磷酸化在酪氨酸 317 和 508 位点对于 PIK3CA/p110α 促进结直肠癌的肿瘤形成至关重要。
Phosphorylation at tyrosine 317 and 508 are crucial for PIK3CA/p110α to promote CRC tumorigenesis.
发表日期：2023 Sep 09
作者：
Ting Wang, Longci Sun, Chengkun Chen, Yingchao Zhang, Baoyu He, Yanhua Zhang, Zhenghe Wang, Hanbing Xue, Yujun Hao
来源：
Cellular & Molecular Immunology
摘要：
PI3K/AKT信号通路在人类肿瘤发生中起重要作用。蛋白质磷酸化对该通路的信号传导至关重要。PIK3CA基因编码PI3K复合物的催化亚单位p110α，是人类肿瘤中最常发生突变的癌基因之一。然而，PIK3CA/p110α的磷酸化位点及其在肿瘤发生中的机制目前尚不清楚。通过质谱法鉴定出PIK3CA/p110α的酪氨酸磷酸化位点。应用Crispr/CAS9策略生成Y317F和Y508F突变体细胞克隆。通过体外和体内评估细胞的生长和转移能力。应用磷酸蛋白质组学分析和Western blot技术证明PIK3CA/p110α酪氨酸磷酸化的下游信号通路。应用体外激酶活性测定鉴定PIK3CA/p110α酪氨酸磷酸化的激酶。PIK3CA/p110α的酪氨酸磷酸化受EGF、HGF和PDGF等生长因子的刺激。在PIK3CA/p110α上鉴定到两个酪氨酸残基Y317和Y508。Y317或Y508的磷酸化对结直肠癌的发生至关重要。p110α的Y317的突变通过Src-MLC2途径减少肿瘤细胞的增殖、迁移和侵袭能力，而p110α的Y508突变则影响AKT信号通路。此外，Src与p110α相互作用并磷酸化p110α。PIK3CA/p110α在Y317和Y508的磷酸化通过两个独立途径在结直肠癌的发生中起重要作用。© 2023. Society of Chinese Bioscientists in America (SCBA).
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.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.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.PIK3CA/p110α phosphorylation at Y317 and Y508 play important role in tumorigenesis of colorectal cancer through two independent pathways.© 2023. Society of Chinese Bioscientists in America (SCBA).