受体型磷酸酶PTPRO通过去磷酸化MET调控谷氨酰胺代谢抑制食管鳞癌干性的机制

受体型蛋白酪氨酸磷酸酶（PTPRO）在肿瘤中的作用和临床价值日显重要。前期发现PTPRO和食管鳞癌干性负相关，Ptpro基因敲除小鼠测序结合细胞实验发现PTPRO缺失促进谷氨酰胺分解代谢，蛋白高通量分析提示PTPRO和参与谷氨酰胺代谢调控的MET激酶互作，细胞实验结合临床标本表明PTPRO调节MET酪氨酸磷酸化。假说：PTPRO由MET介导调控谷氨酰胺分解进而抑制食管鳞癌干性。拟1）在细胞、动物和临床标本水平阐明PTPRO抑制肿瘤干性；2）通过体外、体内和临床标本分析明确谷氨酰胺分解代谢在PTPRO调控肿瘤干性中的重要作用；3）在分子、细胞和动物水平证明MET是PTPRO的底物，并介导PTPRO调控谷氨酰胺代谢和肿瘤干性；4）评价PTPRO-MET-谷氨酰胺代谢通路的临床价值。本课题探索酪氨酸去磷酸化修饰调控谷氨酰胺代谢和肿瘤干性的机制，从代谢重编程和肿瘤干性角度为临床诊治提供基础。

Emerging evidence indicates the importance and clinical value of protein tyrosine phosphatase receptor type O (PTPRO) in cancers. We previously found that PTPRO expression reversely correlated with cancer stemness in esophageal squamous cell carcinoma (ESCC). By RNA sequencing using model of Ptpro knockout mice, we found that Ptpro deficiency promotes glutaminolysis, which is supported by cellular experimental evidence. Bimolecular Fluorescence Complementation (BiFC) revealed that PTPRO may interact with MET kinase, which is involved in regulation of glutaminolysis and cancer stemness. Cellular experiments along with assay of patient specimen showed that PTPRO regulates tyrosine phosphorylation of MET. Based on these preliminary results, we propose a hypothesis that PTPRO suppresses cancer stemness through MET-regulated glutaminolysis in ESCC. We thus set out to conduct the multi-level experiments to prove the hypothesis: 1) illuminating whether PTPRO suppress the cancer stemness of ESCC by using cellular and mouse models, along with assay of patient specimen; 2) validating whether glutaminolysis is required for PTPRO- suppressed cancer stemness in ESCC in vitro and in vivo; 3) verifying whether MET is a substrate of PTPRO and therefore mediates PTPRO-modulated glutaminolysis and cancer stemness in ESCC, by using molecular experiments, cultured cells and mouse models; and 4) evaluating the clinical potentials of PTPRO-MET-glutaminolysis pathways in diagnosis and outcome prediction in human ESCC. With the insight for the understanding the mechanism of how tyrosine dephosphorylation regulates glutamine metabolism and cancer stemness, the study will focus on metabolic reprogramming and cancer stemness, and will provide the basis of cancer theranostics.