zaprinast and Melanoma

Eleven phosphodiesterase (PDE) gene families (PDE1-11) have been identified, and some PDE isoforms are selectively expressed in various cell types. Previously, we reported PDE1, PDE3 and PDE4 expressions in human malignant melanoma cells. However, the expression and role of PDE5 in malignant melanoma cells is not clear. Therefore, we characterized PDE5 in human malignant melanoma MAA cells.. PDE5 activity and PDE5A mRNA expression were investigated in MAA cells. The full open reading frames for human PDE5A1 were sequenced. Effects of PDE5 inhibitors on cell growth were determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assays.. PDE5 activity and PDE5A1 mRNA expression were detected in MAA cells. The nucleotide sequence of PDE5A1 was identical to that of human PDE5A1, previously published. Two PDE5 inhibitors inhibited the growth of cells.. PDE5A1 mRNA is expressed and may play an important role in the growth of human malignant melanoma MAA cells.

Topics: Blotting, Western; Cell Proliferation; Cyclic Nucleotide Phosphodiesterases, Type 5; Humans; Melanoma; Phosphodiesterase 5 Inhibitors; Phosphodiesterase Inhibitors; Purinones; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

When secreted from malignant cells, hyaluronan facilitates tumor invasion and metastasis, as inhibition of its export by zaprinast inhibited metastasis formation in mice. However, the precise steps of the metastatic cascade, which were influenced by zaprinast, have not been identified as yet. Here we analyzed the cell biological effects of the inhibitor on three human melanoma cell lines that differed in their hyaluronan production and their metastatic capability when xenografted into SCID mice. We measured the influence of zaprinast on cellular hyaluronan export, surface coat formation, proliferation, random migration, colony formation in soft agar, adhesion, and transepithelial resistance. Concentrations of zaprinast not affecting cell proliferation, adhesion and transepithelial resistance, nevertheless reduced hyaluronan export by 50%, surface coat formation, random migration, and colony formation in soft agar. These results indicate that hyaluronan enhances metastasis formation primarily in those steps of the metastatic cascade, which involves tumor cell migration.

Topics: Cell Adhesion; Cell Line, Tumor; Cell Movement; Cell Proliferation; Humans; Hyaluronic Acid; Melanoma; Neoplasm Invasiveness; Neoplasm Metastasis; Purinones