• YAKHAK HOEJI
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• v.49 no.1
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• pp.60-67
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• 2005

Nonclassical aminobenz[cd]indole antifolates 4, 5 and 6, in which the glutamic acid moiety of the classical antifolates is substituted by 2-phenylglycinamide or 3-aminobenzamide, were synthesized and their in vitro antitumor activity was evaluated. The purpose of this substitution is that the lipophilicity is enhanced due to the aromatic ring of the target compounds for the passive transport through lipid membrane of cells while the hydrogen bonding of the amide is retained in the active site of the enzyme, thymidylate synthase, where the glutamate is originally present. The target compounds were highly cytotoxic against tumor cell lines of murine and human origin with micromolar to nanomolar $IC_{50}$ values. Most effective was compound 4 ($N^6-methyl-N^6$-[4-[(${\alpha}$(S)-aminocarbonylbenzyl) aminocarbonyl]benzyl]-2,6-diaminobenz[cd]indole)with $IC_{50}$ of 2 nM against SW480, human colon adenocarcinoma cell line, which is 650-fold more potent than the reference compound 3.

• Nutrition Research and Practice
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• v.14 no.2
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• pp.95-101
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• 2020

BACKGROUND/OBJECTIVES: Folate plays a critical role in DNA synthesis and methylation. Intracellular folate homeostasis is maintained by the enzymes folylpolyglutamate synthase (FPGS) and γ-glutamyl hydrolase (GGH). FPGS adds glutamate residues to folate upon its entry into the cell through a process known as polyglutamylation to enhance folate retention in the cell and to maintain a steady supply of utilizable folate derivatives for folate-dependent enzyme reactions. Thereafter, GGH catalyzes the hydrolysis of polyglutamylated folate into monoglutamylated folate, which can subsequently be exported from the cell. The objective of this review is to summarize the scientific evidence available on the effects of intracellular folate homeostasis-associated enzymes on cancer chemotherapy. METHODS: This review discusses the effects of FPGS and GGH on chemosensitivity to cancer chemotherapeutic agents such as antifolates, such as methotrexate, and 5-fluorouracil. RESULTS AND DISCUSSION: Polyglutamylated (anti)folates are better substrates for intracellular folate-dependent enzymes and retained for longer within cells. In addition to polyglutamylation of (anti)folates, FPGS and GGH modulate intracellular folate concentrations, which are an important determinant of chemosensitivity of cancer cells toward chemotherapeutic agents. Therefore, FPGS and GGH affect chemosensitivity to antifolates and 5-fluorouracil by altering intracellular retention status of antifolates and folate cofactors such as 5,10-methylenetetrahydrofolate, subsequently influencing the cytotoxic effects of 5-fluorouracil, respectively. Generally, high FPGS and/or low GGH activity is associated with increased chemosensitivity of cancer cells to methotrexate and 5-fluorouracil, while low FPGS and/or high GGH activity seems to correspond to resistance to these drugs. Further preclinical and clinical studies elucidating the pharmocogenetic ramifications of these enzyme-induced changes are warranted to provide a framework for developing rational, effective, safe, and customized chemotherapeutic practices.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1898-1906
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• 2004

Nonclassical quinazolinone analogs I, II, and III, in which the glutamic acid moiety of the classical antifolates is substituted by phenylglycine, phenylalanine or aminobenzoic acid and their methyl esters, were synthesized and evaluated as lipophilic inhibitors of thymidylate synthase (TS). The target compounds were generally potent inhibitors of L. casei and human TS with $IC_{50}$ values within the narrow range of 0.2-10 ${\mu}$M and 0.003-0.03 ${\mu}$M, respectively. Further, most of the target compounds showed cytotoxicity against tumor cell lines of murine and human origin with $IC_{50}$ values of as low as 0.050 ${\mu}$M. Substitution of another hydroxyl or carboxylic acid/ester group at the phenyl ring further increased the potency of TS inhibition and cell growth inhibition. Most effective were compounds If and Ic in which extra carboxylic acid/ester was present at the phenyl ring with nanomolar $IC_{50}$ values of 0.0044 and 0.0093 ${\mu}$M against human TS and submicromolar cytotoxic growth inhibition against all four tumor cell lines.

• YAKHAK HOEJI
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• v.50 no.4
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• pp.278-286
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• 2006

Classical dihydropyrrole[3,4-f]quinazoline antifolates 7,8 and 9, in which the tricyclic ring is structurally similar to the pteridine ring of $CH_2-THF(1)$, the cofactor of thymidylate synthase (TS), were synthesized, and their in vitro antitumor activity was evaluated by measuring the cell growth inhibitory activity against cancer cell lines. The target compounds were cytotoxic against CCRF-CEM, human T-cell acute lymphoblastic leukemia, with the cell growth inhibitory activity $(IC_{50})$ of $0.8{\sim}8.3\;{\mu}M$. Among the three compounds, 3-amino analog 7 was 10- and 3.5-fold more cytotoxic compared to the 3-methyl analogs 8 and 9, and its cytotoxicity was similar to that of the reference compound with the $IC_{50}$ value of $0.83\;{\mu}M$. This result was supposed as the consequence of the fact that dihydropyrroloquinazolinone ring with amino group was able to bind well in the active site of TS. In the case of 3-methyl analogs, analog 9, which has two-carbon bridge between the dihydropyrroloquinazolinone ring and benzoyl-L-glutamic acid, was 3-times more potent in cytotoxicity than analog 8 which has one-carbon bridge, and this result indicates that the distance and conformational orientation of the benzoyl-L-glutamic acid moiety with respect to the tricyclic ring may also be a crucial determinant of cell growth inhibitory activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.6
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• pp.839-845
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• 1993

One of the major problems of cancer chemotheraphy is the development of drug resistance in tumors, resulting in reduced responsiveness to subsequent treatments. The folate antagonists are being used to treat such diverse illnesses as cancer, leukemia, psoriasis, rheumatoid arthritis, etc. Previous studies have established that resistance to antifolates may occur in mammalian tumor cells by one or more of five mechanisms ; (a) an increase in the levels of the target enzyme, generally as a consequence of gene amplification ; (b) an alteration in the target enzyme, leading to an enzyme with a decreased binding affinity for the drug ; (c) a decrease in the uptake of the drug into the cells ; (d) increased extrusion of drugs out of cells ; (e) impaired ability to polyglutamylate the parent drug which is capable of being intracellularly metabolized to longer chain length.

• Proceedings of the PSK Conference
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• 2000.10a
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• pp.211.3-212
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• 2000

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.11
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• pp.4727-4732
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• 2015

Background: Folylpolyglutamate synthetase (FPGS), an important enzyme in the folate metabolic pathway, plays a central role in intracellular accumulation of folate and antifolate in several mammalian cell types. Loss of FPGS activity results in decreased cellular levels of antifolates and consequently to polyglutamatable antifolates in acute lymphoblastic leukemia (ALL). Materials and Methods: During May 1997 and December 2003, 134 children diagnosed with ALL were recruited from one hospital in Thailand. We performed a mutation analysis in the coding regions of the FPGS gene and the association between single nucleotide polymorphisms (SNPs) within FPGS in a case-control sample of childhood ALL patients. Mutation screening was conducted by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and subsequently with direct sequencing (n=72). Association analysis between common FPGS variants and ALL risk was done in 98 childhood ALL cases and 95 healthy volunteers recruited as controls. Results: Seven SNPs in the FPGS coding region were identified by mutation analysis, 3 of which (IVS13+55C>T, g.1297T>G, and g.1508C>T) were recognized as novel SNPs. Association analysis revealed 3 of 6 SNPs to confer significant increase in ALL risk these being rs7039798 (p=0.014, OR=2.14), rs1544105 (p=0.010, OR= 2.24), and rs10106 (p=0.026, OR=1.99). Conclusions: These findings suggested that common genetic polymorphisms in the FPGS coding region including rs7039789, rs1544105, and rs10106 are significantly associated with increased ALL risk in Thai children.

• Toxicological Research
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• v.14 no.3
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• pp.371-377
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• 1998

We have cloned a soluble type human folate receptor(hFR type${\gamma}$) from human thymus cDNA library using the PCR amplification technique. To examine whether hFR type${\gamma}$ has a folate transport activity, CHO cells were transfected with the pcDNAhFR${\gamma}$ expression plasmid, and the stable cell line CHO/hFR${\gamma}$ expressing a high level of the hFR type${\gamma}$ was identified by northern and western blot analysis. The CHO/hFR${\gamma}$ cells produced a [$H^3$]folic acid binding protein in the culture medium. However, we couldn't detect any cell surface [$H^3$] folic acid binding and transport activities. The growth of the CHO/hFR${\gamma}$ cells was more rapidly inhibited than the wild type CHO cells in the low concentration folic acid media. These observations indicate that although soluble type human folate receptor can bind [$H^3$]folate, it does not involve in folate transport.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2433-2442
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• 2011

The three dimensional quantitative structure activity relationship (3D QSAR) models were developed using Comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA) and docking studies. The fit of Quinazolinone antifolates inside the active site of modeled bovine dihydrofolate reductase (DHFR) was assessed. Both ligand based (LB) and receptor based (RB) QSAR models were generated, these models showed good internal and external statistical reliability that is evident from the $q^2_{loo}$, $r^2_{ncv}$ and $r^2_{pred}$. The identified key features enabled us to design new Quinazolinone analogues as DHFR inhibitors. This study is a building bridge between docking studies of homology modeled bovine DHFR protein as well as ligand and target based 3D QSAR techniques of CoMFA and CoMSIA approaches.

• Parasites, Hosts and Diseases
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• v.36 no.3
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• pp.191-198
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• 1998

The responses to antifolales of ToxopLasmc Bondii were investigated by measuring the dihydrorolate redLlctase (DHFR) activity. quantity of DHFR mRNA, and single-strand conformational polymorphism (SSCP) pattern. Pyrimethamine (PYM) and methotrexate (MTX) were tested ds anlifolates. When T. gondii was treated wish PYM, the viability was decreased by the increasing concentration of PYM. DHFR activity tended to increase as the passage proceeded. and the quantity of mRNA expressed was also increased according to passages. The viability of 7. gonnii was decreased by the increasing concentration of MTX, but it was maintained over 40% up to $100{\;}{\mu\textrm{m}}$ MTX. DHFR activity was 77.4% in the 1st passage ($1{\;}{\mu\textrm{m}}$). 82.2% in the 4th passage ($10{\;}{\mu\textrm{m}}$), and 141.3% in the 7th passage ($100{\;}{\mu\textrm{m}}$) But no changes were detected in SSCP pattern of T gondii rxposvd to FYM and MTX. both. These results suggested that the response of T gondii to FYN was rofulalcd by transrriptional level and that, in MTX. the viability of T. gonnii was derived from increasing DHFK activity.