Interferon-y-Induced Growth Inhibition of Neuroblastoma Cells is Independent of Induction of Nitric Oxide Synthase and Indoleamine 2,3-dioxygenase

Abstract

We investigated a possible involvement of nitric oxide formed by inducible nitric oxide synthase (iNOS) in the signaling cascade leading to growth inhibition and differentiation in the human neuroblastoma cell line SK-NSII. Treatment of SK-N-SH with interferon-γ (IFN-γ) plus interleukin-lß (IL-lß) led to induction of iNOS, growth inhibition and an altered cell shape. However two inhibitors of iNOS were not able to prevent cytokine induced changes. In addition, IFN-γ alone led to growth inhibition in absence of iNOS induction. Inhibition of the induced indoleamine 2,3-dioxygenase (IDO) activity also did not prevent growth inhibition. Our findings show that mechanisms other than NO and IDO can control interferon-y-induced growth inhibition of SK-N-SH cells.

Keywords

• neuroblastoma
• nitric oxide synthase
• indoleamine 2,3-dioxygenase
• interferon-γ
• interleukin-1-ß