ChemInform Abstract: Methotrexate Analogues. Part 26. Inhibition of Difolate Reductase and Folylpolyglutamate Synthetase Activity and in vitro Tumor Cell Growth by Methotrexate and Aminopterin Analogues Containing a Basic Amino Acid Side Chain.

Analogues of N alpha-(4-amino-4-deoxypteroyl)-N delta-(hemiphthaloyl)-L-ornithine (PT523) with 3',5'-dichloro substitution in the p-aminobenzoyl moiety or with one less or one more CH2 group in the amino acid moiety were synthesized and tested as inhibitors of dihydrofolate reductase (DHFR) activity and cell growth. Replacement of L-ornithine in PT523 by L-2,4-diaminobutanoic acid or L-lysine did not decrease binding to human recombinant DHFR but resulted in some loss of activity against SCC25 human and SCC VII murine squamous cell carcinoma and against MCF-7 human breast carcinoma in culture. PT523 was several times more potent than methotrexate (MTX), aminopterin (AMT), or trimetrexate (TMQ). 3',5'-Dichloro substitution did not decrease either DHFR binding or cytotoxicity. A new synthetic route to PT523 from 2,4-diamino-6-(hydroxymethyl)pteridine and methyl N alpha-(4-aminobenzoyl)-N delta-phthaloyl-L-ornithinate was investigated but was not found superior to previously described methods. In comparative experiments on the ability of PT523 and MTX to competitively inhibit the influx of (6R)-5,10-dideazatetra-hydrofolate (DDATHF, lometrexol), used here as a surrogate for MTX and reduced folates, the Ki of PT523 was lower than that of MTX in both wild-type CCRF-CEM human leukemic lymphoblasts and the transport- and polyglutamylation-defective subline CEM/MTX. The CCRF-CEM cells were 10-fold more sensitive to PT523 than to MTX, whereas the CEM/MTX cells were 240-fold more sensitive. However, in contrast to other MTX-resistant cells where collateral sensitivity to PT523 has been seen. CEM/MTX cells still showed substantial cross resistance to PT523 which may reflect an unusual heightened ability to utilize exogenous folic acid. The good correlation observed with both cell lines between the cytotoxicity of PT523 and MTX and the ability to inhibit DDATHF influx supported the view that PT523 and MTX share, at least in part, a common protein carrier for membrane transport.

Section: Methylmentioning

confidence: 99%

mentioning

confidence: 99%

Synthesis and Biological Activity of N.omega.-Hemiphthaloyl-.alpha.,.omega.-diaminoalkanoic Acid Analogs of Aminopterin and 3',5-Dichloroaminopterin

Rosowsky¹,

Bader²,

Wright³

et al. 1994

“…4,5 Since their pioneering work, numerous ornithine-containing analogues with modified pteroyl moieties have been synthesized and were found, in general, to be very effective inhibitors of FPGS. [6][7][8][9][10] The potency of the inhibitors is dependent on the nature of the pteroyl moiety. They are classified into two groups of interest: (1) specific inhibitors of FPGS, represented by a series of 5,8-dideazapteroyl (quinazoline) analogues of pteroylornithine (e.g., 2), [8][9][10] and (2) so-called "dualsite" inhibitors that act against both FPGS and a second folate-dependent enzyme such as dihydrofolate reductase (DHFR).…”

Section: Introductionmentioning

confidence: 99%

“…They are classified into two groups of interest: (1) specific inhibitors of FPGS, represented by a series of 5,8-dideazapteroyl (quinazoline) analogues of pteroylornithine (e.g., 2), [8][9][10] and (2) so-called "dualsite" inhibitors that act against both FPGS and a second folate-dependent enzyme such as dihydrofolate reductase (DHFR). The methotrexate (MTX) analogue N R -(4-amino-4-deoxy-10-methylpteroyl)-L-ornithine (AMPte-L-Orn, 3) and other 2,4-diamino derivatives [5][6][7]9 belong to this second class. The first class of inhibitors is of interest in connection with the long-standing question of possible cytotoxic effect on cell growth and/or viability elicited by specific inhibition of FPGS.…”

Section: Introductionmentioning

confidence: 99%

“…J ) 6.2 Hz, 1 H),6.56 (d, J ) 8.6 Hz, 2 H), 7.10 (d, J ) 7.5 Hz, 1 H), 7.72 (d, J ) 8.6 Hz, 2 H);13 C NMR (CDCl3) δ 28.0 (3 C), 28.4 (3 C), 30.4, 35.5 (t, J ) 23.9 Hz), 45.4 (t, J ) 30.3 Hz), 48.9, 60.6, 80.6, 82.6, 111.5 (2 C), 121.9, 122.6 (t, J ) 244 Hz), 129.2 (2 C), 152.3, 156.1, 167.2, 170.6; 19 F NMR (CDCl3) δ -23.9 (dtt, J ) 251, 12.6, 17.9 Hz, 1 F), -26.7 (ddq, J ) 251, 19.3, 13.3 Hz, 1 F); MS (EI) m/e (rel intensity) 457 (M + , 5.5), 383 (2.1), 328 (5.9), 300 (6.1), 134 (100); HRMS (EI) m/e calcd for C22H33F2N3O5 (M + ) 457.2388, found 457.2391.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Synthesis and Biological Evaluation of N^α-(4-Amino-4-deoxy-10-methylpteroyl)-dl-4,4-difluoroornithine

Tsukamoto¹,

Haile²,

McGuire³

et al. 1996

N alpha-(4-Amino-4-deoxy-10-methylpteroyl)-DL-4,4-difluoroornithi ne (AMPte-DL-4,4-F2Orn, 4) was synthesized and evaluated as an inhibitor of human folypoly-gamma-glutamate synthetase (FPGS), dihydrofolate reductase (DHFR), and cell growth. Synthesis of 4 involved the use of a protected form of DL-4,4-difluoroornithine 9 which was derived from DL-4,4-difluoroglutamic acid. Biological activities of 4 were compared directly to those of the corresponding nonfluorinated compound N alpha-(4-amino-4-deoxy-10-methylpteroyl)-L-ornithine (AMPte-L-Orn, 3). Although the fluorinated analogue is a potent inhibitor of DHFR, it is a poor inhibitor of FPGS. However, the compound is transported across the cell membrane and inhibits cell growth, presumably due to the inhibition of DHFR. The data obtained with the fluorinated analogue are in contrast to those of the corresponding nonfluorinated compound 3, which is a potent inhibitor of both FPGS and DHFR but shows very low cytotoxicity due to poor transport.

Synthesis and biological evaluation of N.alpha.-(5-deaza-5,6,7,8-tetrahydropteroyl)-L-ornithine

Singh

Singer²,

Ferone³

et al. 1992

A novel folic acid analogue, N alpha-(5-deaza-5,6,7,8-tetrahydropteroyl)-L-ornithine, 3, was prepared via a multistep synthetic sequence. The key steps involved the conversion of 5-deazapteroic acid to its N10-formyl derivative followed by catalytic hydrogenation of the pyridine ring and subsequent heating in dilute sodium hydroxide to afford the new 5-deaza-5,6,7,8-tetrahydropteroic acid. After trifluoroacetylation, this compound was coupled to N delta-(tert-butyl-oxycarbonyl)-L-ornithine using conventional peptide bond forming conditions. Deprotection first in base and then in acid gave the title compound. Compound 3 was an effective inhibitor of hog liver folylpolyglutamate synthetase (Kis, estimated = 64 nM), and was shown to retard the formation of polyglutamates of a structurally related folic acid analogue in HCT-8 cells in vitro.