ROLE OF CASPASE 8 AS A DETERMINANT IN TRAIL SENSITIVITY OF NEUROBLASTOMA CELL LINES

Abstract

Objective: Resistance of neuroblastoma (NB) cells to tumor necrosis factor-related apoptosis inducing ligand (TRAIL)-mediated apoptosis is thought to be caused by loss of caspase 8 expression. The aim of this study is to investigate if induction of caspase 8 by γ-interferon (IFNγ) renders NB cells sensitive to TRAIL. Methods: Caspase 8 expression was monitored by RT-PCR and Western blot analysis. The effects of IFNγ, TRAIL, IFNγ + TRAIL, and caspase 8 inhibitor + TRAIL on the growth and apoptosis of NB cells were detected with the methods of reduction rate of Alamar blue assay and flow cytometry. The relative caspase 8 activity was measured with colorimetric assay. Results: An increased expression of caspase 8 mRNA and protein was found after treatment with IFNγ. IFNγ in combination with TRAIL decreased proliferation of NB cell line SH-SY5Y cells. The killing effect of TRAIL on NB cells expressing caspase 8 was depressed by caspase 8 inhibitor. The relative caspase 8 activity of NB cells expressing caspase 8 increased with the prolongation of TRAIL action time. Conclusions: TRAIL induced apoptosis in NB cells expressing caspase 8.

Keywords :

• caspase 8
• γ-interferon
• neuroblastoma
• TRAIL

ACKNOWLEDGMENT

This study has been supported by the National Natural Science Foundation of China (39470739), the Ministry of Public Health Research Foundation (20122167), and the Department of Education Foundation in Liaoning Province (05L488).

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.