Gene expression study for effectiveness of nicotinamide using chemically-induced mouse bladder cancer model. Mus musculus

The objective of this study was to evaluate the efficacy of nicotinamide in a N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN)-induced urinary bladder cancer model in mice, and to identify through gene expression profiling the molecular signatures of cancer prevention by nicotinamide. We used 20 mice for microarray experiments: five mice with normal bladders (group I), five with nicotinamide-treated bladders (group II), five with BBN-induced mouse bladder tumors (group III), and five with non-tumorigenic bladders treated with BBN and nicotinamide (group IV). Keywords: Gene expression, Mouse bladder cancer, Cancer prevention Overall design: Total RNA was isolated using TRIzol reagent (Life Technologies, NY), according to the manufacturer's protocol. The quality and integrity of the RNA were confirmed by agarose gel electrophoresis and ethidium bromide staining, followed by visual examination under ultraviolet light. Five-hundred nanograms of total RNA were used for labeling hybridization according to the manufacturer’s protocols (Illumina Mouse-6 BeadChips, version 1.0). Arrays were scanned with an Illumina Bead Array Reader confocal scanner (BeadStation 500GXDW; Illumina, Inc., San Diego, CA) according to the manufacturer's instructions. After scanning, the microarray data were normalized using quantile normalization. Measured gene expression values were log2 transformed and median-centered across genes and samples.