乳腺癌是女性最常见的恶性肿瘤，远处转移是90%乳腺癌患者死亡的原因。揭示相关基因在乳腺癌侵袭转移中的作用及其所涉及的信号网络是乳腺癌防治研究的重要课题。基于临床样本表达水平的分析研究提示：SIRT7可能在促进侵袭性肿瘤进展中发挥作用。而具体的分子机制有待进一步探讨。本课题前期的预实验结果显示：1、SIRT7敲低使得乳腺癌细胞迁移能力下降；2、SIRT7与组蛋白去琥珀酰化的调控有关；3、SIRT7在体外能够催化位于组蛋白球形结构域的H3K122、K56、K79三个位点去琥珀酰化。SIRT7是否会通过去琥珀酰化调控位于组蛋白球形结构域中的H3K122和/或其他组蛋白位点修饰从而影响乳腺癌侵袭转移呢？本项目拟利用SILAC标记联合质谱分析鉴定乳腺癌细胞系中SIRT7敲低或过表达后组蛋白修饰谱的改变情况；结合体外、体内酶活性测定确定SIRT7的去琥珀酰化酶活性，确定修饰位点；干扰SIRT7对修饰位

Breast cancer is the most common female malignancies, and metastasis is responsible for over 90% of this cancer-associated mortality. Therefore the most important topic in breast cancer studies is to find the related genes and their signal networks effective in its invasion and metastasis. The studies based on the protein expression level of the clinic samples indicated SIRT7 might play a role in promoting the development of aggressive cancer phenotype. However, the molecular mechanism of this effect is unclear. Our preliminary data showed: 1. SIRT7 knockdown reduced cell migration potential of breast cancer cells; 2. SIRT7 is associated with the regulation of histone succinylation level; 3. In vitro activity assay showed SIRT7 could act as desuccinylase for H3K122, H3K56, H3K79 located in histone globular domain. May SIRT7 regulate the function of H3K122 or other histone sites located in histone globular domain by desuccinylating their modifications, and hence affecting breast cancer invasion and metastasis? Our project is going to utilize SILAC Labeling coupled with mass-spectrometric technique to analyze and identify the landscape of the histone modification changes under the condition of SIRT7 overexpression or knockdown in breast cancer cell lines; combined with the in vivo and in vitro enzyme activity assay of SIRT7 to confirm its desuccinylase activity and map the modification sites; determine the effect of desuccinylase activity of SIRT7 on downstream target gene and breast cancer metastasis. And the present study might provide new clues and theoretical basis for metastatic breast cancer prevention and treatment.

乳腺癌是女性最常见的恶性肿瘤，远处转移是90%乳腺癌患者死亡的原因。揭示相关基因在乳腺癌侵袭转移中的作用及其所涉及的信号网络是乳腺癌防治研究的重要课题。基于临床样本表达水平的分析研究提示：SIRT7可能在促进侵袭性肿瘤进展中发挥作用。而具体的分子机制有待进一步探讨。本课题前期的预实验结果显示：1、SIRT7敲低使得乳腺癌细胞迁移能力下降；2、SIRT7与组蛋白去琥珀酰化的调控有关；3、SIRT7在体外能够催化位于组蛋白球形结构域的H3K122、K56、K79三个位点去琥珀酰化。SIRT7是否会通过去琥珀酰化调控位于组蛋白球形结构域中的H3K122和/或其他组蛋白位点修饰从而影响乳腺癌侵袭转移呢？本课题在近一年的探索中进一步证实了SIRT7敲低和过表达能够影响乳腺癌细胞的迁移；并确认其可以作为组蛋白H3K122位点特异的去琥珀酰化酶催化该位点的去琥珀酰化；用RNAseq寻找并验证了RNAseq的结果，筛选出可能跟转移相关的下游靶基因。