Apple polyphenols modulate expression of selected genes related to toxicological defence and stress response in human colon adenoma cells

Abstract

Apples contain significant amounts of flavonoids that are potentially cancer risk reducing by acting antioxidative or antiproliferative and by favorably modulating gene expression. The purpose of this study was to investigate whether polyphenols from apples modulate expression of genes related to colon cancer prevention in preneoplastic cells derived from colon adenoma (LT97). For this, LT97 cells were treated with effective concentrations of apple extracts (AEs). RNA was isolated and used for synthesis and labeling of cDNA that was hybridized to cDNA-arrays. Gene expression studies were performed using a commercial cDNA-array from Superarray ® that contains a limited number of genes (96 genes) related to drug metabolism, and a custom-made cDNA microarray that contains a higher number of genes (300 genes, including some genes from Superarray) related to mechanisms of carcinogenesis or chemoprevention. Real-time PCR and enzyme activity assays were additionally performed to confirm selected array results. Treatment of cells with AE resulted in 30 and 46 genes expressed over cut-off values ( 1.5-or 0.7-fold) in Superarray and custom array, respectively. Of 87 genes spotted on both arrays, 4 genes (CYP3A7, CYP4F3, CHST7, GSTT2) were regulated with similar directional changes. Expression of selected phase II genes (GSTP1, GSTT2, GSTA4, UGT1A1, UGT2B7), regulated on either array, was confirmed by real-time PCR. The enzyme activities of glutathione S-transferases and UDP-glucuronosyltransferases were altered by treatment of LT97 cells with AE. The observed altered gene expression patterns in LT97 cells, resulting from AE treatment, points to a possible protection of the cells against some toxicological insults.

The effect of gluten-free diet on Th1–Th2–Th3-associated intestinal immune responses in celiac disease

“…The PCRarray system yields high positive call rates and has a high reproducibility [12], which was confirmed in our study where the majority of the 84 genes were detectable. In our study, the five house keeping genes included on the array were used for normalisation of the 84 Th1-Th2-Th3 genes [12,13] and fold-change cut-off values were used for altered expression levels as has previously been described [12,[14][15][16][17].…”

Modulation of gene expression in eicosapentaenoic acid and docosahexaenoic acid treated human colon adenoma cells

“…A FC C2 was defined as gene upregulation whereas a FC B0.33 was used as cut-off for down-regulated genes. Two-tailed t test was performed using Excel software stranded cDNA which was hybridised with a customised cDNA array (PIQOR, Miltenyi Biotec, Bergisch-Gladbach, Germany) containing 300 genes of interest and 6 housekeeping genes as described previously (11). Prior to this, the glass slide arrays were preheated and prehybridised.…”

Gene expression profiles in human peripheral blood mononuclear cells as biomarkers for nutritional in vitro and in vivo investigations

“…Hybridisation was performed on 112 sites (blanks, negative reference spots, housekeeping genes, and 96 human genes related to drug metabolism) on two different cDNA gene macroarrays (Human Drug Metabolism Gene Array HS11 and Human Stress & Toxicity Gene Array HS12, SuperArray Bioscience Corporation, Frederick, MD, United States), as we have described before [46] according to the manufacturer's protocol. Spot intensities of the target genes were based on the signal intensities for GAPDH.…”

“…A number of recent reports are showing that the latest technologies of genomics and proteomics have initiated a new era of biomarker development and many researchers are further developing the methods for cancer detection, treatment, and prevention [19,46]. Different biomarker applications are based on blood cells such as PBMC, since they are obtained less invasively than biopsies and are suitable to measure systemic effects.…”