Cofactor-type inhibitors of inosine monophosphate dehydrogenase via modular approach: targeting the pyrophosphate binding sub-domain.

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Felczak K, Chen L, Wilson D, Williams J, Vince R, Petrelli R, Jayaram HN, Kusumanchi P, Kumar M, Pankiewicz KW

Cofactor-type inhibitors of inosine monophosphate dehydrogenase via modular approach: targeting the pyrophosphate binding sub-domain.

Bioorg Med Chem. 2011 Mar 1;19(5):1594-605. doi: 10.1016/j.bmc.2011.01.042. Epub 2011 Jan 27.

PubMed ID

21324702 [ View in PubMed

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Abstract

Cofactor-type inhibitors of inosine monophosphate dehydrogenase (IMPDH) that target the nicotinamide adenine dinucleotide (NAD) binding domain of the enzyme are modular in nature. They interact with the three sub-sites of the cofactor binding domain; the nicotinamide monophosphate (NMN) binding sub-site (N sub-site), the adenosine monophosphate (AMP) binding sub-site (A sub-site), and the pyrophosphate binding sub-site (P sub-site or P-groove). Mycophenolic acid (MPA) shows high affinity to the N sub-site of human IMPDH mimicking NMN binding. We found that the attachment of adenosine to the MPA through variety of linkers afforded numerous mycophenolic adenine dinucleotide (MAD) analogues that inhibit the two isoforms of the human enzyme in low nanomolar to low micromolar range. An analogue 4, in which 2-ethyladenosine is attached to the mycophenolic alcohol moiety through the difluoromethylenebis(phosphonate) linker, was found to be a potent inhibitor of hIMPDH1 (K(i)=5 nM), and one of the most potent, sub-micromolar inhibitor of leukemia K562 cells proliferation (IC(50)=0.45 muM). Compound 4 was as potent as Gleevec (IC(50)=0.56 muM) heralded as a 'magic bullet' against chronic myelogenous leukemia (CML). MAD analogues 7 and 8 containing an extended ethylenebis(phosphonate) linkage showed low nanomolar inhibition of IMPDH and low micromolar inhibition of K562 cells proliferation. Some novel MAD analogues described herein containing linkers of different length and geometry were found to inhibit IMPDH with K(i)'s lower than 100 nM. Thus, such linkers can be used for connection of other molecular fragments with high affinity to the N- and A-sub-site of IMPDH.

DrugBank Data that Cites this Article

Binding Properties

Drug	Target	Property	Measurement	pH	Temperature (°C)
Mycophenolic acid	Inosine-5'-monophosphate dehydrogenase 1	Ki (nM)	33	N/A	N/A	Details
Mycophenolic acid	Inosine-5'-monophosphate dehydrogenase 2	Ki (nM)	7	N/A	N/A	Details