CDH1 缺失重塑人乳腺上皮细胞基因表达与谱系身份
<i>CDH1</i> loss remodels gene expression and lineage identity in human mammary epithelial cells
研究以寿命有限的人乳腺上皮细胞（HMEC）为模型，比较抗体抑制 E-cadherin 与 siRNA 或 CRISPR/Cas9 敲除 CDH1 的效果，发现靶向方式决定表型：抗体阻断细胞间接触诱导上皮-间质转化（EMT）相关基因特征，而遗传性 CDH1 缺失反而抑制 EMT 特征，使基因表达转向 luminal 上皮表型。RNA-seq、单细胞转录组、流式细胞术、显微成像和 ATAC-seq 结果支持 CDH1 缺失诱导谱系重塑为 luminal 状态，临床 ILC 前驱病变的转录组分析也呈现类似变化。
来源：PLOS Genetics · journals.plos.org
by Maggie Musick, Chinasa A. Ufondu, Carmen E. Rowland, Micaela E. Brown, Joseph L. Sottnik, Madeleine T. Shackleford, Camryn S. Nesiba, Etienne P. Danis, Andrew E. Goodspeed, Richard Zera, Arthur T. Johnson, Kathryn L. Schwertfeger, Andrew C. Nelson, Julie H. Ostrander, Matthew J. Sikora
Invasive lobular carcinoma (ILC) is a common subtype of breast cancer, molecularly defined by genetic loss of CDH1, and subsequent loss of cell adhesion protein E-cadherin, in ~95% of ILC. Though CDH1 loss occurs early in ILC oncogenesis, it is unclear how this facilitates transformation. We modeled early CDH1 loss using “normal” human mammary epithelial cells (HMEC), i.e., finite lifespan cells reflecting early hyperplasia, and targeted E-cadherin signaling using antibodies versus causing genetic CDH1 loss using siRNA or CRISPR/Cas9-knockout. Transcriptome analysis across four HMEC models showed that the mode of E-cadherin targeting is critical for the subsequent phenotype. Antibody-mediated inhibition of cell-cell contacts induced gene signatures of epithelial-mesenchymal transition (EMT), consistent with the role of E-cadherin suppression during the EMT process. Conversely, genetic CDH1 loss – as in ILC oncogenesis – repressed EMT signatures, and instead remodeled gene expression toward a luminal epithelial phenotype. RNA-seq, single cell transcriptomics, flow cytometry, microscopy, and ATAC-seq analyses support that CDH1 loss induces lineage remodeling to a luminal state, which is mirrored in transcriptomic analysis of clinical ILC precursor lesions. By isolating luminal versus basal cells prior to CDH1 knockout, we found that CDH1 loss led to remodeling of lineage identity in both populations, converging on a new lineage homeostasis with a luminal progenitor-like phenotype. Consistent with the shift to a luminal progenitor phenotype, CDH1 loss enhanced proliferative capacity over the finite lifespan of the HMECs, highlighting a feature of early CDH1 loss that may contribute to clonal advantage during tumor initiation. Moreover, CDH1 loss enhanced anoikis resistance, a defining feature of ILC cells. Our findings support that genetic loss of CDH1 in mammary epithelial cells induces transcriptional and phenotypic changes consistent with lineage identity remodeling toward a luminal progenitor-like state, which may underpin the mechanism by which early CDH1 loss mediates ILC oncogenesis.