Notes: 8-Chloroadenosine is a nucleoside analog and an active metabolite of the anticancer agent 8-chloro cAMP.{69006} It is formed from 8-chloro cAMP by phosphodiesterases (PDEs) and upon entry into cells, 8-chloroadenosine is phosphorylated by adenosine kinase to produce 8-chloro-ATP. 8-Chloroadenosine (10 µM) inhibits RNA, but not DNA, synthesis in vitro. It is cytotoxic to patient-derived multiple myeloma cells in a concentration-dependent manner. 8-chloroadenosine (50 mg/kg) reduces tumor growth by 50% in an HCT116 colorectal cancer mouse xenograft model.{69007}