Gene expression in the colon tumor of AOM/DSS-treated RBJ-/- mice. Mus musculus

The purpose of this study was to determine which genes are differentially regulated by the Ras-related small GTPase RBJ after induction by AOM/DSS treatment in the colon of C57BL/6 mice compared to RBJ+/+ mice. The results demonstrate decreased induction of cell proliferation-associated genes in RBJ-/- mice than in RBJ+/+ mice on day 80 after AOM/DSS treatment. The majority of differentially expressed genes are regulated by MEK/ERK signaling pathway. Thus RBJ may be involved in the regulation of tumor progression and tumorigenesis. Overall design: RBJ+/+ and RBJ-/- mice (5/group) were either untreated or treated with AOM (12 mg/kg) on day 0. On day 7, 3 cycles of DSS (2.5% in drinking water; 7 days/cycle) were itiated, each separated by 14 days of vehicle control (water). Mice were sacrificed on day 80 day after AOM treatments.Tumor tissues in distal colon of the mice were prepared for total RNA individually. Equal amounts of RNA derived from 3 individual mice per group were mixed together, and assayed for gene expression using Affymetrix mouse 430 2.0 arrays.