KLF3通过STAT3调控乳腺癌细胞的运动、迁移及侵袭

KLF3 regulates the movement, migration and invasion of breast cancer cells through STAT3

目的 观察人类Krüppel样因子3(KLF3)对乳腺癌细胞中信号转导和转录激活因子3(STAT3)表达的影响,并探索KLF3影响乳腺癌细胞运动、迁移及侵袭的潜在机制.方法 首先在乳腺癌细胞(MCF-7和MDA-MB-231)中,分别通过蛋白质印迹、实时荧光定量聚合酶链式反应(PCR)、荧光素酶报告系统及染色质免疫共沉淀等实验方法验证KLF3对STAT3表达的调控作用;其次构建STAT3启动子的突变型质粒,进一步证实KLF3对STAT3启动子活性的影响;进而利用细胞划痕实验及Transwell法检测细胞运动、迁移、侵袭的能力;最后通过动物实验验证敲减KLF3对动物体内肿瘤转移的影响.结果 在MDA-MB-231细胞中敲低KLF3后STAT3的mRNA水平升高(3.58±0.65)倍,而在MCF-7细胞中敲低KLF3后STAT3的mRNA水平升高(2.28±0.19)倍(P<0.001).KLF3能够结合于STAT3的启动子区域,在MDA-MB-231细胞中敲低KLF3后STAT3的转录活性升高(2.47±0.87)倍,而在MCF-7细胞中敲低KLF3后STAT3的转录活性升高(2.63±0.65)倍(P<0.01);敲减KLF3能够抑制乳腺癌细胞的运动、迁移、侵袭能力,在此基础上沉默STAT3能够部分逆转KLF3的功能;敲减KLF3能够促进小鼠体内肿瘤转移.结论 敲减KLF3能够促进STAT3的转录活性,从而促进后者的蛋白表达;KLF3能够通过STAT3影响乳腺癌细胞的运动、迁移及侵袭,KLF3可能作为治疗转移性乳腺癌的潜在靶点.

Objective To observe the effect of KLF3 on the expression of STAT3 in breast cancer cells, and to explore the potential mechanism of KLF3 affecting the movement, migration and invasion of breast cancer cells. Methods Firstly, the expression of STAT3 was detected by Western blot, real-time fluorescent quantitative PCR, luciferase reporter system and chromatin immunoprecipitation in breast cancer cells. Secondly, the STAT3 promoter mutant was constructed. The plasmid further confirmed the effect of KLF3 on the activity of STAT3 promoter;the cell scratching test and Transwell method were used to detect the ability of cell movement, migration and invasion. Finally, animal experiments were conducted to verify the effect of knockdown of KLF3 on tumor metastasis in animals. Results In breast cancer cells, knockdown of KLF3 promoted STAT3 protein expression. The mRNA level of STAT3 was increased by (3.58 ± 0.65) fold after knockdown of KLF3 in MDA-MB-231 cells, while the mRNA level of STAT3 was increased by (2.28±0.19) fold after KLF3 knockdown in MCF-7 cells (P<0.001). KLF3 boundto the promoter region of STAT3. The transcriptional activity of STAT3 increased by (2.47 ± 0.87) fold after knockdown of KLF3 in MDA-MB-231 cells, while the transcriptional activity of STAT3 increased by (2.63± 0.65) fold after KLF3 knockdown in MCF-7 cells, P<0.01. KLF3 knockdown inhibitedthe movement,migrate and invade of breast cancer cells. Based on this, silence STAT3 partially reversed the function of KLF3. Knockdown of KLF3 promotedtumor metastasis in mice. Conclusions KLF3 knockdown can promote the transcriptional activity of STAT3, which promotes the protein expression of the latter. KLF3 can affect the movement, migration and invasion of breast cancer cells through STAT3. KLF3 may be a potential target for the treatment of metastatic breast cancer.