p53诱导型核蛋白2通过活化β-连环蛋白促进乳腺癌细胞的侵袭转移

P53-induced nuclear protein 2 promotes invasion and metastasis of breast cancer cells through activating β-catenin

目的探讨p53诱导型核蛋白2(TP53INP2)对乳腺癌细胞侵袭转移的影响。方法采用Transwell小室筛选出癌侵袭性(MDA-MB-231-M)和非侵袭性(MDA-MB-231-NM)乳腺癌细胞;采用脂质体转染技术将pCMV6-TP53INP2过表达重组载体质粒转染至MDA-MB-231-NM细胞中,归为OE-TP53INP2组;将pRS-sh-TP53INP2干扰载体质粒转染至MDA-MB-231-M细胞中,以此降低TP53INP2,归为sh-TP53INP2组。OE-TP53INP2组细胞中分别转染β-catenin干扰质粒、加入Wnt/β-catenin信号通路抑制剂(XAV-939),归为OE-TP53INP2+si-β-catenin组、OE-TP53INP2+XAV-939组。荧光定量PCR(RT-qPCR)检测MDA-MB-231-NM和MDA-MB-231-M细胞中TP53INP2的表达,Transwell小室法检测MDA-MB-231-NM和MDA-MB-231-M细胞迁移和侵袭,TOPflash/FOPflash实验检测Wnt/β-catenin信号通路的活性,Western blot检测肿瘤蛋白TP53INP2和β-连环蛋白(β-catenin)、上皮标志物上皮型钙黏蛋白(E-cadherin)、间充质标志物神经型钙黏蛋白(N-cadherin)和波形蛋白(vimentin)的表达水平。两组的定量资料比较采用t检验,多组间比较采用单因素方差分析,组间两两比较采用SNK-q检验。结果与非侵袭性MDA-MB-231-NM细胞比较,侵袭性的MDA-MB-231-M细胞中N-cadherin、vimentin和TP53INP2的蛋白表达水平(1.00±0.10比3.15±0.07,1.00±0.07比2.35±0.06,1.00±0.04比2.13±0.07)均升高,E-cadherin的表达水平(1.00±0.06比0.37±0.05)降低,迁移和侵袭细胞数[(43.67±13.25)个比(154.33±15.05)个,(46.67±12.70)个比(162.33±16.50)个]增加,差异有统计学意义(P均<0.001)。与对照组比较,过表达TP53INP2的MDA-MB-231-NM细胞中N-cadherin、vimentin和β-catenin的表达水平(1.00±0.06比1.85±0.07,1.00±0.07比2.14±0.04,1.00±0.11比3.63±0.05)均升高,E-cadherin的表达水平(1.00±0.05比0.43±0.05)降低,迁移和侵袭细胞数[(118.00±12.45)个比(318.67±12.50)个,(81.67±12.87)个比(287.33±11.70)个]均升高,差异有统计学意义(P均<0.001),干扰TP53INP2基因后得到相反的结果。与过表达TP53INP2组比较,过表达TP53INP2同时干扰β-catenin后,细胞中N-cadherin和vimentin的表达水平(2.65±0.07比0.46±0.05,4.23±0.08比2.34±0.04)均降低,E-cadherin的表达水平(0.24±0.04比1.12±0.08)升高,迁移和侵袭细胞数[(170.67±12.05)个比(62.00±8.82)个,(122.67±13.70)个比(76.00±12.82)个]均降低,差异有统计学意义(P均<0.001),过表达TP53INP2同时加Wnt/β-catenin信号通路抑制剂(XAV-939)后得到类似的结果。结论TP53INP2通过激活Wnt/β-catenin信号通路从而调控E-cadherin、N-cadherin、vimentin蛋白的表达,进而促进乳腺癌细胞的侵袭转移。

Objective To investigate the effect of tumor protein P53 inducible nuclear protein 2 (TP53INP2)on invasion and metastasis of breast cancer cells.Methods The invasive(MDA-MB-231-M) and non-invasive (MDA-MB-231-NM) breast cancer cells were screened by Transwell cell method.Then pCMV6-TP53INP2 overexpression recombinant vector plasmid was transfected into MDA-MB-231-NM cells as OE-TP53INP2 group,while pRS-sh-TP53INP2 interference vector plasmid was transfected into MDA-MB-231-M cells as sh-TP53INP2 group.Cells of OE-TP53INP2 group were transfected with β-catenin interference plasmid or Wnt/ β-catenin signaling pathway inhibitor (XAV-939),which were divided into OE-TP53INP2+si-β-catenin group and OE-TP53INP2 + XAV-939 group respectively.Quantitative real-time PCR (RT-qPCR) was used to detect the expression of TP53INP2 in MDA-MB-231-NM and MDA-MB-231-M cells,and Transwell assay was used to detect the migration and invasion ability of MDA-MB-231-NM and MDA-MB-231-M cells,TOPflash/FOPflash experiment was used to detect the activity of Wnt/ β-catenin signaling pathway,and Western blot was used to detect the protein expression levels of TP53INP2,β-catenin,epithelial marker epithelial cadherin (E-cadherin),mesenchyme markers N-cadherin and vimentin.The quantitative data of the two groups were compared through t-test.One-way analysis of variance was used to compare the difference among multiple groups,and SNK-q test was used to compare the difference between groups.Results Compared with non-invasive MDA-MB-231-NM cells,the protein expression levels of N-cadherin,vimentin and TP53INP2 in invasive MDA-MB-231-M cells were increased (1.00±0.10 vs 3.15±0.07,1.00±0.07 vs 2.35±0.06,1.00±0.04 vs 2.13±0.07),but the protein expression level of E-cadherin was decreased (1.00±0.06 vs 0.37±0.05),and the difference was statistically significant (P < 0.001);at the same time,the number of migration and invasion of cells (43.67±13.25 vs 154.33±15.05,46.67±12.70 vs 162.33±16.50) was significantly increased (P < 0.001).Compared with the control group,the protein expression levels of N-cadherin,vimentin and β-catenin were increased in TP53INP2-overexpressed MDA-MB-231-NM cells (1.00±0.06 vs 1.85±0.07,1.00±0.07 vs 2.14±0.04,1.00±0.11 vs 3.63±0.05),whereas the protein expression level of E-cadherin was decreased (0.43±0.05 vs 1.00±0.05),and the difference was statistically significant (P < 0.001);And the number of migration and invasion of cells (118.00±12.45 vs 318.67±12.50,81.67±12.87 vs 287.33±11.70) was significantly increased (P < 0.001).But all the results were opposite after interference with the TP53INP2 gene.Meanwhile,compared with the TP53INP2 overexpression group,when TP53INP2 overexpression simultaneously interfered with β-catenin,the protein expression levels of N-cadherin and vimentin in cells were decreased (2.65±0.07 vs 0.46±0.05,4.23±0.08 vs 2.34±0.04),the protein expression level of E-cadherin was increased (0.24±0.04 vs 1.12±0.08),and the difference was statistically significant (P <0.001);and the number of migration and invasion of cells (62.00±8.82 vs 170.67±12.05,76.00±12.82 vs 122.67±13.70) were significantly decreased (P < 0.001).Interestingly,similar results were obtained after overexpression of TP53INP2 combined with Wnt/β-catenin signaling pathway inhibitor (XAV-939).Conclusion TP53INP2 can regulate E-cadherin,N-cadherin,and vimentin proteins by activating the Wnt/β-catenin signaling pathway,thus promoting the invasion and metastasis of breast cancer cells.