Synthesis and antitumor activity of a novel series of 6-substituted pyrrolo[2,3-d]pyrimidine thienoyl antifolate inhibitors of purine biosynthesis with selectivity for high affinity folate receptors and the proton-coupled folate transporter over the reduced folate carrier for cellular entry.
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.
Wang
Lei
L
Division of Medicinal Chemistry, Graduate School of Pharmaceutical Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282, USA.
Cherian
Christina
C
Desmoulin
Sita Kugel
SK
Polin
Lisa
L
Deng
Yijun
Y
Wu
Jianmei
J
Hou
Zhanjun
Z
White
Kathryn
K
Kushner
Juiwanna
J
Matherly
Larry H
LH
Gangjee
Aleem
A
D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D016466:CHO Cells; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D002352:Carrier Proteins / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D058973:Folate Receptors, GPI-Anchored; D005493:Folic Acid Antagonists / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D026901:Membrane Transport Proteins / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D016513:Mice, SCID; D010051:Ovarian Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D058979:Proton-Coupled Folate Transporter; D011687:Purines / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011743:Pyrimidines / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000378:metabolism*; D058978:Reduced Folate Carrier Protein
D000970:Antineoplastic Agents; D002352:Carrier Proteins; D058973:Folate Receptors, GPI-Anchored; D005493:Folic Acid Antagonists; D026901:Membrane Transport Proteins; D058979:Proton-Coupled Folate Transporter; D011687:Purines; D011743:Pyrimidines; D011956:Receptors, Cell Surface; D058978:Reduced Folate Carrier Protein; C548699:SLC19A1 protein, human; C505058:SLC46A1 protein, human; C548700:Slc19a1 protein, mouse