Chimeric antisense oligonucleotides and cell transfecting formulations thereof
Chimeric oligonucleotide of the formula 5′-W—X 1 —Y—X 2 —Z-3′, where W represents a 5′-O-alkyl nucleotide, each of X 1 and X 2 represents a block of seven to twelve phosphodiester-linked 2′-O-alkyl ribonucleotides, Y represents a block of five to twelve phosphorothioate-linked deoxyribonucleotides, and Z represents a blocking group effective to block nuclease activity at the 3′ end of the oligonucleotide, are described. These compounds exhibit high resistance to endo- and exonucleases, high sequence specificity, and the ability to activate RNAse H, as evidenced by efficient and long-lasting suppression of target mRNA. The oligonucleotides are preferably transfected into cells in formulations containing a lipid-peptoid conjugate carrier molecule of the formula L-linker-[N(CH 2 CH 2 NH 2 )CH 2 (C═O)—N(CH 2 CH 2 R)CH 2 (C═O)—N(CH 2 CH 2 R)CH 2 (C═O)] 3 —NH 2 , where L is a lipid moiety, including a steroid, and each group R is independently selected from alkyl, aminoalkyl, and aralkyl.
1. A chimeric oligonucleotide having the formula 5′-W—X 1 —Y—X 2 —Z-3′, wherein
W represents a 5′-O-alkyl nucleotide;
each of X 1 and X 2 represents a block of seven phosphodiester linked 2′-O-alkyl ribonucleotides;
Y represents a block of nine to eleven phosphorothioate-linked deoxyribonucleotides; and
Z represents a blocking group effective to block nuclease activity at the 3′ end of the oligonucleotide; and
X 1 —Y—X 2 has a nucleotide sequence selected from the group consisting of SEQ ID NOs: 9 and 10.
2. The oligonucleotide of claim 1 , wherein X 1 —Y—X 2 has the nucleotide sequence SEQ ID NO: 9.
3. The oligonucleotide of claim 1 , wherein X 1 —Y—X 2 has the nucleotide sequence SEQ ID NO: 10.