Gene expression profile and genomic alterations in colonic tumours induced by 1,2-dimethylhydrazine (DMH) in rats

<p>Abstract</p> <p>Background</p> <p>Azoxymethane (AOM) or 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis in rats shares many phenotypical similarities with human sporadic colon cancer and is a reliable model for identifying chemopreventive agents. Genetic mutations relevant to human colon cancer have been described in this model, but comprehensive gene expression and genomic analysis have not been reported so far. Therefore, we applied genome-wide technologies to study variations in gene expression and genomic alterations in DMH-induced colon cancer in F344 rats.</p> <p>Methods</p> <p>For gene expression analysis, 9 tumours (TUM) and their paired normal mucosa (NM) were hybridized on 4 × 44K Whole rat arrays (Agilent) and selected genes were validated by semi-quantitative RT-PCR. Functional analysis on microarray data was performed by GenMAPP/MappFinder analysis. Array-comparative genomic hybridization (a-CGH) was performed on 10 paired TUM-NM samples hybridized on Rat genome arrays 2 × 105K (Agilent) and the results were analyzed by CGH Analytics (Agilent).</p> <p>Results</p> <p>Microarray gene expression analysis showed that <it>Defcr4</it>, <it>Igfbp5</it>, <it>Mmp7, Nos2, S100A8 </it>and <it>S100A9 </it>were among the most up-regulated genes in tumours (Fold Change (FC) compared with NM: 183, 48, 39, 38, 36 and 32, respectively), while <it>Slc26a3</it>, <it>Mptx</it>, <it>Retlna </it>and <it>Muc2 </it>were strongly down-regulated (FC: -500; -376, -167, -79, respectively). Functional analysis showed that pathways controlling cell cycle, protein synthesis, matrix metalloproteinases, TNFα/NFkB, and inflammatory responses were up-regulated in tumours, while Krebs cycle, the electron transport chain, and fatty acid beta oxidation were down-regulated. a-CGH analysis showed that four TUM out of ten had one or two chromosomal aberrations. Importantly, one sample showed a deletion on chromosome 18 including <it>Apc</it>.</p> <p>Conclusion</p> <p>The results showed complex gene expression alterations in adenocarcinomas encompassing many altered pathways. While a-CGH analysis showed a low degree of genomic imbalance, it is interesting to note that one of the alterations concerned <it>Apc</it>, a key gene in colorectal carcinogenesis. The fact that many of the molecular alterations described in this study are documented in human colon tumours confirms the relevance of DMH-induced cancers as a powerful tool for the study of colon carcinogenesis and chemoprevention.</p

A single-cell survey of the small intestinal epithelium

Intestinal epithelial cells (IECs) absorb nutrients, respond to microbes, provide barrier function and help coordinate immune responses. We profiled 53,193 individual epithelial cells from mouse small intestine and organoids, and characterized novel subtypes and their gene signatures. We showed unexpected diversity of hormone-secreting enteroendocrine cells and constructed their novel taxonomy. We distinguished between two tuft cell subtypes, one of which expresses the epithelial cytokine TSLP and CD45 (Ptprc), the pan-immune marker not previously associated with non-hematopoietic cells. We also characterized how cell-intrinsic states and cell proportions respond to bacterial and helminth infections. Salmonella infection caused an increase in Paneth cells and enterocytes abundance, and broad activation of an antimicrobial program. In contrast, Heligmosomoides polygyrus caused an expansion of goblet and tuft cell populations. Our survey highlights new markers and programs, associates sensory molecules to cell types, and uncovers principles of gut homeostasis and response to pathogens

Mucosal pentraxin (Mptx), a novel rat gene 10-fold down-regulated in colon by dietary heme

Consumption of red meat is associated with increased colon cancer risk. Our previous work indicated that this association might be due to the heme content of red meat. In rat studies, dietary heme increased colonic cytotoxicity and epithelial cell turnover, carcinogenesis biomarkers. Here we apply DNA microarray technology to examine effects of heme on colonic gene expression. A rat colon-specific microarray was constructed and hybridized in duplicate to RNA extracts from colon scrapings of rats fed diets with or without heme (n=6¿7). We were able to reproducibly identify changes in colonic mRNA abundance in response to heme. Most striking was a >10-fold down-regulation of a single rat gene, an unprecedented gene-modulating effect of a dietary component. Based on homology, the novel gene encodes a pentraxin, the first identified in colon. Pentraxins are postulated to be involved in dealing with dying cells. Quantitative PCR confirmed the strong heme-induced down-regulation of this gene, which we named mucosal pentraxin (Mptx). Overall, our data support the efficacy of cDNA array expression profiling to investigate effects of specific nutrients in an in vivo system and may provide an approach to establishing markers for diet-induced stress of mammalian colonic mucosa.¿van der Meer-van Kraaij, C., van Lieshout, E. M. M., Kramer, E., van der Meer, R., Keijer, J. Mucosal pentraxin (Mptx), a novel rat gene 10-fold down-regulated in colon by dietary heme

Mucosal pentraxin (Mptx), a novel rat gene 10-fold down-regulated in colon by dietary heme

Consumption of red meat is associated with increased colon cancer risk. Our previous work indicated that this association might be due to the heme content of red meat. In rat studies, dietary heme increased colonic cytotoxicity and epithelial cell turnover, carcinogenesis biomarkers. Here we apply DNA microarray technology to examine effects of heme on colonic gene expression. A rat colon-specific microarray was constructed and hybridized in duplicate to RNA extracts from colon scrapings of rats fed diets with or without heme (n=6¿7). We were able to reproducibly identify changes in colonic mRNA abundance in response to heme. Most striking was a >10-fold down-regulation of a single rat gene, an unprecedented gene-modulating effect of a dietary component. Based on homology, the novel gene encodes a pentraxin, the first identified in colon. Pentraxins are postulated to be involved in dealing with dying cells. Quantitative PCR confirmed the strong heme-induced down-regulation of this gene, which we named mucosal pentraxin (Mptx). Overall, our data support the efficacy of cDNA array expression profiling to investigate effects of specific nutrients in an in vivo system and may provide an approach to establishing markers for diet-induced stress of mammalian colonic mucosa.¿van der Meer-van Kraaij, C., van Lieshout, E. M. M., Kramer, E., van der Meer, R., Keijer, J. Mucosal pentraxin (Mptx), a novel rat gene 10-fold down-regulated in colon by dietary heme

Differential gene expression in rat colon by dietary heme and calcium

Dietary heme and calcium are alleged modulators of colon cancer risk. Little is known about the molecular and cellular changes in the colon epithelium that are induced by consumption of these unabsorbed nutrients. In this nutrigenomics study, we fed rats high- and low-calcium diets with or without heme. In agreement with previous studies, we found that dietary heme increased the cytotoxicity of fecal water in the colon and elevated epithelial proliferation, a risk factor in colon carcinogenesis. Calcium reduced cytotoxicity and inhibits heme-induced effects. Among 365 colon-expressed genes, we could identify 10 diet-modulated genes that show >2-fold altered expression, of which several are related to colon cell turnover and disease. Mucosal pentraxin (Mptx) was the strongest differentially expressed gene, similar to10-fold down-regulated by dietary heme and 3-fold up-regulated by calcium. cDNA microarray and quantitative PCR analysis show that calcium significantly inhibits the effects of heme, which correlates with the physiological effects. Our results indicate that Mptx expression is related to colonic cell turnover, and that Mptx might be a marker for diet-modulated mucosal integrity. We also show that Mptx expression is restricted to the intestine, and occurs predominantly in the colon

Differential gene expression in rat colon by dietary heme and calcium

Dietary heme and calcium are alleged modulators of colon cancer risk. Little is known about the molecular and cellular changes in the colon epithelium that are induced by consumption of these unabsorbed nutrients. In this nutrigenomics study, we fed rats high- and low-calcium diets with or without heme. In agreement with previous studies, we found that dietary heme increased the cytotoxicity of fecal water in the colon and elevated epithelial proliferation, a risk factor in colon carcinogenesis. Calcium reduced cytotoxicity and inhibits heme-induced effects. Among 365 colon-expressed genes, we could identify 10 diet-modulated genes that show >2-fold altered expression, of which several are related to colon cell turnover and disease. Mucosal pentraxin (Mptx) was the strongest differentially expressed gene, similar to10-fold down-regulated by dietary heme and 3-fold up-regulated by calcium. cDNA microarray and quantitative PCR analysis show that calcium significantly inhibits the effects of heme, which correlates with the physiological effects. Our results indicate that Mptx expression is related to colonic cell turnover, and that Mptx might be a marker for diet-modulated mucosal integrity. We also show that Mptx expression is restricted to the intestine, and occurs predominantly in the colon

Dietary modulation and structure prediction of rat mucosal pentraxin (Mptx) protein and loss of function in humans

Mucosal pentraxin (Mptx), identified in rats, is a short pentraxin of unknown function. Other subfamily members are Serum amyloid P component (SAP), C-reactive protein (CRP) and Jeltraxin. Rat Mptx mRNA is predominantly expressed in colon and in vivo is strongly (30-fold) regulated by dietary heme and calcium, modulators of colon cancer risk. This renders Mptx a potential nutrient sensitive biomarker of gut health. To support a role as biomarker, we examined whether the pentraxin protein structure is conserved, whether Mptx protein is nutrient-sensitively expressed and whether Mptx is expressed in mouse and human. Sequence comparison and 3D modelling showed that rat Mptx is highly homologous to the other pentraxins. The calcium-binding site and subunit interaction sites are highly conserved, while a loop deletion and charged residues contribute to a distinctive “top” face of the pentamer. In accordance with mRNA expression, Mptx protein is strongly down-regulated in rat colon mucosa in response to high dietary heme intake. Mptx mRNA is expressed in rat and mouse colon, but not in human colon. A stop codon at the beginning of human exon two indicates loss of function, which may be related to differences in intestinal cell turnover between man and rodents

Resistance Exercise Training Increases Muscle Mass and Strength in Prostate Cancer Patients on Androgen Deprivation Therapy

PURPOSE: To assess the effects of 20 weeks resistance exercise training with or without protein supplementation on body composition, muscle mass, muscle strength, physical performance and aerobic capacity in prostate cancer patients receiving androgen deprivation therapy (ADT). METHODS: Sixty prostate cancer patients receiving ADT were randomly assigned to perform 20 weeks of resistance exercise training with supplementation of 31 g whey protein (EX+PRO, n = 30) or placebo (EX+PLA, n = 30), consumed immediately after exercise and every night before sleep. A separate control group (CON, n = 36) only received usual care. At baseline and after 20 weeks, body composition (dual-energy X-ray absorptiometry), muscle mass (computed tomography scan), muscle strength (1-repetition maximum strength tests), physical performance (Timed Up and Go Test, 30-second Chair Stand Test, Stair Climb Test), aerobic capacity (cardiopulmonary exercise test) and habitual dietary intake (food diary), were assessed. Data were analyzed using a two-factor repeated-measures ANOVA. RESULTS: Over time, muscle mass and strength increased in EX+PRO and EX+PLA and decreased in CON. Total fat mass and fat percentage increased in EX+PRO and CON, but not in EX+PLA. Physical performance did not significantly change over time in either group. Aerobic capacity was maintained in EX+PLA, while it decreased in EX+PRO and CON. Habitual protein intake (without supplements) averaged >1.0 g·kg body weight-1·day-1, with no differences over time or between groups. CONCLUSIONS: In prostate cancer patients, resistance exercise training counteracts the adverse effects of ADT on body composition, muscle mass, muscle strength and aerobic capacity, with no additional benefits of protein supplementation