This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Chlapowski, F. J. Articles by Nemecek, G. M. Search for Related Content PubMed PubMed Citation Articles by Chlapowski, F. J. Articles by Nemecek, G. M.

Aberrant Cyclic Adenosine 3':5'-Monophosphate Metabolism in Cultures of Tumorigenic Rat Urothelium¹

Department of Biochemistry, University of Massachusetts Medical Center, Worcester, Massachusetts 01605

The cyclic adenosine 3':5'-monophosphate (cyclic AMP) metabolism of stratified normal rat urothelium propagated in vitro on a floating collagen matrix was characterized and used as a basis for identifying potential biochemical lesions in tumorigenic cell lines. The four neoplastic urothelial cell types studied (AY-27, AY-32, AY-33, and AY-34) were derived from Fischer 344 rats fed the carcinogen N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide. Epinephrine or prostaglandin E₁ caused a rise in the cyclic AMP content of normal cultures which was potentiated in the presence of the cyclic nucleotide phosphodiesterase inhibitor 1-methyl-3-isobutylxanthine or by forskolin, a diterpene activator of adenylate cyclase in intact cells. The expected, normal profile of cyclic AMP accumulation in response to ß-adrenergic receptor agonists was epinephrine > norepinephrine > phenylephrine. By every measure, the tumorigenic AY-27 cells demonstrated an overall decrease of functional adenylate cyclase activity. This was evidenced most by the low accumulation of cyclic AMP observed in response to forskolin. While prostaglandin E₁ elicited a heightened cyclic AmP level in these cells, their vanishingly low response to catecholamines also suggested a potential lack of functional ß-adrenergic receptors. Cyclic AMP phosphodiesterase activity was elevated in soluble enzyme preparations obtained from cultures of AY-27 cells. Observations of AY-32 cells were diametrically opposite to the findings with AY-27 cells. In AY-32 cells, prostaglandin E₁ receptors appeared to be functionally absent. The ß-adrenergic receptor agonist response profile was abnormal in AY-32 cells. Norepinephrine produced a greater accumulation of cyclic AMP than epinephrine, and phenylephrine stimulated a much greater than normal response. Forskolin stimulation indicated an average level of adenylate cyclase activity in AY-32 cultures. Soluble preparations from AY-32 cells demonstrated a normal amount of cyclic AMP phosphodiesterase activity. AY-33 cells were comparable to normal urothelial cells in all respects save one. These tumorigenic cells had elevated levels of cyclic AMP phosphodiesterase activity. AY-34 cells, like AY-32 cells, were deficient in their responsiveness to prostaglandin E₁. However, unlike the other tumorigenic lines, AY-34 cells had an excess of adenylate cyclase as demonstrated by their extraordinary responsiveness to forskolin. In addition, the accumulation of cyclic AMP in AY-34 cells in response to stimulation by epinephrine and norepinephrine, but not phenylephrine, was unusually great. Cyclic AMP phosphodiesterase activity in AY-34 cells appeared to be normal. Thus, our data demonstrated that each of the chemically transformed urothelial cell lines was abnormal with regard to one or more aspects of cyclic AMP metabolism.

¹ Supported by NIH Grant AM 32937.

² Recipient of Grant CA 21612 from the National Bladder Cancer Project. To whom requests for reprints should be addressed.

³ Recipient of Grant HL 21320 from the USPHS as well as of the NIH Heart, Lung, and Blood Institute Young Investigator Research Award. Present address: Preclinical Research Division, Sandox, Inc., East Hanover, NJ 07936.

Received 6/ 4/84. Accepted 10/ 3/84.