Abstract: Objective To investigate the function of BRIX1, a large subunit component of ribosome, in triple negative breast cancer cell line in vitro. Methods The expression difference of BRIX1 in normal tissue and triple negative breast cancer was analyzed by GEPIA2 database. Two SiRNAs were designed and transferred into triple negative breast cancer cell lines HS578T and MDA-MB-231 respectively to silence the expression of BRIX1, and Western Blot was used to verify the knock inefficiency of BRIX1. The proliferation of cells after BRIX1 knockdown was detected by CCK-8 and colony cloning formation assay, and the invasion and migration ability of cells after BRIX1 knockdown was detected by Transwell assay. MDA-MB-231 cells were divided into three groups, which were transferred into siNC, siBRIX1#1 and siBRIX1#2 respectively, and total RNA of the cells was extracted for RNA-Seq detection, and the difference of gene expression was analyzed. Results The results of GEPIA2 database showed that BRIX1 was highly expressed in triple negative breast cancer （P<0.05）, and the number of clones was decreased in HS578T and MDA-MB-231 cells （P<0.05）. The OD value of cck8 was decreased, which proved that the cell proliferation activity decreased after knocking down BRIX1. TranswellTM experiment showed that the invasion and migration ability of breast cancer was weakened after knocking down BRIX1. Biological process （BP）, molecular function （MF）, and cell composition （CC） of RNA-seq data were enriched by GO, and the top10 signaling pathways with high correlation were finally revealed. The results showed that after knockdown BRIX1, ERBB-ERK and WNT signaling pathways were activated, while P53 signaling pathways were inhibited. Conclusion Down-regulated BRIX1 expression could significantly inhibited the proliferation, migration and invasion of triple negative breast cancer cells, it suggesting that BRIX1 gene could be a potential molecular target for triple negative breast cancer therapy.

Key words: triple negative breast cancer, BRIX1, proliferation, migration and invasion

摘要： 目的 探讨核糖体生物发生蛋白BRX1同源物（BRIX1）在三阴乳腺癌（TNBC）中的功能。方法 通过 GEPIA2数据库分析BRIX1在正常组织和三阴乳腺癌的表达差异;设计两条 siRNA 并分别转入三阴乳腺癌细胞系 HS578T 和 MDA-MB-231 细胞内沉默 BRIX1 的表达,利用 Western Blot 验证 BRIX1 的敲低效率;使用CCK-8和集落克隆形成实验检测敲低BRIX1后细胞的增殖情况,使用Transwell实验检测敲低BRIX1后细胞的侵袭迁移能力;使用MDA-MB-231细胞,分为三组分别转入siNC、siBRIX1#1、siBRIX1#2后提取细胞的total RNA进行RNA-seq检测,进行基因表达差异分析。结果 GEPIA2数据库结果显示三阴乳腺癌中高表达BRIX1（P<0.05）,在HS578T 和 MDA-MB-231 细胞内敲低,克隆形成数目减少（P<0.05）;cck-8检测OD值减弱,证明敲低BRIX1后细胞增殖活性下降;TranswellTM实验显示敲低BRIX1后,乳腺癌侵袭迁移能力减弱;RNA-Seq数据进行GO功能富集分析生物学过程（BP）,分子功能（MF）,细胞组成（CC）,最终展示了top10相关性较高的信号通路,结果显示敲低BRIX1后,ERBB-ERK信号通路和WNT信号通路被激活,P53信号通路被抑制。结论 BRIX1基因敲低后明显抑制三阴乳腺癌细胞的增殖能力和迁移侵袭,提示BRIX1基因具有成为三阴乳腺癌治疗的潜在分子靶点。

关键词: 三阴乳腺癌, BRIX1, 细胞增殖迁移侵袭