Positional effect of chemical modifications on short interference RNA activity in mammalian cells.
A systematic study on the effect of 2'-sugar modifications (2'-F (2'-F-2'-deoxy-nucleoside residues), 2'-O-Me (2'-O-methyl-nucleoside residues), and 2'-O-MOE [2'-O-(2-methoxyethyl)]-nucleoside residues) in the antisense and sense strands of short interference RNA (siRNA) was performed in HeLa cells. The study of the antisense strand of siRNAs demonstrated that activity depends on the position of the modifications in the sequence. The siRNAs with modified ribonucleotides at the 5'-end of the antisense strand were less active relative to the 3'-modified ones. The 2'-F sugar was generally well-tolerated on the antisense strand, whereas the 2'-O-Me showed significant shift in activity depending on the position of modification. The 2'-O-MOE modification in the antisense strand resulted in less active siRNA constructs regardless of placement position in the construct. The incorporation of the modified residues, e.g., 2'-O-Me and 2'-O-MOE, in the sense strand of siRNA did not show a strong positional preference. These results may provide guidelines to design effective and stable siRNAs for RNA interference mediated therapeutic applications.
Department of Medicinal Chemistry, Isis Pharmaceuticals, Inc., 2292 Faraday Avenue, Carlsbad, California 92008, USA. tprakash@isisph.com
Thazha P
TP
Prakash
Charles R
CR
Allerson
Prasad
P
Dande
Timothy A
TA
Vickers
Namir
N
Sioufi
Russell
R
Jarres
Brenda F
BF
Baker
Eric E
EE
Swayze
Richard H
RH
Griffey
Balkrishen
B
Bhat
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D018095:Germ-Line Mutation; D006367:HeLa Cells; D006801:Humans; D008322:Mammals; D051059:PTEN Phosphohydrolase; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors / Q000235:genetics*; D034622:RNA Interference / Q000187:drug effects; D016372:RNA, Antisense / Q000737:chemistry / Q000494:pharmacology; D012334:RNA, Neoplasm / Q000187:drug effects; D034741:RNA, Small Interfering / Q000737:chemistry / Q000494:pharmacology*; D025521:Tumor Suppressor Proteins / Q000037:antagonists & inhibitors / Q000235:genetics*
D016372:RNA, Antisense; D012334:RNA, Neoplasm; D034741:RNA, Small Interfering; D025521:Tumor Suppressor Proteins; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human