Effects of synthetic adenosine receptor agonists on growth characteristics of G : 5 : 113 fibrosarcoma cells in vitro
The effects of several synthetic adenosine receptor agonists on the growth characteristics of murine G:5:113 fibrosarcoma cells in vitro were evaluated. Cell number and viability, as well as proportions of cells in individual cell cycle phases, were determined after 48 h cultivation of the cells in the presence of concentrations of adenosine receptor agonists ranging between 0.01 and 500 muM. Effects of the non-selective adenosine receptor agonist NECA, as well as of agonists selective for A(1) (CPA), A(2A) (CGS 21680), and A(3) receptors (IB-MECA) were evaluated. A slight increase in cell number was observed at a narrow range of concentrations between 30-50 muM of NECA, which was reproduced by CPA, a selective A, receptor agonist, in concentrations ranging from 20-50 muM. The most important finding was that of significant inhibitory effects of adenosine receptor agonists on cell number in concentrations above 50 muM. This effect was most pronounced after treatment of the G:5:113 fibrosarcoma cells with the selective A(3) receptor agonist, IB-MECA, as revealed also by calculated values of generation time and EC50. The results suggest that adenosine A(3) receptor might represent a target for pharmacological anticancer approaches aimed at suppressing the growth of fibrosarcoma cell population. (C) 2003 Wiley-Liss, Inc.