Phosphodiesterase 3 as a potential target for therapy of malignant tumors in the submandibular gland.

Phosphodiesterase (PDE) 3s have been characterized in human neoplastic submandibular gland intercalated duct HSG cells. There have been no reports on PDE3 in malignant salivary gland cells. PDE3 activity was detected in homogenates of HSG cells. About 75% of PDE3 activity in HSG cells was recovered in supernatant fractions and 25% in particulate fractions. PDE3A and 3B mRNAs were detected by reverse transcription-polymerase chain reaction in RNA from HSG cells. The nucleotide sequences of the fragments were identical to those of human PDE3A and 3B. The PDE3-specific inhibitor, cilostamide, inhibited the growth of HSG cells. Our results indicate that PDE3s may be important in the growth of HSG cells. PDE3 thus appears to be a potential new target for antiproliferative therapies.