Expression pattern of fatty acid-binding proteins in human normal and cancer prostate cells and tissues

Purpose: Fatty acid-binding protein (FABP) expression patterns were evaluat ed as potential markers and therapeutic targets for prostate cancer. Experimental design: FABP expression levels were determined by reverse tran scription-PCR in cultured prostate normal and tumor cells and in human biop sy samples, Regulation of cellular processes,vas examined using FABP antise nse constructs. Results: Prostate cells express a variety of different FABPs. Liver (L)- an d intestine-FABPs were elevated 5-9-fold in prostate cancer compared with n ormal primary prostate cells, In contrast, adipose- and epidermal-FABPs wer e markedly down-regulated (3-20-fold) in cancer versus normal cells, Simila r expression patterns mere found in human tissue biopsy samples. However, b rain-FABP had a distinct pattern of expression: it was overexpressed only i n LNCaP cells and in well-differentiated tissue samples, suggesting a stage -specific expression profile. Secretion of L-FABP protein was observed from DU 145 prostate cancer cells, but not in the culture fluid of normal prost ate epithelial cells. Antisense oligodeoxynucleotides, designed to block pr oduction of epidermal-FABP (a marker for normal prostate cells), caused inc reased proliferation in DU 145 prostate cancer cells. In vivid contrast, an tisense oligodeoxynucleotides to L-FABP (overexpressed in prostate cancer) decreased proliferation and caused apoptosis, Conclusions: We propose that there is a distinct balance between these grou ps of FABPs, whose altered regulation in cells may play a role in prostate cancer. Furthermore, the pattern of expression and secretion of FABPs have the potential to serve as a diagnostic marker for an aggressive phenotype o f prostate cancer.