MNNG诱导TERC基因沉默的16HBE细胞恶性转化模型的建立

目的: 建立N-甲基em>N’-硝基-N-亚硝基胍(N-methyl-N-nitro-N-nitrosoguanidine, MNNG)诱导的人端粒酶RNA组分(telomerase RNA component, TERC)缺陷的人支气管上皮细胞株(16HBE)恶性转化细胞模型。方法:将靶向TERC基因的shRNA干扰质粒载体转染16HBE细胞,G418抗性克隆筛选得到稳定转染的16HBE-1细胞,RT-PCR检测16HBE-1细胞TERC mRNA的干扰效率;用1 mg/L MNNG对16HBE-1细胞进行隔代染毒,每次染毒1 h;直到染毒27次转化灶的出现。分离扩增转化灶细胞并命名为16HBE-T,用软琼脂克隆形成实验和裸鼠成瘤实验鉴定细胞的转化程度。结果:从转化灶分离培养的细胞能在软琼脂中生长,且转化细胞能在裸鼠体内成瘤,HE染色后光镜下显示为鳞癌。结论:成功建立MNNG诱导的TERC基因缺陷的16HBE细胞恶性转化模型。     

siRNA沉默LBH基因促进人支气管上皮细胞周期进展

目的: 利用合成的小分子干扰RNA(siRNA)转染人支气管上皮细胞16HBE,观察LBH(limb-bud and heart) 基因表达下调对16HBE细胞周期及相关基因表达的影响。方法: 脂质体2000转染靶向LBH 基因的siRNA到16HBE细胞,荧光定量RT-PCR检测siRNA转染后LBH基因表达,流式细胞术检测LBH基因沉默后16HBE 细胞周期的改变,荧光定量RT-PCR及Western blotting检测LBH基因沉默后细胞周期素E1和E2表达水平。结果: 50 nmol/L siRNA转染16HBE细胞48 h后, LBH基因的表达水平只有对照组的14%;siRNA转染16HBE细胞48 h,其G₁期细胞百分率比对照组减少9.28%,而S期细胞百分比增加14.08%;16HBE细胞在50 nmol/L siRNA的转染后,细胞周期素E2的表达水平为对照组的2倍,而细胞周期素E1的表达没有发生明显改变。结论: 靶向于LBH基因的siRNA能有效沉默16HBE细胞中LBH基因的表达,LBH基因的表达下调促进了16HBE细胞周期G₁/S期的进展;细胞周期素E2的表达上调参与了LBH沉默导致的细胞周期G₁/S期的进展。     

miR-29b抑制LPS诱导的人支气管上皮细胞系16HBE的凋亡

目的研究miR-29b对脂多糖(LPS)诱导的人支气管上皮细胞系16HBE凋亡的影响。方法将16HBE细胞分为对照组、LPS组(含50μg/mL LPS的细胞培养液培养)、转染mimics control组和转染miR-29b mimics组。MTT法检测增殖;流式细胞测量术检测凋亡;Western blot检测c-caspase-3、c-caspase-12、糖调节蛋白78(GRP78)和CCAAT/增强子结合蛋白同源蛋白(CHOP)蛋白表达。在16HBE细胞中共转染miR-29b mimics、pcDNA-CHOP,同样利用上述方法检测增殖、凋亡。结果与对照组比较,LPS组细胞增殖活性降低、凋亡率升高(P0.05),细胞中c-caspase-3、c-caspase-12、GRP78和CHOP蛋白表达水平升高(P0.05)。与转染mimics control组比较,转染miR-29b mimics组细胞增殖活性升高、凋亡率降低(P0.05),细胞中c-caspase-3、c-caspase-12、GRP78和CHOP蛋白表达水平降低(P0.05)。pcDNA-CHOP可以逆转miR-29b mimics对LPS条件下支气管上皮细胞增殖和凋亡的影响。结论 miR-29b抑制LPS诱导的16HBE细胞的凋亡,其作用机制与抑制内质网应激有关。     

Elafin真核表达载体的构建及其对气道粘液高分泌的调节

目的:构建天然内生多肽Elafin真核表达载体,探讨其对气道粘液高分泌的影响。方法:抽提Elafin行RT-PCR获取Elafin cDNA,双酶切后将片段装载到pMD18-T载体上。以pMD18-T-Elafin为模板行PCR反应,产物胶回收并双酶切后定向克隆至pEGFP-N1上,转化,筛选,双酶切鉴定重组质粒。将pEGFP-N1-Elafin转染正常人支气管上皮细胞HBE16,给予脂多糖(LPS)刺激,Western blot检测细胞内Elafin蛋白的相对含量,RT-PCR检测各组Elafin mRNA和粘蛋白(MUC)5AC mRNA表达水平,荧光素酶报告基因检测系统测定核转录因子-κB(NFκ-B)的活性;ELISA法分析各组细胞MUC5AC蛋白的相对含量。结果:成功构建Elafin真核表达载体,转染重组Elafin的HBE16细胞成功表达Elafin蛋白。LPS刺激可增强NF-κB的活性,该活性在转染重组Elafin后显著降低;MUC5AC蛋白含量及mRNA水平在LPS刺激后也显著升高,在转染重组Elafin后二者的表达水平明显降低。结论:Elafin真核表达载体成功构建,初步发现Elafin可通过降低NFκ-B的活性来下调MUC5AC的表达,为进一步深入研究其对气道粘液高分泌的调节机制奠定了基础。     

屋尘螨提取物激活气道上皮细胞EphA2-STAT3/p38 MAPK信号通路介导气道炎症

目的 探讨受体酪氨酸激酶肝配蛋白A型受体2(EphA2)对屋尘螨提取物(HDM)诱导气道上皮细胞表达炎症细胞因子的作用及其机制.方法 用EphA2小干扰RNA(siRNA)转染气道上皮细胞株16HBE细胞建立EphA2敲减的细胞模型,HDM刺激16HBE细胞后,采用实时定量PCR检测EphA2、白细胞介素6(IL-6)...     

人乳头瘤病毒16型变异株E7蛋白在HeLa细胞中的表达及亚细胞定位

目的构建增强绿色荧光蛋白(EGFP)-人乳头瘤病毒16型变异株E7(HPV16-HBE7)重组质粒pEGFP-HBE7,研究HPV16-HBE7蛋白亚细胞定位,为进一步了解其生物学功能奠定基础。方法采用分子克隆技术,将HPV16-HBE7基因克隆在pEGFP-C1表达载体上,用脂质体法导入宫颈癌细胞中;West-ern印迹检测HBE7蛋白的表达;同时借助免疫荧光技术和EGFP-融合蛋白技术,采用激光共聚焦显微镜观察HBE7蛋白的亚细胞定位。结果重组质粒经PCR、酶切和测序鉴定,其目的片段大小、插入位点和核苷酸序列完全正确;结果表明,转染细胞HBE7蛋白的相对表达量其胞浆明显多于胞核;各个时间段HBE7蛋白均以胞浆分布为主,绿色荧光密集点状分布于细胞浆内,而野生株E7(WE7)蛋白分布在核内。结论人乳头瘤病毒16型变异株E7蛋白主要分布在细胞浆内,以胞浆为主的分布可能和HBE7基因发生突变后丢失核定位信号有关。     

Caveolin-1在TGF-β1诱导人支气管上皮细胞间质化中的作用

目的:探究小窝蛋白1(caveolin-1)在转化生长因子β1(TGF-β1)诱导的人支气管上皮细胞(16HBE细胞)上皮-间充质转化(EMT)中的作用。方法:以16HBE细胞株为研究对象,免疫荧光、RT-q PCR和Western blot实验检测16HBE细胞EMT过程中caveolin-1的mRNA和蛋白表达;Western blot检测siRNA干扰caveolin-1对16HBE细胞EMT的影响。结果:Caveolin-1广泛存在于16HBE细胞膜上,TGF-β1刺激后,caveolin-1的mRNA和蛋白表达减少(P0.05)。与TGF-β1组比较,caveolin-1 siRNA和TGF-β1共同作用促进了细胞形态的转化,抑制了E-钙黏蛋白的蛋白表达而促进了α-SMA的蛋白表达(P0.05)。TGF-β1刺激16HBE细胞后,AKT和Smad3在30 min磷酸化水平最高,与0 min对照组比较显著增加(P0.05);用siRNA干扰caveolin-1基因后再用TGF-β1刺激16HBE细胞30 min,下游信号蛋白分子AKT和Smad3的磷酸化水平增高,与TGF-β1组比较显著增加(P0.05)。结论:TGF-β1能下调16HBE细胞的caveolin-1表达水平;caveolin-1可能参与了TGF-β1诱导的16HBE细胞EMT过程中TGF-β1/Smad通路和PI3K-AKT通路的活化。     

人γ-谷氨酰半胱氨酸合成酶催化亚单位基因E-box元件功能初步分析

目的：探讨人支气管上皮细胞γ-谷氨酰半胱氨酸合成酶催化亚单位（GCLC）基因上游调控序列E-box元件的功能。方法:利用PCR法克隆人GCLC基因上游调控序列，PCR重叠延伸法对2个E-box元件分别和同时进行定点突变。扩增获得的突变体片段克隆入PMD18-T载体，DNA测序鉴定后，亚克隆入野生型GCLC-Luc荧光素酶报道载体。将3个突变体质粒和野生型质粒转染人肺泡上皮细胞A549和人支气管上皮细胞16HBE，检测转染后细胞荧光素酶活性值。结果:测序结果证实，成功将E-box1 CACGGG突变为AGCGGG；E-box2 CACGTG突变为CACGGA。GCLC-Luc、GCLC-mEbox1-Luc（突变E-box1）、GCLC-mEbox2-Luc（突变E-box2）、GCLC-mEbox12-Luc（突变E-box1和E-box2）转染A549细胞后荧光素酶活性值分别为（5 197 852±132 206）U、（5 455 692±127 431）U、（5 315 722±244 197）U、（5 174 303±183 179）U，转染16HBE细胞后荧光素酶活性值分别为（141 157±18 907）U、（126 454±23 724）U、（137 315±22 179）U、（132 441±28 970）U。经过统计学分析，各组荧光酶活性没有显著差别，均P>0.05。结论:E-box元件不参与基础状态下A549细胞和16HBE细胞GCLC基因转录调控。     

人T细胞免疫球蛋白黏蛋白-4 cDNA全长真核表达载体的构建及其在16HBE细胞中的表达

目的克隆人T细胞免疫球蛋白黏蛋白-4(TIM-4)基因cDNA,构建其真核表达载体pEGFP-C2-TIM-4,并转染16HBE细胞。方法根据GeneBank中人TIM-4 cDNA序列(编号:NM-138379.2),设计出带有EcoRI和BamHI的上下游引物,应用RT-PCR技术,从人骨髓中扩增出TIM-4基因编码区序列,克隆到pMD18-T载体,形成pMD18-T-TIM-4重组质粒,经菌落PCR,双酶切,测序鉴定获得人TIM-4基因cDNA片段,然后将其亚克隆入pEGFP-C2绿色荧光载体中,并通过菌落PCR,双酶切,测序鉴定其重组体。将测序正确的pEGFP-C2-TIM-4质粒转染人气道上皮细胞(16HBE),用实时定量PCR检测目的基因的表达。结果成功扩增出人TIM-4 cDNA全长1134 bp,经T-A克隆构建的pMD18-T-TIM-4重组质粒经菌落PCR,双酶切,测序证实载体中含有正确的TIM-4编码区片段。由此构建的真核表达载体pEGFP-C2-TIM-4,经菌落PCR扩增出1134 bp左右的片段,经双酶切后产生4.7 kb和1134 bp左右的2条带,DNA测序显示与GeneBan...     

TRPC1在TGF-β1诱导支气管上皮细胞间充质转化中的作用

目的:探究经典瞬时受体电位通道1(TRPC1)在转化生长因子β1(TGF-β1)诱导人支气管上皮细胞(16HBE)间充质转化(EMT)中的作用。方法:以16HBE细胞株为研究对象,免疫荧光、RT-PCR和Western blotting检测16HBE细胞EMT过程中TRPC1 mRNA和蛋白的表达;Western blotting检测TRPC1阻断剂和siRNA干扰对16HBE细胞EMT的影响。结果:(1)TGF-β1刺激后细胞形态明显改变,E-钙黏蛋白表达减少(P0.01),而α-SMA蛋白表达增加(P0.05)。(2)TRPC1广泛存在于16HBE细胞,且TGF-β1刺激后TRPC1 mRNA和蛋白的表达增加(P0.05)。(3)与TGF-β1组相比,阻断剂和TGF-β1共同作用组或siRNA和TGF-β1共同作用组细胞形态改变受抑制,E-钙黏蛋白和α-SMA蛋白表达受抑制(P0.05)。结论:TGF-β1诱导16HBE细胞发生EMT,其机制可能与其上调16HBE细胞TRPC1有关。     

高渗诱导人气道上皮细胞系黏液高分泌

目的研究高渗条件对正常人气道上皮细胞(HBE)黏蛋白(MUC)5AC分泌的影响,以及蛋白激酶C(PKC)-热休克蛋白(HSP)70信号途径在其中的可能作用。方法 采用高渗盐水诱导培养HBE16细胞的方法复制黏液高分泌体外模型,分别用PKCμ抑制剂G 6976、PKCα抑制剂Safingol、PKCβ抑制剂LY333531和PKCδ抑制剂Rot-tlerin干预HBE16细胞。Western blot检测HSP70-2的蛋白含量;RT-PCR检测人HSP70-2转录水平;ELISA检测培养上清MUC5AC蛋白含量c各高渗组的培养上清MUC5AC蛋白含量、HSP70-2蛋白和转录水平较对照组显著升高,并随着培养时间的延长而逐渐增加(P<0.05)。G 6976处理组的上述指标显著降低(P<0.01),但仍高于对照组(P<0.05);而Safingol、LY333531和Rottlerin处理组均无改变。结论 高渗盐水可诱导人气道上皮细胞MUC5AC的高分泌,HSP70-2系通过PKC中的μ亚型在该过程中起重要作用的。     

TNF-α与香烟烟雾在诱导气道上皮细胞株黏蛋白表达的相互作用

目的 探讨肿瘤坏死因子TNF-α与香烟提取物共同诱导气道黏液高分泌的相互关系及作用特点。方法 培养的人气道上皮细胞BEAS-2B,转染核转录因子（NF）-κB"decoy"寡核苷酸（ODNs）,并以乱序NF-κB ODNs为对照转染组,各组均分别予以TNF-α、10%香烟提取物（CSE）单独刺激及共同刺激,以Western blot、ELISA及RT-PCR法检测各组刺激前后磷酸化表皮生长因子受体（p-EGFR）、黏蛋白（MUC5AC）蛋白及mRNA水平。结果 转染乱序NF-κB ODNs的细胞予以TNF-α、10% CSE刺激后,各组细胞中p-EGFR蛋白水平较对照组升高,伴随MUC5AC蛋白含量及基因转录水平的提高(P<0.05);共孵育组中较单独刺激组升高更为显著（P<0.05）。转染NF-κB"decoy"ODNs组再予以TNF-α刺激,细胞中MUC5AC蛋白含量及mRNA水平与未转染组相比升高不明显,而单用CSE刺激组中的MUC5AC、p-EGFR水平仍有明显升高（P<0.05）;共孵育组显示出与CSE单独刺激组相似的结果。结论 TNF-α、CSE能协同促进气道上皮细胞中黏蛋白合成,转录因子NF-κB主要参与TNF-α所致的MUC5AC表达,而在CSE诱导的效应过程中作用不明显。     

Study on TRPV1-mediated mechanism for the hypersecretion of mucus in respiratory inflammation

Transient receptor potential vanilloid 1 (TRPV1) is sensitized by the high affinity TrkA receptor, which promotes pro-inflammatory cytokine production and mediates mucus hypersecretion in bronchial epithelial cells. The purpose of this study was to investigate the mechanism of TRPV1-mediated mucus hypersecretion and respiratory inflammation. Firstly, using Western blot analysis we found that epidermal growth factor receptor (EGFR) and TRPV1 were highly co-expressed in human bronchial epithelial cells (HBE16) with HNE and capsaicin co-treated, the levels of pro-inflammatory cytokines and MUC5AC were also highly co-expressed; however, TRPV1 receptor expression was low in these cells with only HNE stimulation, which demonstrated that sensitization of TRPV1 was not increased in HBE16 cells treated with HNE alone. Secondly, the EGF receptor antagonist (AG1478) and the TrkA receptor inhibitor (K252a) significantly inhibited TRPV1 sensitivity and the expression of MUC5AC and pro-inflammatory cytokines. Furthermore, the PI3K inhibitor LY294002, the PKC inhibitor bisindoylmaleimide (BIM) and the TRPV1 antagonist capsazepine completely abrogated the EGF sensitizing effect. Furthermore, the hypoxia-inducible factor (HIF-1α) inhibitor 2-methoxyestradiol (2-ME2) decreased the activity of PKC by a specific pathway. These findings strongly suggest that TRPV1 sensitization influences the hypersecretion of mucus and inflammatory cytokines, is associated with the PI3K and PKC signaling pathways and is involved HIF-1α activity.     

TMEM16A-Mediated Mucin Secretion in IL-13-Induced Nasal Epithelial Cells From Chronic Rhinosinusitis Patients

Purpose

Chronic rhinosinusitis with nasal polyps (CRSwNP), a mainly Th2 cytokine-mediated disease, often involves mucus secretion. Recent evidence suggests that transmembrane protein 16A (TMEM16A), a calcium-activated Cl^- channel (CaCC), can regulate mucus secretion from airway epithelium by transepithelial electrolyte transport and hydration. However, the role of TMEM16A in mucin production/secretion in the airway epithelium is not clear. This study was conducted to determine the role of TMEM16A in mediating mucin secretion in human nasal polyp epithelial cells (HNPECs) induced by IL-13.

Methods

Human sinonasal mucosa tissue and dissociated sinonasal epithelium from control subjects and patients with CRSwNP were assessed for the expression of TMEM16A and the secretion of human mucin 5AC (MUC5AC) by immunohistochemistry, Western blot analysis, and enzyme-linked immuno-sorbent assay (ELISA). A model of the Th2 inflammatory environment was created by exposure of primary air-liquid interface (ALI)-cultured HNPECs to interleukin-13 (IL-13) for 14 days, with subsequent assessment of TMEM16A expression in cell lysates by Western blotting and MUC5AC secretion in apical washings of cells by ELISA.

Results

The expressions of TMEM16A and MUC5AC were increased in human nasal polyp tissue and dissociated nasal polyp epithelium. TMEM16A was detected in IL-13-treated HNPECs, specifically in MUC5AC-positive cells but not in ciliated cells. IL-13 treatment increased percentages of TMEM16A-positive cells, MUC5AC-positive cells, and cells coexpressing TMEM16A/MUC5AC, the expression of TMEM16A protein, and the secretion of MUC5AC. T16Ainh-A01, a TMEM16A inhibitor, attenuated these IL-13-induced effects.

Conclusions

The expression of TMEM16A and MUC5AC are increased in CRSwNP, which might be a direct effect of Th2 cytokines present in the sinonasal mucosa in CRSwNP. Down-regulation of TMEM16A expression and MUC5AC secretion in HNPECs by T16Ainh-A01 indicates that TMEM16A might play an important role in mucin secretion in upper airway inflammatory diseases.     

MUC5AC, a gel-forming mucin accumulating in gallstone disease, is overproduced via an epidermal growth factor receptor pathway in the human gallbladder

Despite evidence that mucin overproduction is critical in the pathogenesis of gallstones, the mechanisms triggering mucin production in gallstone disease are unknown. Here, we tested the potential implication of an inflammation-dependent epidermal growth factor receptor (EGF-R) pathway in the regulation of gallbladder mucin synthesis. In gallbladder tissue sections from subjects with cholesterol gallstones, mucus accumulation was associated with neutrophil infiltration and with increased expressions of EGF-R and of tumor necrosis factor-alpha (TNF-alpha). In primary cultures of human gallbladder epithelial cells, TNF-alpha induced EGF-R overexpression. In the presence of TNF-alpha, EGF-R ligands (either EGF or transforming growth factor-alpha) caused significant increases in MUC5AC mRNA and protein production, whereas expression of the other gallbladder mucins MUC1, MUC3, and MUC5B was unchanged. In addition, on gallbladder tissue sections from subjects with gallstones, increased MUC5AC immunoreactivity was detected in the epithelium and within mucus gel in the lumen. Studies in primary cultures demonstrated that MUC5AC up-regulation induced by the combination of TNF-alpha with EGF-R ligands was completely blunted by inhibitors of EGF-R tyrosine kinase and mitogen-activated protein/extracellular signal-related kinase kinase. In conclusion, an inflammation-dependent EGF-R cascade causes overproduction of the gel-forming mucin MUC5AC, which accumulates in cholesterol gallstone disease. The ability to interrupt this cascade is of potential interest in the prevention of cholesterol gallstones.     

AGR2 is induced in asthma and promotes allergen-induced mucin overproduction

Mucins are gel-forming proteins that are responsible for the characteristic viscoelastic properties of mucus. Mucin overproduction is a hallmark of asthma, but the cellular requirements for airway mucin production are poorly understood. The endoplasmic reticulum (ER) protein anterior gradient homolog 2 (AGR2) is required for production of the intestinal mucin MUC2, but its role in the production of the airway mucins MUC5AC and MUC5B is not established. Microarray data were analyzed to examine the relationship between AGR2 and MUC5AC expression in asthma. Immunofluorescence was used to localize AGR2 in airway cells. Coimmunoprecipitation was used to identify AGR2-immature MUC5AC complexes. Agr2(-/-) mice were used to determine the role of AGR2 in allergic airway disease. AGR2 localized to the ER of MUC5AC- and MUC5B-producing airway cells and formed a complex with immature MUC5AC. AGR2 expression increased together with MUC5AC expression in airway epithelium from "Th2-high" asthmatics. Allergen-challenged Agr2(-/-) mice had greater than 50% reductions in MUC5AC and MUC5B proteins compared with allergen-challenged wild-type mice. Impaired mucin production in Agr2(-/-) mice was accompanied by an increase in the proportion of mucins contained within the ER and by evidence of ER stress in airway epithelium. This study shows that AGR2 increases with mucin overproduction in individuals with asthma and in mouse models of allergic airway disease. AGR2 interacts with immature mucin in the ER and loss of AGR2 impairs allergen-induced MUC5AC and MUC5B overproduction.     

Gene expression of gastric type mucin (MUC5AC) in pancreatic tumors: its relationship with the biological behavior of the tumor

Previously it has been found that the MUC2 gene for intestinal type secretory mucin is highly expressed in intraductal papillary mucinous tumors (IPMT), which are characterized by non-invasive growth and a favorable outcome. In contrast, MUC2 mRNA is rarely expressed in invasive ductal carcinomas (IDC), which have poor outcomes. The gastric type secretory mucin, MUC5AC, is strongly expressed in the surface mucous cells of gastric mucosa. As both MUC2 and MUC5AC mucins share the characteristics of forming highly viscous gels, it is expected that not only MUC2 mucin expression but also MUC5AC mucin expression may be associated with a favorable prognosis in patients with pancreatic tumors. MUC5AC mucin gene expression was examined in 24 cases of IPMT and 38 cases of IDC by in situ hybridization using a digoxigenin-labeled oligonucleotide. The results were compared with MUC2 mucin gene expression. Neither MUC5AC mRNA nor MUC2 mRNA was detected in normal pancreatic tissues. MUC5AC mRNA was expressed in 20 of 24 cases of IPMT (83%) and in five of 38 cases of IDC (13%). In contrast, MUC2 mRNA was expressed in 14 of 24 cases of IPMT (58%) and in none of the 38 cases of IDC (0%). The expression rates of MUC5AC mRNA and MUC2 mRNA in IPMT were significantly higher than those in IDC (P< 0.001, respectively). Intraductal papillary mucinous tumors are characterized by three histological types: (i) villous dark cell type; (ii) papillary clear cell type; and (iii) compact cell type. The villous dark cell type generally expressed both MUC5AC+ and MUC2+ genes. Alternatively, the papillary clear cell type and the compact cell type usually showed MUC5AC+ and MUC2- expression. Patients with MUC5AC mRNA expression had a significantly better survival prognosis than those with no MUC5AC mRNA expression (P< 0.005). In conclusion, MUC5AC gene expression occurs in a majority of IPMT cases, even in those with no MUC2 production. MUC5AC expression can be     

Mechanisms of mucin production by rhinovirus infection in cultured human airway epithelial cells

Mucus hypersecretion relates to exacerbations of bronchial asthma and chronic obstructive pulmonary disease (COPD) caused by rhinovirus (RV) infection. We examined the mechanisms of RV infection-induced mucin production in human tracheal surface epithelial cells and submucosal gland cells. RV14 up-regulated the mRNA expression of MUC2, MUC3, MUC5AC, MUC5B and MUC6, and increased MUC5AC and total mucin concentration in supernatants and lysates of the surface cells. An inhibitor of the nuclear factor kappaB caffeic acid phenylethyl ester, inhibitors of selective p44/42 mitogen-activated protein kinase-kinase PD98059 and U0126, and a selective Src inhibitor PP1 attenuated MUC5AC mRNA expression, and secretion and production of MUC5AC and total mucin glycoprotein in the surface cells. In the gland cells, RV14 also increased mRNA expression of MUC2, MUC5AC, MUC5B and MUC7, and the inhibitors attenuated the secretion of total mucin glycoprotein. Src-related p44/42 mitogen-activated protein kinase pathway may be associated with RV-induced mucin hypersecretion in human airways.     

Expression of mucin core proteins in extramammary Paget's disease

Extramammary Paget's disease (EPD) is a relatively common skin cancer wherein tumor cells have mucin in their cytoplasm. However, little is known about mucin expression in EPD. We examined immunohistochemically the expression of mucin core proteins (MUC1, MUC2, MUC5AC and MUC6) in 36 cases of EPD and found different patterns of expression in intraepithelial (n = 36), microinvasive (n = 13) and invasive lesions (n = 6). In normal skin, MUC1 was expressed in the sebaceous, eccrine and apocrine glands. MUC2, MUC5AC and MUC6 were not expressed in any of these. In the 36 intraepithelial lesions, MUC1 and MUC5AC were expressed in 35 and 36 lesions, respectively. MUC1 expression was also observed in all 13 microinvasive lesions and in all six invasive lesions. In contrast to the intraepithelial lesions, a decrease or loss of MUC5AC expression was observed in five out of 13 microinvasive lesions and in all six invasive lesions. MUC2 and MUC6 were not expressed in any of the EPD lesions examined. The combination of immunohistochemical staining for MUC1 and MUC5AC was useful for identifying invasive Paget cells. The decrease or loss of MUC5AC expression may have an important role in the invasive growth of Paget cells.