摘要
目的探讨蛋白磷酸酶2A催化性C亚基（PP2Ac）在胰腺癌组织和细胞系中的表达水平，及其对JNK／c-Jun／AP-1信号通路的调控作用和对癌细胞生长的影响。方法采用实时PCR检测PP2Ac表达水平，MTF法检测细胞活力，Western印迹检测蛋白表达水平和磷酸化水平，流式细胞术检测细胞周期，荧光素酶报告基因检测转录活性。结果胰腺癌组织中PP2Ac表达水平显著低于癌旁组织，胰腺癌细胞系中PP2Ac也呈低水平表达，在胰腺癌细胞中过表达PP2Ac可抑制癌细胞生长（转染PP2Acct、PP2Acl348h后可使细胞活力分别下降（24．85±4．85）％、（11．31±4．62）％；72h后细胞活力分别下降（33．89±2．05）％、（16．66±2．81）％；PP2Ac低水平表达可上调JNK／c．Jun／AP-1通路的活性，在胰腺癌细胞中过表达PP2Ac可下调JNK、C-Jun的磷酸化水平并抑制AP-1的转录沿眭；采用抑制剂阻断JNK通路，可阻滞细胞周期于G2／M期，进而抑制细胞生长。结论胰腺癌细胞中PP2Ac呈低表达，通过上调JNK／c-Jun／AP-1通路的活性促进胰腺癌细胞生长。
Objective To investigate the expression of protein phosphatase 2A catalytic subunit （PP2Ac） in pancreatic cancer and the regulation of this gene on JNK/c-Jun/AP-1 pathway and cell growth. Methods Expression of PP2Ac was determined by real-time PCR. Cell viability was tested by MTT. Expression and phosphorylation levels of proteins were detected by Western blotting. Cell cycle was assayed by flow cytometry. Transcription activity was measured by luciferase reporter gene assay. Results Suppressed PP2Ac expression was detected in pancreatic cancer tissues. PP2Ac expression in the pancreatic cancer cell lines was also at a low level. Overexpression of the two isoforms of PP2Ac,PP2Acct and PP2Aα, in. pancreatic cancer cells repressed cell growth. Cell viability decreased （33.89 ± 2. 05 ） % （ t = 28. 607, P〈0.001） and （16.66 ±2. 81）% （t = 10.257, P = 0.001） respectively 72 hours after transfection. Overexpression of PP2Acα and PP2Acl3 down-regulated the phosphorylation levels of JNK and c- Jun,and made the transcriptional activity of AP-1 decrease （47. 18 ＋2. 28） % （t = 11. 230,P 〈0. 001 ） and （30. 89 ± 8.09 ） % （ t = 6. 612, P = 0. 003 ） respectively, indicating the down-regulation of PP2Ac up- regulated the activity of JNK/c-Jun/AP-1 pathway. Blocking the JNK pathway using a selective inhibitor, SP600125, induced G2/M cell cycle arrest and repressed cell proliferation. Cell viability decreased （31.38± 1.33） % （ t = 40. 930,P 〈 0. 001 ） after treatment with JNK inhibitor for 72 hours. Conclusion Suppressed expression of PP2Ac in pancreatic cancer facilitated cell growth through up-regulating the activity of JNK/c- Jun/AP-1 pathway.
出处
《中华医学杂志》
CAS
CSCD
北大核心
2014年第2期86-89,共4页
National Medical Journal of China
基金
国家自然科学基金（81072031、81101867、81272542、81200369）
江苏省自然科学基金（BK2010585）
江苏省中医药局科技项目（1213236）
苏州市科教兴卫青年科技项目（SWKQ1003、SWKQ1011）
