Functional and mechanistic study of FOXA1 in promoting the proliferation of breast cancer by regulating the transcription of XBP1

doi:10.3969/j.issn.1009-976X.2023.01.003

Abstract

Abstract: Objective To explore the function and molecular mechanism of FOXA1 in breast cancer. Methods Thec BioPortal and TCGA databases were used to analyze the mutation of FOXA1 in tumors, the mRNA expression level of FOXA1 in breast cancer, and its correlation with the patient′s prognosis. The effects of FOXA1 and XBP1 on the proliferation of ERα-positive breast cancer cells were investigated by CCK-8 and colony formation assay. The effect of FOXA1 on the cell cycle was analyzed by flow cytometry. Transcriptome analysis and the GEO database were used to analyze the genes and pathways regulated by FOXA1. Western blot and RT-qPCR were used to verify the expression levels of genes regulated by FOXA1. Results FOXA1 is mutated in multiple tumors. The expression levels of FOXA1 in breast cancer tissues are significantly higher than in normal tissues, and breast cancer patients with high expression levels of FOXA1 are associated with poor prognosis. FOXA1 was significantly overexpressed in the Luminal subtype compared with other breast cancer subtypes. Transcriptome and chromatin immunoprecipitation analysis identified 177 genes directly regulated by FOXA1, including XBP1. Pathway enrichment analysis showed that the genes regulated by FOXA1 were significantly enriched in cell cycle and DNA replication pathways. In ER-positive breast cancer cell lines, knockdown of FOXA1 or XBP1 significantly inhibited cell proliferation, and silencing of FOXA1 increased the number of G1 phase cells. Conclusion The pioneer transcription factor FOXA1 is highly expressed in ER-positive breast cancer and is associated with poor prognosis. FOXA1 promotes the proliferation of breast cancer cells by regulating the expression of a series of oncogenes, including XBP1.

Key words: breast cancer, FOXA1, prognosis, proliferation, XBP1

摘要： 目的探究先锋转录因子FOXA1在乳腺癌中的功能及其发挥功能的分子机制。方法利用cBioPortal数据库分析FOXA1在肿瘤中的突变情况,利用TCGA数据库分析FOXA1在乳腺癌组织中的mRNA表达水平及其与患者预后的关系;采用CCK-8和克隆集落形成实验探究FOXA1和X盒结合蛋白1（XBP1）对ERα阳性乳腺癌细胞增殖能力的影响;采用流式细胞技术分析FOXA1对ERα阳性乳腺癌细胞周期的影响;联合转录组学和GEO数据库分析乳腺癌中受FOXA1调控的基因及信号通路;采用蛋白质印迹技术和RT-qPCR技术验证受FOXA1调控的基因的表达情况。结果在肿瘤中,FOXA1在多个位点发生突变;FOXA1在乳腺癌组织中的表达水平显著高于正常组织,并且FOXA1的高表达与患者的不良预后呈正相关;相比于其他乳腺癌分型,FOXA1在Luminal型乳腺癌中呈显著高表达;转录组和染色质免疫共沉淀分析一共鉴定到177个受FOXA1直接转录调控的基因,其中包括XBP1;通路富集分析表明,受FOXA1调控的基因显著富集在细胞周期和DNA复制通路上;在ERα阳性乳腺癌细胞系中,沉默FOXA1或者XBP1的表达显著抑制细胞增殖,沉默FOXA1的表达导致G1期细胞增多。结论先锋转录因子FOXA1在ERα阳性乳腺癌中高表达,并且与患者不良预后相关。FOXA1通过调控包括XBP1在内的一系列癌基因的表达从而促进乳腺癌细胞的增殖。

关键词: 乳腺癌, FOXA1, 预后, 增殖, XBP1

CLC Number:

R737.9

YAO Xin-yi, XU Bao-hong, ZHANG Meng-ting, HUANG Yong-xin. Functional and mechanistic study of FOXA1 in promoting the proliferation of breast cancer by regulating the transcription of XBP1[J]. Lingnan Modern Clinics In Surgery, 2023, 23(01): 10-18.

姚欣逸, 徐宝红, 张孟婷, 黄泳欣. FOXA1通过调控XBP1的转录促进乳腺癌增殖的功能及机制研究[J]. 岭南现代临床外科, 2023, 23(01): 10-18.

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