Abstract: Provided is a novel technique for treating cancer using structurally-reinforced S-TuD. Provided are: a composition for the prevention or treatment of tumors, said composition comprising an miRNA inhibitory complex including RNA of analog thereof; and a method for preventing or treating tumors using said composition. The miRNA inhibitory complex preferably includes at least one double-stranded structure and an miRNA-binding sequence. Two strands of the miRNA binding sequence preferably bind individually to two strands on at least one end of the double-stranded structure. According to some of the aspects of the present invention, there is provided a delivery system for delivering such an miRNA inhibitory complex.

Abstract: Disclosed is a double-stranded oligonucleotide decoy including two transcription factor-binding sites, while keeping its size small. The double-stranded oligonucleotide decoy showing binding affinities for two transcription factors includes a first binding site for a first transcription factor and a second binding site for a second transcription factor. A first strand including the sense strand of the first binding site and a second strand including the sense strand of the second binding site are hybridized to form a double strand in which the sense strand of the first binding site and the sense strand of the second binding site are at least partly hybridized.

Abstract: Provided are non-aggregating immunostimulatory oligonucleotides. The present invention also provides a delivery agent for an immunostimulatory-oligonucleotide nucleic acid medicine, said delivery agent including a nucleic acid that contains a phosphorothioated nucleotide. According to another aspect, the present invention further provides an oligonucleotide including a bioactive core, and a nucleic acid that contains a phosphorothioated nucleotide. The present invention yet further provides an immunostimulator including the bioactive core of a type A/D, type B/K, or type C immunostimulatory oligonucleotide.

Abstract: The present invention pertains to a method for synthesizing a ribonucleic acid H-phosphonate monomer, and a method for performing oligonucleotide synthesis in which said monomer is used. The present invention pertains to a method for manufacturing an inexpensively manufacturable H-phosphonate nucleoside derivative in which selective protection is provided to position 2? of a ribonucleoside monomer required in RNA oligonucleotide synthesis. The present invention is characterized in that: hydroxyl groups in position 2? and position 3?, which have slightly different reactivity, are caused to react with an aromatic acyl halide at low temperature to selectively esterify position 2?; and subsequently the hydroxyl group at position 3? in one pot is captured by a phosphityl group to prevent position 2? and position 3? transfer of the acyl group.

Abstract: The present invention pertains to the improvement of a miRNA inhibitor (a synthesized Tough Decoy (S-TuD)). The present invention provides a miRNA inhibitory complex including RNA or an analog thereof, wherein the RNA inhibitory complex includes at least one double-stranded structure and a miRNA binding sequence, each of two strands of the miRNA binding sequence being bound to two strands of at least one end of the double-stranded structure, and the miRNA inhibitory complex further includes at least one crosslinked nucleic acid.

Abstract: Disclosed is a double-stranded oligonucleotide decoy including two transcription factor-binding sites, while keeping its size small. The double-stranded oligonucleotide decoy showing binding affinities for two transcription factors includes a first binding site for a first transcription factor and a second binding site for a second transcription factor. A first strand including the sense strand of the first binding site and a second strand including the sense strand of the second binding site are hybridized to form a double strand in which the sense strand of the first binding site and the sense strand of the second binding site are at least partly hybridized.