate or even revert the aging of intestinal stem cells.

Sox9, Hopx, and survivin and tuft cell marker DCLK1 expression in normal canine intestine and in intestinal adenoma and adenocarcinoma.

Self-renewal of the intestinal epithelium originates from stem cells located at the crypt base. Upregulation of various stem cell markers in intestinal epithelial neoplasms indicates a potential role of stem cells in tumorigenesis. In this study, the immunoreactivity of potential intestinal stem cell markers (Sry box transcription factor 9 [Sox9], homeodomain-only protein [Hopx], survivin) and tuft cell marker doublecortin-like kinase 1 (DCLK1) in normal canine intestine and intestinal epithelial neoplasms was investigated. Formalin-fixed paraffin-embedded (FFPE) small and large intestine as well as intestinal neoplasms (55 colorectal adenomas [CRAs], 17 small intestinal adenocarcinomas [SICs], and 12 colorectal adenocarcinomas [CRCs]) were analyzed immunohistologically. Potential stem cell markers Sox9, Hopx, and survivin were detected in the crypts of normal canine small and large intestine. DCLK1+ tuft cells were present in decreasing numbers along the crypt-villus axis of the jejunum and rarely detectable in large intestine. In canine intestinal epithelial tumors, nuclear Sox9 immunoreactivity was detectable in 84.9% (CRA), 80% (CRC), and 77% of epithelial neoplastic cells (SIC). Hopx and survivin were expressed within cytoplasm and nuclei of neoplastic cells in benign and malignant tumors. DCLK1 showed a cytoplasmic reaction within neoplastic cells. The combined score of Hopx, DCLK1, and survivin varied among the examined cases. Overall, malignant tumors showed lower DCLK1 scores but higher Hopx scores in comparison with benign tumors. For survivin, no differences were detectable. In conclusion, stem cell markers Sox9, Hopx, and survivin were detectable at the crypt base and the immunoreactivity of Sox9, DCLK1, survivin, and Hopx was increased in canine intestinal adenomas and adenocarcinomas compared with normal mucosa.

Inhibition of Musashi-1 enhances chemotherapeutic sensitivity in gastric cancer patient-derived xenografts.

Musashi-1 (MSI1), a neural RNA-binding protein, is considered a gastric and intestinal stem cell marker. Although the function of MSI1 in gastric cancer has attracted increasing interest, it is not known whether MSI1 can be used as a biomarker to monitor gastric cancer development and response to treatment. Here, the role of MSI1 in the chemotherapeutic sensitivity of gastric cancer was investigated. Patients with high MSI1 levels had poor outcomes, implicating the gene in the development and progression of the disease. We overexpressed and silenced MSI1 in the human gastric cancer cell lines MKN45 and HGC27, finding that knockdown reduced proliferation, invasion, and migration, while promoting apoptosis. A patient-derived xenograft gastric cancer model was constructed in which mice received chemical drugs, si-MSI1, or a drug-si-MSI1 combination. It was found that blocking MSI1 expression reduced gastric cancer drug tolerance. The combination treatment with si-MSI1 was superior to 5F-dUMP and cisplatin, either separately or in combination, indicating that including si-MSI1 was better than drug therapy alone. Transcriptome sequencing analysis showed that MSI1 altered cell cycle regulation and growth signal transduction, including that of blood vessel epicardial substance (BVES). These results suggest that MSI1 reduces the tolerance of gastric cancer to chemical drugs through modulation of MSI1/BVES signaling.

Canonical TGF\u03b2 signaling induces collective invasion in colorectal carcinogenesis through a Snail1- and Zeb1-independent partial EMT

Local invasion is the initial step towards metastasis, the main cause of cancer mortality. In human colorectal cancer (CRC), malignant cells predominantly invade as cohesive collectives and may undergo partial epithelial-mesenchymal transition (pEMT) at the invasive front. How this particular mode of stromal infiltration is generated is unknown. Here we investigated the impact of oncogenic transformation and the microenvironment on tumor cell invasion using genetically engineered organoids as CRC models. We found that inactivation of the Apc tumor suppressor combined with expression of oncogenic KrasG12D and dominant-negative Trp53R172H did not cell-autonomously induce invasion in vitro. However, oncogenic transformation primed organoids for activation of a collective invasion program upon exposure to the prototypical microenvironmental factor TGFβ1. Execution of this program co-depended on a permissive extracellular matrix which was further actively remodeled by invading organoids. Although organoids shed some epithelial properties particularly at the invasive edge, TGFβ1-stimulated organoids largely maintained epithelial gene expression while additionally implementing a mesenchymal transcription pattern, resulting in a pEMT phenotype that did not progress to a fully mesenchymal state. Notably, while TGFβ1 induced pEMT and promoted collective invasion, it abrogated self-renewal capacity of TKA organoids which correlated with the downregulation of intestinal stem cell (ISC) marker genes. Mechanistically, induction of the non-progressive pEMT required canonical TGFβ signaling mediated by Smad transcription factors (TFs), whereas the EMT master regulators Snail1 and Zeb1 were dispensable. Gene expression profiling provided further evidence for pEMT of TGFβ1-treated organoids and showed that their transcriptomes resemble those of human poor prognosis CMS4 cancers which likewise exhibit pEMT features. We propose that collective invasion in colorectal carcinogenesis is triggered by microenvironmental stimuli through activation of a novel, transcription-mediated form of non-progressive pEMT independently of classical EMT regulators.

AUPHOS, A “FIRST-IN CLASS“ ORAL AGENT FOR CORRECTING METABOLIC DYSFUNCTION IN IBD

Abstract BACKGROUND Mucosal repair is the goal of medical therapy in IBD. Prospective inception cohort pediatric studies suggest that suppression of mitochondrial genes lead to unfavorable clinical outcomes in ulcerative colitis (UC) and Crohn’s disease (CD). We posit that the inability to restore epithelial mitochondrial respiration impairs ulcer healing in IBD. In the current study, we tested whether a novel compound (AuPhos) that improves mitochondrial function promotes ulcer healing in IBD. METHODS Biodistribution and pharmacokinectic (PK) studies were performed (6h, 12h, 24h) after single oral dose (25mg/kg) of AuPhos using C57/BL/6 (WT) mice. Mitochondrial uptake of AuPhos was determined by measuring gold content in normal colonocytes (NCM460) using graphite furnace atomic absorption spectroscopy. Oxygen consumption rate (OCR) in isolated crypt-IECs from AuPhos-fed WT mice were examined using high-resolution respirometry. The effect of AuPhos in colitis was tested in DSS (2%; 7d) WT (B6) mice. Disease activity index (DAI) (weight loss, diarrhea, and hematochezia), intestinal permeability (FITC-dextran), histological scoring and the frequency of fissioning crypts were determined throughout the 21d time course. Tissue mRNA levels for mitochondrial enzyme, cytokine, chemokine and intestinal stem cell (ISC) marker genes were assessed by RT-qPCR. RESULTS Biodistribution and PK studies revealed that higher levels of orally administered AuPhos in small intestine and colon tissue, with limited systemic absorption. AuPhos displayed a dose-dependent mitochondrial uptake in IEC where respirometry showed >30% increase in OCR after oral dosing in vivo. AuPhos treatment decreased DAI (**; p<0.01), histologic colitis scores D11-15 (*; p<0.05) and FITC-dextran permeability in DSS colitis mice. Notably, AuPhos increased fissioning crypt numbers near healing ulcers in DSS-colitis mice (**; p<0.01) while it reduced mRNA for pro-inflammatory cytokines/chemokines (IL-1β, IL-6, IFN-γ, IP10). AuPhos induced mRNA for ISC markers [Lgr4 (*; p<0.05), Lgr5, Lrig1 (***; p<0.001)] and mitochondrial complexes [mtCO1 (**; p<0.01) and COX2 (***; p<0.001)]. These findings suggest that AuPhos-induced mitochondrial respiration drives transcriptomic regulation of IEC genes involved in colitis ulcer healing. CONCLUSION Our data suggests that AuPhos compound improves ulcer healing under acute colitis conditions by increasing mucosal OxPHOS metabolism. Specifically, we find that AuPhos increases mitochondrial respiration-induced crypt fissioning and ulcer healing associated with reduced mucosal inflammation and increased barrier integrity. Overall, AuPhos may be an important “first-in class” oral therapeutic for correcting the metabolic dysfunction central to IBD pathogenesis.

P099 Serum proteomic analysis reveals novel biomarkers associated with disease activity in pediatric patients with Crohn’s disease

Abstract Background Although Crohn’s disease (CD) is associated with a marked hyper-inflammatory response, identifying serum biomarkers associated with disease activity and outcomes is considered challenging, given lack of sensitivity of different assays. Our aim was to identify novel markers using Olink, a novel technology based on proximity extension assay, enabling detection of minute amounts of proteins. Methods Serum samples were obtained from pediatric patients with CD at the time of diagnosis and following induction therapy, and from control subjects, consisting of pediatric patients with normal endoscopic procedures, without past or present history of an immune-mediated disorder (e.g. celiac, diabetes). Serums were subjected to Olink (two panels used, consisting of 184 proteins), and analysis was performed on a Normalized Protein eXpression file by supervised, multivariate, principal component analysis and verification by univariate ANOVA with Benjamini-Hochberg and post-hoc Tukey analysis. Results Eighty-eight serum samples were collected: 30 from control subjects and 58 from 32 patients with CD (24 of them pre- and post-induction therapy). The median age of patients in the control and CD groups was 13.9 years (IQR 11.1–16.6) and 14.6 years (IQR 12.2–16.9), respectively (P=0.32). Twenty-four patients were treated with anti-TNFa agents and 8 with EEN. The median pediatric Crohn’s Disease Activity Index (PCDAI) decreased from 35 (22.5–42.5) to 5 (0–12.5, P<0.001) following induction therapy. We identified 72 proteins that significantly differed between patients and controls, and many of them were associated with CRP or ESR levels. String analysis identified several important nodes linking different proteins, including MMPs, MPO, EGFR and TNFRSF1A. Many proteins, such as resistin and different MMPs, showed a strong positive correlation with disease activity, based on PCDAI, while others, such as EGFR, showed a negative correlation. Several novel markers were identified to be highly expressed in the serum of patients with CD, including LRIG1, an intestinal stem cell marker, that was highly correlated with disease activity among the patients. Conclusion We identified novel serum markers that are associated with disease activity in pediatric patients with CD. These findings should be validated in future studies, and be complemented with expression and functional studies to define their role in mediating intestinal immune responses.

Intestinal Stem Cell Marker ASCL2 is a Novel Prognostic Predictor in Esophageal Adenocarcinoma.

PurposeIntestinal stem cell markers play a significant role in esophageal adenocarcinoma carcinogenesis via Barrett’s esophagus; however, its utility as a prognostic biomarker has not been established.MethodsWe analyzed the immunohistochemical expression of intestinal stem cell markers, ASCL2 and LGR5, using whole slides (35 cases) and tissue microarray (TMA; 64 cases). On TMA slides, adjacent normal squamous epithelium, metaplastic glandular epithelium (Barrett's esophagus), and dysplastic glandular epithelium were inserted when applicable. Two pathologists semi-quantitatively scored stained slides independently, and the results were correlated with clinicopathologic factors and outcomes.ResultsIn whole slides, 51% and 57% expressed high ASCL2 and high LGR5; in TMA, 69% and 88% expressed high ASCL2 and high LGR5, respectively. In TMA, high ASCL2 and low LGR5 expression significantly correlated to a higher number of involved lymph nodes (p=0.027 and p=0.0039), and LGR5 expression significantly correlated to the pathological stage (p=0.0032). Kaplan-Meier analysis showed a negative impact of high ASCL2 expression on overall survival (OS; WS p=0.0168, TMA p=0.0276) as well as progression-free survival (PFS; WS p=0.000638, TMA p=0.0466) but not LGR5. Multivariate Cox regression analysis revealed that ASCL2 expression is an independent prognostic factor for esophageal adenocarcinoma (OS; WS p=0.25, TMA p=0.011. PFS; WS p=0.012, TMA p=0.038). Analysis of the TCGA dataset showed that ASCL2 mRNA levels were correlated to nodal status but not overall survival.ConclusionHigh expression of the intestinal stem cell marker ASCL2 may predict unfavorable outcomes in surgically resected esophageal adenocarcinoma.

Survival of Stem Cells and Progenitors in the Intestine Is Regulated by LPA5-Dependent Signaling.

Background & AimsRegeneration of the epithelium by stem cells in the intestine is supported by intrinsic and extrinsic factors. Lysophosphatidic acid (LPA), a bioactive lipid mediator, regulates many cellular functions, including cell proliferation, survival, and cytokine secretion. Here, we identify LPA5 receptor as a potent regulator of the survival of stem cells and transit-amplifying cells in the intestine.MethodsWe have used genetic mouse models of conditional deletion of Lpar5, Lpar5f/f;Rosa-CreERT (Lpar5KO), and intestinal epithelial cell–specific Lpar5f/f;AhCre (Lpar5IECKO) mice. Mice were treated with tamoxifen or β-naphthoflavone to delete Lpar5 expression. Enteroids derived from these mice were used to determine the effect of Lpar5 loss on the apoptosis and proliferation of crypt epithelial cells.ResultsConditional loss of Lpar5 induced ablation of the intestinal mucosa, which increased morbidity of Lpar5KO mice. Epithelial regeneration was compromised with increased apoptosis and decreased proliferation of crypt epithelial cells by Lpar5 loss. Interestingly, intestinal epithelial cell–specific Lpar5 loss did not cause similar phenotypic defects in vivo. Lpar5 loss reduced intestinal stem cell marker gene expression and reduced lineage tracing from Lgr5+ ISCs. Lpar5 loss induced CXCL10 expression which exerts cytotoxic effects on intestinal stem cells and progenitors in the intestinal crypts. By co-culturing Lpar5KO enteroids with wild-type or Lpar5KO splenocytes, we demonstrated that lymphocytes protect the intestinal crypts via a LPA5-dependent suppression of CXCL10.ConclusionsLPA5 is essential for the regeneration of intestinal epithelium. Our findings reveal a new finding that LPA5 regulates survival of stem cells and transit-amplifying cells in the intestine.

A Proximal-to-Distal Survey of Healthy Adult Human Small Intestine and Colon Epithelium by Single-Cell Transcriptomics.

Background & AimsSingle-cell transcriptomics offer unprecedented resolution of tissue function at the cellular level, yet studies analyzing healthy adult human small intestine and colon are sparse. Here, we present single-cell transcriptomics covering the duodenum, jejunum, ileum, and ascending, transverse, and descending colon from 3 human beings.MethodsA total of 12,590 single epithelial cells from 3 independently processed organ donors were evaluated for organ-specific lineage biomarkers, differentially regulated genes, receptors, and drug targets. Analyses focused on intrinsic cell properties and their capacity for response to extrinsic signals along the gut axis across different human beings.ResultsCells were assigned to 25 epithelial lineage clusters. Multiple accepted intestinal stem cell markers do not specifically mark all human intestinal stem cells. Lysozyme expression is not unique to human Paneth cells, and Paneth cells lack expression of expected niche factors. Bestrophin 4 (BEST4)+ cells express Neuropeptide Y (NPY) and show maturational differences between the small intestine and colon. Tuft cells possess a broad ability to interact with the innate and adaptive immune systems through previously unreported receptors. Some classes of mucins, hormones, cell junctions, and nutrient absorption genes show unappreciated regional expression differences across lineages. The differential expression of receptors and drug targets across lineages show biological variation and the potential for variegated responses.ConclusionsOur study identifies novel lineage marker genes, covers regional differences, shows important differences between mouse and human gut epithelium, and reveals insight into how the epithelium responds to the environment and drugs. This comprehensive cell atlas of the healthy adult human intestinal epithelium resolves likely functional differences across anatomic regions along the gastrointestinal tract and advances our understanding of human intestinal physiology.

Identifying the E2F3-MEX3A-KLF4 signaling axis that sustains cancer cells in undifferentiated and proliferative state.

Rationale: Dysregulation of signaling that governs self-renewal and differentiation of intestinal stem cells (ISCs) is a major cause of colorectal cancer (CRC) initiation and progression.Methods: qRT-PCR, western blotting, in situ hybridization, immunohistochemistry and immunofluorescence assays were used to detect the expression levels of MEX3A, KLF4 and E2F3 in CRC tissues. The biological functions of MEX3A were studied using Mex3a knockout (KO) and intestinal epithelium specific conditional knockout (cKO) mice, AOM-DSS mouse colorectal tumor model, Apc floxed mouse tumor model and intestinal and tumor organoids. Transcriptomic RNA sequencing (RNA-seq), RNA crosslinking immunoprecipitation (CLIP) and luciferase reporter assays were performed to explore the molecular mechanisms of MEX3A.Results: RNA-binding protein MEX3A, a specific ISC marker gene, becomes ectopically upregulated upon CRC and its levels negatively correlate with patient survival prognosis. MEX3A functions as an oncoprotein that retains cancer cells in undifferentiated and proliferative status and it enhances their radioresistance to DNA damage. Mechanistically, a rate limiting factor of cellular proliferation E2F3 induces MEX3A, which in turn activates WNT pathway by directly suppressing expression of its pro-differentiation transcription factor KLF4. Knockdown of MEX3A with siRNA or addition of KLF4 agonist significantly suppressed tumor growth both by increasing differentiation status of cancer cells and by suppressing their proliferation.Conclusions: It identifies E2F3-MEX3A-KLF4 axis as an essential coordinator of cancer stem cell self-renewal and differentiation, representing a potent new druggable target for cancer differentiation therapy.

Mechanism of RNA recognition by a Musashi RNA-binding protein.

The Musashi RNA-binding proteins (RBPs) regulate translation of target mRNAs and maintenance of cell stemness and tumorigenesis. Musashi-1 (MSI1), long considered as an intestinal and neural stem cell marker, has been more recently found to be over expressed in many cancers. It has served as an important drug target for treating acute myeloid leukemia and solid tumors such as ovarian, colorectal and bladder cancer. One of the reported binding targets of MSI1 is Numb, a negative regulator of the Notch signaling. However, the dynamic mechanism of Numb RNA binding to MSI1 remains unknown, largely hindering effective drug design targeting this critical interaction. Here, we have performed extensive all-atom microsecond-timescale simulations using a robust Gaussian accelerated molecular dynamics (GaMD) method, which successfully captured multiple times of spontaneous and highly accurate binding of the Numb RNA from bulk solvent to the MSI1 protein target site. GaMD simulations revealed that Numb RNA binding to MSI1 involved largely induced fit in both the RNA and protein. The simulations also identified important low-energy intermediate conformational states during RNA binding, in which Numb interacted mainly with the β2-β3 loop and C terminus of MSI1. The mechanistic understanding of RNA binding obtained from our GaMD simulations is expected to facilitate rational structure-based drug design targeting MSI1 and other RBPs.

Olfactomedin 4 Is Not a Precise Marker for Human Intestinal Stem Cells, But Is Involved in Intestinal Carcinogenesis

Olfactomedin 4 Is Not a Precise Marker for Human Intestinal Stem Cells, But Is Involved in Intestinal Carcinogenesis

Expression profile of CD98 heavy chain and L-type amino acid transporter 1 and its prognostic significance in colorectal cancer

L-type amino acid transporter (LAT1) is a neutral amino acid transporter, forming a heterodimer complex with the CD98 heavy chain (CD98hc). In this study, we studied the expression profiles of LAT1 and CD98hc in colorectal cancer (CRC) and its precursor lesions. Transcription levels of CD98hc and LAT1 were significantly increased in CRC compared to the matched normal mucosa. CD98hc and LAT1 expression showed no significant correlations with cancer stem cell markers and intestinal stem cell markers, whereas both had positive correlations with Wnt target genes, AXIN2, and EPHB2, suggesting an association with aberrant Wnt signaling activation. Immunohistochemical analysis revealed that CD98hc and LAT1 are not expressed in normal colonic mucosa and various benign lesions including hyperplastic polyps and sessile and traditional serrated adenomas. CD98hc and LAT1 expressions began to appear in tubular adenomas and further increased in carcinomas. Of interest, CD98hc expression decreased during lymph node metastasis. Survival analysis demonstrated that CD98hc and LAT1 have no significant prognostic effect in CRCs. In conclusion, CD98hc and LAT1 are not normally expressed in colonic mucosa and most benign lesions. Their expression began to appear in tubular adenomas and further increased during the adenoma-to-carcinoma transition. CD98hc expression decreased while metastasizing to regional lymph nodes. However, CD98hc and LAT1 expressions had no prognostic value in patients with CRC.

Changes in progenitors and differentiated epithelial cells of neonatal piglets.

This study aimed to assess the changes of small intestinal morphology, progenitors, differentiated epithelial cells, and potential mechanisms in neonatal piglets. Hematoxylin and eosin staining of samples from 36 piglets suggested that dramatic changes were observed in the jejunum crypts depth and crypt fission index of neonatal piglets (P < 0.001). The number of intestinal stem cells (ISC) tended to increase (P < 0.10), and a decreased number of enteroendocrine cells appeared in the jejunal crypt on d 7 (P < 0.05). Furthermore, the mRNA expression of jejunal chromogranin A (ChgA) was down-regulated in d 7 piglets (P < 0.05). There was an up-regulation of the adult ISC marker gene of SPARC related modular calcium binding 2 (Smoc2), and Wnt/β-catenin target genes on d 7 (P < 0.05). These results were further verified in vitro enteroid culture experiments. A mass of hollow spheroids was cultured from the fetal intestine of 0-d-old piglets (P < 0.001), whereas substantial organoids with budding and branching structures were cultured from the intestine of 7-d-old piglets (P < 0.001). The difference was reflected by the organoid budding efficiency, crypt domains per organoid, and the surface area of the organoid. Furthermore, spheroids on d 0 had more Ki67-positive cells and enteroendocrine cells (P < 0.05) and showed a decreasing trend in the ISC and goblet cells (P < 0.10). Moreover, the mRNA expression of spheroids differed markedly from that of organoids, with low expression of intestinal differentiation gene (Lysozyme; P < 0.05), epithelial-specific markers (Villin, E-cadherin; P < 0.05), and adult ISC markers (leucine-rich repeat-containing G protein-coupled receptor 5 [Lgr5], Smoc2; P < 0.001), and up-regulation of fetal marker (connexin 43 [Cnx43]; P < 0.05). The mRNA expression of relevant genes was up-regulated, and involved in Wnt/β-catenin, epidermal growth factor (EGF), Notch, and bone morphogenetic protein (BMP) signaling on d 7 organoids (P < 0.05). Spheroids displayed low differentiated phenotype and high proliferation, while organoids exhibited strong differentiation potential. These results indicated that the conversion from the fetal progenitors (spheroids) to adult ISC (normal organoids) might largely be responsible for the fast development of intestinal epithelial cells in neonatal piglets.

REGγ drives Lgr5+ stem cells to potentiate radiation induced intestinal regeneration.

Leucine-rich repeat containing G protein-coupled receptor 5 (Lgr5), a marker of intestinal stem cells (ISCs), is considered to play key roles in tissue homoeostasis and regeneration after acute radiation injury. However, the activation of Lgr5 by integrated signaling pathways upon radiation remains poorly understood. Here, we show that irradiation of mice with whole-body depletion or conditional ablation of REGγ in Lgr5+ stem cell impairs proliferation of intestinal crypts, delaying regeneration of intestine epithelial cells. Mechanistically, REGγ enhances transcriptional activation of Lgr5 via the potentiation of both Wnt and Hippo signal pathways. TEAD4 alone or cooperates with TCF4, a transcription factor mediating Wnt signaling, to enhance the expression of Lgr5. Silencing TEAD4 drastically attenuated β-catenin/TCF4 dependent expression of Lgr5. Together, our study reveals how REGγ controls Lgr5 expression and expansion of Lgr5+ stem cells in the regeneration of intestinal epithelial cells. Thus, REGγ proteasome appears to be a potential therapeutic target for radiation-induced gastrointestinal disorders.

109 Diet-induced Clinical Responsiveness of Translational Dog Model for Human Western Diet (WD)-related Disease Research

Abstract Human consumption of Western diets (WD) has been strongly associated with increased central obesity, adipocyte hypertrophy, intestinal epithelial stemness/proliferation, dyslipidemia, and blood pressure. These changes reflect metabolic dysfunction and contribute to increased risk of type 2 diabetes mellitus and colorectal cancer. As comprehensive molecular/clinical comparisons have not been performed, the objective of this study was to evaluate diet-induced changes in dogs as a clinically-responsive model for human WD-related disease research. Methods: In a crossover design, 10 dogs were fed either a 1.) control diet (CON) formulated based on the Acceptable Macronutrient Distribution Ranges and fiber recommendations for humans; or 2.) Western diet (WD) formulated based on National Health and Nutrition Examination Survey dataset parameters. Diets were prepared cooked with the same ingredients and formulated to meet/exceed nutrient/energy requirements for both humans/dogs and fed isocalorically based on calculated metabolizable energy (ME). Following each period (~7–8 weeks), experimental parameters were measured. Results/Conclusions: Mean body weights were 8.83 and 9.28kg for CON and WD diets, respectively (P = 0.0018). Fasted (10-hour) blood samples differed significantly (P &amp;lt; 0.01) for mean fasting bile acids (CON=0.79, WD=8.94μmol/L), serum triglycerides (CON=45.70, WD=67.80mg/dL), and serum cholesterol (CON=140.10, WD=175.40mg/dL) demonstrating diet-dependent alterations in lipid profiles. Mean systolic blood pressures were 131.66 and 140.02mmHg for CON and WD, respectively (P &amp;lt; 0.0001). Histological analysis revealed diet-dependent changes in colonic epithelial villus height (CON=182, WD=207μm) and villus:crypt ratio (CON=2.61, WD=3.89). Preliminary RNA-ISH analysis (n = 3 dogs) showed increased LGR5+ expression (intestinal stem-cell marker) in WD compared to CON group (P = 0.0019) suggesting an increased “stemnness” of colonic epithelium. Further, mean adipocyte diameters were increased in omental fat biopsies (CON=58.6, WD=62.5μm; P &amp;lt; 0.0001) but not subcutaneous fat biopsies (P &amp;gt;0.05) following WD feeding, consistent with centralized obesity. Collectively, these results demonstrate effects of diet-induced changes in dogs as a clinically-responsive model for human WD-related disease research.

267 INTESTINAL STEM CELL MARKERS AND ITS POTENTIAL USE IN THE CLINICOPATHOLOGICAL SETTING OF ESOPHAGEAL ADENOCARCINOMA

Abstract Barrett’s esophagus (BE) is the primary precursor lesion of esophageal adenocarcinoma (EAC), which not only resembles the intestinal mucosa morphologically but also expresses various intestinal stem cell (ISC) markers. We hypothesized that ISC markers, Lgr5 (also a cancer stem cell marker), Ascl2 (fate determinator of ISC),Bmi1 (quiescent counterpart of Lgr5) and Cdx2 (primary regulator of ISC gene expression) have clinicopathological significance and could potentially be a predictor for survival in EAC. Methods Tissue microarray consisted of 64 EAC and 22 BE, and the expressions of Lgr5, Ascl2, Bmi1 and Cdx2 were analyzed using immunohistochemistry and scored independently by two pathologists. Clinicopathological factors (age, pathological grade and stage, affected lymph nodes, neoadjuvant therapy) were confounding factors, and univariable analysis using Fisher's exact tests as well as survival analysis using the Kaplan–Meier (KM) method and Cox proportional hazards regression (Cox PH) were performed to investigate its statistical significance. We performed a bioinformatic analysis of the TCGA dataset to validate the immunohistochemical findings. Results Among EAC, 69%, 88%, 64% and 70% expressed high Ascl2, Lgr5, Bmi1 and Cdx2, respectively. High Ascl2 and low Lgr5 expression significantly correlated to a higher number of involved lymph nodes; high Bmi1 expression significantly correlated to the pathological stage. Cdx2 was not correlated to any markers. KM analysis showed a negative impact of high Ascl2 expression on overall survival (OS; p = 0.0276) as well as progression-free survival (PFS; p = 0.0466), but not Lgr5, Bmi1 nor Cdx2. Cox PH analysis revealed Ascl2 (p = 0.011), and Cdx2 (p = 0.015) expression are independent prognostic factors for EAC. Conclusion Our results suggest that among the four ISC markers, Ascl2 and Cdx2 protein holds potential to be utilized as a prognostic biomarker. TCGA dataset revealed the association of ASCL2 mRNA expression with the number of positive lymph nodes but not overall survival, which implies further research is needed to explain the mechanism of Ascl2 overexpression in EAC carcinogenesis via ISC regulation.

BTF3-mediated regulation of BMI1 promotes colorectal cancer through influencing epithelial-mesenchymal transition and stem cell-like traits

The critical roles of transcription factors in cell differentiation and the delineation of cell phenotypes have been reported. The current study aimed to characterize the functions of the basic transcription factor 3 (BTF3) gene and its regulation of the intestinal stem cell marker B cell-specific Moloney murine leukemia virus insertion site 1 (BMI1) gene in colorectal cancer (CRC). Stem cell-like traits and epithelial-mesenchymal transition (EMT) of cultured human CRC cell line HCT116 were evaluated by CD133+ subpopulation counting, colony formation, tumorosphere generation, and expression of EMT-specific markers and stem cell markers. The interaction of BTF3 with BMI1 was analyzed. BTF3 was overexpressed in CRC tissues, which was associated with poor patient survival. BTF3 knockdown impaired the retention of stem cell-like traits of HCT116 and inhibited the EMT of HCT116 cells. BMI1 expression changed in a BTF3-dependent manner, and its overexpression could partially restore stem cell-like traits and EMT of cultured HCT116 cells after BTF3 knockdown. In parallel, treatment with the BMI1 inhibitor PTC-209 mimicked the effects of BTF3 knockdown on stem cell-like traits and EMT of cultured HCT116 cells. Together, these results support the notion that BTF3 and BMI1 are potential therapeutic targets to limit CRC metastasis.

The Intestinal Stem Cell Marker SMOC2 Is an Independent Prognostic Marker Associated With Better Survival in Gastric Cancer.

SPARC-related modular calcium-binding protein 2 (SMOC2), a secreted matricellular protein, is reported to be involved in cancer progression such as cell cycle, angiogenesis, and invasion. In this study, we aimed to investigate the expression of SMOC2 in various gastric lesions and assessed its prognostic value in a large cohort of gastric cancer (GC) patients. SMOC2 mRNA levels were measured by quantitative real-time PCR using 26 matched fresh-frozen GC samples. SMOC2 protein expression was determined by immunohistochemistry on tissue microarrays including 734 GC specimens and its correlations with clinicopathological features and survival were evaluated. The transcription level of SMOC2 was higher in GC samples compared to normal mucosa (p=0.006). Its expression levels were associated with the intestinal stem cell (ISC) marker, LGR5, but there were no correlations with EPHB2 and OLFM4 or the candidate cancer stem cell markers CD133 and CD44. SMOC2 expression was significantly increased in the intestinal metaplasia and was further increased in gastric adenomas and early gastric cancers (EGC). In total, 34% of GCs were positive for SMOC2, and SMOC2 positivity was higher in old (p=0.001) and male (p<0.001) patients, and in well-differentiated GC (p<0.001). SMOC2 expression had a negative association with perineural invasion (p<0.001) and tumor stage (p<0.001). In survival analysis, SMOC2-positive GC patients had much better clinical outcomes in overall survival rates (p<0.001) compared to SMOC2-negative GC patients. The prognostic impact of SMOC2 remained significant both in intestinal (p<0.001) and diffuse-type GC (p<0.001). Remarkably, a multivariate analysis demonstrated SMOC2 as an independent prognostic marker [hazard ratio (HR)=0.732, p=0.045] along with venous invasion (p=0.012), tumor stage (p<0.001) and CDX2 (p=0.028). Our results suggest that SMOC2 can be a prognostic marker for better clinical outcomes in GC.

Active elimination of intestinal cells drives oncogenic growth in organoids.

SummaryCompetitive cell interactions play a crucial role in quality control during development and homeostasis. Here, we show that cancer cells use such interactions to actively eliminate wild-type intestine cells in enteroid monolayers and organoids. This apoptosis-dependent process boosts proliferation of intestinal cancer cells. The remaining wild-type population activates markers of primitive epithelia and transits to a fetal-like state. Prevention of this cell-state transition avoids elimination of wild-type cells and, importantly, limits the proliferation of cancer cells. Jun N-terminal kinase (JNK) signaling is activated in competing cells and is required for cell-state change and elimination of wild-type cells. Thus, cell competition drives growth of cancer cells by active out-competition of wild-type cells through forced cell death and cell-state change in a JNK-dependent manner.