中文摘要：

趋化因子CCL21（CC-chemokine ligand 21,CCL21）与其受体CCR7（CC-chemokine receptor7,CCR7）的结合可以促进肿瘤的侵袭和转移.本研究旨在构建人趋化因子CCL21的截短突变体,竞争性抑制CCL21与CCR7的结合,从而抑制肿瘤的转移.本研究构建了CCL21的10个截短突变体,通过Transewell细胞迁移实验,筛选出具有良好趋化抑制活性的C端截短体mCCL21-a（1-57）.Western印迹和体外细胞迁移实验表明,经原核表达的mCCL21-a（1-57）多肽能够阻断CCL21介导的细胞外信号调节激酶（extracellular signal-regulated kinase,ERK）的磷酸化,抑制CCL21对人结肠癌细胞SW480的趋化作用.本研究成功制备了趋化因子CCL21的拮抗性多肽mCCL21-a（1-57）,并初步鉴定其体外生物活性,为下一步体内功能研究奠定了良好基础.

英文摘要：

The migration of tumor cells into the lymph nodes is an important aspect of cancer.CC-chemokine receptor 7（CCR7） has been shown to play an important role in tumor cell migration and lymph node metastasis.In our study,ten truncated mutants of CC-chemokine ligand 21（CCL21） were constructed.mCCL21-a（1-57）,a novel C-terminal deletion mutant of human CCL21,exhibited favorable antagonistic effect on CCL21-stimulated chemotaxis of human colorectal carcinoma cell line SW480 in the pre-screening assays.Prokaryotic expression system is used to express this mutant so as to further investigate its biological activity in vitro and in vivo.In the chemotaxis assays,SW480 cells exhibited CCL21-induced migration,but it was significantly suppressed by mCCL21-a（1-57） in a dose-dependent manner.Further observation illustrated that mCCL21-a（1-57） inhibits the activation of extracellular signal-regulated kinase（ERK） induced by CCL21.In summary,the C-terminal of CCL21 is essential for CCL21 mediated cell migration and activation of ERK and the mCCL21-a（1-57） was an effective antagonist of CCL21 in vitro.