Differential induction of indoleamine-2,3-dioxygenase (IDO) by interferon-gamma in human gynecologic cancer cells.

Induction of indoleamine-2,3-dioxygenase (IDO) by interferon-gamma (IFN-gamma) is thought to be one mechanism underlying IFN-gamma's antineoplastic properties. Since clinical trials with IFN-gamma have yielded variable efficacy in treating cancers of gynecological origin, we tested the effects of IFN-gamma on cell growth and IDO activity in cell lines from seven gynecologic and five breast cancers. At a dose of 250 IU/ml, IFN-gamma suppressed cell growth and induced IDO activity in one cervical (C41), one vulva (A431), one breast (HS578T) and two ovarian (OVCAR-3, CAOV-3) cancer cell lines. Differing inhibition of cell growth, but with no induction of IDO activity, was found with IFN-gamma treatment of the other cell lines.