花生四烯酸通过COX-2酶代谢氧化失活PTEN促进结直肠癌生长

Arachidonic Acid Promotes the Growth of Colorectal Cancer by Oxidative Inactivation of PTEN Through COX-2 Enzyme Metabolism

目的:本研究旨在阐明过表达COX-2的结直肠癌中花生四烯酸代谢与PTEN及其下游通路的相互关系。方法:利用过表达COX-2结直肠癌细胞系CT26和ApcMin/+小鼠腺瘤模型,联合花生四烯酸、COX-2抑制剂NS-398和COX-2基因敲除的干预,采用流式细胞仪检测细胞凋亡、细胞周期及活性氧的产生;Transwell和克隆形成试验观察细胞的迁移和增殖能力;Western blot和免疫组化检测PTEN及其下游相关蛋白的表达。结果:花生四烯酸通过COX-2酶代谢产生活性氧并失活PTEN抑癌基因表达,从而激活PI3K-AKT蛋白促进CT26结直肠癌细胞迁移和增殖,抑制细胞凋亡;而COX-2抑制剂NS-398阻止了花生四烯酸在CT26结直肠癌细胞中的恶性生物学行为。同时,在COX-2基因敲除ApcMin/+小鼠腺瘤组织中,减弱了氧化应激水平,增加了PTEN表达,抑制了PI3K-AKT磷酸化,进一步抑制腺瘤生长,提高小鼠生存率。结论:花生四烯酸通过COX-2酶代谢产生活性氧下调PTEN活性,并激活PI3K-AKT促进结直肠癌生长;COX-2抑制剂可间接促进PTEN表达,抑制结直肠癌生长,能够作为CRC的潜在治疗靶点。

Objective: This study aimed to clarify the relationship between arachidonic acid metabolism, PTEN and its downstream pathways in COX-2 overexpressing colorectal cancer. Methods: By using an over-expressed COX-2 of colorectal cancer cell line CT26 and ApcMin/+mouse adenoma model, combined with arachidonic acid, COX-2 inhibitor NS-398 treatment and COX-2 gene knockout intervention, flow cytometry was used to detect apoptosis, cell cycle and the generation of reactive oxygen species;transwell and colony formation assay were used to test the migration and proliferation capacity of cells;western blot and immunohistochemistry were used to detect the expression of PTEN and its downstream related proteins. Results: In CT26 colorectal cancer,arachidonic acid is metabolized by COX-2 enzymes to produce reactive oxygen species and inactivate PTEN, thereby activating PI3 K-AKT protein to promote cell migration and proliferation, and inhibit apoptosis;while COX-2 inhibitor NS-398 prevents the malignant biological behavior of arachidonic acid in CT26 colorectal cancer cells. Moreover, in the COX-2 gene knockout ApcMin/+mouse adenomas tissue, NS-398 treatment reduced the level of oxidative stress, increased the expression of PTEN, inhibited the phosphorylation of PI3 K-AKT, further inhibited the growth of adenomas, and improved the survival rate of mice. Conclusion: Arachidonic acid could produce active oxygen to down-regulate PTEN activity and activate PI3 K-AKT to promote colorectal cancer growth through COX-2 enzyme;COX-2 inhibitors can indirectly promote PTEN expression and inhibit colorectal cancer growth, and can act as a potential target for CRC treatment.