酪氨酸317和508位点的磷酸化对于PIK3CA/p110α促进结直肠癌肿瘤发生至关重要。

Phosphorylation at tyrosine 317 and 508 are crucial for PIK3CA/p110α to promote CRC tumorigenesis.

作者信息

Wang Ting, Sun Longci, Chen Chengkun, Zhang Yingchao, He Baoyu, Zhang Yanhua, Wang Zhenghe, Xue Hanbing, Hao Yujun

机构信息

State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200032, China.

Department of Gastrointestinal Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China.

出版信息

Cell Biosci. 2023 Sep 9;13(1):164. doi: 10.1186/s13578-023-01102-7.

DOI:10.1186/s13578-023-01102-7

PMID:37689735

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10493024/

Abstract

BACKGROUND

PI3K/AKT signaling pathway plays important role in tumorigenesis of human cancer. Protein phosphorylation is crucial for signaling transduction of this pathway. PIK3CA, encoding the catalytic subunit p110α of PI3K complex, is one of the most frequently mutated oncogenes in human cancers. However, phosphorylation sites of PIK3CA/p110α and their underlying mechanism in tumorigenesis are largely unknown.

METHODS

Tyrosine phosphorylation sites of PIK3CA/p110α are identified with Mass-Spectrum. Crispr/CAS9 strategy is applied to generate Y317F and Y508F mutant knock-in cell clones. The growth and metastasis abilities of cells are evaluated in vitro and in vivo. Phospho-proteomics analysis and Western blots are used to demonstrate downstream signaling pathways of PIK3CA/p110α tyrosine phosphorylation. In vitro kinase assay is applied to identify the kinase of PIK3CA/p110α tyrosine phosphorylation.

RESULTS

Tyrosine phosphorylation of PIK3CA/p110α is stimulated by growth factors such as EGF, HGF and PDGF. Two tyrosine residues, Y317 and Y508, are identified on PIK3CA/p110α. Either Y317 or Y508 phosphorylation is essential for tumorigenesis of CRC. Mutation at Y317 of p110α reduces the proliferation, migration, and invasion of cancer cells through Src-MLC2 pathway, while mutation at Y508 of p110α impairs AKT signaling. Moreover, Src interacts with and phosphorylates p110α.

CONCLUSIONS

PIK3CA/p110α phosphorylation at Y317 and Y508 play important role in tumorigenesis of colorectal cancer through two independent pathways.

摘要

背景

PI3K/AKT信号通路在人类癌症的肿瘤发生中起重要作用。蛋白质磷酸化对于该通路的信号转导至关重要。PIK3CA编码PI3K复合物的催化亚基p110α，是人类癌症中最常发生突变的致癌基因之一。然而，PIK3CA/p110α的磷酸化位点及其在肿瘤发生中的潜在机制在很大程度上尚不清楚。

方法

用质谱法鉴定PIK3CA/p110α的酪氨酸磷酸化位点。应用Crispr/CAS9策略生成Y317F和Y508F突变敲入细胞克隆。在体外和体内评估细胞的生长和转移能力。磷酸化蛋白质组学分析和蛋白质免疫印迹法用于证明PIK3CA/p110α酪氨酸磷酸化的下游信号通路。应用体外激酶分析来鉴定PIK3CA/p110α酪氨酸磷酸化的激酶。

结果

PIK3CA/p110α的酪氨酸磷酸化受表皮生长因子（EGF）、肝细胞生长因子（HGF）和血小板衍生生长因子（PDGF）等生长因子的刺激。在PIK3CA/p110α上鉴定出两个酪氨酸残基Y317和Y508。Y317或Y508的磷酸化对于结直肠癌的肿瘤发生至关重要。p110α的Y317突变通过Src-MLC2途径降低癌细胞的增殖、迁移和侵袭，而p110α的Y508突变则损害AKT信号传导。此外，Src与p110α相互作用并使其磷酸化。