Department of Pathology, First Affiliated Hospital of Zhengzhou University, Zhengzhou   450052, Henan Province, China

Dongling Gao, Principal scientific officer, Department of Pathology, First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, Henan Province, China Supported by: Key Program of Tenth Five-Year Plan and the 211 Key Subject Construction Foundation, No. 2002-2* Gao DL, Zhao ZW, Zhang HX, Zhang L, Chen KS, Zhang YH. Expression of tumor necrosis factor related apoptosis inducing ligand  receptor in glioblastoma. Neural Regen Res 2008;3(5):538-41

Abstract

BACKGROUND: Receptors for tumor necrosis factor related apoptosis inducing ligand (TRAIL) include death receptor 4, death receptor 5, decoy receptor 1, and decoy receptor 2. Activation of death receptor 4 and 5 selectively kills tumor cells.

OBJECTIVE: To detect TRAIL receptor expression in glioblastoma by immunohistochemistry and RT-PCR, and to compare this expression to that in normal brain tissue.

DESIGN: Observational analysis.

SETTING: Department of Pathology, the First Affiliated Hospital of Zhengzhou University; Henan Tumor Pathology Key Laboratory.

PARTICIPANTS: Twenty-five patients (17 males and 8 females) who received glioblastoma resection were selected from the Fifth Affiliated Hospital of Zhengzhou University, between September 2003 to June 2004. All glioblastoma samples were diagnosed pathologically. Twenty patients (12 males and 8 females) with craniocerebral injury who received normal brain tissue resection were selected in the same time period. There were no significant differences in sex and age between glioblastoma patients or between craniocerebral injury patients (P > 0.05). All patients and appropriate relatives provided informed consent, and this study was approved by the local research ethics committee.

METHODS: Polyclonal antibody against TRAIL receptors and an immunohistochemical kit (batch number: 200502) were purchased from Boster Company, Wuhan. Immunohistochemistry: Expression of death receptor 4, death receptor 5, decoy receptor 1, and decoy receptor 2 were observed in both glioblastoma and normal brain tissue. The experiment was performed according to the kit instructions, and positive staining was brown-yellow. Assessment: There were no positive signals (–); weakly positive signals, positive cells < 25% (+); weakly positive signals, positive cells 25%–50% (++); strongly positive signals, positive cells 50%–75% (+++); strongly positive signals, positive cells > 75% (++++). Evaluation: Expression levels of TRAIL receptors were estimated in both normal brain tissue and glioblastoma. Expression of decoy receptor 1 and decoy receptor 2 mRNA in glioblastoma were detected by reverse transcription polymerase chain reaction, and expression of decoy receptor in glioblastoma was estimated.

MAIN OUTCOME MEASURES: Comparison of death receptor and decoy receptor protein expression between glioblastoma and normal brain tissue; decoy receptor mRNA expression in glioblastoma.

RESULTS: Death receptor protein expression was strongly positive (+++) in glioblastoma, while it was weakly positive (+, ++) in normal brain tissue. Therefore, expression rate of death receptor protein in the glioblastoma was significantly higher than that in the normal brain tissue (χ² = 18.48, 23.03, P < 0.01). Decoy receptor protein expression in the glioblastoma was significantly lower than that in the normal brain tissue (χ² = 6.65, 18.76, P < 0.01). The level of decoy receptor mRNA expression in glioblastoma was significantly higher than those of protein expression  (χ² = 9.82, 10.09, P < 0.01).

CONCLUSION: High expression of death receptor and low expression of decoy receptor are frequently observed in glioblastoma, suggesting that TRAIL receptor genes show an anti-tumor and expressive response during the initiation and development of the tumor. There are significant differences in decoy receptor expression between normal brain tissue and glioblastoma, suggesting that the restricted expression of decoy receptor in glioblastoma is regulated at the post-transcriptional level.

Key Words: glioblastoma; tumor necrosis factor related apoptosis inducing ligand; apoptosis; immunohistochemistry; reverse transcription polymerase chain reaction

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