Otic placode cell specification and proliferation are regulated by Notch signaling in avian development

Background: The entire inner ear including the cochlear‐vestibular ganglion arises from a simple epithelium, the otic placode. Precursors for the placode originate from a pool of progenitors located in ectoderm next to the future hindbrain, the pre‐otic field, where they are intermingled with future epibranchial and epidermal cells. While the importance of secreted proteins, such as FGFs and Wnts, in imparting otic identity has been well studied, how precursors for these different fates segregate locally is less well understood. Results: (1) The Notch ligand Delta1 and the Notch target Hes5‐2 are expressed in a part of pre‐otic field before otic commitment, indicative of active Notch signaling, and this is confirmed using a Notch reporter. (2) Loss and gain‐of‐function approaches reveal that Notch signaling regulates both proliferation and specification of pre‐otic progenitors. Conclusions: Our results identify a novel function of Notch signaling in cell fate determination in the pre‐otic field of avian embryos. Developmental Dynamics 244:839–851, 2015. © 2015 Wiley Periodicals, Inc.     

In vivo Notch reactivation in differentiating cochlear hair cells induces Sox2 and Prox1 expression but does not disrupt hair cell maturation

Background: Notch signaling is active in mouse cochlear prosensory progenitors but declines in differentiating sensory hair cells (HCs). Overactivation of the Notch1 intracellular domain (NICD) in progenitors blocks HC fate commitment and/or differentiation. However, it is not known whether reactivation of NICD in differentiating HCs also interrupts their developmental program and reactivates its downstream targets. Results: By analyzing Atoh1^CreER+; Rosa26‐NICD^loxp/+ or Atoh1^CreER+; Rosa26‐NICD^loxp/+; RBP‐J^loxp/loxp mice, we demonstrated that ectopic NICD in differentiating HCs caused reactivation of Sox2 and Prox1 in an RBP‐J‐dependent manner. Interestingly, Prox1 reactivation was exclusive to outer HCs (OHCs). In addition, lineage tracing analysis of Prox1^CreER/+; Rosa26‐EYFP^loxp/+ and Prox1^CreEGFP/+; Rosa26‐EYFP^loxp/+ mice showed that nearly all HCs experiencing Prox1 expression were OHCs. Surprisingly, these HCs still matured normally with expression of prestin, wild‐type‐like morphology, and uptake of FM4‐64FX dye at adult ages. Conclusions: Our results suggest that the developmental program of cochlear differentiating HCs is refractory to Notch reactivation and that Notch is an upstream regulator of Sox2 and Prox1 in cochlear development. In addition, our results support that Sox2 and Prox1 should not be the main blockers for terminal differentiation of HCs newly regenerated from postnatal cochlear SCs that still maintain Sox2 and Prox1 expression. Developmental Dynamics 241:684–696, 2012. © 2012 Wiley Periodicals, Inc.     

Notch信号通路及其在肺癌发生中的作用

Notch信号通路存在于多种动物体内,是许多细胞信号转导通路的交汇点,不仅对正常组织、细胞的分化、发育起重要作用,而且和一些肿瘤的发生、发展相关。Notch信号在肺癌中的作用多样，在不同类型肺癌中呈现出不同的促癌或抑癌功能。了解Notch和肺癌的关系有利于进一步阐明肺癌发生机制,提出预防和治疗肺癌的新途径，为肿瘤基因治疗提供一个新的有希望的靶点。     

Notch3诱导人小细胞肺癌H446细胞G_0/G_1期阻滞及其机制

目的探究Notch3对人小细胞肺癌H446细胞增殖和细胞周期的影响及其分子机制。方法将人Notch3真核表达质粒、人HES1真核表达质粒、人鼠双微基因2(MDM2)基因沉默表达质粒及其空质粒分别转染H446细胞,采用流式细胞术检测细胞周期,采用RT-PCR法检测Notch3和MDM2的mRNA水平,采用Western blotting方法检测Notch3、HES1、MDM2、Rb和P21蛋白表达水平。结果 Notch3可抑制H446细胞增殖并导致G_0/G_1期阻滞(P0.05),上调HES1蛋白表达水平和下调MDM2蛋白表达水平(P0.05);HES1高表达也能使MDM2蛋白表达水平下降(P0.05),但对其mRNA水平无影响;沉默MDM2基因可抑制H446细胞增殖(P0.05),并使H446细胞中Rb和P21蛋白表达水平升高(P0.05)。结论 Notch3可通过HES1抑制MDM2蛋白表达,进而上调Rb和P21蛋白表达水平,抑制H446细胞增殖并阻滞H446细胞于G_0/G_1期。     

Notch信号转导对小细胞肺癌的调控及其机制研究

目的 探讨Notch信号转导对小细胞肺癌的调控作用及可能机制.方法 应用重组质粒转染的方法,在小细胞肺癌细胞株NCI-H446中表达组成性活化的Notch1(NIC转染组),同时设立转染空质粒组和未转染组作为对照组,待筛选出稳定细胞株后,以MTT法检测细胞活力,应用半定量RT-PCR技术测定Notch1及其下游基因(HES1和hASH1)表达,并应用免疫细胞化学标记和Westernblot技术对神经内分泌标志物嗜铬粒素A(CgA)、神经元特异性烯醇化酶(NSE)的表达行半定量[阳性单位(PU)值]分析.结果 未转染组和转染空质粒组Notch1及其下游基因HES1表达不明显,而hASH1表达显著,转染组细胞Notch1及HES1表达升高,同时伴有hASH1表达明显降低.与两对照组比较,转染组细胞增殖速度显著降低,连续6 d测得的吸光度(A)值均小于未转染组和转染空质粒组(均P<0.05).免疫细胞化学染色显示,NIC转染组、转染空质粒组、未转染组的CgA染色的PU值分别为8.81±0.77、38.10±1.55、38.97±0.80,NSE染色的PU值分别为7.21±0.59、28.25±1.46、30.57±1.31,NIC转染组CgA和NSE的PU值均小于转染空质粒组和未转染组(均P<0.01).Western blot检测结果中,将未转染组的条带灰度值设为1.00,NIC转染组、转染空质粒组的CgA条带灰度值分别为0.54±0.03、0.99±0.05,NSE条带灰度值分别为0.43±0.02、1.07±0.09,NIC转染组cgA和NSE条带的灰度值均小于转染空质粒组和未转染组(均P<0.01).结论 Notch信号途径对小细胞肺癌的调控可能是通过靶基因HES1对分化效应基因hASH1的转录抑制来实现的;Notch信号途径可以抑制小细胞肺癌细胞的增殖,降低其神经内分泌标志物的表达.     

转录因子Sox2 SUMO修饰位点突变体的构建及真核表达

目的:构建Sox2及突变体Sox2 K247R的真核表达载体, 并在293FT细胞中表达.方法:以含有Sox2基因全长的馈赠质粒为模板, 用循环延伸PCR法得到该基因的突变体Sox2 K247R, 并将野生型及突变型基因定向亚克隆到真核表达载体pCMV-HA上.得到的重组质粒经限制性内切酶消化和DNA测序鉴定.其后用脂质体包埋法将pCMV-HA-Sox2及pCMV-HA-Sox2 K247R分别单独转染或与pCMV-Myc-SUMO1共转染293FT细胞.采用Western blot分析蛋白表达情况及SUMO修饰情况.结果:经酶切和DNA序列测定, 重组子序列正确, 突变体第247位密码子由AAG转变为CGG.Western blot结果显示野生型及突变型的Sox2都在细胞内得到了很好的表达, SUMO修饰位点突变后, Sox2不能与SUMO蛋白结合.结论:Sox2野生型及突变型真核表达载体构建成功, 在蛋白水平体现了SUMO修饰的差异性.     

E3 ubiquitin-protein ligase 2 inhibits cell proliferation,migration, and invasion of non-small cell lung cancer through ubiquitination of Notch1

This study aimed to explore the role of MIB2 in non-small cell lung cancer (NSCLC) and the underlying mechanism. Quantitative real-time PCR (QRT-PCR) and western blot were first performed to detect MIB2 expression in tumor tissues obtained from NSCLC patients (n = 30) and NSCLC cells, respectively. 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) and transwell assays were then used to examine the effect of MIB2 on the proliferation, migration and invasion of NSCLC cells. Western blot was further performed to examine the effect of Mind bomb 2 (MIB2), an E3 ligase on Notch1 protein and its ubiquitination. MIB2 was significantly down-regulated in NSCLC tissues and cells, both in mRNA and protein level. MIB2 also note worthily inhibited the proliferation, migration, and invasion of NSCLC cells. Furthermore, MIB2 only down-regulated Notch1 protein level, while facilitated the ubiquitination of Notch1. Additionally, Notch1 significantly relieved the repressed proliferation, migration and invasion of NSCLC cells induced by MIB2. Conclusively, MIB2 inhibited cell proliferation, migration and invasion via inducing Notch1 ubiquitination and degradation in NSCLC.     

The expression profile of Oct4 and Sox2 in the carcinogenesis of oral mucosa

This study is to detect the co-expression of embryonic stem cell-related markers (Oct4 and Sox2) in the carcinogenesis of oral mucosa. The expression profile of these markers was studied by immunohistochemistry assay in rat and human samples. The normal oral mucosa (20 cases) and the transforming oral mucosa (20 cases) were performed in rat samples. The precancerous lesions (20 cases), OSCCs in primary site (116 cases), corresponding epithelial non-cancer tissues adjacent to the OSCC (20 cases) and 46 paired metastatic OSCCs in lymph nodes were performed in human samples. The co-expression of the two markers was defined as both of them are positively detected in the same site of one case under one selected field of microscope. The results indicated that Oct4 and Sox2 were individually detected in normal oral mucosa, but they cannot be co-expressed in the same site of one case. The co-expression of Oct4 and Sox2 (Oct4⁺Sox2⁺) was frequently detected in the transforming oral mucosa of rat (16/20), precancerous lesions of human (12/20) and epithelial non-cancer tissues adjacent to the OSCC (18/20). Also, Oct4⁺Sox2⁺ profile was remarkable noted in the primary sites of OSCCs (38/116). In the 46 paired OSCCs (primary sites with lymph node metastasis), Oct4⁺Sox2⁺ profile (8/46) was less frequently detected than Oct4^low/-Sox2^low/- (14/46) profile in the metastatic sites. To conclude, this study suggests Oct4 and Sox2 are expressed in normal oral mucosa, premalignant diseases, primary sites of OSCCs and metastasis sites of OSCCs. Oct4⁺Sox2⁺ profile may contribute to the malignant transformation of oral mucosa.     

Down-regulation of Notch receptor signaling pathway induces caspase-dependent and caspase-independent apoptosis in lung squamous cell carcinoma cells

Notch receptor signaling pathway (NRSP) is increasingly linked to carcinogenesis. Non-small cell lung cancer (NSCLC) appears to actively utilize this conserved developmental pathway. The aims of this study are to determine whether or not Notch 1-4 are overexpressed in NSCLC tissues compared with normal lung tissues and whether inhibiting NRSP could induce caspase-dependent or caspase-independent apoptosis. Immunohistochemistry was used to evaluate the expression of Notch 1-4 in 101 NSCLC tissue samples and 30 normal lung tissue samples. DAPT was used to repress NRSP in SK-MES-1 cells. Apoptosis was determined by Annexin V and PI staining. Cleaved poly ADP-ribose polymerase (PARP) was measured by Western blot; X-linked inhibitor of apoptosis protein (XIAP) and Survivin were assessed by qRT-PCR and Western blot; the release of second mitochondria-derived activator of caspase (Smac) from mitochondria to cytoplasm was evaluated by Western blot; the subcellular locations of endonuclease G (Endo G) and apoptosis inducing factor (AIF) were observed by Western blot and indirect immunofluorescence analysis. (Mech Dev, 98, 2000, 95) Notch 1-4 are up-regulated in NSCLC tissues and Notch 1, 2 are positively correlated with lymph node metastasis, (Proc Natl Acad Sci U S A, 106, 2009, 22293) DAPT treatment could inhibit NRSP and induce apoptosis, with a marked increase in cleaved PARP, decreases in XIAP and Survivin proteins and concomitant release of Smac, EndoG, and AIF from mitochondria, indicating that inhibiting NRSP by DAPT triggers caspase-dependent and caspase-independent apoptosis.     

Notch1和Notch2在星形细胞瘤及髓母细胞瘤中的表达及其意义

目的 探讨Notch1和Notch2在人脑星形细胞瘤及髓母细胞瘤中的表达及其在肿瘤形成和发展中的作用.方法 应用组织芯片和免疫组织化学SP法染色以及Western blot技术检测正常脑组织、不同级别大脑星形细胞瘤、小脑髓母细胞瘤中Notch1和Notch2蛋白的表达情况.结果 正常脑组织中Notch1和Notch2蛋白呈阴性表达;Notch1在Ⅳ级星形细胞瘤中阳性比为15/15,Ⅲ级中阳性比为14/15,Ⅱ级中阳性比为10/15,Ⅰ级中阳性比为9/15,总阳性率为80.0%(48/60),阳性部位均为胞质.Ⅰ、Ⅱ、Ⅲ、Ⅳ级星形细胞瘤中表达阳性比及表达强度随肿瘤级别增高而增高.在髓母细胞瘤中阳性比为2/10,且表达水平较低.Notch2在Ⅳ级星形细胞瘤中无表达(0/15),Ⅲ级表达阳性比为1/15,Ⅱ级中阳性比为2/15,Ⅰ级中阳性比为3/15,总阳性率为10%(6/60),表达率及表达强度都很低.在髓母细胞瘤中阳性比为9/10.Notch1在各级别胶质瘤中表达强度的差异均有统计学意义(x2=18.495,P<0.05).Spearman等级相关检验证实肿瘤病理分级与Notch1表达强度之间呈正相关(r=0.859,P<0.05).在星形细胞瘤中,Notch1和Notch2表达的总阳性率差异有统计学意义(x2=56.807,P<0.05),在髓母细胞瘤中,Notch1和Notch2的表达差别有统计学意义(x2=13.778,P<0.05).结论 Notch1和Notch2在星形细胞瘤及髓母细胞瘤中表达不同,并呈现相反的趋势,可能与两者在脑发育过程中的作用不同有关.     

Effects of Notch2 and Notch3 on Cell Proliferation and Apoptosis of Trophoblast Cell Lines

Aims: To investigate the effect of Notch2 and Notch3 on cell proliferation and apoptosis of two trophoblast cell lines, BeWo and JAR.Methods: Notch2 and Notch3 expression in BeWo and JAR cells was upregulated or downregulated using lentivirus-mediated overexpression or RNA interference. The effect of Notch2 and Notch3 on cell proliferation was assessed by the CCK-8 assay. The effect of Notch2 and Notch3 on the apoptosis of BeWo and JAR cells was evaluated by flow cytometry using the Annexin V-PE Apoptosis kit. Lentivirus-based overexpression vectors were constructed by cloning the full-length coding sequences of human Notch2 and Notch3 C-terminally tagged with GFP or GFP alone (control) into a lentivirus-based expression vector. Lentivirus-based gene silencing vectors were prepared by cloning small interfering sequences targeting human Notch2 and Notch3 and scrambled control RNA sequence into a lentivirus-based gene knockdown vector. The effect of Notch2 and Notch3 on cell proliferation was assessed by the CCK-8 assay. And the effect of Notch2 and Notch3 on the apoptosis of BeWo and JAR cells was evaluated by flow cytometry using the Annexin V PE Apoptosis kit.Results: We found that the downregulation of Notch2 and Notch3 gene expression in BeWo and JAR cells resulted in an increase in cell proliferation, while upregulation of Notch3 and Notch2 expression led to a decrease in cell proliferation. Moreover, the overexpression of Notch3 and Notch2 in BeWo and JAR cells reduced apoptosis in these trophoblast cell lines, whereas apoptosis was increased in the cells in which the expression of Notch3 and Notch2 was downregulated.Conclusions: Notch2 and Notch3 inhibited both cell proliferation and cell apoptosis in BeWo and JAR trophoblast cell lines.     

携带人Sox2和EGFP基因慢病毒表达载体构建

目的构建携带人Sox2和EGFP基因的慢病毒表达载体pFUSGW。方法XhoⅠ线性化pLenti-EF1a-Sox2-IRES-EGFP,回收片段并补平XhoⅠ切口,接着BamHⅠ酶切该片段,回收2.356kb片段而获连接用Sox2-IRES-EGFP;EcoRⅠ线性化pFUGW,回收并补平EcoRⅠ切口,然后BamHⅠ酶切该片段,回收9.174kb片段获连接用载体片段,最后使用DNA连接试剂盒（TaKaRa）中的SolutionⅠ将其与连接用Sox2-IRES-EGFP连接,连接产物转化,次日挑选单菌落,提取质粒并行酶切鉴定。所构建载体命名为pFUSGW。获pFUSGW后,按Invitrogen公司推荐的标准程序进行慢病毒包装和确认慢病毒是否成功生产;携带Sox2和EGFP基因的慢病毒感染小鼠胚胎成纤维细胞（MEFs）、人胚肺成纤维细胞（HLFs）和人神经胶质瘤细胞（U87）以建立相应病毒感染体系。结果酶切证实成功构建了pFUSGW,按标准程序生产的携带Sox2和EGFP基因的慢病毒上清高效率感染MEFs、HLFs及U87。结论成功构建携带人Sox2和EGFP基因的慢病毒表达载体pFUSGW,为相关后续的研究打下了良好的基础。     

非小细胞肺癌中Notch1、HIF-1、VEGF蛋白及Notch1 mRNA的表达及意义

目的 探讨Notch1、HIF-1、VEGF蛋白及Notch1 mRNA在非小细胞肺癌(non-small cell lung cancer,NSCLC)组织的表达及其临床病理学意义.方法 采用免疫组化SP法和原位杂交法分别检测65例NSCLC组织、15例正常支气管上皮组织中Notch1、HIF-1、VEGF蛋白及Notch1 mRNA的表达.结果 Notch1、HIF-1、VEGF蛋白及Notch1 mRNA在非小细胞肺癌中阳性表达率分别为81.5%(53/65)、96.9%(63/65)、93.8%(61/65)、73.8%(48/65),均明显高于正常支气管上皮组织阳性表达率(P<0.05);NSCLC中Notch1、HIF-1、VEGF蛋白及Notch1 mRNA的表达均与临床分期、淋巴结转移有关(P<0.05);Notch1、HIF-1与VEGF蛋白间均正相关;Notch1蛋白与Notch1 mRNA的表达呈正相关.结论Notch1、HIF-1、VEGF蛋白及Notch1 mRNA在NSCLC中均表达上调,提示在肺癌的发生、发展中可能起重要作用;检测NSCLC组织Notch1蛋白及mRNA可作为判断肿瘤侵袭与转移的重要指标.     

Sox2 enhances the tumorigenicity and chemoresistance of cancer stem-like cells derived from gastric cancer

Gastric cancer stem-like cells(GCSCs) have been identified to possess the ability of self-renewal and tumor initi-ation.However,the mechanisms involved remain largely unknown.Here,we isolated and characterized the GCSCs by side population(SP) sorting procedure and cultured sphere cells(SC) from human gastric cancer cell lines SGC-7901,BGC-823,MGC-803,HGC-27 and MKN-28.The sorting and culture assay revealed that SP cells proliferated in an asymmetric division manner.In addition,SP cells exhibited a higher potential of spheroid colony formation and greater drug resistance than non-SP cells(NSP).Moreover,the SC were found with enhanced capabilities of drug resistance in vitro and tumorigenicity in vivo.Sox2 mRNA and protein was highly and significantly overex-pressed in the SP cells and SC.Importantly,downregulation of Sox2 with siRNA obviously reduced spheroid colony formation and doxorubicin efflux,as well as increased apoptosis rate in sphere cells in vitro and suppressed tumori-genicity in vivo.These results suggest that both SP cells and cultured SC enrich with GCSCs and that Sox2 plays a pivotal role in sustaining stem cell properties and might be a potential target for gastric cancer therapy.     

Reprogramming of cancer-associated fibroblasts by apoptotic cancer cells inhibits lung metastasis via Notch1-WISP-1 signaling

The interplay between apoptotic cancer cells and the tumor microenvironment modulates cancer progression and metastasis. Cancer-associated fibroblasts (CAFs) play a crucial role in promoting these events through paracrine communication. Here, we demonstrate that conditioned medium (CM) from lung CAFs exposed to apoptotic cancer cells suppresses TGF-β1-induced migration and invasion of cancer cells and CAFs. Direct exposure of CAFs to apoptotic 344SQ cells (ApoSQ) inhibited CAF migration and invasion and the expression of CAF activation markers. Enhanced secretion of Wnt‐induced signaling protein 1 (WISP-1) by CAFs exposed to ApoSQ was required for these antimigratory and anti-invasive effects. Pharmacological inhibition of Notch1 activation or siRNA-mediated Notch1 silencing prevented WISP-1 production by CAFs and reversed the antimigratory and anti-invasive effects. Enhanced expression of the Notch ligand delta-like protein 1 on the surface of ultraviolet-irradiated apoptotic lung cancer cells triggered Notch1-WISP-1 signaling. Phosphatidylserine receptor brain-specific angiogenesis inhibitor 1 (BAI1)-Rac1 signaling, which facilitated efferocytosis by CAFs, participated in crosstalk with Notch1 signaling for optimal production of WISP-1. In addition, a single injection of ApoSQ enhanced WISP-1 production, suppressed the expression of CAF activation markers in isolated Thy1⁺ CAFs, and inhibited lung metastasis in syngeneic immunocompetent mice via Notch1 signaling. Treatment with CM from CAFs exposed to ApoSQ suppressed tumor growth and lung metastasis, whereas treatment with WISP-1-immunodepleted CM from CAFs exposed to ApoSQ reversed the antitumorigenic and antimetastatic effects. Therefore, treatment with CM from CAFs exposed to apoptotic lung cancer cells could be therapeutically applied to suppress CAF activation, thereby preventing cancer progression and metastasis.     

High Notch1 protein expression is an early event in breast cancer development and is associated with the HER‐2 molecular subtype

Zardawi S J, Zardawi I, McNeil C M, Millar E K A, McLeod D, Morey A L, Crea P, Murphy N C, Pinese M, Lopez‐Knowles E, Oakes S R, Ormandy C J, Qiu M R, Hamilton A, Spillane A, Soon Lee C, Sutherland R L, Musgrove E A & O’Toole S A
(2010) Histopathology 56, 286–296 High Notch1 protein expression is an early event in breast cancer development and is associated with the HER‐2 molecular subtype Aims: Activation of Notch signalling results in hyperplasia and tumorigenesis in murine mammary epithelium. However, there is little information regarding the expression of Notch1 in premalignant lesions and early breast cancer. We investigated expression of Notch1 in breast cancer development and its association with molecular subtypes. Methods and results: Immunohistochemical expression of Notch1 was determined in a murine model of mammary carcinogenesis and in breast tissue from two cohorts of breast cancer patients, the first (n = 222) comprising a histological progression series and the second an outcome series of 228 patients with operable invasive ductal carcinoma. Enhanced expression of Notch1 protein was an early event in both murine and human breast cancer development with progressive increases in expression with the development of hyperplasia and malignancy. High Notch1 was not prognostic in the outcome cohort. There was, however, a highly significant association of high Notch1 protein with the HER‐2 molecular subtype of breast cancer (P = 0.008). Conclusions: These data demonstrate that aberrant Notch regulation is an early event in mammary carcinogenesis and is associated with the HER‐2 molecular subtype of breast cancer, and suggest the Notch signalling pathway may be a potential therapeutic target worthy of further investigation.