Dataset Information

Overexpressed Claudin-1 Can Be Visualized Endoscopically in Colonic Adenomas In Vivo.

ABSTRACT: Conventional white-light colonoscopy aims to reduce the incidence and mortality of colorectal cancer (CRC). CRC has been found to arise from missed polypoid and flat precancerous lesions. We aimed to establish proof-of-concept for real-time endoscopic imaging of colonic adenomas using a near-infrared peptide that is specific for claudin-1.We used gene expression profiles to identify claudin-1 as a promising early CRC target, and performed phage display against the extracellular loop of claudin-1 (amino acids 53-80) to identify the peptide RTSPSSR. With a Cy5.5 label, we characterized binding parameters and showed specific binding to human CRC cells. We collected in vivo near-infrared fluorescence images endoscopically in the CPC;Apc mouse, which develops colonic adenomas spontaneously. With immunofluorescence, we validated specific peptide binding to adenomas from the proximal human colon.We found a 2.5-fold increase in gene expression for claudin-1 in human colonic adenomas compared with normal. We showed specific binding of RTSPSSR to claudin-1 in knockdown and competition studies, and measured an affinity of 42 nmol/L and a time constant of 1.2 minutes to SW620 cells. In the mouse, we found a significantly higher target-to-background ratio for both polypoid and flat adenomas compared with normal by in vivo images. On immunofluorescence, we found significantly greater intensity for human adenomas (mean ± SD, 25.5 ± 14.0) vs normal (mean ± SD, 9.1 ± 6.0) and hyperplastic polyps (mean ± SD, 3.1 ± 3.7; P = 10-5 and 8 × 10-12, respectively), and for sessile serrated adenomas (mean ± SD, 20.1 ± 13.3) vs normal and hyperplastic polyps (P = .02 and 3 × 10-7, respectively).Claudin-1 is overexpressed in premalignant colonic lesions, and can be detected endoscopically in vivo with a near-infrared, labeled peptide.

SUBMITTER: Rabinsky EF

PROVIDER: S-EPMC4980721 | biostudies-literature | 2016 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Overexpressed Claudin-1 Can Be Visualized Endoscopically in Colonic Adenomas In Vivo.

Rabinsky Emily F EF Joshi Bishnu P BP Pant Asha A Zhou Juan J Duan Xiyu X Smith Arlene A Kuick Rork R Fan Shuling S Nusrat Asma A Owens Scott R SR Appelman Henry D HD Wang Thomas D TD

Cellular and molecular gastroenterology and hepatology 20151213 2

<h4>Background & aims</h4>Conventional white-light colonoscopy aims to reduce the incidence and mortality of colorectal cancer (CRC). CRC has been found to arise from missed polypoid and flat precancerous lesions. We aimed to establish proof-of-concept for real-time endoscopic imaging of colonic adenomas using a near-infrared peptide that is specific for claudin-1.<h4>Methods</h4>We used gene expression profiles to identify claudin-1 as a promising early CRC target, and performed phage display a ...[more]

PMID: 27840845

Similar Datasets

Project description:Thiol-disulfide interconversions play a crucial role in the chemistry of biological systems. They participate in the major systems that control the cellular redox potential and prevent oxidative damage. In addition, thiol-disulfide exchange reactions serve as molecular switches in a growing number of redox-regulated proteins. We developed a differential thiol-trapping technique combined with two-dimensional gel analysis, which in combination with genetic studies, allowed us to obtain a snapshot of the in vivo thiol status of cellular proteins. We determined the redox potential of protein thiols in vivo, identified and dissected the in vivo substrate proteins of the major cellular thiol-disulfide oxidoreductases, and discovered proteins that undergo thiol modifications during oxidative stress. Under normal growth conditions most cytosolic proteins had reduced cysteines, confirming existing dogmas. Among the few partly oxidized cytosolic proteins that we detected were proteins that are known to form disulfide bond intermediates transiently during their catalytic cycle (e.g., dihydrolipoyl transacetylase and lipoamide dehydrogenase). Most proteins with highly oxidized thiols were periplasmic proteins and were found to be in vivo substrates of the disulfide-bond-forming protein DsbA. We discovered a substantial number of redox-sensitive cytoplasmic proteins, whose thiol groups were significantly oxidized in strains lacking thioredoxin A. These included detoxifying enzymes as well as many metabolic enzymes with active-site cysteines that were not known to be substrates for thioredoxin. H(2)O(2)-induced oxidative stress resulted in the specific oxidation of thiols of proteins involved in detoxification of H(2)O(2) and of enzymes of cofactor and amino acid biosynthesis pathways such as thiolperoxidase, GTP-cyclohydrolase I, and the cobalamin-independent methionine synthase MetE. Remarkably, a number of these proteins were previously or are now shown to be redox regulated.

Project description:Claudins are tight junction proteins that are involved in tight junction formation and function. Previous studies have shown that claudin-7 is frequently upregulated in epithelial ovarian cancer (EOC) along with claudin-3 and claudin-4. Here, we investigate in detail the expression patterns of claudin-7, as well as its possible functions in EOC. Initially a total of 95 ovarian tissue samples (7 normal ovarian tissues, 65 serous carcinomas, 11 clear cell carcinomas, 8 endometrioid carcinomas and 4 mucinous carcinomas) were studied for claudin-7 expression using RT-PCR analysis. The gene for claudin-7, CLDN7, was found to be significantly upregulated in all the tumor tissue samples studied. Similarly, immunohistochemical analysis and western blotting showed that claudin-7 protein was significantly overexpressed in the vast majority of EOCs. Two cell lines(OVCAR-2 and OVCA420) were chosen for microarray based gene expression analysis using small interfering RNA-mediated(SiRNA) knockdown of claudin-7. This treatment led to significant changes in gene expression that was validated by RT-PCR and immunoblotting. Ovarian cancer lines OVCA420 and OVCAR-2 were cultured in duplicate in McCoy’s 5A growth medium (Invitrogen) supplemented with 10% fetal bovine serum (FBS) and antibiotics (100 units/ml penicillin and 100 mg/ml streptomycin). Cells cultured in 6-well plates were transfected with either Claudin-7 specific siRNA oligos duplexes (Ambion, Inc.Austin, TX) or control siRNA #1 (Dharmacon) using LipofectAMINE 2000 (Invitrogen). Cells were treated for 72 hours to allow maximum knockdown, after which they were harvested for RNA preparation. Total RNA, was extracted using Trizol, quality and quantity were checked using the Agilent 2100 Bioanalyzer with RNA 6000 Nano chip, (Agilent Technologies UK Ltd, West Lothian, UK). Biotinylated cRNA was generated using the Illumina TotalPrep RNA Amplification Kit (Ambion; Austin, TX) starting with approximately 500 ng total RNA. Hybridization of the cRNA was to the Sentrix HumanRef-8 Expression BeadChip (Illumina, Inc., San Diego, CA). Microarray data processing and analysis was performed using Illumina Bead Studio software. Hierarchical clustering analysis of the significant genes was done using the JMP 6.0.0 software. Validation of the expression patterns of selected genes was performed using RT-PCR.

Project description:BACKGROUND AND AIMS:Colorectal epithelial cells are prone to malignant transformation. Therefore, identification of differences in gene expression in the process from normal colonic crypts to adenomas with low grade dysplasia is essential for further insights into early tumorigenesis. To achieve this goal, a novel gene expression analysis strategy, screening for expressed transcripts in small histologically defined tissue samples, was performed. METHODS:First, laser mediated microdissection was used to isolate normal and adenomatous crypts from colonic cryosections. Then, nested RNA arbitrarily primed polymerase chain reaction (RAP-PCR) for differential display was performed to screen mRNA populations and to generate hybridisation probes for cDNA expression arrays. After evaluation of cDNA expression arrays, differential expression was confirmed at the protein level by immunohistochemistry. RESULTS:Evaluation of gene expression profiles of normal versus adenomatous colonic crypts of six different patients revealed, in general, dysregulation of up to 11% of all analysed genes (total number n=588): specifically, p21-rac1 was upregulated in four of six patients, mitogen activated protein kinase (MAPK) p38alpha in three of six patients, and interferon gamma receptor in three of six patients. Conversely, FAST kinase was found to be downregulated in three of six patients, p53 in three of six patients, and thrombospondin 2 in three of six patients. CONCLUSIONS:For the first time, distinct gene expression profiles of dysplastic areas within colonic adenomas, using the combination of laser mediated microdissection with RAP-PCR and cDNA expression array, were shown. In these samples, upregulation of proliferation associated genes (ras-oncogene related p21-rac1 and MAPK p38alpha) as well as downregulation of apoptosis related genes (FAST kinase and p53) most likely reflects specific alterations in adenomas with low grade dysplasia. Based on upregulation of p21-rac1 and MAPK p38alpha, activation of the MAPK pathway appears to be an early event in colonic carcinogenesis.

Dataset Information

Overexpressed Claudin-1 Can Be Visualized Endoscopically in Colonic Adenomas In Vivo.

Publications

Overexpressed Claudin-1 Can Be Visualized Endoscopically in Colonic Adenomas In Vivo.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets