[Role of caspase-8 and DR5 in TRAIL-induced apoptosis of neuroblastoma cells].
OBJECTIVE
Tumor necrosis factor related apoptosis inducing ligand (TRAIL) induces cell death in a variety of tumors but not in normal cells. TRAILdouble ended arrow-resistance of most neuroblastoma (NB) cell lines is related to the loss of caspase-8 expression and the expression and distribution of membrane TRAIL-receptors. This study investigated the role of caspase-8 and DR5 in TRAIL-induced apoptosis of NB cell line SKNDZ.


METHODS
The expression of caspase-8 mRNA was detected by RT-PCR. The expression of DR5 protein was detected by Western Blot analysis. The effects of TRAIL, IFNgamma +TRAIL, chemotherapeutic agent (adriamycin or etoposide) + TRAIL, and chemotherapeutic agent +TRAIL+ IFNgamma on the growth and apoptosis of SKNDZ cells were detected by MTT assay and flow cytometry.


RESULTS
caspase-8 was not expressed in SKNDZ cells but IFNgamma treatment resulted in an increase of caspase-8 expression. Expression of DR5 protein was not detected in SKNDZ cells but an increased DR5 protein expression was found after treatment with adriamycin or etoposide. The SKNDZ cells expressing caspase-8 were not sensitive to TRAIL but those SKNDZ cells expressing both caspase-8 and DR5 were sensitive. The early apoptosis rates of the adriamycin /etoposide + IFNgamma+TRAIL groups [(17.9 +/- 3.6)%, (14.8 +/- 3.3)%] were higher than that of the IFNgamma+TRAIL group [(3.9 +/- 1.2)% ](F=26.233, P < 0.01).


CONCLUSIONS
SKNDZ cells expressing both caspase-8 and DR5 restored the TRAIL sensitivity. Caspase-8 and DR5 play a key role in TRAIL-induced apoptosis of NB cells.
Tong
Hai-Xia
HX
Department of Clinical Laboratory, Shengjing Hospital of China Medical University, Shenyang110004, China.
Zhang
Ji-Hong
JH
Ma
Li
L
Lu
Chun-Wei
CW
Zhang
Jin-Hua
JH
D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000494:pharmacology*; D015153:Blotting, Western; D053181:Caspase 8; D020169:Caspases / Q000502:physiology*; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D009447:Neuroblastoma / Q000473:pathology*; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor / Q000502:physiology*; D053221:TNF-Related Apoptosis-Inducing Ligand; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D016159:Tumor Suppressor Protein p53 / Q000502:physiology
D051017:Apoptosis Regulatory Proteins; D008562:Membrane Glycoproteins; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor; D053221:TNF-Related Apoptosis-Inducing Ligand; C505639:TNFRSF10B protein, human; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; D016159:Tumor Suppressor Protein p53; D007371:Interferon-gamma; C505530:CASP8 protein, human; D053181:Caspase 8; D020169:Caspases