NS-065/NCNP-01: An Antisense Oligonucleotide for Potential Treatment of Exon 53 Skipping in Duchenne Muscular Dystrophy.

Duchenne muscular dystrophy (DMD), the most common lethal heritable childhood disease, is caused by mutations in the DMD gene that result in the absence of functional dystrophin protein. Exon skipping mediated by antisense oligonucleotides has recently emerged as an effective approach for the restoration of dystrophin, and skipping of exon 51 of DMD has received accelerated approval. Identifying antisense sequences that can provide the highest possible skipping efficiency is crucial for future clinical applications.

Chemical synthesis of diastereomeric diadenosine boranophosphates (ApbA) from 2'-O-(2-cyanoethoxymethyl)adenosine by the boranophosphotriester method.

We have synthesized diastereomerically pure diadenosine 3',5'-boranophosphates (Ap(b)A) by using the boranophosphotriester method from ribonucleosides protected with the 2'-hydroxy protecting group 2-cyanoethoxymethyl (CEM). Melting curves of the triple-helical complex of the dimer Ap(b)A and 2poly(U) at high ionic strength revealed that presumptive (Sp)-Ap(b)A had a much higher affinity and presumptive (Rp)-Ap(b)A a much lower affinity for poly(U) than the natural dimer ApA did. In contrast, the affinities of these dimers for poly(dT) were similar.

Chemical synthesis of oligoribonucleotides with 2'-O-(2-cyanoethoxymethyl)-protected phosphoramidites.

An RNA synthetic method with 2-cyanoethoxymethyl (CEM) as the 2'-hydroxyl protecting group allows the synthesis of long oligoribonucleotides from CEM-amidites with an efficiency and final purity comparable to that obtained in DNA synthesis. The CEM-amidites give a high coupling efficiency, because the CEM group minimizes steric hindrance in the coupling reaction. The CEM group shows satisfactory stability under solid-phase synthetic conditions, avoids the generation of asymmetric centers, and is easily cleaved to give the final product.

A novel RNA synthetic method with a 2'-O-(2-cyanoethoxymethyl) protecting group.

A novel method for the synthesis of RNA oligomers with 2-cyanoethoxymethyl (CEM) as the 2'-hydroxyl protecting group has been developed. The new method allows the synthesis of oligonucleotides with an efficiency and final purity comparable to that obtained in DNA synthesis.(1) In addition, the CEM method has the potential for application to the synthesis of very long RNA oligonucleotides.

Asymmetric synthesis by the intramolecular haloetherification reaction of ene acetal: discrimination of prochiral dienes in cyclohexane systems.

A novel asymmetric synthesis of the cyclohexane derivative functionalized by some substituents has been developed from the diene acetals (1), prepared from the corresponding diene aldehyde and (+)-hydrobenzoin. The treatment of 1 with NBS in the presence of MeOCH2CH2OH predominantly afforded 2 in a stereoselective manner. Subsequent alkylation of the methoxyethoxy group produced the optically active cyclohexene compounds (3) in good yields.

A new RNA synthetic method with a 2'-O-(2-cyanoethoxymethyl) protecting group.

A novel method for the synthesis of RNA oligomers with 2-cyanoethoxymethyl (CEM) as the 2'-hydroxyl protecting group has been developed. The new method allows the synthesis of oligoribonucleotides with an efficiency and final purity comparable to that obtained in DNA synthesis. [structure: see text]

Antitumor activity of small interfering RNA/cationic liposome complex in mouse models of cancer.

Purpose: The RNA interference effect is an alternative to antisense DNA as an experimental method of down-regulating a specific target protein. Although the RNA interference effect, which is mediated by small interfering RNA (siRNA) or micro-RNA, has potential application to human therapy, the hydrodynamic method usually used for rapid administration of oligonucleotides is unsuitable for use in humans. In this study, we have investigated the antitumor activity of a synthetic siRNA, B717, which is sequence specific for the human bcl-2 oncogene, complexed with a novel cationic liposome, LIC-101.

Stereoselective synthesis and structure-activity relationship of novel ceramide trafficking inhibitors. (1R,3R)-N-(3-hydroxy-1-hydroxymethyl-3-phenylpropyl)dodecanamide and its analogues.

New ceramide trafficking inhibitors, (1R,3R)-N-(3-hydroxy-1-hydroxymethyl-3-phenylpropyl)dodecanamide (HPA-12) and a series of its analogues, were synthesized in diastereomerically and enantiomerically pure forms, and the structure-activity relationship was investigated. These analogues were stereoselectively synthesized via catalytic enantioselective Mannich-type reactions using a Cu(II)-chiral diamine 4 complex. Analysis of HPA-12 analogues having various lengths of the amide side chain showed that the optimal chain length for the inhibition of sphingomyelin biosynthesis is 13 with an IC(50) of approximately 50 nM.

Catalytic, asymmetric Mannich-type reactions of N-acylimino esters: reactivity, diastereo- and enantioselectivity, and application to synthesis of N-acylated amino acid derivatives.

In the presence of a catalytic amount of Cu(OTf)(2)-chiral diamine 3e complex, N-acylimino esters reacted with silyl enol ethers to afford the corresponding Mannich-type adducts in high yields with high enantioselectivities. A wide variety of silyl enol ethers derived from ketones, as well as esters and thioesters, reacted smoothly. In the reactions of alpha-substituted silyl enol ethers (alpha-methyl or benzyloxy), the desired syn-adducts were obtained in high yields with high diastereo- and enantioselectivities.

Catalytic, asymmetric Mannich-type reactions of N-acylimino esters for direct formation of N-acylated amino acid derivatives. Efficient synthesis of a novel inhibitor of ceramide trafficking, HPA-12.

[reaction: see text] Catalytic, enantioselective Mannich-type reactions of N-acylimino esters for direct formation of N-acylated amino acid derivatives are described. A chiral copper catalyst prepared from Cu(OTf)(2) and a chiral diamine ligand is used. A novel inhibitor of ceramide trafficking, HPA-12, is efficiently synthesized using this reaction.

Asymmetric Induction via an Intramolecular Haloetherification Reaction of Chiral Ene Acetals: A Novel Approach to Optically Active 1,4- and 1,5-Diols.

An asymmetric synthesis of chiral 1,4- and 1,5-diols has been developed from the ene acetals 1a and 1c, prepared from the corresponding aldehydes and chiral C(2)-symmetric diols, involving remote asymmetric induction as a key step. In the first step, treatment of 1 with I(coll)(2)ClO(4) in the presence of an alcohol afforded the macrocyclic acetals (3-5 and 7) in a highly stereoselective manner. Subsequent nucleophilic substitution of iodide followed by a Grignard reaction with complete retention of stereochemistry and a final deprotection of the diphenylethylene or diphenylpropylene unit successfully gave optically active 1,4- and 1,5-diols in good yields.