Abstract: The object of the invention are hammerhead ribozymes directed against the sequence of miR-21 and/or miR-21 precursors, having the ability to specifically cleave miR-21 and/or miR-21 precursors, and wherein they have a catalytic core with a sequence as shown in SEQ ID No 1. The invention also relates to a composition comprising such ribozymes, a therapeutic agent comprising them, a use of such ribozymes and a method of selective cleavage of miR-21 and/or miR-21 precursors employing such ribozymes.

Abstract: A cytosine analog, a method of preparation of a cytosine analog, a DNA methyltransferase 1 inhibitor, and a method for DNA methylation inhibition, is provided for the treatment of diseases associated with deviations from normal DNA methylation. The analog of cytosine may be comprised of 1, N4, 5 and 6-substituted derivatives of cytosine or 5,6-dihydrocytosine, wherein the analog can be described by the chemical formula where R1 is H, R3, R4, 2?-deoxyribosyl, R4 is alkyl or aryl, X is N or C, wherein if X in the analog of formula I is N, then R5 is no substituent and if X in the analog of formula I and/or II is C or if X in the analog of formula II is N, then R5 and R6 are independently alkyl, aryl, hydroxyalkyl, aminoalkyl, hydroxyl, carboxyl, amino group, alkoxyl, aryloxyl, aminoalkyl, aminoaryl, thio group, sulfonyl, sulfinyl or halogen.

Abstract: This invention provides a cytosine analogue, a method of preparation of a cytosine analogue, a DNA rhethyltransferase 1 inhibitor, a method for DNA methylation inhibition, the use of the analogue in the treatment of diseases associated with deviations from normal DNA methylation. More precisely, the invention relates to various derivatives of cytosine, as well as methods of preparation of mono- and multi-1,4,5 and 6-substituted cytosines. In general, the solution relates to providing effective modulators of DNA methylation which could be used in prevention and treatment of diseases associated with DNA methylation level disorders.