pemetrexed and Carcinoma--Squamous-Cell

2-Amino-4-oxo-6-substituted pyrrolo[2,3-d]pyrimidines with a thienoyl side chain and four to six carbon bridge lengths (compounds 1-3) were synthesized as substrates for folate receptors (FRs) and the proton-coupled folate transporter (PCFT). Conversion of acetylene carboxylic acids to alpha-bromomethylketones and condensation with 2,4-diamino-6-hydroxypyrimidine afforded the 6-substituted pyrrolo[2,3-d]pyrimidines. Sonogashira coupling with (S)-2-[(5-bromo-thiophene-2-carbonyl)-amino]-pentanedioic acid diethyl ester, followed by hydrogenation and saponification, afforded 1-3. Compounds 1 and 2 potently inhibited KB and IGROV1 human tumor cells that express FR alpha, reduced folate carrier (RFC), and PCFT. The analogs were selective for FR and PCFT over RFC. Glycinamide ribonucleotide formyltransferase was the principal cellular target. In SCID mice with KB tumors, 1 was highly active against both early (3.5 log kill, 1/5 cures) and advanced (3.7 log kill, 4/5 complete remissions) stage tumors. Our results demonstrate potent in vitro and in vivo antitumor activity for 1 due to selective transport by FRs and PCFT over RFC.

Topics: Animals; Antineoplastic Agents; Carcinoma, Squamous Cell; Carrier Proteins; Cell Proliferation; Cells, Cultured; CHO Cells; Cricetinae; Cricetulus; Female; Folate Receptors, GPI-Anchored; Folic Acid Antagonists; Humans; Membrane Transport Proteins; Mice; Mice, Inbred ICR; Mice, SCID; Ovarian Neoplasms; Proton-Coupled Folate Transporter; Purines; Pyrimidines; Receptors, Cell Surface; Reduced Folate Carrier Protein

Novel antifolates with a 6-5 fused ring system, 6,7-dihydrocyclopenta [d]pyrimidine, (3a,b and 4a,b) were synthesized on the basis of combined modification of the heterocycle and bridge regions of the folate molecule. The synthetic method involves (1) synthesis of key intermediates of tert-butyl 4-[omega-(2-substituted-3-oxocyclopentanyl) alkyl]benzoates (8a,b and 9a,b) by a carbon-carbon radical coupling of tert-butyl 4-(omega-iodoalkyl)benzoates (7a,b) with 2-substituted-2-cyclopenten-1-ones (5 and 6) utilizing tributyltin hydride, (2) cyclization of either the methyl enol-ethers derived from the 2-cyanocyclopentanones (8a,b) or the 2-(methoxycarbonyl)cyclopentanones (9a,b) themselves by treatment with guanidine which leads to 6,7-dihydrocyclopenta [d]pyrimidines with a 4-(tert-butoxycarbonyl)phenylalkyl group (11a,b and 14a,b), (3) deprotection to the corresponding carboxylic acids (12a,b and 15a,b), and (4) amidation with diethyl glutamate and deesterification. Potent dihydrofolate reductase inhibition and highly potent cell growth inhibition were found with 2,4-diaminopyrimidine-fused cyclopentene compounds containing the trimethylene (3a) or ethylene bridge (3b) but not with the corresponding 2-amino-4-hydroxy analogs (4a,b). Compounds 3a and 3b were more growth inhibitory to several tumor cell lines (P388, colon 26, colon 38, and KB) than was methotrexate, with 3a being the most potent. Both 3a and 3b gave increases in the lifespan of P388 leukemic mice comparable to that observed with MTX. Both compounds were therapeutic against colon 26 colorectal carcinoma in mice. Compound 3a was highly effective against LC-6 non-small cell lung carcinoma in nude mice.

Topics: Animals; Antineoplastic Agents; Carcinoma, Squamous Cell; Cell Division; Colonic Neoplasms; Folic Acid Antagonists; Glutamates; Humans; Leukemia P388; Methotrexate; Mice; Mice, Inbred BALB C; Mice, Inbred DBA; Mice, Nude; Neoplasm Transplantation; Pyrimidines; Structure-Activity Relationship; Tumor Cells, Cultured