Calmodulin-dependent cyclic nucleotide phosphodiesterase (PDE1) is a pharmacological target of differentiation-inducing factor-1, an antitumor agent isolated from Dictyostelium.
The differentiation-inducing factor-1 (DIF-1) isolated from Dictyostelium discoideum is a potent antiproliferative agent that induces growth arrest and differentiation in mammalian cells in vitro. However, the specific target molecule(s) of DIF-1 has not been identified. In this study, we have tried to identify the target molecule(s) of DIF-1 in mammalian cells, examining the effects of DIF-1 and its analogs on the activity of some candidate enzymes. DIF-1 at 10-40 micro M dose-dependently suppressed cell growth and increased the intracellular cyclic AMP concentration in K562 leukemia cells. It was then found that DIF-1 at 0.5-20 micro M inhibited the calmodulin (CaM)-dependent cyclic nucleotide phosphodiesterase (PDE1) in vitro in a dose-dependent manner. Kinetic analysis revealed that DIF-1 acted as a competitive inhibitor of PDE1 versus the substrate cyclic AMP. Because DIF-1 did not significantly affect the activity of other PDEs or CaM-dependent enzymes and, in addition, an isomer of DIF-1 was a less potent inhibitor, we have concluded that PDE1 is a pharmacological and specific target of DIF-1.
Shimizu
Kasumi
K
Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Mie University, Mie, Japan.
Murata
Taku
T
Tagawa
Toshiro
T
Takahashi
Katsunori
K
Ishikawa
Ryoki
R
Abe
Yumiko
Y
Hosaka
Kohei
K
Kubohara
Yuzuru
Y
D001667:Binding, Competitive; D000242:Cyclic AMP / Q000378:metabolism; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1; D006588:Hexanones / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D020014:K562 Cells; D010726:Phosphodiesterase Inhibitors / Q000378:metabolism / Q000494:pharmacology*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*
D006588:Hexanones; D010726:Phosphodiesterase Inhibitors; C053433:1-((3,5-dichloro)-2,6-dihydroxy-4-methoxyphenyl)-1-hexanone; D000242:Cyclic AMP; D010727:Phosphoric Diester Hydrolases; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1