Extracellular adenosine-induced apoptosis of CW2 human colonic cancer cells by activating caspase-3, -8 and -9, and the effect was enhanced by adding EHNA, an adenosine deaminase inhibitor. Adenosine-induced CW2 cell death was inhibited by 8-CPT, an A(1) adenosine receptor inhibitor, but otherwise 2-chloroadenosine, an A(1) adenosine receptor agonist, and MDL-12330A, an inhibitor of adenylate cyclase, mimicked the adenosine effect. For mice inoculated with CW2 cells, intraperitoneal injection with adenosine reduced tumor growth and more prominent reduction was obtained with co-injection with EHNA. Adenosine, thus, suppresses CW2 human colonic cancer growth by inducing apoptosis as mediated via A(1) adenosine receptors.
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