Immunohistochemical expression of cyclin D1, cyclin E, p21/waf1 and p27/kip1 in inflammatory bowel disease: correlation with other cell-cycle-related proteins (Rb, p53, ki-67 and PCNA) and clinicopathological features

Profiles and interactions of gut microbiome and intestinal microRNAs in pediatric Crohn's disease

Gut dysbiosis is closely related to dysregulated microRNAs (miRNAs) in the intestinal epithelial cells, which plays an important role in the pathogenesis of Crohn's disease (CD). We investigated the relationship between fecal gut microbiome (GM) and intestinal tissue miRNAs in different stages of pediatric CD. Metagenomic analysis and miRNA sequencing were conducted to examine the GM and intestinal miRNA profiles of CD patients before and after clinical induction therapy and the controls. Twenty-seven newly diagnosed, therapy-naïve pediatric patients with active CD and 11 non-inflammatory bowel disease (IBD) controls were recruited in this study. Among CD patients, 11 patients completed induction treatment and reached clinical remission. Both GM and miRNA profiles were significantly changed between CD patients and controls. Seven key bacteria were identified at species level including Defluviitalea raffinosedens, Thermotalea metallivorans, Roseburia intestinalis, Dorea sp. AGR2135, Escherichia coli, Shigella sonnei, and Salmonella enterica, the exact proportions of which were further validated by real-time quantitative PCR analysis. Eight key miRNAs were also identified including hsa-miR-215-5p, hsa-miR-194-5p, hsa-miR-12135, hsa-miR-509-3-5p, hsa-miR-212-5p, hsa-miR-4448, hsa-miR-501-3p, and hsa-miR-503-5p. The functional enrichment analysis of differential miRNAs indicated the significantly altered cyclin protein, cyclin-dependent protein, and cell cycle pathway. The close interactions between seven key bacteria and eight key miRNAs were further investigated by miRNA target prediction. The association between specific miRNA expressions and key gut bacteria at different stages of CD supported their important roles as potential molecular biomarkers. Understanding the relationship between them will help us to explore the molecular mechanisms of CD.

IMPORTANCE

Since previous studies have focused on the change of the fecal gut microbiome and intestinal tissue miRNA in pediatric Crohn's disease (CD), the relationship between them in different stages is still not clear. This is the first study to explore the gut microbiota and miRNA and their correlations with the Pediatric Crohn's Disease Activity Index (PCDAI). Crohn's Disease Endoscopic Index of Severity (CDEIS), and calprotectin, by applying two omics approach in three different groups (active CD, CD in remission with exclusive enteral nutrition or infliximab induction therapy, and the healthy controls). Both gut microbiome structure and the miRNA profiles were significantly changed in the different stage of CD. Seven key gut microbiome at species and eight key miRNAs were found, and their close interactions were further fully investigated by miRNA target prediction.

Therapeutic effects of epigallocatechin-3-gallate for inflammatory bowel disease: A preclinical meta-analysis

BACKGROUND

Epigallocatechin-3-gallate (EGCG), the primary active compound in green tea, is recognized for its significant anti-inflammatory properties and potential pharmacological effects on inflammatory bowel disease (IBD). However, comprehensive preclinical evidence supporting the use of EGCG in treating IBD is currently insufficient.

PURPOSE

To evaluate the efficacy of EGCG in animal models of IBD and explore potential underlying mechanisms, serving as a groundwork for future clinical investigations.

METHODS

A systematic review of pertinent preclinical studies published until September 1, 2023, in databases such as PubMed, Embase, Web of Science, and Cochrane Library was conducted, adhering to stringent quality criteria. The potential mechanisms via which EGCG may address IBD were summarized. STATA v16.0 was used to perform a meta-analysis to assess IBD pathology, inflammation, and indicators of oxidative stress. Additionally, dose-response analysis and machine learning models were utilized to evaluate the dose-effect relationship and determine the optimal dosage of EGCG for IBD treatment.

RESULTS

The analysis included 19 studies involving 309 animals. The findings suggest that EGCG can ameliorate IBD-related pathology in animals, with a reduction in inflammatory and oxidative stress indicators. These effects were observed through significant changes in histological scores, Disease Activity Index, Colitis Macroscopic Damage Index and colon length; a decrease in markers such as interleukin (IL)-1β, IL-6 and interferon-γ; and alterations in malondialdehyde, superoxide dismutase, glutathione, and catalase levels. Subgroup analysis indicated that the oral administration route of EGCG exhibited superior efficacy over other administration routes. Dose-response analysis and machine learning outcomes highlighted an optimal EGCG dosage range of 32-62 mg/kg/day, with an intervention duration of 4.8-13.6 days.

CONCLUSIONS

EGCG exhibits positive effects on IBD, particularly when administered at the dose range of 32 - 62 mg/kg/day, primarily attributed to its ability to regulate inflammation and oxidative stress levels.

Hyper Mucinous Proliferations in the Mucosa of Patients with Inflammatory Bowel Disease: Histological Lesions with a Real Potential for Neoplastic Evolution?

BACKGROUND AND AIMS

Mucin disfunction is a critical event in the pathogenesis of inflammatory bowel disease (IBD). Although hyper mucinous conditions have a still debated implication in the clinical evolution of this disorder, hyper mucinous villous proliferations were found to have a preneoplastic biologic potential. We studied morphologic and immunophenotypic characteristics of these lesions in ileocolonic resections for IBD to add evidence about the evolutive potential of these lesions in samples with well oriented wall structures.

METHODS

Morphologic characteristics of bowel samples from 20 patients resected for IBD and with raised lesions at gross examination were studied and sections from cases with hyper mucinous lesions were stained with the following antibodies: Ki 67, p21, and p27, which were employed to evaluate the characteristics of the proliferative and differentiative activity of the epithelial structures; mismatch repair proteins and p53 have been studied as proteins implicated in carcinogenesis in IBD-affected mucosa; mucins subtypes in hyper mucinous structures were evaluated with MUC-2 and MUC-6. The results in 11 cases of saplings were that they harbored hyper mucinous proliferations. The occurrence of hyper mucinous structures was not related to dysplastic lesions, pseudo pyloric metaplasia, subtype of disease, or activity. In only one of our cases, mild cytologic atypia in the proliferative compartment was detected. Proliferation markers (Ki 67, p53) were expressed in the proliferative compartments of mucosal crypts and antiproliferative proteins p21 and p27 were expressed in differentiated epithelium. MMR proteins expression was limited to the proliferative compartment of the hyper mucinous projections. Mucin subtypes distribution was regular in the epithelium of hyper mucinous proliferations.

CONCLUSIONS

The present monocentric retrospective study was conducted on surgical samplings with well oriented crypts. Collected data show that hyper mucinous features are frequent occurrences in raised lesions in IBD patients. In hyper mucinous proliferations of the selected cases, the status of the proliferative cycle, the expression of the proteins most frequently involved in carcinogenetic pathways of mucosa affected by IBD, and the mucins subtypes expression have no evident anomalies. Findings are not consistent with the increased risk of neoplastic evolution observed in other studies; rather, they suggest a hyperplastic nature. However, the capacity of hyper mucinous raised lesions for neoplastic evolution should be ruled out with more extensive prospective studies to identify functional defects that could explain the hypothesized neoplastic potential.

Investigating the shared genetic architecture between primary sclerosing cholangitis and inflammatory bowel diseases: a Mendelian randomization study

BACKGROUND

Several studies have found that primary sclerosing cholangitis (PSC) and inflammatory bowel disease (IBD) are closely associated. However, the direction and causality of their interactions remain unclear. Thus, this study employs Mendelian Randomization to explore whether there are causal associations of genetically predicted PSC with IBD.

METHODS

Genetic variants associated with the genome-wide association study (GWAS) of PSC were used as instrumental variables. The statistics for IBD, including ulcerative colitis (UC), and Crohn's disease (CD) were derived from GWAS. Then, five methods were used to estimate the effects of genetically predicted PSC on IBD, including MR Egger, Weighted median (WM), Inverse variance weighted (IVW), Simple mode, and Weighted mode. Last, we also evaluated the pleiotropic effects, heterogeneity, and a leave-one-out sensitivity analysis that drives causal associations to confirm the validity of the analysis.

RESULTS

Genetically predicted PSC was significantly associated with an increased risk of UC, according to the study (odds ratio [OR] IVW= 1.0014, P<0.05). However, none of the MR methods found significant causal evidence of genetically predicted PSC in CD (All P>0.05). The sensitivity analysis results showed that the causal effect estimations of genetically predicted PSC on IBD were robust, and there was no horizontal pleiotropy or statistical heterogeneity.

CONCLUSIONS

Our study corroborated a causal association between genetically predicted PSC and UC but did not between genetically predicted PSC and CD. Then, we identification of shared SNPs for PSC and UC, including rs3184504, rs9858213, rs725613, rs10909839, and rs4147359. More animal experiments and clinical observational studies are required to further clarify the underlying mechanisms of PSC and IBD.

Green tea EGCG effectively alleviates experimental colitis in middle-aged male mice by attenuating multiple aspects of oxi-inflammatory stress and cell cycle deregulation

Age-dependent increased risk of inflammatory bowel diseases such as ulcerative colitis is being increasingly realized, and yet therapies targeting this disorder within the purview of aging are limited. The present study attempted to assess the efficacy of green tea epigallocatechin gallate (EGCG) consumption in preventing the severity and progression of dextran sulphate sodium (DSS)-induced ulcerative colitis in 18 months old middle-aged male mice. Acute colitis was induced in animals using DSS and protective effects of EGCG consumption were examined. Different parameters related to disease progression and molecular markers related to oxi-inflammatory stress, localized and systemic cytokine response, epithelial barrier integrity, and cell cycle progression profile were evaluated. DSS treatment induced rapid and severe symptoms of colitis such as consistently increased DAI score, shortened and inflamed colon accompanied by increased levels of inflammatory proteins (TNFα/IL-6/IL-1β) in both the colon tissue and cultured splenocytes indicating exaggerated Th1 immune response. Markers of oxidative stress increased while antioxidant defences and the expression of tight junction genes in the colonic cells were attenuated. Dysregulation in the expression of cell cycle inhibitory genes (p53/p21^WAF1/p16^Ink4a) indicated possible induction of colitis-induced dysplasia. On the other hand, EGCG consumption strongly attenuated all the measured ostensible as well as molecular markers of the disease progression as evidenced by improved DAI score, cellular antioxidant capacity, attenuated Th1 cytokine response both in the colon and cultured splenocytes, enhanced expression of tight junction genes, and cell cycle inhibitors thereby suggesting systemic effects of EGCG. Together, these observations suggest that drinking EGCG-rich green tea can be a significant way of managing the severity of colitis during aging.

siRNA Targeting and Treatment of Gastrointestinal Diseases

RNA interference via small interfering RNA (siRNA) offers opportunities to precisely target genes that contribute to gastrointestinal (GI) pathologies, such as inflammatory bowel disease, celiac, and esophageal scarring. Delivering the siRNA to the GI tract proves challenging as the harsh environment of the intestines degrades the siRNA before it can reach its target or blocks its entry into its site of action in the cytoplasm. Additionally, the GI tract is large and disease is often localized to a specific site. This review discusses polymer and lipid‐based delivery systems for protection and targeting of siRNA therapies to the GI tract to treat local disease.

G protein-coupled estrogen receptor mediates anti-inflammatory action in Crohn's disease

Estrogens exert immunomodulatory action in many autoimmune diseases. Accumulating evidence highlights the meaningful impact of estrogen receptors in physiology and pathophysiology of the colon. However, the significance of G protein-coupled estrogen receptor (GPER) on Crohn's disease (CD), one of the inflammatory bowel disease (IBD) types, is still elusive. Our study revealed GPER overexpression at the mRNA and protein levels in patients with CD. To evaluate the effects of GPER activation/inhibition on colitis development, a murine 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced model of CD was used. We showed that activation of GPER reduces mortality, improves macroscopic and microscopic scores and lowers C-reactive protein (CRP) level. The impact of estrogen signaling on the suppression of the intestinal inflammation was proved by immunohistochemistry. It was demonstrated that GPER activation is accompanied by modulation of extracellular-signal regulated kinase (ERK) signaling pathway and expression level of genes involved in signal transmission and immune response as well as the expression of some microRNAs (miR-145, miR-148-5p and miR-592). Our study revealed that the membrane-bound estrogen receptor GPER mediates anti-inflammatory action and seems to be a potent therapeutic target in maintaining remission in CD.

Inactivation of JNK2 as carcinogenic factor in colitis-associated and sporadic colorectal carcinogenesis

We recently reported that dysregulated c-Jun N-terminal kinases (JNK) activity causes defective cell cycle checkpoint control, inducing neoplastic transformation in a cellular ulcerative colitis (UC) model. In the quiescent chronic phase of UC, p-p54 JNK was down-regulated and p-p46 JNK was up-regulated. Both were up-regulated in the acute phase. Consequently, increased p21WAF1 and γ-H2AX, two JNK-regulated proteins, induced cell cycle arrest. Their down-regulation led to checkpoint override, causing increased proliferation and undetected DNA damage in quiescent chronic phase, all characteristics of tumorigenesis. We investigated expression of p-JNK2, p-JNK1-3, p21WAF1, γ-H2AX and Ki67 by immunohistochemistry in cases of quiescent UC (QUC), active UC (AUC), UC-dysplasia and UC-related colorectal carcinoma (UC-CRC). Comparison was made to normal healthy colorectal mucosa, sporadic adenoma and colorectal carcinoma (CRC), diverticulitis and Crohns disease (CD). We found p-JNK2 up-regulation in AUC and its early down-regulation in UC-CRC and CRC carcinogenesis. With down-regulated p-JNK2, p21WAF1 was also decreased. Ki67 was inversely expressed, showing increased proliferation early in UC-CRC and CRC carcinogenesis. p-JNK1-3 was increased in AUC and QUC. Less increased γ-H2AX in UC-CRC compared to CRC gave evidence that colitis-triggered inflammation masks DNA damage, thus contributing to neoplastic transformation. We hypothesize that JNK-dependent cell cycle arrest is important in AUC, while chronic inflammation causes dysregulated JNK activity in quiescent phase that may contribute to checkpoint override, promoting UC carcinogenesis. We suggest restoring p-JNK2 expression as a novel therapeutic strategy to early prevent the development of UC-related cancer.

Defective Myb Function Ablates Cyclin E1 Expression and Perturbs Intestinal Carcinogenesis

Cyclin E1 is essential for the reentry of quiescent cells into the cell cycle. When hypomorphic mutant Myb mice (Myb(Plt4)) were examined, it was noted that Cyclin E1 (Ccne1) expression was reduced. Furthermore, the induction of Ccne1 in recovering intestinal epithelia following radiation-induced damage was ablated in Myb-mutant mice. These data prompted us to investigate whether Myb directly regulated Ccne1 and to examine whether elevated Myb in colorectal cancer is responsible for Cyclin E1-driven tumor growth. Here, it was found that Myb/MYB and Ccne1/CCNE1 expressions were coupled in both mouse and human adenomas. In addition, the low molecular weight Cyclin E1 was the predominant form in intestinal crypts and adenomatous polyposis coli (Apc)-mutant adenomas. Chromatin immunoprecipitation (ChIP) analysis confirmed that Myb bound directly to the Ccne1 promoter and regulated its endogenous expression. In contrast, Myb(Plt4) served as a dominant-negative factor that inhibited wild-type Myb and this was not apparently compensated for by the transcription factor E2F1 in intestinal epithelial cells. Myb(Plt4/Plt4) mice died prematurely on an Apc(Min/) (+) background associated with hematopoietic defects, including a myelodysplasia; nevertheless, Apc(Min/) (+) mice were protected from intestinal tumorigenesis when crossed to Myb(Plt4/) (+) mice. Knockdown of CCNE1 transcript in murine colorectal cancer cells stabilized chromosome ploidy and decreased tumor formation. These data suggest that Cyclin E1 expression is Myb dependent in normal and transformed intestinal epithelial cells, consistent with a cell-cycle progression and chromosome instability role in cancer.

IMPLICATIONS

This study demonstrates that Myb regulates Cyclin E1 expression in normal gastrointestinal tract epithelial cells and is required during intestinal tumorigenesis.

AMP-18 Targets p21 to Maintain Epithelial Homeostasis

Dysregulated homeostasis of epithelial cells resulting in disruption of mucosal barrier function is an important pathogenic mechanism in inflammatory bowel diseases (IBD). We have characterized a novel gastric protein, Antrum Mucosal Protein (AMP)-18, that has pleiotropic properties; it is mitogenic, anti-apoptotic and can stimulate formation of tight junctions. A 21-mer synthetic peptide derived from AMP-18 exhibits the same biological functions as the full-length protein and is an effective therapeutic agent in mouse models of IBD. In this study we set out to characterize therapeutic mechanisms and identify molecular targets by which AMP-18 maintains and restores disrupted epithelial homeostasis in cultured intestinal epithelial cells and a mouse model of IBD. Tumor necrosis factor (TNF)-α, a pro-inflammatory cytokine known to mediate gastrointestinal (GI) mucosal injury in IBD, was used to induce intestinal epithelial cell injury, and study the effects of AMP-18 on apoptosis and the cell cycle. An apoptosis array used to search for targets of AMP-18 in cells exposed to TNF-α identified the cyclin-dependent kinase inhibitor p21^WAF1/CIP1. Treatment with AMP-18 blunted increases in p21 expression and apoptosis, while reversing disturbed cell cycle kinetics induced by TNF-α. AMP-18 appears to act through PI3K/AKT pathways to increase p21 phosphorylation, thereby reducing its nuclear accumulation to overcome the antiproliferative effects of TNF-α. In vitamin D receptor-deficient mice with TNBS-induced IBD, the observed increase in p21 expression in colonic epithelial cells was suppressed by treatment with AMP peptide. The results indicate that AMP-18 can maintain and/or restore the homeostatic balance between proliferation and apoptosis in intestinal epithelial cells to protect and repair mucosal barrier homeostasis and function, suggesting a therapeutic role in IBD.

NMR metabonomics of serum in a rat model of abnormal savda disease carrying ulcerative colitis

AIM: To develop a rat model of abnormal savda disease carrying ulcerative colitis (UC), and to identify serum markers by applying the nuclear magnetic resonance (NMR)-based metabolomics technology.

METHODS: According to the theory of traditional Uyghur medicine, a rat model of abnormal savda syndrome was established, and on this basis, UC was induced with 2,4-dinitrochlorobenzene (DNCB) and acetic acid. ¹H NMR based metabolomics analysis was performed using serum samples from different groups of animals. Biomarkers accounting for the metabolic signature perturbation were then identified.

RESULTS: Compared with normal rats, lactate, acetone, acetoacetate, β-hydroxybutyrate, carnitine, alanine, and formic acid were increased, and α-glucose, β-glucose, creatine, low density lipoprotein (LDL), pyruvate, methionine, and glutamine were reduced in serum of rats with simple UC; α-ketoglutarate, acetone, acetoacetate, β-hydroxybutyrate, and formic acid were increased, and very low density lipoprotein (VLVD), methyl-histidine, pyruvate, and glutamine were reduced in serum of abnormal savda disease carrying UC rats. Compared with rats with simple UC, lactate, acetoacetate, α-glucose, β-glucose, creatine, LDL, and formic acid were increased, and citric acid was reduced in serum of abnormal savda disease carrying UC rats.

CONCLUSION: The metabolites in sera of UC rats, abnormal savda disease carrying UC rats and normal rats are significantly different. Dysregulation of lipid metabolism is the common pathophysiological process of simple UC and abnormal savda disease carrying UC.

Gastrointestinal dysplasia

The term dysplasia (intraepithelial neoplasia) is used to refer to neoplastic but non-invasive epithelium. Dysplasia in the gastrointestinal tract is considered a carcinoma precursor and a marker of high cancer risk for the site at which it is found. It is diagnosed by pathologists using a set of cytological and architectural features. There are many pitfalls in the diagnosis of gastrointestinal dysplasia. One reason for difficulty in dysplasia diagnosis is the significant heterogeneity in the appearances of each grade of dysplasia. In addition, the features that characterise dysplasia are only subtly different from those of regenerating epithelium, particularly at the low end of the spectrum, making this distinction difficult. For these reasons, and because of significant implications of this diagnosis for patient care, the interpretations of biopsies taken for dysplasia surveillance are considered challenging by most pathologists. In this article, we review definition, classification, and histological features and grading of gastrointestinal dysplasia with focus on Barrett's oesophagus (BE) related dysplasia, gastric epithelial dysplasia (GED) and dysplasia arising in the background of inflammatory bowel disease (IBD). We also discuss observer variability and the role of adjunctive markers in dysplasia diagnosis, and limitation with regard to surveillance of patients with BE and IBD due to sampling error.

Role of immunohistochemical markers in predicting progression of dysplasia to advanced neoplasia in patients with ulcerative colitis

BACKGROUND

Although dysplasia is thought to be the precursor lesion in the development of colitis-associated colorectal cancer (CRC), a significant proportion of patients with ulcerative colitis (UC) and low-grade (LGD) or indefinite (IND) dysplasia remain cancer-free during endoscopic follow-up. There is a need for biomarkers that predict neoplastic progression. We studied the value of a series of immunohistochemical markers in UC patients with flat LGD or IND with regard to neoplastic progression.

METHODS

Tissue samples were collected from 12 UC patients (six flat LGD, six IND) without progression and from 10 UC patients (eight flat LGD, two IND) with documented progression to HGD and/or CRC during a median of 25 and 23 months of colonoscopic follow-up, respectively. Immunohistochemistry using monoclonal antibodies was performed for p53, CD44, Ki67, AMACR, β-catenin, cyclin D1, p21, and ALDH. Positive and negative staining patterns were compared for progression to advanced neoplasia.

RESULTS

When patients showed coexpression of p53 and AMACR, 6/7 patients (86%) developed advanced neoplasia, compared to 4/15 patients (27%) without p53/AMACR coexpression (P = 0.02). Patients with p53/AMACR coexpression developed advanced neoplasia in a time period of 19 months (median, range 1-101) compared to 80 months (median, range 8-169) in patients without p53/AMACR coexpression (P = 0.14). Interestingly, in three patients with progression and previous dysplasia-negative biopsies, two out of three biopsies were p53-positive a median of 12 months (range 10-14) before the LGD/IND diagnosis.

CONCLUSIONS

This study suggests a role for p53/AMACR coexpression as a potential marker of neoplastic progression in patients with UC.

Molecular mechanisms of basic fibroblast growth factor effect on healing of ulcerative colitis in rats

We demonstrated previously that basic fibroblast growth factor (bFGF) accelerated the healing of experimental duodenal ulcers, and we now hypothesize that bFGF might also accelerate the healing of experimental ulcerative colitis (UC). We also explored the potential molecular mechanisms involved in the accelerated healing of UC in rats treated with bFGF. The results demonstrated that colonic lesions were significantly reduced by bFGF treatment, whereas neutralization of bFGF aggravated iodoacetamide-induced UC. Protein expression of bFGF was increased during the healing stage of UC. Tumor necrosis factor-α levels and myeloperoxidase activity were significantly decreased in UC rats treated with bFGF, whereas they increased in rats treated with anti-bFGF antibody. Real-time polymerase chain reaction and immunohistochemistry showed decreased levels of p27 in the UC rats compared with the healthy controls, which was reversed by bFGF treatment in a dose-dependent manner. By immunohistochemistry and double labeling of Ki-67 and CD34, prominent positive staining of Ki-67 and CD34 was seen after bFGF treatment, indicating the enhanced proliferation of fibroblasts and epithelial and endothelial cells, i.e., angiogenesis. We conclude that bFGF plays a beneficial role in the healing of UC in rats. The molecular mechanisms of bFGF in UC healing not only involve the expected increased cell proliferation, especially angiogenesis, but also encompass the reduction of inflammatory cytokines and infiltration of inflammatory cells. Thus, bFGF enema may be a new therapeutic option for UC.

Improvement of mitochondrial energy and oxidative balance during intestinal differentiation

Mitochondria vary in their number and function, but how these variations are associated with intestinal cell differentiation remains elusive. The object of this study was to investigate the underlying mechanisms of inosine-mediated intestinal cell maturation, analysing the effects of this nutrient on metabolic functionality, mitochondrial biogenesis and mitochondrial function in human colonic cells. The role of oxidative stress in the control of intestinal cell growth was also explored. We report the novel finding that inosine-mediated differentiation improves aerobic metabolism through an increase in mitochondrial bioenergetics and biogenesis in colonic cells, which probably confers them greater resistance to cytotoxic oxidative stress.

Epigenetic modifications induced by RGC-32 in colon cancer

First described as a cell cycle activator, RGC-32 is both an activator and a substrate for CDC2. Deregulation of RGC-32 expression has been detected in a wide variety of human cancers. We have now shown that RGC-32 is expressed in precancerous states, and its expression is significantly higher in adenomas than in normal colon tissue. The expression of RGC-32 was higher in advanced stages of colon cancer than in precancerous states or the initial stages of colon cancer. In order to identify the genes that are regulated by RGC-32, we used gene array analysis to investigate the effect of RGC-32 knockdown on gene expression in the SW480 colon cancer cell line. Of the 230 genes that were differentially regulated after RGC-32 knockdown, a group of genes involved in chromatin assembly were the most significantly regulated in these cells: RGC-32 knockdown induced an increase in acetylation of histones H2B lysine 5 (H2BK5), H2BK15, H3K9, H3K18, and H4K8. RGC-32 silencing was also associated with decreased expression of SIRT1 and decreased trimethylation of histone H3K27 (H3K27me3). In addition, RGC-32 knockdown caused a significantly higher percentage of SW480 cells to enter S phase and subsequently G2/M. These data suggest that RGC-32 may contribute to the development of colon cancer by regulating chromatin assembly.

Expression of p53, VEGF, microvessel density, and cyclin-D1 in noncancerous tissue of inflammatory bowel disease

We aimed to evaluate the carcinogenesis risk in inflammatory bowel disease via p53 mutation and its relation with hyperproliferation (cyclin-D1) and angiogenesis (with vascular endothelial growth factor [VEGF] and microvessel density) and whether these events play important roles in pathogenesis of inflammatory bowel disease. Colonic tissue samples of 26 ulcerative colitis, 6 Crohn's disease, and 8 amoebic colitis patients as well as samples of 10 healthy controls were stained with p53, cyclin-D1, CD34, and VEGF monoclonal antibodies by immunohistochemistry and evaluated semiquantitatively. Expression of p53 was higher in ulcerative colitis than in the healthy control and amoebic colitis groups (4.15 +/- 2.07, 1.4 +/- 1.5, 1.3 +/- 1.5; P < 0.001). The Crohn's disease group had the highest p53 expression (4.6 +/- 1.6). The Crohn's disease, ulcerative colitis, and amoebic colitis groups all had higher VEGF expression than did the healthy controls (respectively, 4.3 +/- 1.2, 2.92 +/- 2.0, 2.3 +/- 1.5, 0.6 +/- 0.97; P < 0.001). Also, microvessel density was statistically higher in all three colitis groups than in healthy controls. Cyclin-D1 expression in all four groups was similar. The study showed that p53 mutation was present in nonneoplastic mucosa of inflammatory bowel disease patients. Detecting strong p53 overexpression with VEGF overexpression may help in differentiating inflammatory bowel disease from other colitis.

Role of MutS homolog 2 (MSH2) in intestinal myofibroblast proliferation during Crohn's disease stricture formation

Tissue remodeling and mesenchymal cell accumulation accompanies chronic inflammatory disorders involving joints, lung, vasculature, and bowel. Chronic inflammation may alter DNA-mismatch repair (MMR) systems in mesenchymal cells, but is not defined in Crohn's disease (CD) and its associated intestinal remodeling and stricture formation. We determined whether DNA-MMR alteration plays a role in the pathogenesis of CD tissue remodeling. Control and CD bowel tissues were used to generate primary cultures of muscularis mucosa myofibroblasts, which were assessed directly or following stimulation with TNF-alpha/LPS or H2O2. MutS homolog (MSH)2, MSH3, and MSH6 expression in tissues and myofibroblasts was determined. Immunohistochemical staining revealed an increased expression of MSH2 in CD muscularis mucosa and submucosal tissues compared with controls or uninvolved CD tissue, and MSH2 expression was increased in CD myofibroblasts compared with control cells. TNF-alpha/LPS and H2O2 further enhanced MSH2 expression in both control and CD cells, which were decreased by simvastatin. There were no significant changes in MSH3 and MSH6 expression. Proliferating cell nuclear antigen and Ki67 staining of CD tissue revealed increased proliferation in the muscularis mucosa and submucosa of chronically inflamed tissues, and enhanced proliferation was seen in CD myofibroblasts compared with controls. Simvastatin reversed the effects of inflammatory stress on the DNA-MMR and inhibited proliferation of control and CD myofibroblasts. Gene silencing with MSH2 siRNA selectively decreased CD myofibroblast proliferation. These data demonstrate a potential role for MSH2 in the pathogenesis of nonneoplastic mesenchymal cell accumulation and intestinal remodeling in CD chronic inflammation.

Loss of fragile histidine triad protein expression in inflammatory bowel disease

AIM: To investigate the expression of fragile histidine triad (FHIT) protein in 64 patients with ulcerative colitis (UC) and Crohn’s disease (CD), and its relation with clinicopathological data.

METHODS: Rabbit-anti-FHIT antibody was used to detect FHIT protein expression in 64 formalin-fixed, paraffin-embedded tissue specimens of inflammatory bowel disease (IBD) by citrate-microwave-streptavidin (SP)-HRP immunohistochemical method.

RESULTS: The positive FHIT protein expression was 22.79% ± 16.16%, 42.14% ± 16.82% in active and remittent phases of UC, 36.07% ± 19.23% in CD, and 57.05% ± 8.86% in normal colon mucosa. Statistically significant differences in FHIT protein expression were observed between the active and remittent phases of UC, between the active phase of UC and normal colon mucosa, as well as between the remittent phase of UC and normal colon mucosa, and between CD and normal colon mucosa.

CONCLUSION: Our results show that FHIT protein expression is completely absent or reduced in IBD, suggesting that the FHIT gene might be associated with the oncogenesis and progression of IBD, an early event from inflammatory conditions to carcinoma in IBD.

The effects of short-chain fatty acids on colon epithelial proliferation and survival depend on the cellular phenotype

PURPOSE

The short-chain fatty acids (SCFA) are produced via anaerobic bacterial fermentation of dietary fiber within the colonic lumen. Among them, butyrate is thought to protect against colon carcinogenesis. However, few studies analyze the effects of butyrate, and other SCFA, on normal epithelial cells and on epithelial regeneration during disease recovery. Since there are controversial in vitro studies, we have explored the effects of SCFA on different biological processes.

METHODS

We used both tumoral (HT-29) and normal (FHC) epithelial cells at different phenotypic states. In addition, we analyzed the in vivo activity of soluble dietary fiber and SCFA production in the proliferation rate and regeneration of intestinal epithelial cells.

RESULTS

The effect of butyrate on epithelial cells depends on the phenotypic cellular state. Thus, in nondifferentiated, high proliferative adenocarcinoma cells, butyrate significantly inhibited proliferation while increased differentiation and apoptosis, whereas other SCFA studied did not. However, in normal cells or in differentiated cultures as well as in in vivo studies, the normal proliferation and regeneration of damaged epithelium is not affected by butyrate or SCFA exposure.

CONCLUSION

Although butyrate could exert antiproliferative effects in tumor progression, its production is safe and without consequences for the normal epithelium growth.