Specific inhibition of DNA synthesis by liposomes containing c-myc antisense oligonucleotides.

Human CEM cells were incubated with liposomes containing 15 mer oligodeoxyribonucleotide sequences. When the sequence was complementary to the 5'end of c-myc proto-oncogene mRNA, proliferation of the cells was blocked. Inhibition was not seen for empty lipsomes or lipsomes containing sequences irrelevant to c-myc mRNA. Nor was it seen when non-encapsulated oligonucleotides were incubated with cells, probably because non-encapsulated oligonucleotides are sensitive to nucleases. Oligodeoxyribonucleotides encapsulated in liposomes resists DNAse, and inhibit cell proliferation specifically.