Altered cyclic adenosine 3':5'-monophosphate metabolism and enzymatic profiles of a transplantable murine submaxillary gland carcinoma (myoepithelioma)
Malamud, D.; Irwin, D.
Cancer Research 38(9): 2945-2949
1978
ISSN/ISBN: 0008-5472 PMID: 209890 Document Number: 132550
The cyclic nucleotide system was characterized in a transplantable mouse submaxillary gland carcinoma. Thymidine incorporation into tumor cell DNA during log phase growth was 10-fold greater than in normal submaxillary gland and was not affected by isoproterenol (IPR). Injection of IPR increased thymidine incorporation into submaxillary gland DNA 6-fold. Tumor adenylate cyclase activity was depressed relative to submaxillary gland and was not stimulated by IPR. Submaxillary gland adenylate cyclase activity was increased 3-fold in response to 10-4 IPR. The tumor high-Km cytosol cyclic AMP and CGMM phosphodiesterase activities were elevated 2- and 9-fold, respectively, over submaxillary gland. Endogenous CAMP levels in the tumor were about 1/3 the level in normal salivary glands. Normal submaxillary gland secretory products (amylase and epidermal and nerve growth factors) were reduced in tumor preparations. The carcinoma can be characterized as a rapidly dividing, malignant tumor with decreased levels of submaxillary gland secretory products and a loss in the ability to respond to .beta.-adrenergic stimulation.