Antisense oligodeoxynucleoside methylphosphonate inhibition of mouse c-myc p65 protein expression in E mu-c-myc...

In transgenic mice bearing a murine immunoglobulin enhancer/c-myc fusion transgene (E mu-myc), it was found that methylphosphonates do not induce acute toxicity following intravenous administration of a 300 nmol dose. In addition, recovery of methylphosphonates from the blood plasma of treated mice indicated that the oligomers remained intact up to 3 hours, while their concentrations decreased rapidly for the first hour, then slowly decreased over the next two hours. Finally, methylphosphonate oligomers targeted against c-myc mRNA inhibited production of c-myc p65 protein in peripheral and splenic lymphocytes, relative to a scrambled sequence oligomer, 4 hours after injection of a 300 nmol dose, as indicated by immunofluorescence of fixed cells stained with an anti-c-myc antiserum.