miR-5694/AF9/Snail 轴在基底样乳腺癌中提供转移优势和治疗靶点。

The miR-5694/AF9/Snail Axis Provides Metastatic Advantages and a Therapeutic Target in Basal-like Breast Cancer.

机构信息

Cancer Research Institute, The First Affiliated Hospital of China Medical University, Shenyang, China; Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou 510006, China.

CAS Key Laboratory of Tissue Microenvironment and Tumor, Institute of Health Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China; Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou 510006, China.

出版信息

Mol Ther. 2021 Mar 3;29(3):1239-1257. doi: 10.1016/j.ymthe.2020.11.022. Epub 2020 Nov 20.

DOI:10.1016/j.ymthe.2020.11.022

PMID:33221433

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC7934584/

Abstract

Epigenetic deregulation, especially mutagenesis or the abnormal expression of epigenetic regulatory factors (ERFs), plays an important role in malignant tumorigenesis. To screen natural inhibitors of breast cancer metastasis, we adopted small interfering RNAs (siRNAs) to transiently knock down 591 ERF-coding genes in luminal breast cancer MCF-7 cells and found that depletion of AF9 significantly promoted MCF-7 cell invasion and migration. A mouse model of metastasis further confirmed the suppressive role of AF9 in breast cancer metastasis. RNA profiling revealed enrichment of AF9 targets genes in the epithelial-mesenchymal transition (EMT). Mechanistically, tandem mass spectrometry showed that AF9 interacts with Snail, which hampers Snail transcriptional activity in basal-like breast cancer (BLBC) cells. AF9 reconstitutes an activated state on the promoter of Snail, which is a master regulator of EMT, and derepresses genes by recruiting CBP or GCN5. Additionally, microRNA-5694 (miR-5694) targeted and degraded AF9 messenger RNA (mRNA) in BLBC cells, further enhancing cell invasion and migration. Notably, AF9 and miR-5694 expression in BLBC clinical samples correlated inversely. Hence, miR-5694 mediates downregulation of AF9 and provides metastatic advantages in BLBC. Restoring expression of the metastasis suppressor AF9 is a possible therapeutic strategy against metastatic breast cancer.

摘要

表观遗传失调，特别是诱变或表观遗传调控因子（ERF）的异常表达，在恶性肿瘤发生中起重要作用。为了筛选乳腺癌转移的天然抑制剂，我们采用小干扰 RNA（siRNA）瞬时敲低腔乳腺癌 MCF-7 细胞中的 591 个 ERF 编码基因，发现 AF9 的耗竭显著促进 MCF-7 细胞侵袭和迁移。转移的小鼠模型进一步证实了 AF9 在乳腺癌转移中的抑制作用。RNA 谱分析显示 AF9 靶基因在上皮-间充质转化（EMT）中富集。从机制上讲，串联质谱显示 AF9 与 Snail 相互作用，这会阻碍基底样乳腺癌（BLBC）细胞中 Snail 的转录活性。AF9 在 Snail 启动子上重建激活状态，Snail 是 EMT 的主要调节因子，并通过募集 CBP 或 GCN5 来抑制基因表达。此外，miR-5694（miR-5694）在 BLBC 细胞中靶向并降解 AF9 信使 RNA（mRNA），进一步增强细胞侵袭和迁移。值得注意的是，BLBC 临床样本中的 AF9 和 miR-5694 表达呈负相关。因此，miR-5694 介导 AF9 的下调，并为 BLBC 提供转移优势。恢复转移抑制因子 AF9 的表达可能是治疗转移性乳腺癌的一种策略。