DEC1激活破骨细胞功能促进乳腺癌骨转移及在药物治疗骨转移中的作用及机制

申请者基于DEC1在乳腺癌组织表达高于癌旁组织；DEC1增加乳腺癌细胞的迁移和侵袭力；过度表达DEC1增加乳腺癌细胞Runx2、RANKL、NFATc-1和CTSK等破骨相关蛋白，而敲减DEC1则降低上述指标；过度表达DEC1增加乳腺癌细胞的IL-1β、IL-6、TNFα mRNA水平、增加成骨细胞Runx2的表达；DEC1还能增加破骨细胞功能的基础上，提出DEC1通过激活破骨细胞功能促进乳腺癌骨转移的假设。本项目拟用裸鼠心脏注射（WT-、OE-、KD-DEC1）乳腺癌细胞、小鼠（DEC1+/+、DEC1-/-）胫骨原位注射4T1细胞制备乳腺癌骨转移模型，乳腺癌细胞与股骨组织及乳腺癌细胞与成骨细胞共培养等模型，应用分子克隆技术、分子生物学等方法，研究并阐明DEC1通过激活破骨细胞功能促进乳腺癌骨转移的作用及分子机制，为寻找乳腺癌骨转移临床生物标志物及研发DEC1拮抗剂治疗骨转移提供依据。

Based on the following data we had gotten before: (1) DEC1 expression in breast cancer tissue increases compared with that in the adjacent normal tissue of patients. (2) DEC1 increases the migration and invasion of breast cancer cells(MDA-MB-231, MCF7). (3) The overexpression of DEC1 increases the expression of proteins associated with osteoclast differentiation such as Runx2, RANKL, NFATc-1 and CTSK in the MDA-MB-231 cells, whereas the knockdown of DEC1 decreases those proteins. （4）The overexpression of DEC1 increases cytokine mRNA levels such as IL-1β, IL-6 and TNFα in the MDA-MB-231 cells. (5) The overexpression of DEC1 increases Runx2 in the MC3T3-E1 cells. (6) DEC1 increases the osteoclast differentiation and function. Therefore, it is hypothesized that DEC1 activates the osteoclast differentiation and function, which promotes breast cancer bone metastasis. Preparation of breast cancer bone metastasis models with intracardiac injection of MDA-MB-231(WT-,OE- and KD-DEC1) in null mice, or intratibial injection of 4T1 cells in the WT and KO (DEC1+/+, DEC1-/-) mice, co-culturing MDA-MB-231 with bone tissue or MC3T3-E1 cells, and preparation of cytokines (IL-1β, IL-6, TNFα and PTHrP)-induced models with the primary cultured bone marrow-mesenchymal stem cells(BMSCs) or bone marrow mononuclear cells(BMMs), we will, on the systemic and the cellular levels, investigate the roles and mechanisms of DEC1 on promoting the breast cancer bone metastasis (BM) through the activation of the function of osteoclast, through using molecular cloning technology and modern molecular biology methods. This study provides a academic evidence on finding the clinical biomarkers of breast cancer bone metastasis and developing the DEC1 antagonists for treatment of bone metastasis.