Telomerase activity in human leukemic cell lines is inhibited by antisense pentadecadeoxynucleotides targeted against c-myc mRNA.

Telomerase is a ribonucleoprotein complex that is thought to add telomeric repeats to the ends of chromosomes during the replicative phase of the cell cycle. We tested the hypothesis that proto-oncogene c-myc plays an essential role in the regulation of telomerase activity in vertebrate cells by exposing three human leukemic cell lines, HL60, U937, and K562, to 15-mer antisense c-myc oligonucleotides. All the treated cells showed a profound decrease in telomerase activity after c-myc antisense oligomer treatment, whereas cells treated with c-myc sense oligomers showed essentially no change in telomerase activity.