EFFECT OF ANTISENSE MITOGEN-ACTIVATED PROTEIN-KINASE OLIGONUCLEOTIDESON RAT VASCULAR SMOOTH-MUSCLE CELL-PROLIFERATION INDUCED BY EGF IN-VITRO

AIM: To study the preventive effect of down-regulating mitogen-activat ed protein kinase (MAPK) on vascular smooth muscle cell (VSMC) prolife ration. METHODS: Cultured rat VSMC was pretreated with a phosphorothio ate-protected 17-mer antisense MAPK oligodeoxynucleotides (ODN) direct ed against the initiation of translation sites of the p42- and p44-MAP K isoforms by liposomal transfectinon. A 17-mer sense and a random seq uence MAPK ODN were used as control. After liposomal transfection, cel ls were exposed to epidermal growth factor (EGF) 1 nmol . L-1 for 10 m in and then harvested in lysis buffer. MAPK activity was measured by W estern blot and P-81 phosphocellulose filter papers method by using [g amma-P-32]ATP and myelin basic protein as substrate. DNA synthesis was measured by [H-3]thymidine incorporation. RESULTS: Antisense ODN 0.2 mu mol . L-1 reduced EGF-induced MAPK activities by 84 %, and inhibite d VSMC [H-3]thymidine incorporation stimulated by EGF. CONCLUSION: A 1 7-mer MAPK antisense oligonucleotide directed against the initiation o f translation sites of the p44- and p42-MAPK inhibited EGF-stimulated rat VSMC proliferation.