The basics of epithelial-mesenchymal transition

The origins of the mesenchymal cells participating in tissue repair and pathological processes, notably tissue fibrosis, tumor invasiveness, and metastasis, are poorly understood. However, emerging evidence suggests that epithelial-mesenchymal transitions (EMTs) represent one important source of these cells. As we discuss here, processes similar to the EMTs associated with embryo implantation, embryogenesis, and organ development are appropriated and subverted by chronically inflamed tissues and neoplasias. The identification of the signaling pathways that lead to activation of EMT programs during these disease processes is providing new insights into the plasticity of cellular phenotypes and possible therapeutic interventions.     

非编码RNA在腹膜间皮细胞上皮间质转化中的研究进展

腹膜纤维化是患者退出腹膜透析的主要原因,其关键步骤是腹膜间皮细胞上皮间质转化(epithelialmesenchymal transition,EMT)。越来越多的证据表明非编码RNA在腹膜间皮细胞EMT过程中有重要调控的作用。本文对非编码RNA在腹膜间皮细胞EMT中的研究发现进行综述,总结micro RNA和lnc RNA作为腹膜纤维化的诊断预测和治疗靶点的最新进展。     

Role of epithelial-mesenchymal transition in chemoresistance in pancreatic ductal adenocarcinoma

Pancreatic cancer (PC) is the seventh leading cause of cancer death worldwide. The vast majority of patients who have PC develop metastases, resulting in poor treatment effects. Although great progress in therapeutic approaches has been achieved in recent decades, extensive drug resistance still persists, representing a major hurdle to effective anticancer therapy for pancreatic ductal adenocarcinoma (PDAC). Therefore, there is an urgent need to better understand the drug resistance mechanisms and develop novel treatment strategies to improve patient outcomes. Numerous studies suggest that chemoresistance is closely related to epithelial-mesenchymal transition (EMT) of PDAC cells. Thus, this article summarizes the impact of EMT on PDAC from the perspective of chemotherapy resistance and discusses the possible novel applications of EMT inhibition to develop more effective drugs against PDAC.     

MicroRNA在肿瘤EMT调控中的作用

MicroRNA（miRNA）是一类长度约19-25个核苷酸的小分子非编码RNA,通过翻译抑制或MRNA降解发挥转录后水平调控基因表达。研究表明,miRNA在上皮细胞-间充质转化（EMT）调控中发挥关键的角色。 EMT是上皮细胞通过特定程序转化为具有间质表型细胞的生物学过程,上皮细胞黏附分子如E-钙粘素等表达减少或缺失,细胞失去极性;细胞具有间充质特征,获得了较高的迁移与侵袭能力,间质特征性分子,如Twist、Snail、Slug和Vimentin 等表达增高。近年来发现,miRNA 参与调控肿瘤细胞发生EMT改变。本文着重对EMT形成过程中miRNA的作用进行扼要综述。此外,回顾分析各种肿瘤中MiRNA的角色,靶向miRNA可能会成为癌症治疗的新型策略。     

IL-33诱导气道上皮细胞发生间质转分化样改变

目的探讨白细胞介素-33(IL-33)对小鼠气道上皮细胞细胞间质样转分化(EMT)的影响。方法体外培养小鼠上皮细胞,将小鼠气道上皮细胞分为三组,分别为IL-33组、抗IL-33组及对照组。IL-33组、抗IL-33组分别给予0.04 mg/ml的IL-33抗体和抗IL-33抗体刺激小鼠气道上皮细胞48 h,对照组不做处理;采用Western blot方法分别检测三组EMT标志物E-钙黏蛋白(E-cadherin)、α-平滑肌肌动蛋白(α-SMA)及Ⅰ型胶原(collagen-Ⅰ)表达水平;应用实时定量聚合酶链式反应(RT-PCR)测定EMT标志物E-钙黏蛋白、α-SMA及Ⅰ型胶原m RNA水平的表达,应用SPSS 17.0软件进行统计处理,两组间比较采用t检验。结果与对照组相比,IL-33组α-SMA及Ⅰ型胶原在蛋白水平的表达明显增高(1.45±0.12,P<0.05;1.52±0.10,P<0.01);IL-33组α-SMA及Ⅰ型胶原的基因表达比对照组增高(79.1±4.62 vs.50.2±3.59,P<0.05;69.8±5.89 vs.48.2±3.56,P<0.05);IL-33组E-钙黏蛋白在蛋白水平的表达比对照组低(0.82±0.08,P<0.05),IL-33组E-钙黏蛋白的基因表达比对照组降低(80.4±4.39 vs.145.9±7.82)。抗IL-33组与对照组E-钙黏蛋白、α-SMA及Ⅰ型胶原在蛋白和基因水平表达无统计学差异(P>0.05)。结论 IL-33能刺激小鼠气道上皮细胞发生间质转分化样改变。     

Notch2通过上皮-间质转化促进生长激素腺瘤的侵袭

目的探讨Notch2在生长激素腺瘤侵袭中的作用以及对上皮-间质转化(EMT)相关基因的影响。方法回顾性分析2013年1月至2015年12月首都医科大学附属北京天坛医院收治的62例生长激素腺瘤,按照Knosp分级分为侵袭组(28例)和非侵袭组(34例)。应用免疫组织化学染色检测Notch2和Vimentin在生长激素腺瘤中的表达情况,并分析两者的相关性。将小鼠垂体瘤细胞(GT1-1)分为对照组、空载体组和干扰组(Sh-A、Sh-B、Sh-C、ShD)。干扰组使用Sh-A、Sh-B、Sh-C、Sh-D 4种片段在GT1-1细胞中干扰Notch2的表达并选择干扰效果最佳的两种进行后续实验。采用MTS法检测GT1-1细胞增殖能力,采用小室实验检测GT1-1细胞的侵袭能力,酶联免疫吸附实验(ELISA)检测GT1-1细胞培养上清中生长激素(GH)水平,采用实时定量-PCR(RT-PCR)实验检测EMT相关基因的mRNA水平。结果免疫组织化学染色显示在生长激素腺瘤中,Notch2的表达水平与Vimentin呈正相关(r=0. 456,P=0. 027)。Notch2在侵袭组中的表达水平较非侵袭组明显升高(P <0. 05)。同样,侵袭组Vimentin表达水平较非侵袭组水平明显升高(P <0. 05)。RT-PCR和Western blotting实验筛选出干扰Notch2表达的有效片段为ShB和Sh-C。MTS实验显示,与对照组比较,Sh-B组细胞活力24 h、48 h和72 h时分别下降(6. 8±2. 1)%、(29. 2±4. 1)%和(43. 1±5. 2)%,差异均具有统计学意义(P <0. 05);Sh-C组分别下降(5. 2±2. 3)%、(17±3. 5)%和(26. 9±3. 8)%,差异均具有统计学意义(P <0. 05)。小室实验显示,对照组穿膜阳性细胞为(407±53)个/视野,Sh-B组为(126±35)个/视野,Sh-C组为(163±41)个/视野,差异均具有统计学意义(P <0. 05)。ELISA结果显示,处理72 h后,Sh-B和Sh-C的GH水平分别为对照组的(27. 7±7. 3)%和(36. 4±8. 5)%,差异具有统计学意义(P <0. 05)。Sh-B组及Sh-C组细胞E-cadherin较对照组升高,N-cadherin和Vimentin mRNA水平均较对照组明显降低,差异均具有统计学意义(P <0. 05)。结论 Notch2通过调控E-cadherin、N-Cadherin和vimentin的表达影响EMT,促进生长激素腺瘤侵袭性生长。     

IL-6在胃癌细胞株HGC-27上皮间质转化中的作用

摘要：目的：探讨白细胞介素-6(IL-6)对人胃癌细胞株HGC-27上皮间质转化(epithelial mesenchymal transition, EMT)的影响。 方法：体外用IL-6刺激培养HGC 27细胞,倒置显微镜下观察细胞形态学变化;实时荧光定量RT-PCR及western blot检测EMT相关标志分子E-cadherin、N-cadherin和Vimentin表达情况;Transwell迁移实验和平板克隆形成实验分别检测IL-6处理前后HGC-27细胞迁移和克隆形成能力的变化。 结果：IL-6能诱导HGC-27细胞向间质细胞样形态转化,多数细胞表现为类似成纤维状,部分细胞呈明显的梭形;实时荧光定量RT-PCR结果表明,IL-6作用于HGC-27细胞后E-cadherin表达量明显降低(P<0.01),而N-cadherin和Vimentin表达则显著增强(P均<0.05)。western blot结果表明,IL-6作用HGC-27细胞后E-cadherin蛋白表达量降低(P<0.05),而N-cadherin和Vimentin蛋白表达量均增加(P均<0.05);Transwell实验及平板克隆形成实验结果显示,IL-6作用后HGC-27细胞的克隆形成能力及迁移能力均增强(P均<0.01)。 结论：IL-6可诱导胃癌细胞发生EMT和进一步恶化的潜能。     

Hedgehog signaling regulates epithelial-mesenchymal transition during biliary fibrosis in rodents and humans

Epithelial-mesenchymal transitions (EMTs) play an important role in tissue construction during embryogenesis, and evidence suggests that this process may also help to remodel some adult tissues after injury. Activation of the hedgehog (Hh) signaling pathway regulates EMT during development. This pathway is also induced by chronic biliary injury, a condition in which EMT has been suggested to have a role. We evaluated the hypothesis that Hh signaling promotes EMT in adult bile ductular cells (cholangiocytes). In liver sections from patients with chronic biliary injury and in primary cholangiocytes isolated from rats that had undergone bile duct ligation (BDL), an experimental model of biliary fibrosis, EMT was localized to cholangiocytes with Hh pathway activity. Relief of ductal obstruction in BDL rats reduced Hh pathway activity, EMT, and biliary fibrosis. In mouse cholangiocytes, coculture with myofibroblastic hepatic stellate cells, a source of soluble Hh ligands, promoted EMT and cell migration. Addition of Hh-neutralizing antibodies to cocultures blocked these effects. Finally, we found that EMT responses to BDL were enhanced in patched-deficient mice, which display excessive activation of the Hh pathway. Together, these data suggest that activation of Hh signaling promotes EMT and contributes to the evolution of biliary fibrosis during chronic cholestasis.     

高密度接种对转化生长因子β1诱导上皮间充质转化的影响

背景：细胞密度是影响细胞分化状态的因素之一,对于细胞密度在转化生长因子β1诱导HaCaT细胞上皮间充质转化中的作用尚缺乏深入研究。目的：观察细胞密度对转化生长因子61诱导HaCaT细胞上皮间充质转化的影响。方法：将HaCaT细胞分别以低密度10^3／cm^2和高密度10^5／cm^2接种于六孔板,使用2ug／L的转化生长因子β1作用48h,观察细胞形态变化,应用Realtime PCR检测上皮型钙黏蛋白、紧密连接蛋白1和波形蛋白、神经型钙黏蛋白的转录水平,Western blot检测上皮型钙黏蛋白和波形蛋白表达水平。结果与结论：低密度组的HaCaT细胞在转化生长因子B1处理48h后细胞间隙变大,细胞形态由多角形变为长梭形,高密度组的细胞间隙变大,但形态变化不明显：Realtime PCR结果显示两组上皮细胞标志物上皮型钙黏蛋白和紧密连接蛋白1的转录均较对照组明显下调（P＜0．05）,但高密度组没有低密度组下调明显（P〈0．05）,间充质细胞标志物神经型钙黏蛋白和波形蛋白的转录均较对照组明显上调（P〈0．05）,而高密度组与低密度组间差异无显著性意义;Wesfern blot进一步验证了上述上皮型钙黏蛋白和波形蛋白的变化。说明高接种密度抑制转化生长因子β1诱导HaCaT细胞上皮间充质转化。     

口腔鳞状细胞癌侵袭和转移过程中上皮-间充质细胞转换作用的研究进展

上皮-间充质细胞转换（epithelial—mesenehymaltransition,EMT）是一个动态的、可逆的过程,使细胞从鹅卵石状的上皮表型转向细长的间充质表型。受微环境和很多因素的诱导,EMT参与胚胎发育、慢性炎症、伤口愈合及肿瘤侵袭转移过程。细胞经历EMT后具有多种生物学特性,包括迁移、侵袭、被诱导成干细胞、防止凋亡、防止衰老及抑制免疫等,在肿瘤的转移、复发和耐药中起着关键作用。弄清EMT在口腔鳞状细胞癌（oralsquamouscellcarcinoma,OSCC）中的作用机制,有助于了解OSCC发展的生物学行为,以发现新的生物标志物用于OSCC患者的诊断、靶向治疗和预后判定。     

The role of epithelial-mesenchymal transition in oral squamous cell carcinoma and oral submucous fibrosis

Epithelial-mesenchymal transition (EMT) is an indispensable mechanism during morphogenesis. Interest and research in EMT are currently at a high level due to its important role in cancer and fibrosis. Emerging evidence suggests that EMT is also a crucial event in oral squamous cell carcinoma (OSCC). Oral submucous fibrosis (OSF) is a chronic debilitating disease and a premalignant condition of the oral cavity. It is characterized by a generalized submucosal fibrosis. The pathogenesis of the disease is not well established. Epidemiological evidence strongly indicates an association between the betel quid (BQ) chewing habit and OSF. In a simplistic view, OSF represents a failed wound-healing process of the oral mucosa after chronic, sustained injury. This review highlights the signaling pathways involved in EMT, recent advances in the study of EMT in OSCC, and summarizes the evidence supporting a role for EMT in the pathogenesis of OSF.     

miRNA-29b suppresses prostate cancer metastasis by regulating epithelial-mesenchymal transition signaling

Prostate cancer remains the second leading cause of cancer deaths among American men. Early diagnosis increases survival rate in patients; however, treatments for advanced disease are limited to hormone ablation techniques and palliative care. Thus, new methods of treatment are necessary for inhibiting prostate cancer disease progression. Here, we have shown that miRNA-29b (miR-29b) expression was lower in prostate cancer cells (PC3 and LNCaP) as compared with immortalized prostate epithelial cells. Between these two prostate cancer cell lines, metastatic prostate cancer PC3 cells displayed lower expression of miR-29b. We also observed a significant downregulation of miR-29b expression in human prostate cancer tissues as compared with patient-matched nontumor tissues. PC3 cells ectopically expressing miR-29b inhibited wound healing, invasiveness, and failed to colonize in the lungs and liver of severe combined immunodeficient mice after intravenous injection, while PC3 cells expressing a control miRNA displayed metastasis. Epithelial cell marker E-cadherin expression was enhanced miR-29b transfected in prostate cancer cells as compared with cells expressing control miRNA. On the other hand, N-cadherin, Twist, and Snail expression was downregulated in PC3 cells expressing miR-29b. Together these results suggested that miR-29b acts as an antimetastatic miRNA for prostate cancer cells at multiple steps in a metastatic cascade. Therefore, miR-29b could be a potentially new attractive target for therapeutic intervention in prostate cancer.     

Genome-wide DNA hypermethylation opposes healing in patients with chronic wounds by impairing epithelial-mesenchymal transition

An extreme chronic wound tissue microenvironment causes epigenetic gene silencing. An unbiased whole-genome methylome was studied in the wound-edge tissue of patients with chronic wounds. A total of 4,689 differentially methylated regions (DMRs) were identified in chronic wound-edge skin compared with unwounded human skin. Hypermethylation was more frequently observed (3,661 DMRs) in the chronic wound-edge tissue compared with hypomethylation (1,028 DMRs). Twenty-six hypermethylated DMRs were involved in epithelial-mesenchymal transition (EMT). Bisulfite sequencing validated hypermethylation of a predicted specific upstream regulator TP53. RNA-Seq analysis was performed to qualify findings from methylome analysis. Analysis of the downregulated genes identified the TP53 signaling pathway as being significantly silenced. Direct comparison of hypermethylation and downregulated genes identified 4 genes, ADAM17, NOTCH, TWIST1, and SMURF1, that functionally represent the EMT pathway. Single-cell RNA-Seq studies revealed that these effects on gene expression were limited to the keratinocyte cell compartment. Experimental murine studies established that tissue ischemia potently induces wound-edge gene methylation and that 5′-azacytidine, inhibitor of methylation, improved wound closure. To specifically address the significance of TP53 methylation, keratinocyte-specific editing of TP53 methylation at the wound edge was achieved by a tissue nanotransfection-based CRISPR/dCas9 approach. This work identified that reversal of methylation-dependent keratinocyte gene silencing represents a productive therapeutic strategy to improve wound closure.