Inhibition of the proliferative effect of transforming growth factor‐α by c‐myc antisense DNA in human ovarian cancer cells

In search of critical genes associated with the mechanism of transforming growth factor-alpha (TGF alpha) action in human ovarian cancer, it was found that TGF alpha stimulates c-myc gene expression in human ovarian NIH:OVCAR-3. The role of c-myc in TGF alpha-stimulated growth of NIH:OVCAR-3 cells was examined by the use of the synthetic antisense-myc phosphorothioate oligonucleotide (OPT). Prior exposure of NIH:OVCAR-3 cells to an antisense-myc OPT inhibited TGF alpha-stimulated cell growth and DNA synthesis in a dose-dependent and sequence-specific manner over 4 days. c-Myc protein expression was down-regulated in the antisense-myc treated cells. These results demonstrate both the specific and durable effects of the antisense-myc OPT. Furthermore, the results suggest a role for c-myc in TGF alpha-stimulated cell proliferation.