Sheng S H, Zhao C M, Sun G G
Department of Breast Surgery, Tangshan Workers Hospital, Tangshan, 063000, China.
Tumour Biol. 2014 Apr;35(4):3317-26. doi: 10.1007/s13277-013-1437-0. Epub 2013 Nov 24.
This study aimed to analyze the expression, clinical significance of B cell translocation gene 1 (BTG1) in breast carcinoma and the biological effect in its cell line by BTG1 overexpression. Immunohistochemistry and western blot were used to analyze BTG1 protein expression in 72 cases of breast cancer and 36 cases of normal tissues to study the relationship between BTG1 expression and clinical factors. Recombinant lentiviral vector was constructed to over-express EMP-1 and then infect breast cancer MCF-7 cell line. Quantitative real-time RT-PCR (qRT-PCR) and western blot were used to detect the mRNA level and protein of BTG1. MTT assay, cell apoptosis, cell cycles, migration and invasion assays were also conducted as to the influence of the upregulated expression of BTG1 that might be found on MCF-7 cells biological effect. The level of BTG1 protein expression was found to be significantly lower in breast cancer tissue than normal tissues (P < 0.05). Decreased expression of BTG1 was significantly correlated with tumor invasion, lymph node metastasis, clinic stage and histological grade of patients with breast cancer (P < 0.05). Meanwhile, loss of BTG1 expression correlated significantly with poor overall survival time by Kaplan-Meier analysis (P < 0.05). The result of biological function shown that MCF-7 cell transfected BTG1 had a lower survival fraction, higher percentage of the G0/G1 phases, higher cell apoptosis, significant decrease in migration and invasion, and lower CyclinD1, Bcl-2, and MMP-9 protein expression compared with MCF-7 cell untransfected BTG1 (P < 0.05). BTG1 expression decreased in breast cancer and correlated significantly lymph node metastasis, clinic stage, histological grade, poor overall survival, proliferation, and metastasis in breast cancer cell by regulating CyclinD1, Bcl-2, and MMP-9 protein expression, suggesting that BTG1 may play important roles as a negative regulator to breast cancer cell.
本研究旨在分析B细胞易位基因1（BTG1）在乳腺癌中的表达、临床意义及其过表达对乳腺癌细胞系的生物学效应。采用免疫组织化学和蛋白质印迹法分析72例乳腺癌组织和36例正常组织中BTG1蛋白的表达情况，以研究BTG1表达与临床因素之间的关系。构建重组慢病毒载体以过表达BTG1，然后感染乳腺癌MCF-7细胞系。运用定量实时逆转录聚合酶链反应（qRT-PCR）和蛋白质印迹法检测BTG1的mRNA水平和蛋白表达。还进行了MTT法、细胞凋亡检测、细胞周期分析、迁移和侵袭实验，以研究BTG1表达上调对MCF-7细胞生物学效应的影响。结果发现，乳腺癌组织中BTG1蛋白表达水平明显低于正常组织（P<0.05）。BTG1表达降低与乳腺癌患者的肿瘤侵袭、淋巴结转移、临床分期及组织学分级显著相关（P<0.05）。同时，通过Kaplan-Meier分析，BTG1表达缺失与患者总体生存时间短显著相关（P<0.05）。生物学功能实验结果显示，与未转染BTG1的MCF-7细胞相比，转染BTG1的MCF-7细胞存活率更低，G0/G1期细胞百分比更高，细胞凋亡率更高，迁移和侵袭能力显著降低，细胞周期蛋白D1（CyclinD1）、Bcl-2和基质金属蛋白酶-9（MMP-9）蛋白表达水平更低（P<0.05）。BTG1在乳腺癌中表达降低，通过调节CyclinD1、Bcl-2和MMP-9蛋白表达，与乳腺癌淋巴结转移、临床分期、组织学分级、总体生存差、增殖及转移显著相关，提示BTG1可能作为乳腺癌细胞的负调控因子发挥重要作用。
