环氧化酶-2特异抑制剂SC236对NF-κB活性的阻断作用

A specific COX-2 inhibitor SC236 suppresses NF-κB activation by inhibition of p65 nuclear translocation

目的 探讨环氧化酶 2抑制剂的抗炎和抗肿瘤作用机理。方法 利用NF κB报告基因暂时转染人胃上皮细胞 ,使用环氧化酶 2特异抑制剂SC2 36和PMA共同处理转染的细胞后 ,双重虫荧光素酶系统鉴定基因的活性。用免疫蛋白印迹法检测NF κB亚单位IκB α和p6 5的含量。结果 在人胃上皮细胞AGS和MKN2 8细胞内 ,SC2 36有效地抑制NF κB介导的基因转录。SC2 36的作用比非特异性环氧化酶抑制剂阿斯匹林更强大。SC2 36与阿斯匹林的作用点不同 ,SC2 36对PMA引起的IκB α的磷酸化或降解没有作用 ,SC2 36的作用点在于抑制p6 5亚单位的核易位。结论 环氧化酶 2特异抑制剂的抗炎和抗肿瘤作用可能部分地通过抑制NF κB发挥作用。特异的COX 2抑制剂抑制NF κB活性的作用点不同于非特异的环氧化酶抑制剂。

Objective To study the molecular mechanism of anti-inflammation and anti-tumor by specific COX-2 inhibitor. Methods Two human gastric epithelial cell lines were transiently transfected with NF-κB luciferase reporter plasmid and then treated with a specific COX-2 (Cyclooxygenase) inhibitor SC236 plus PMA. Firefly lucifease activities were measured using the Dual-Luciferase Reporter assay system. Western blot analysis was used to detect phospho-IκB-α, IκB-α, and p65 protein. Results SC236 can effectively suppress nuclear NF-κB mediated gene transcription in two human epithelial gastric cancer cell lines. The potency of SC236 is more than one magnitude higher than that of the non-specific COX inhibitor aspirin. Furthermore, it appears that SC236 acts through different mechanisms. Unlike aspirin, SC236 had no significant effect on PMA-induced IκB-α phosphorylation and degradation. Instead, SC236 works through suppressing the nuclear translocation of the NF-κB subunit, p65 protein. Conclusion Our study suggests an important molecular mechanism by which a COX-2 inhibitor can reduce inflammation and carcinogenesis in gastric epithelial cells.