An adenosine analog (IB-MECA) inhibits anchorage-dependent cell growth of various human breast cancer cell lines

A(3) adenosine receptor agonists have been reported to influence cell death and survival. Here we report the effects of an A(3) adenosine receptor agonist, IB-MECA, on the cell growth of human breast cancer cell lines, MCF-7 (estrogen receptor positive) and MDA-MB468 (estrogen receptor negative). Therefore, this study was aimed to investigate the expression and possible action of A(3) receptor in the human breast cancer cell lines. IB-MECA, at 1-100 muM, resulted in a significant cell growth inhibition (P < 0.05) which reached the maximum at 48 h, in the cell lines. In both cell lines, agonist-induced effects were antagonized by pretreatment with a selective A(3) adenosine receptor antagonist, MRS1220. Using RT-PCR method, further confirmation was provided by the presence of mRNA of A(3) receptor in the cells. In addition, IB-MECA was able to inhibit forskolin-stimulated cAMP levels, which indicate the functional form of A(3) receptor on the cell surface of these breast cancer cell lines. These results suggest that the inhibitory effect of IB-MECA on the growth of human breast cancer cell lines is mediated through activation of A(3) adenosine receptor. (C) 2004 Elsevier Ltd. All rights reserved.