BRG1对乳腺癌细胞迁移和侵袭的影响及其分子机制探讨

The role of BRG1 gene on cell migration and invasion of human breast cancer cells and its molecular mechanisms

目的探讨沉默BRG1基因对乳腺癌细胞迁移和侵袭的影响及其分子机制。方法体外化学合成BRG1小干扰RNA（siRNA）和Control siRNA（si—Ctr1），脂质体介导转染乳腺癌MDA—MB-231和BT-549细胞，Transwell迁移实验和侵袭实验观察沉默BRG1基因对2种乳腺癌细胞迁移和侵袭能力的影响，明胶酶谱实验检测基质金属蛋白酶-2（matrix metalloproteinase-2，MMP-2）变化，Westernblot检测基质金属蛋白酶组织抑制因子-2（tissue inhibitor of metalloproteinase-2，TIMP-2）及MMP-2蛋白表达。结果转染BRG1 siRNA可以有效减少乳腺癌MDA—MB-231和BT-549细胞BRG1的表达，细胞迁移和侵袭能力下降。BRG1沉默后TIMP-2表达升高，MMP-2表达下降且酶活性降低。结论BRG1沉默后通过上调TIMP-2抑制MMP-2的表达，破坏TIMP-2／MMP-2平衡，最终抑制乳腺癌细胞迁移和侵袭能力。

Objective To investigate the effect of silence of the Brahma - related gene 1 （ BRG1 ） in breast cancer cell lines on cell migration, invasion and its molecular mechanism. Methods Chemically synthesized small interfering RNA （siRNA） and control siRNA （si -Ctr1） targeting BRG1 were transfected into human breast cancer cell lines by si- LentFect lipid reagent. The migration ability of two breast cancer cells was detected by cell migration assay. The invasive ability was detected by cell invasion assay. The matrix metalloproteinase -2 （MMP- 2） enzyme activities were detected by gelatin zymography and the MMP - 2 and tissue inhibitor of metalloproteinase - 2 （ TIMP - 2 ） protein expressions were detected by Western blot. Results BRG1 interference could drastically decreased the ability of cell invasion and migra- tion in both breast cancer cells. The Western blot results showed that BRG1 knock - down increased TIMP - 2 and de- creased MMP - 2 expression. BRG siRNA could also suppress MMP - 2 enzyme activity. Conclusions Silence of BRG1 can suppress human breast cancer cell invasion through up - regulation of TIMP - 2 and down - regulation of MMP - 2.