The Expression Of DKK1 In Gliomas And Its Correlation With Malignancy Of The Tumor

Objective:To detect the expressions of DKK1 protein and gene in glioma cell lines,tumor tissues ,serum and CSF. To study its correlation with malignancy of glioma,exploring a new tumor marker.Methods:Cell lines: The 14 human glioma cell lines was used in this study included twelve glioblastoma cell lines(U251,SF767,SF295,T98G,MGR1,MGR2,MGR3,SKMG1,SKMG4,UWR7,UW28,SKI-N2),one medulloblastoma cell line (D341), one low-grade glioma cell line (SHG44).Human astrocytes was uesd as a normal control.Cell culture supernatant and cell lysate levels of DKK1 were measured by ELISA,while DKK1 gene levels in these cells were detected by semiquantitative reverse transcription-PCR.Tumor tissues: Formalin-fixed primary gliomas and normal brain tissue samples were used for immunocytochemical analysis to detect the level of DKK1 protein.Frozen primary gliomas and normal brain tissue samples were used for RT-PCR to detect the level of DKK1 gene .Serum and CSF samples: Serum and CSF samples were obtained from patients with glioma ,other benign tumors in CNS and healthy control individuals. Serum and CSF samples levels of DKK1 were measured by ELISA.Results:1. DKK1 protein expression in cell culture supernatant and cell lysate detected by ELISAâ‘ We confirmed that DKK1 were overexpressed in cell culture supernatant and cell lysate of 12 glioblastoma cell lines,while absent in D341,SHG44 and human astrocytes. There was a significant difference between the expression levels of DKK1 in high grade glioma cell lines and low grade cell line.â‘¡In the group of high grade glioma cell lines, there was a significant difference between the expression levels of DKK1 in cell culture supernatant and cell lysate.2. DKK1 protein expression in serum and CSF samples detected by ELISAâ‘ The expression level of DKK1 protein in CSF of glioma patients were remarkbly more than those in patients with benign tumors in CNS and healthy control individuals. There was a significant difference between the expression levels of DKK1 in high and low grades glioma.No significant difference was found between patients with benign tumors in CNS and healthy control individuals.â‘¡There were no significant difference of the expression levels of DKK1 among glioma patients, patients with benign tumors in CNS and healthy control individuals.3.DKK1 protein expression in formalin-fixed tissues detected by immunocytochemical.â‘ The positive expression rate of DKK1 protein in glioma tissues was 91.5 persents,while 18.1 persents in normal brain tissues. There was a significant difference between the expression levels of DKK1 in glioma and normal brain tissues.â‘¡There was a positive correlation between the expression levels of DKK1 and the histological grading of tumors.4.DKK1 gene expression detected by RT-PCRâ‘ RT-PCR showed that DKK1 transcripts were over-expressed in glioblastoma cell lines, which were absent in D341,SHG44 and human astrocytes.â‘¡There was a significant difference between the expression levels of DKK1 gene in glioma and normal brain tissues.Conclusions:1. DKK1 levels were significantly higher in glioma patients than in healthy controls.2. There was a positive correlation between the expression levels of DKK1 and the histological grading of glioma.3. The expression level of DKK1 protein in CSF of glioma patients were remarkbly more than those in patients with benign tumors in CNS and healthy control individuals. DKK1 should be useful as a novel diagnostic/prognostic biomarker in clinic and probably as a therapeutic target for glioma.