INCREASED GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE GENE-EXPRESSION INLATE PATHOLOGICAL STAGE HUMAN PROSTATE-CANCER

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a multifunctional enzyme best known to many investigators as a 'housekeeping' gene used as a loading control on northern blots. Prior studies, however, have s hown that GAPDH RNA levels vary greatly among different prostate cance r cell lines. We undertook this study to determine the level of GAPDH gene expression within primary human prostate tumors and to determine the validity of using GAPDH as a loading control for northern analysis of human prostate cancer specimens and normal human organs. We found that GAPDH expression was significantly higher in specimens from patie nts with pathological stage C and D prostate cancer than those with st age B disease. Within the human prostate cancer cell lines TSUPr1, DU1 45, LNCaP and PC-3 and a normal neonatal prostate epithelial cell line FNC 267 beta 1, LNCaP cells expressed the highest level of GAPDH but all cell lines, including the normal neonate prostate cell line had ve ry strong GAPDH gene expression. GAPDH RNA levels were highly variable among 16 normal human adult organs and four human fetal organs examin ed. We conclude that GAPDH RNA levels in human prostate tumors correla te with pathologic stage and that GAPDH should not be used as a loadin g control in northern blot experiments. Other controls, such as beta-a ctin or 28s ribosomal RNA, would be more suitable for such purposes.