Effect of ZBTB18 on gene expression and chromatin organization [ATAC-seq]. Effect of ZBTB18 on gene expression and chromatin organization [ATAC-seq]

This study set out to delineate gene expression programs that are differentially modulated in metastatic breast cancer cells with high versus low ability to further metastasize. To this end, the gene expression profiles of E0771GFP cells, M11GFP and M12GFP cells were determined. Analysis of these data sets identified ZBTB18 as a transcriptional repressor with lower activity in tumor cells that retain a high metastatic potential. To determine how ZBTB18 affects gene expression and chromatin organization, ZBTB18 was overexpressed in E0771GFP breast cancer cells. Gene expression profiles and differentially accessible DNA regions analyses were performed and identified Tgfbr2 as one of the genes most significantly repressed by ZBTB18. To determine the contribution of the TGFb1 -TGFBR2 signaling axis towards ZBTB18-mediated effects, E0771GFP cells overexpressing ZBTB18 were transduced with a doxycycline-inducible Tgfbr2 construct. These cells were then treated with doxycycline and recombinant TGFb1 or vehicle control and gene expression profiles were determined. These studies revealed that inhibition of ZBTB18 activity in tumor cells promotes metastasis by increasing chromatin accessibility and by enabling pro-metastatic TGFb1-TGFBR2-driven changes. Overall design: This project aims at identifying the global changes in gene expression and open chromatin regions between ZBTB18-overexpressing and control mouse cancer cell lines.本研究旨在阐明在具备不同继发转移能力的转移性乳腺癌细胞中，受差异调控的基因表达程序。为此，我们检测了E0771GFP细胞、M11GFP细胞及M12GFP细胞的基因表达谱。对上述数据集的分析显示，ZBTB18是一种转录抑制因子，在保留高转移潜能的肿瘤细胞中活性更低。为探究ZBTB18对基因表达与染色质组织的调控机制，我们在E0771GFP乳腺癌细胞中过表达ZBTB18。随后开展基因表达谱分析与差异开放染色质区域分析，鉴定出Tgfbr2是受ZBTB18显著抑制的核心基因之一。为明确TGFb1-TGFBR2信号轴在ZBTB18介导的生物学效应中的作用，我们向过表达ZBTB18的E0771GFP细胞中转导了多西环素（doxycycline）诱导型Tgfbr2表达载体。将上述细胞分别经多西环素、重组TGFb1及溶剂对照处理后，检测其基因表达谱。本研究结果显示，在肿瘤细胞中抑制ZBTB18活性，可通过增强染色质开放程度、激活促转移的TGFb1-TGFBR2通路介导的基因表达变化，进而促进肿瘤转移。整体实验设计：本项目旨在鉴定ZBTB18过表达组与对照组小鼠肿瘤细胞系之间，全基因组范围内基因表达与开放染色质区域的整体变化。