牛蒡苷元下调CIP2A抑制三阴性乳腺癌转移的作用及机制研究

Arctigenin-induced Inhibition of Metastasis:the Mechanism of CIP2A Downregulation in Triple-negative Breast Cancer Cells

目的:以往研究表明,一种新型STAT3抑制剂牛蒡苷元(Arctigenin,Atn)在三阴性乳腺癌(triple negative breast cancer,TNBC)中能诱导显著的细胞毒性。本研究将进一步阐述Atn在TNBC细胞中通过下调蛋白磷酸酶2A(PP2A)的癌性抑制因子(cancerous inhibitor of protein phosphatase 2A,CIP2A)触发细胞毒性的新型分子机制。方法:Western blot法、实时荧光定量PCR法检测TNBC系中CIP2A的表达变化;Western blot法检测CIP2A下游分子Akt、ERK、PP2A的表达及活化;PP2A活性测定检测TNBC系中PP2A的活性;侵袭实验、划痕愈合实验检测TNBC的侵袭和迁移能力;siRNA干扰技术转染TNBC细胞系,检测转染后TNBC细胞侵袭能力。结果:Atn显著下调TNBC系CIP2A的表达;CIP2A下调导致PP2A活性增加和Akt的磷酸化水平下降;沉默CIP2A表达增强Atn对TNBC细胞转移行为的抑制作用;Atn通过重激活PP2A抑制TNBC增殖和侵袭。结论:研究发现Atn在TNBC中的新型作用机制,即Atn通过抑制CIP2A表达而活化PP2A,进而抑制Akt活化,从而抑制细胞的转移。

Objective Previous studies show that Aretigenin（ Atn）,a novel STAT3 inhibitor,could induce significant cytotoxicity in triple-negative breast cancer（ TNBC） cells. This study further delineated molecular mechanisms where Atn triggered cytotoxicity in TNBC cells through downregulating cancer inhibiting protein phosphatase 2 A（ CIP2 A）. Methods The expression of CIP2 A in TNBC cells was determined by Western blot analysis and real-time quantitative PCR（ RT-q PCR）;The expression of CIP2 A downstream molecules of Akt、ERK and PP2 A was determined by Western blot analysis; The activity of PP2 A was determined by PP2 A activity assay. Invasion assay and scratch healing assay were used to detect the invasion and migration ability of TNBC cells. SiRNA was used to transfect TNBC cells and then to detect the invasion ability of TNBC cells after transfection. Results Atn significantly down-regulated the expression of CIP2 A in TNBC cells; The dwonregulation of CIP2 A could lead to the increase of activated PP2 A and decrease of phosphorylated Akt in TNBC cells;Silencing CIP2 A enhanced Atn-induced metastasis inhibition; Reactivation of PP2 A was essential for Atn-induced inhibition of proliferation and invasion in TNBC cells. Conclusion The study found the novel molecular mechanism of Atn in TNBC cells. Atn activates PP2 A through inhibiting the expression of CIP2 A,thereby inhibiting Akt activity and cell metastasis.