Enhanced effect of IFNgamma on the induced apoptosis of neuroblastoma cells by cytotoxic drugs.

The objective of this study was to explore the antitumor effects of cytotoxic drugs combined with IFN gamma on neuroblastoma cell line SH-SY5Y cells. The expression of caspase 8 mRNA and protein was detected with RT-PCR and Western blot analysis. The effects of cytotoxic drugs and IFN gamma combined with cytotoxic drugs on the growth and apoptosis of SH-SY5Y cells were detected with the methods of MTT and flow cytometry. Caspase 8 activity was measured by colorimetric assay. Caspase 8 was undetectable in SH-SY5Y cells with an increased expression of caspase 8 after the treatment of IFN gamma. SH-SY5Y cells were sensitive to Adriamycin relatively but resistant to TNF alpha and TRAIL, while IFN gamma-pretreated SH-SY5Y cells were more sensitive to the cytotoxic drugs with an increase of caspase 8 activity. The authors conclude that IFN gamma can sensitize SH-SY5Y cells to Adriamycin-, TNF alpha-, and TRAIL-induced apoptosis and this may be realized by the upregulation of caspase 8.