Makoto Nomura

1,2,3-Triazole-Containing Uracil Derivatives with Excellent Pharmacokinetics as a Novel Class of Potent Human Deoxyuridine Triphosphatase Inhibitors

Deoxyuridine triphosphatase (dUTPase) has emerged as a potential target for drug development as a 5-fluorouracil-based combination chemotherapy. We describe the design and synthesis of a novel class of human dUTPase inhibitors, 1,2,3-triazole-containing uracil derivatives. Compound 45a, which possesses 1,5-disubstituted 1,2,3-triazole moiety that mimics the amide bond of tert-amide-containing inhibitor 6b locked in a cis conformation showed potent inhibitory activity, and its structure-activity relationship studies led us to the discovery of highly potent inhibitors 48c and 50c (IC(50) = ~0.029 μM). These derivatives dramatically enhanced the growth inhibition activity of 5-fluoro-2-deoxyuridine against HeLa S3 cells in vitro (EC(50) = ~0.05 μM). In addition, compound 50c exhibited a markedly improved pharmacokinetic profile as a result of the introduction of a benzylic hydroxy group and significantly enhanced the antitumor activity of 5-fluorouracil against human breast cancer MX-1 xenograft model in mice. These data indicate that 50c is a promising candidate for combination cancer chemotherapies with TS inhibitors.

Nucleosides and nucleotides. Part 212: Practical large-scale synthesis of 1-(3-C-ethynyl-β-d-ribo-pentofuranosyl)cytosine (ECyd), a potent antitumor nucleoside. Isobutyryloxy group as an efficient anomeric leaving group in the Vorbrüggen glycosylation reaction ☆

Abstract A practical synthetic route to the antitumor nucleoside, 1-(3- C -ethynyl-β- d - ribo -pentofuranosyl)cytosine (ECyd, 1 ) from 1,2- O -isopropylidene- d -xylofuranose ( 3 ) has been developed. Since most of the compounds were obtained as crystals, the target ECyd was prepared without any chromatographic purification in 31% overall yield from compound 3 . The isobutyryloxy group was found to be an effective leaving group at the anomeric position of the 3-β- C -ethynyl glycosyl donors in the key Vorbruggen glycosylation reaction. Using a similar procedure without chromatographic purification, the uracil congener EUrd [1-(3- C -ethynyl-β- d - ribo -pentofuranosyl)uracil ( 2 ), which also has a potent antitumor effect, was synthesized from 3 in 39% overall yield.

Discovery of a novel class of potent human deoxyuridine triphosphatase inhibitors remarkably enhancing the antitumor activity of thymidylate synthase inhibitors

Inhibition of human deoxyuridine triphosphatase (dUTPase) has been identified as a promising approach to enhance the efficacy of 5-fluorouracil (5-FU)-based chemotherapy. This study describes the development of a novel class of dUTPase inhibitors based on the structure-activity relationship (SAR) studies of uracil derivatives. Starting from the weak inhibitor 7 (IC(50) = 100 μM), we developed compound 26, which is the most potent human dUTPase inhibitor (IC(50) = 0.021 μM) reported to date. Not only does compound 26 significantly enhance the growth inhibition activity of 5-fluoro-2-deoxyuridine (FdUrd) against HeLa S3 cells in vitro (EC(50) = 0.075 μM) but also shows robust antitumor activity against MX-1 breast cancer xenograft model in mice when administered orally with a continuous infusion of 5-FU. This is the first in vivo evidence that human dUTPase inhibitors enhance the antitumor activity of TS inhibitors. On the basis of these findings, it was concluded that compound 26 is a promising candidate for clinical development.

Synthesis of the cyclic and acyclic acetal derivatives of 1-(3-C-Ethynyl-β-d-ribo-pentofuranosyl)cytosine, a potent antitumor nucleoside. Design of prodrugs to be selectively activated in tumor tissues via the bio-Reduction–Hydrolysis mechanism ☆

We have designed and synthesized the acetal derivatives of 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)cytosine (ECyd, 1), the 2,3-O-nitrobenzylidene derivatives 2 and 3 and the 5-O-(alkoxy)(nitrophenyl)methyl derivatives 6-10 as potential prodrugs of ECyd. These prodrugs can be selectively activated in tumor tissues via a bio-reduction-hydrolysis mechanism owing to the characteristic properties of tumor tissues, such as hypoxia and lower pH. Although the 2,3-O-(4-nitrobenzylidene) derivatives 2 and 3 were converted bio-reductively into the corresponding 4-aminobenzylidene derivatives by rat S-9 mix, the reduction products, that is, the corresponding amino congeners 4 and 5, proved to be rather stable in an aqueous solution at pH 6.5 used as a pH model for acidic tumor tissues. In contrast, the 5-O-(alkoxy)(4-nitropheny)methyl derivatives 6-8 were also reduced by rat S-9 mix to the corresponding amino congeners 11-13, which were hydrolyzed to release ECyd more effectively at pH 6.5 than at pH 7.4. Accordingly, the acyclic acetals 6-8 may be efficient prodrugs of ECyd, that are effectively reduced under physiological conditions releasing ECyd in acidic tumor tissues.

An Efficient Method for the Preparation of 1′α-Branched-Chain Sugar Pyrimidine Ribonucleosides from Uridine: The First Conversion of a Natural Nucleoside into 1′-Substituted Ribonucleosides

The 1alpha-phenylselenouridine derivative 13 was successfully synthesized by enolization of the 3,5-O-TIPDS-2-ketouridine 8, and was subjected to a radical reaction with a vinylsilyl tether--an efficient procedure for preparing 1alpha-branched-chain sugar pyrimidine nucleosides. Successive treatment of 8 with LiHMDS and PhSeCl in THF at < -70 degrees C gave the desired 1-phenylseleno products in 85% yield as an anomeric mixture of the 1alpha-product 11 and the 1beta-product 12 (11/12= 2.5:1). Highly stereoselective reduction at the 2-carbonyl of the 1alpha-product 11 occurred from the beta-face by using NaBH4/CeCl3 in MeOH, and subsequent introduction of a dimethylvinylsilyl tether at the 2-hydroxyl gave the radical reaction substrate 14. The photochemical radical atom-transfer reaction of 14 by using a high-pressure mercury lamp proceeded effectively in benzene to give the exo-cyclized PhSe-transferred product 18, in which (PhSe)2 proved to be essential as an additive for radical atom-transfer cyclization reactions. Subsequent phenylseleno-group elimination of 18 gave the sugar-protected 1alpha-vinyluridine. With this procedure, 1alpha-vinyluridine (22) and -cytidine (25), designed to be potential antitumor agents, were successfully synthesized. This study is the first example of functionalization at the anomeric 1-position of a nucleoside by starting from a natural nucleoside to produce a ribo-type 1-modified nucleoside.

Discovery of highly potent human deoxyuridine triphosphatase inhibitors based on the conformation restriction strategy.

Human deoxyuridine triphosphatase (dUTPase) inhibition is a promising approach to enhance the efficacy of thymidylate synthase (TS) inhibitor based chemotherapy. In this study, we describe the discovery of a novel class of human dUTPase inhibitors based on the conformation restriction strategy. On the basis of the X-ray cocrystal structure of dUTPase and its inhibitor compound 7, we designed and synthesized two conformation restricted analogues, i.e., compounds 8 and 9. These compounds exhibited increased in vitro potency compared with the parent compound 7. Further structure-activity relationship (SAR) studies identified a compound 43 with the highest in vitro potency (IC(50) = 39 nM, EC(50) = 66 nM). Furthermore, compound 43 had a favorable oral PK profile and exhibited potent antitumor activity in combination with 5-fluorouracil (5-FU) in the MX-1 breast cancer xenograft model. These results suggested that a dUTPase inhibitor may have potential for clinical usage.

Synthesis and discovery of N-carbonylpyrrolidine- or N-sulfonylpyrrolidine-containing uracil derivatives as potent human deoxyuridine triphosphatase inhibitors.

Recently, deoxyuridine triphosphatase (dUTPase) has emerged as a potential target for drug development as part of a new strategy of 5-fluorouracil-based combination chemotherapy. We have initiated a program to develop potent drug-like dUTPase inhibitors based on structure-activity relationship (SAR) studies of uracil derivatives. N-Carbonylpyrrolidine- and N-sulfonylpyrrolidine-containing uracils were found to be promising scaffolds that led us to human dUTPase inhibitors (12k) having excellent potencies (IC(50) = 0.15 μM). The X-ray structure of a complex of 16a and human dUTPase revealed a unique binding mode wherein its uracil ring and phenyl ring occupy a uracil recognition region and a hydrophobic region, respectively, and are stacked on each other. Compounds 12a and 16a markedly enhanced the growth inhibition activity of 5-fluoro-2-deoxyuridine against HeLa S3 cells in vitro (EC(50) = 0.27-0.30 μM), suggesting that our novel dUTPase inhibitors could contribute to the development of chemotherapeutic strategies when used in combination with TS inhibitors.

Lower-limb muscle strength according to bodyweight and muscle mass among middle age patients with type 2 diabetes without diabetic neuropathy

[Purpose] This study assessed the effects of type 2 diabetes without diabetic polyneuropathy on muscle strength according to body composition in middle age patients. [Subjects and Methods] This study included 45 non-diabetic individuals (control group) and 50 patients with type 2 diabetes (DM group), 40 to 64u2005years of age. The body composition was examined, including the leg muscle volume (LMV), which was the sum of the lower-limb muscle mass. The muscle strength was also examined, and the knee extension force (KEF), ankle dorsiflexion force (ADF). The KEF and ADF were normalized to the bodyweight, and the total leg muscle force (TLMF) were calculated by combining the KEF and ADF. The leg muscle quality (LMQ) was calculated as the TLMF normalized with the LMV. [Results] While no significant differences were found in the LMV between groups, the body mass index were higher in the DM group than in the control group. Significant differences were observed in %KEF, %ADF, and the LMQ in the DM group, with 15.8%, 18.7%, and 11.5% lower values than those in the control group, respectively. [Conclusion] The results of this study may demonstrate that muscle weakness occurs before diabetes progresses to a severe condition.

Serum levels of retinol, inorganic phosphate and polyunsturated fatty acid and their relationship in diabetic patients with early nephropathy

Abstract We investigated the relationship between the serum levels of retinol (Ret) and inorganic phosphate (IP) and the composition of fatty acids in twenty NIDDM (non-insul in-dependent diabetes mellitus) patients with early diabetic nephropathy (serum creatinine: 1.5±0.8 mg/100 ml). The mean level of Ret, IP and triglycerides (TG) was 101 μg/100 ml, 3.85 mg/100 ml and 120 mg/100 ml, respectively. The percentage of polyunsaturated fatty acids (PUFA) to total fatty acid was 44.8% ±4.3%. Serum creatinine was positively correlated to Ret, IP and TG (r=0.81, p