The Regulation And Mechanism Of DNA-binding Protein TF15 On The Growth Characteristics Of Breast Cancer Stem Cells

Objective:Breast cancer is a common malignant tumors among female. Though about 50% of it can be cured by the combination of operation and chemoradiotherapy or biological treatment, there are still some patients suffer from recurrence and metastasis within 5 years which eventually leads to treatment failure. As a result, recurrence and metastasis become the important factors of death in patients with breast cancer. Studies have confirmed that there is a small number of cells which have properties of self-renewal,multi-directional differentiation and high tumorigenesis in breast cancer cells. Those cells are often called breast cancer stem cells ( BCSCs ). BCSCs can intervene many procedures including development, progression, invasion or even clinical therapeutic effect. TF15 is a kind of homeodomain gene which intervenes the earlier stage of embryonic development and affect the formation of embryonic stem cells and neurogenesis. But the correlation between TF15 gene and the breast cancer is still unknown, so we begin to analyze the influence of TF15 on growth and invasion of BCSCs.We also hope our work can provide a new line for clinical treatment of breast cancer.Methods:1. Detecting the effect of TF15 on the quantity and growth characteristics of BCSCs with Flow cytometry, suspension culture and tumor formation in nude mice experiment. 2. Using RT-PCR and immunofluorescent staining analyze the connection of TF15 and epithelial mesenchymal transition ( EMT ). 3. Screening transcription factors involving the the interaction between TF15 and BCSCs.Results:1. Establish breast cancer cell lines which expresses TF15 gene stably. After overexpressing TF15, the number of BCSCs is increasing obviously and the ability of generating microsphere is enforced heavily. In mice, TF15 can increase the tumorigenicity of breast cancer cells. 2. Both in transcriptional level and protein level, TF15 can lead to E-cadherin's lower exxpression and higher expression of N-cadherin and Vinmintin, but it doesn't affect the promoter activity. 3. The results of Western blot and RT-PCR confirmed that TF15's impacts on BCSCs may relate to Notch-1 and C-myc.Conclusion:Overexpression of TF15 may increase the number of BCSCs and strengthen tumorigenic ability through Notch-1 and C-myc.