Gene expression studies related to
cancer diagnosis and treatment are important. In order to conduct such experiment accurately, absolutely reliable housekeeping genes are essential to normalize
cancer related gene expression. The most important characteristics of such genes are their presence in all cells and their expression levels remain relatively constant under different experimental conditions. However, no single gene of this group of genes manifests always stable expression levels under all experimental conditions. Incorrect choice of housekeeping genes leads to interpretation errors of experimental results including evaluation and quantification of pathological gene expression. Here, we examined (a) the degree of GAPDH expression regulation in Hep-1-6 mouse
hepatoma and Hep-3-B and HepG2 human
hepatocellular carcinoma cell lines as well as in human
lung adenocarcinoma epithelial cell line (A-549) in addition to both HT-29, and HCT-116
colon cancer cell lines, under hypoxic conditions in vitro in comparison to other housekeeping genes like
beta-actin, serving as experimental loading controls, (b) the potential use of GAPDH as a target for
tumor therapeutic approaches was comparatively examined in vitro on both
protein and
mRNA level, by western blot and semi quantitative RT-PCR, respectively.
FINDINGS: CONCLUSION: