NAD-based inhibitors with anticancer potential.

Three classes of novel inhibitors of inosine monophosphate dehydrogenase have been prepared and their anti-proliferative properties were evaluated against several cancer cell lines. (1) Mycophenolic adenine dinucleotide analogues (8-13) containing a substituent at the C2 of adenine ring were found to be potent inhibitors of IMPDH (Ki's in range of 0.6-82nM) and sub-μM inhibitors of leukemic K562 cell proliferation. (2) Mycophenolic adenosine (d and l) esters (20 and 21) showed a potent inhibition of IMPDH2 (Ki=102 and Ki=231nM, respectively) and inhibition of K562 cell growth (IC50=0.5 and IC50=1.6μM). These compounds serve both as inhibitors of the enzyme and as a depot form of mycophenolic acid. The corresponding amide analogue 22, also a potent inhibitor of IMPDH (Ki=84nM), did not inhibit cancer cell proliferation. (3) Mycophenolic-(l)- and (d)-valine adenine di-amide derivatives 25 (Ki=9nM) and 28 (Ki=3nM) were found to be very potent enzymatically, but did not inhibit proliferation of cancer cells.