SEQUENCE-SPECIFIC INHIBITION OF HUMAN TYPE-II PHOSPHOLIPASE A(2) ENZYME-ACTIVITY BY PHOSPHOROTHIOATE OLIGONUCLEOTIDES

Phosphorothioate oligonucleotides were identified which directly inhibited human type II phospholipase A(2) (PLA(2)) enzyme activity in a sequence specific manner. The minimum pharmacophore common to all oligonucleotides which inhibited FLAP enzyme activity consisted of two sets of three or more consecutive guanosine residues in a row. These oligonucleotides appear to form G quartets resulting in the formation of oligonucleotide aggregates. Additionally, a phosphorothioate backbone was required to be effective inhibitors of type II PLA(2). The activity of one oligodeoxynucleotide, IP 3196 (6'-GGGTGGGTATAGAAGGGCTCC-3') has been characterized in more detail. IP 3196 inhibited PLA(2) enzyme activity when the substrate was presented in the form of a phospholipid bilayer but not when presented in the form of a mixed micelle with anionic detergents. Human type II PLA, was 50-fold more sensitive to inhibition by IP 3196 than venom and pancreatic type I enzymes. These data demonstrate that phosphorothioate oligonucleotides can specifically inhibit human type II PLA(2) enzyme activity in a sequence specific manner.