title: Direct in vitro selection of a 2'-O-methyl aptamer to VEGF.
abstract: Aptamers (protein binding oligonucleotides) have potential as a new class of targeted therapeutics. For applications requiring chronic systemic administration, aptamers must achieve high-affinity target binding while simultaneously retaining high in vivo stability, tolerability, and ease of chemical synthesis. To this end, we describe a method for generating aptamers composed entirely of 2'-O-methyl nucleotides (mRmY). We present conditions under which 2'-O-methyl transcripts can be generated directly and use these conditions to select a fully 2'-O-methyl aptamer from a library of 3 x 10(15) unique 2'-O-methyl transcripts. This aptamer, ARC245, is 23 nucleotides in length, binds to vascular endothelial growth factor (VEGF) with a Kd of 2 nM, and inhibits VEGF activity in cellular assays. Notably, ARC245 is so stable that degradation cannot be detected after 96 hr in plasma at 37 degrees C or after autoclaving at 125 degrees C. We believe ARC245 has considerable potential as an antiangiogenesis therapeutic.
authors.affiliation: Archemix Corporation, 1 Hampshire Street, Cambridge, MA 02139, USA.
authors.forename: Paula E
authors.initials: PE
authors.lastname: Burmeister
authors.forename: Scott D
authors.initials: SD
authors.lastname: Lewis
authors.forename: Robert F
authors.initials: RF
authors.lastname: Silva
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Preiss
authors.forename: Lillian R
authors.initials: LR
authors.lastname: Horwitz
authors.forename: P Shannon
authors.initials: PS
authors.lastname: Pendergrast
authors.forename: Thomas G
authors.initials: TG
authors.lastname: McCauley
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Kurz
authors.forename: David M
authors.initials: DM
authors.lastname: Epstein
authors.forename: Charles
authors.initials: C
authors.lastname: Wilson
authors.forename: Anthony D
authors.initials: AD
authors.lastname: Keefe
mesh_terms: D020533:Angiogenesis Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects; D015723:Gene Library; D006801:Humans; D006868:Hydrolysis; D051379:Mice; D009841:Oligonucleotides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D013997:Time Factors; D042442:Vascular Endothelial Growth Factors / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D020533:Angiogenesis Inhibitors; D009841:Oligonucleotides; D042442:Vascular Endothelial Growth Factors; D012321:DNA-Directed RNA Polymerases