转移是结直肠癌（CRC）患者死亡主要原因,而针对转移性结直肠癌（mCRC）的靶向治疗及靶标研究均遇到瓶颈。我们发现：1）支链α-酮酸脱氢酶激酶(BCKDK)在mCRC中高表达，与患者生存率负相关；2）沉默BCKDK抑制CRC细胞的迁移和侵袭；3）Src在Y246磷酸化BCKDK。故提出“Src磷酸化BCKDK促CRC转移”的假说，拟开展以下实验：1）应用LC-MS/MS确定Src磷酸化BCKDK的位点，并在Src和BCKDK敲除细胞、BCKDK磷酸化位点突变细胞中验证该磷酸化对CRC细胞的迁移和侵袭的影响；2）应用SILAC标记定量蛋白组学技术寻找BCKDK的底物及下游信号通路，并在细胞系中验证；3）制备Y246磷酸化抗体，检测mCRC临床标本中p-BCKDK表达，并探讨其临床意义及应用价值；4）在裸鼠CRC转移模型中验证假说。本研究将揭示Src-BCKDK全新信号通路在mCRC中的作用。

Metastasis is the major cause for the matality of colorectal patients, and meanwhile targeted therapy and biomarker research for metastatic colorectal cancer meet the bottleneck. Our study indicated that: 1）the branched-chain α-keto acid dehydrogenase complex kinase(BCKDK) is highly expressed in metastatic colorectal cancer, and correlated to the overall survival negatively; 2）the migration and invation ability were impaired in shBCKDK cells campared to shMock cells; 3）BCKDK can be phosphorylated by Src in vitro at Y246. Therefore, we proposed that “Src phosphorylates BCKDK and promotes metastasis in CRC”, and plan to perform the following studies: 1）the phosphorylation site of BCKDK by Src will be confirmed by LC-MS/MS, and the impact of BCKDK to the ability of the migration and invation will be tested in Src knockout, site mutated BCKDK, shBCKDK or BCKDK Knockout cell lines; 2）The substrates of BCKDK and downstream signalings pathway will be explored by SILAC Quantitative Phosphorylation Proteomics, and the results of analysis will be confirmed in cell lines related, and and signaling pathway of metastasis will be explored; 3）anti-phospho-Y246 antibody will be prepared and purified, and the expression of phospho-BCKDK will be tested in a big volume of clinic samples, the clinic value of BCKDK will be determined combined with the clinical data; 4）the metastasis nude mouse or BCKDK knockout mouse model will be performed to test our hypothesis. The study will explore the role of Src-BCKDK signal pathway in metastatic colorectal cancer.