Elevated expression of Dickkopf-1 increases the sensitivity of human glioma cell line SHG44 to BCNU

Background: Studies have shown that Dickkopf-1 (DKK-1) is involved in tumorigenesis. Recently, we found that 9 out of 12 human glioma cell lines had high level of DKK-1 protein while the other 3 had very low or non-detectable level of DKK-1. The aim of this study is to further examine the function of DKK-1 in glioma cells. Materials and methods: The glioma cell line SHG(44) was obtained from a patient with grade II-III astrocytoma. SHG(44) cells were transfected with a human DKK-1 gene. Transfection of the empty vector pcDNA3.1 was used as negative control. Sensitivity to BCNU was measured by Annexin-V staining. Expression of bax, bcl-2 and caspase-3 of three groups was determined by immunohistochemistry. Results: The tranfection was confirmed by PCR, RT-PCR and Western blot. More apoptotic cell death was observed in the DKK-1 transfected cells, comparing to the non-transfected cells, or cells with empty vector. The expression of bax and caspase-3 of the SHG(44) -DDK-1 increased, whereas the expression of bcl-2 decreased Conclusion: Our results indicated that DKK-1 has a pro-apoptotic function of in glioma.