Rat Osteogenic Sarcoma Cells: Isolation and Effects of Hormones on the Production of Cyclic AMP and Cyclic GMP

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Abstract
Viable cells were isolated from a 32P-induced rat osteogenic sarcoma by digestion with collagenase/hyaluronidase followed by centrifugation over Ficoll/Triosil. The cell preparation, which remained viable in terms of glucose consumption for at least 5 h, consisted of tumor cells, the only contamination being approximately 5-10% macrophages. In the presence of 10 mM theophylline, cyclic[c]AMP levels were increased by parathyroid hormone (PTH), prostaglandins E1, E2 and F2.alpha., isoproterenol, thyroxine and calcitonin. A range of other hormones did not significantly increase cAMP levels. Only insulin caused a significant increase cGMP levels in these cells. The effect of PTH was maximal within 5 min of adding the hormone. The lowest effective concentration of PTH was 8 mU/ml and half-maximal stimulation occurred at 100 mU/ml. Responses to calcitonin were small, but agreed with the effects of the hormone on cAMP levels in other systems. The relative potencies of the prostaglandins were similar to those necessary to stimulate bone resorption in culture. The ability of this osteogenic sarcoma to form osteoid and mineralize it in vivo suggests a resemblance of the cells to bone cells. The data presented in this paper show that hormones which have effects on cAMP levels in bone have similar effects on isolated tumor cells and hormones not active on bone are ineffective. This tumor, and its cells, is a potentially useful tissue for studying PTH and prostaglandin action on cells of bony origin and for evaluating the significance of PTH and other hormones for tumor cell growth and differentiation.