[Effect of death decoy receptor 3 on prognosis of breast cancer and function of breast cancer cells in vitro]

Objective: To study the effect of death decoy receptor 3 on the prognosis of breast cancer and the invasive function of breast cancer cells in vitro. Methods: Expression of DcR3 were assessed qualitatively by Q-PCR to analyze the correlation in 115 mammary tissue samples with a 10-year median follow-up. The expression of DcR3 was examined in MCF7 and MDA-MB-231 cell lines using immunocytochemical staining and RT-PCR. DcR3 knock-down cell sub-lines were constructed. The effects of reduced DcR3 expression were observed by establishing invasion and migration models. Results: Patients were divided into the good prognosis group (n=81) and the poor prognosis group (n=26). The expression of DcR3 in the poor prognosis group (133 350+49 646 copies/50 ng RNA)was significantly higher than that in the good prognosis group (5 393+1 428 copies/50 ng RNA, P=0.020). DcR3 transcripts were found to be increased significantly in grade 2 cancers compared to well differentiated grade 1(82 844±34 068 copies/50 ng RNA, n=39,) vs (5 371±3 500 copies/50 ng RNA, n=20, P=0.029).The DcR3 gene of MCF7 cell line and MDA-MB-231 cell line were successfully knocked out and verified that DcR3 knockout. And the invasion and migration of MCF7 cells were inhibited (P=0.009, P=0.001). However, no significant difference was found in these two aspects of the MDA-MB-231 cell line (P=0.475, P=0.102). Conclusion: DcR3 promotes the capacity of invasion of breast cancer cells and plays an important role in the metastasis of breast cancer. DcR3 detection is helpful to the judgment about prognosis of breast cancer.