5′-Deoxy-5′-methylthioadenosine

5′-Deoxy-5′-methylthioadenosine (MTA) has been shown to be a potent inhibitor of protein carboxylmethyltransferase and a naturally occurring co-product of polyamine biosynthesis. This nucleoside has been reported to potently inhibit the growth of certain cells by causing apoptosis. Treatment of cells with this compound has caused inhibition of cAMP phosphodiesterase which subsequently increases cAMP levels resulting in cell growth arrest. More specific studies demonstrate that MTA-treated cells display an arrest in the M phase of the cell cycle. Other data suggest that MTA displays agonist and antagonist characteristics towards adenosine A1-receptor (adenosine A1-R) and Adenosine A2-R, respectively. 5′-Deoxy-5′-methylthioadenosine is a substrate of 5′-methylthioadenosinephosphorylase (MTAP), an enzyme known to be expressed by tumor suppressor genes.