Stathmin1磷酸化修饰谱在乳腺癌转移中的作用及分子调控机制

Metastasis is a major cause of death in patients with breast cancer. Stathmin1 (STMN1), an important regulatory protein of microtubule dynamics, has been found to express in various malignant cells and cause uncontrolled cell proliferation. The activity of STMN1 can be modulated by its phosphorylation of multiple Serine residues (Ser16, Ser25, Ser38, and Ser63). By using breast cancer tissue samples from 310 patients, we have very recently demonstrated that the expression levels of phosphorylated STMN1 significantly associates with breast cancer metastasis after radical mastectomy, but the relevant mechanism on STMN1 regulating tumor metastasis keeps unknown..In this study, we propose to screen the different phosphorylation of STMN1 between breast cancer cell lines with high and low metastatic potency, by using Phospho-specific protein microarray analysis. Then, we will confirm the relationship between STMN1 phosphorylation and cancer metastasis through in vitro and in vivo approaches, which will help us to uncover the molecular mechanism on STMN1 phosphorylation regulating breast cancer metastasis. Finally, we will also try to effectively inhibit breast cancer metastasis by targeting STMN1 phosphorylation in a tumor-bearing animal model..Significance and impact of this study can not only help to understand the molecular mechanisms on STMN1 regulating the metastasis of breast cancer, but also to develop novel therapy to reduce the metastasis risk for breast cancer patients.

申请人最近在310例根治性切除乳腺癌患者的组织中发现Stathmin1（STMN1）的表达水平及其磷酸化状态与乳腺癌术后转移密切相关，但其作用及机制尚不清楚。本课题将在前期工作的基础上，继续深入探讨STMN1在乳腺癌转移中的作用及调控机制。首先在细胞模型上，利用蛋白磷酸化芯片分析，对高、低转移潜能乳腺癌细胞株内STMN1蛋白各磷酸化位点（Ser16、Ser25、Ser38和Ser63）进行检测和分析，筛选出与乳腺癌转移密切相关的位点并进行验证。接着应用蛋白质谱技术对筛选出的与乳腺癌转移密切相关的磷酸化位点进行鉴定，继而通过功能研究，明确STMN1磷酸化修饰谱在乳腺癌细胞转移中的作用及调控的分子机制，为将来研究抑制乳腺癌转移的分子靶向治疗提供依据和奠定工作基础。

本研究人通过310例根治性切除乳腺癌患者的组织中发现Stathmin1（STMN1）的表达水平及其磷酸化状态与乳腺癌术后转移密切相关，并在细胞模型上，利用蛋白磷酸化芯片分析，对STMN1蛋白各磷酸化位点（Ser16、Ser25、Ser38和Ser63）进行检测和分析，筛选并验证出STMN1磷酸化修饰谱与乳腺癌细胞转移能力的密切联系。应用蛋白质谱技术筛选出并验证GRP78可与STMN1发现依赖Ser25和Ser38位点磷酸化状态的特异性结合，该结合受上游激酶MEK调控，并影响乳腺癌细胞转移能力，明确了STMN1磷酸化修饰谱在乳腺癌细胞转移中的作用及调控的部分分子机制，构建基于STMN1磷酸化修饰谱和GRP78表达的乳腺癌患者预后模型，为将来研究抑制乳腺癌转移的分子靶向治疗提供依据和奠定工作基础。