槲皮素通过G4调控癌基因表达影响肿瘤细胞增殖与凋亡

Quercetin Regulates the Expression of Oncogenes through G-quadruplex and Affects the Proliferation and Apoptosis of Tumor Cells

该研究采用CCK-8法、流式细胞术、免疫印迹法、实时定量PCR和体外结合实验等方法检测了槲皮素对Hep-2和MCF-7细胞生长和凋亡,以及对受G4调控基因表达的影响。结果显示,槲皮素对Hep-2和MCF-7细胞生长具有明显抑制作用,并诱导细胞周期停滞在S期;槲皮素诱导Hep-2和MCF-7细胞凋亡,表现出磷脂酰丝氨酸外翻、细胞膜通透性增加、染色质凝集、caspase活化等凋亡特征;槲皮素显著抑制c-Myc、KRAS、YY1等受G4调控基因的表达;槲皮素促进c-Myc启动子区G4形成序列Pu27形成G4结构并抑制核蛋白与其结合。以上结果表明,槲皮素可能通过促进细胞内G4形成序列形成稳定G4结构并抑制G4解旋酶对其解旋,引起受G4调控的肿瘤相关基因表达降低,最终抑制肿瘤细胞生长并诱导细胞凋亡。

The effect of quercetin on Hep-2 and MCF-7 cells growth and G4-regulated tumor-associated genes expression were investigated by using CCK-8,flow cytometry,immunoblotting,Real-time PCR and in vitro binding assay.The results showed that quercetin significantly inhibited the growth of Hep-2 and MCF-7 cells and induced cell cycle arrest in S phase.Quercetin also induced Hep-2 and MCF-7 cells apoptosis and showed typical apoptotic characteristics such as phosphatidylserine eversion,cell membrane incompletion,chromatin condensation,procaspases activation.Meanwhile,Quercetin significantly inhibited the expression of G4-regulated tumorassociated genes such as c-Myc,KRAS,YY1.Furthermore,Quercetin promoted 27 nucleotide c-Myc promoter G4(G-quadruplex)formation sequence Pu27 to form stable G4 structures and inhibited binding of the nuclear protein to G4-Pu27.These results indicate that quercetin may inhibit the expression of G4-regulated tumor-associated gene through inducing intracellular G4 structure formation and inhibiting the resolving by G4 helicases,which results into tumor cell growth inhibition and cell apoptosis.