Synergistic antiproliferative effect of interferons and azidothymidine on HL60 cells.

Proliferation of human leukemia cells, HL60, was synergistically inhibited by a combination of human interferons and azidothymidine in vitro. Combination of interferon-gamma (3000 U/ml) and azidothymidine (30 microM) inhibited cell growth by 76%, whereas interferon-gamma alone suppressed growth by 23% and azidothymidine alone by 33%. Interferon-alpha-2a and interferon-beta also exerted synergistic effects with azidothymidine, but the potentiation was weaker than that by the combination of interferon-gamma and aziodthymidine.