PMID: 26317331

Authors:

Wang L, Wallace A, Raghavan S, Deis SM, Wilson MR, Yang S, Polin L, White K, Kushner J, Orr S, George C, O'Connor C, Hou Z, Mitchell-Ryan S, Dann CE 3rd, Matherly LH, Gangjee A

Title:

6-Substituted Pyrrolo[2,3-d]pyrimidine Thienoyl Regioisomers as Targeted Antifolates for Folate Receptor alpha and the Proton-Coupled Folate Transporter in Human Tumors.

Journal:

J Med Chem. 2015 Sep 10;58(17):6938-59. doi: 10.1021/acs.jmedchem.5b00801. Epub, 2015 Aug 28.

Abstract:

2-Amino-4-oxo-6-substituted-pyrrolo[2,3-d]pyrimidine antifolate thiophene regioisomers of AGF94 (4) with a thienoyl side chain and three-carbon bridge lengths [AGF150 (5) and AGF154 (7)] were synthesized as potential antitumor agents. These analogues inhibited proliferation of Chinese hamster ovary (CHO) sublines expressing folate receptors (FRs) alpha or beta (IC50s < 1 nM) or the proton-coupled folate transporter (PCFT) (IC50 < 7 nM). Compounds 5 and 7 inhibited KB, IGROV1, and SKOV3 human tumor cells at subnanomolar concentrations, reflecting both FRalpha and PCFT uptake. AGF152 (6) and AGF163 (8), 2,4-diamino-5-substituted-furo[2,3-d]pyrimidine thiophene regioisomers, also inhibited growth of FR-expressing CHO and KB cells. All four analogues inhibited glycinamide ribonucleotide formyltransferase (GARFTase). Crystal structures of human GARFTase complexed with 5 and 7 were reported. In severe combined immunodeficient mice bearing SKOV3 tumors, 7 was efficacious. The selectivity of these compounds for PCFT and for FRalpha and beta over the ubiquitously expressed reduced folate carrier is a paradigm for selective tumor targeting.