Control of cyclin D1 expression by antisense oligonucleotides in three ovarian cancer cell lines.

Cyclin D1 is a critical gene controlling the G1 phase progression through the cell cycle. Alterations of cyclin D1 have been demonstrated in a variety of cancer types. We recently reported that increased cyclin D1 expression is associated with malignancy also in ovarian tumors. Three human ovarian cancer cell lines (SW626, OVCAR-3, IGROV1), expressing high levels of this gene, were used to investigate the effects induced by antisense oligonucleotides to cyclin D1 as antiproliferative compounds. Unmodified 18 mer oligomers, targeted to the translation start site of the cyclin D1 cDNA, were able to inhibit the growth of the three cell lines after a single administration of 40 microM. The pattern of cell number reduction ranged between 30 and 55% after 48 h of treatment. Moreover, by RT-PCR and Western blotting, a marked decrease of the cyclin D1 transcript and protein (up to 77% in the SW626) was detected after 24 and 48 h, respectively, from antisense exposure. Conversely, no relevant inhibition was reported in the sense-treated cells. The present data confirm the role of cyclin D1 expression in the proliferative behavior of ovarian cancer and provide additional information that might be helpful in the search for new therapeutic strategies of this disease. Copyright 1998 Academic Press.