Characterization of phosphodiesterase 3 in human malignant melanoma cell line.

ABSTRACT

Little is known concerning the expression, distribution and function of phosphodiesterase (PDE) 3s in malignant tumor cells, including human malignant melanoma HMG and osteosarcoma HOSM-1 cells. PDE3 activity was detected in homogenates of HMG cells; however, much less activity was found in HOSM-1 cells. In HMG cells, most of the PDE3 activity was in the particulate fraction. PDE3A and 3B mRNAs were detected by RT-PCR in RNA from HMG cells only. The nucleotide sequences of the fragments were identical to those of human PDE3A and 3B. The PDE3-specific inhibitors, trequinsin and cilostamide, did not inhibit the proliferation of HMG or HOSM-1 cells. Although two PDE3 isoforms may be expressed in human malignant melanoma cells, their functional importance is not known.