A rapid and sensitive bioassay involving cultured rat glioma cells to screen for substances capable of elevating intracellular cyclic AMP concentration.
Cultured rat glioma (ASK) cells are morphologically converted from a spindle to an astrocyte form when treated with dibutyryl cAMP. This morphologic transformation is discernible by light microscopy and can be visually quantitated. As described herein, dose-dependent astrocyte generation was demonstrated by treatment of confluent monolayers with forskolin [1], a compound known to activate adenylate cyclase, and the potency of four forskolin derivatives was found to correlate with previously established biologic potential. Neither a crude ginseng extract nor purified ginsenosides were active in the process, but supplementation of the otherwise inactive ginseng extract with 1 demonstrated 50% of the cells were morphologically converted to the astrocyte form at a concentration of approximately 0.0008%. Retinoic acid was also active in this test system; the morphologic transformation was reversed on treatment with colchicine, and intracellular cAMP concentration was elevated approximately 10-fold. Evaluation of 15 retinoids established a general correlation between the activity in this system and other systems reported in the literature. Thus, the astrocyte formation assay appears to provide several advantages that make it attractive as a screen for the detection or evaluation of substances capable of elevating intracellular cAMP concentration. In addition to technical ease, the procedure is rapid, sensitive, and relatively inexpensive.
Swanson
S M
SM
Program for Collaborative Research in the Pharmaceutical Sciences, College of Pharmacy, University of Illinois, Chicago 60612.
Jiang
J X
JX
Chang
Y S
YS
De Souza
N J
NJ
Pezzuto
J M
JM
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D005910:Glioma / Q000378:metabolism; D008722:Methods; D005894:Panax / Q000032:analysis; D010936:Plant Extracts / Q000494:pharmacology; D010946:Plants, Medicinal; D051381:Rats; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects* / Q000378:metabolism
D010936:Plant Extracts; D005576:Colforsin; D014212:Tretinoin; D000242:Cyclic AMP