Inhibition of Notch signaling enhances transdifferentiation of the esophageal squamous epithelium towards a Barrett's-like metaplasia via KLF4
Inhibition of Notch signaling enhances transdifferentiation of the esophageal squamous epithelium towards a Barrett's-like metaplasia via KLF4
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DOI：
10.4161/15384101.2014.972875
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发表时间：
2014-12-15
期刊：
影响因子：
4.3
通讯作者：
Rustgi, Anil K.
中科院分区：
文献类型：
--
作者：
Vega, Maria E.;Giroux, Veronique;Rustgi, Anil K.
Barrett食管（BE）是一种不完全的肠上皮化生，其特征通常是在食管的原复层鳞状上皮中存在柱状细胞和杯状细胞。BE被认为是食管腺癌的前兆。目前，人类BE的起源细胞尚未明确确定。因此，我们研究了Notch信号传导在BE化生起始中的作用。亲和素基因表达微阵列显示BE样品表达水平降低的Notch受体（NOTCH 2和NOTCH 3）和配体之一（JAG 1）。此外，BE组织芯片显示NOTCH 1及其下游靶点HES 1的表达降低。因此，Notch信号传导在人食管上皮细胞中通过显性负性-Mastermind样（dnMAML）的表达被抑制，与MYC和CDX 1过表达一致。然后通过3D器官型培养和BE谱系特异性基因表达的评价来评估细胞转分化。Notch抑制促进食管上皮细胞向柱状样细胞的转分化，如柱状角蛋白（K8、K18、K19、K20）和腺粘蛋白（MUC 2、MUC 3B、MUC 5 B、MUC 17）表达增加和鳞状角蛋白（K5、K13、K14）表达减少所证明的。在3D培养中，在具有Notch抑制的上皮基底层中观察到伸长的细胞。此外，我们观察到KLF 4的表达增加，这是通过Notch抑制观察到的变化的潜在驱动因素。有趣的是，KLF 4的敲低逆转了Notch抑制对BE样化生的影响。总之，Notch信号传导抑制促进食管细胞向BE样化生转分化，部分是通过上调KLF 4。这些结果支持了食管上皮转分化促进BE进化的新机制。
Barrett's esophagus (BE) is defined as an incomplete intestinal metaplasia characterized generally by the presence of columnar and goblet cells in the formerly stratified squamous epithelium of the esophagus. BE is known as a precursor for esophageal adenocarcinoma. Currently, the cell of origin for human BE has yet to be clearly identified. Therefore, we investigated the role of Notch signaling in the initiation of BE metaplasia. Affymetrix gene expression microarray revealed that BE samples express decreased levels of Notch receptors (NOTCH2 and NOTCH3) and one of the the ligands (JAG1). Furthermore, BE tissue microarray showed decreased expression of NOTCH1 and its downstream target HES1. Therefore, Notch signaling was inhibited in human esophageal epithelial cells by expression of dominant-negative-Mastermind-like (dnMAML), in concert with MYC and CDX1 overexpression. Cell transdifferentiation was then assessed by 3D organotypic culture and evaluation of BE-lineage specific gene expression. Notch inhibition promoted transdifferentiation of esophageal epithelial cells toward columnar-like cells as demonstrated by increased expression of columnar keratins (K8, K18, K19, K20) and glandular mucins (MUC2, MUC3B, MUC5B, MUC17) and decreased expression of squamous keratins (K5, K13, K14). In 3D culture, elongated cells were observed in the basal layer of the epithelium with Notch inhibition. Furthermore, we observed increased expression of KLF4, a potential driver of the changes observed by Notch inhibition. Interestingly, knockdown of KLF4 reversed the effects of Notch inhibition on BE-like metaplasia. Overall, Notch signaling inhibition promotes transdifferentiation of esophageal cells toward BE-like metaplasia in part via upregulation of KLF4. These results support a novel mechanism through which esophageal epithelial transdifferentiation promotes the evolution of BE.