HGF/c-Met信号通路在克唑替尼诱导不同肺癌细胞株凋亡中的作用

 目的: 观察克唑替尼(crizotinib)诱导不同肺癌细胞株凋亡中HGF/c-Met信号通路的变化并探讨其调控机制。方法: 采用噻唑蓝(MTT)法检测克唑替尼对H1993(c-Met扩增的肺腺癌细胞)、H2228(含有EML4-ALK融合基因的肺癌细胞)和A549细胞的活力抑制情况;采用流式细胞术检测3种细胞在克唑替尼作用后24 h、48 h和72 h的凋亡率;采用Western blot检测细胞在克唑替尼作用前后HGF/c-Met信号通路中MET蛋白及其磷酸化形式p-MET的水平,同时观察其下游通路关键蛋白AKT、ERK、p-AKT和p-ERK的变化情况。结果: MTT结果表明克唑替尼作用72 h后,H1993、H2228和A549细胞株的细胞活力抑制率均呈剂量依赖性升高。流式细胞术检测发现随着克唑替尼作用时间的延长,细胞凋亡率呈时间依赖性增加(P<0.05)。Western blot检测结果提示在H1993细胞株和H2228细胞株中,p-MET、p-AKT和p-ERK随着时间的延长蛋白水平呈现下降趋势。而在A549细胞株中p-AKT、p-ERK和p-MET在药物作用72 h后的变化趋势不明显。结论: 初步证实HGF/c-Met信号通路与克唑替尼诱导肺癌细胞株H1993和H2228凋亡相关。     

旁路信号通路激活介导的EML4-ALK融合基因阳性肺癌细胞株H3122对alectinib继发耐药的研究

目的:本研究旨在探讨肝细胞生长因子(HGF)、表皮生长因子(EGF)及转化生长因子α(TGF-α)是否以旁路激活的方式诱导EML4-ALK融合基因阳性肺癌细胞株H3122对alectinib的耐药,并进一步探讨旁路信号激活在alectinib耐药中的作用。方法:用不同浓度的alectinib、克唑替尼(crizotinib)、17-DMAG或(和)HGF(50μg/L)、EGF(100μg/L)、TGF-α(100μg/L)处理EML4-ALK阳性肺癌细胞株H3122,采用CCK-8法检测细胞活力,流式细胞术检测细胞凋亡,应用Western blot技术检测细胞中ALK、c-Met、EGFR及相应磷酸化蛋白的表达,观察其下游通路关键蛋白AKT、ERK、p-AKT和p-ERK水平。结果:Alectinib作用72 h后,H3122细胞株的活力随着alectinib药物浓度的增加而逐渐下降,呈剂量依赖性。HGF、EGF和TGF-α诱导后,alectinib抑制H3122细胞的生长曲线往右移,HGF、EGF和TGF-α处理能够降低alectinib对肺癌细胞活力的抑制作用。0.05μmol/L alectinib作用H3122细胞株48 h后的凋亡率为(20.12±1.36)%,而alectinib联合HGF、EGF和TGF-α后的凋亡率分别为(7.85±1.03)%、(5.60±0.79)%和(4.58±1.00)%,显著低于alectinib单药处理(P0.05)。Alectinib单药成功抑制p-ALK及其下游信号通路,HGF明显增加细胞中p-Met及其下游p-AKT、p-ERK的蛋白水平,EGF和TGF-α明显增加细胞中p-EGFR及其下游p-AKT、p-ERK的表达,alectinib抑制p-ALK,但不能抑制HGF、EGF和TGF-α诱导的pAKT和p-ERK的蛋白表达。此外,联合应用crizotinib和17-DMAG可以抑制因HGF和EGFR配体而导致的H3122耐药细胞的活力。结论:HGF、EGF和TGF-α可通过旁路激活的方式诱导EML4-ALK阳性肺癌细胞H3122对alectinib耐药,其机制可能与HGF激活c-Met磷酸化、EGF和TGF-α激活EGFR磷酸化有关。     

免疫组化染色及FISH法检测肺鳞状细胞癌中ALK蛋白的表达

目的：探讨棘皮类微管蛋白4(echinoderm microtubule-associated protein-like 4, EML4)与间变性淋巴瘤激酶基因(ana-plastic lymphoma kinase, ALK)融合在肺鳞状细胞癌中的发生率,为进一步开展靶向治疗提供参考。方法采用高度特异性和敏感性的ALK抗体(D5F3)对219例肺鳞状细胞癌石蜡包埋组织标本进行免疫组化染色,并对阳性标本行EML4-ALK荧光原位杂交技术(fluorescence in situ hybridization, FISH)检测。结果免疫组化染色检出ALK强阳性标本4例(1．8%,4/219)、中等强度3例和弱阳性6例。 FISH检测确认ALK强阳性标本存在EML4-ALK基因融合,中等和弱阳性标本为假阳性。结论肺鳞状细胞癌中存在少量EML4-ALK基因融合,其是否对Crizotinib治疗敏感亟需进行临床研究;免疫组化检测ALK蛋白强阳性才能判断为EML4-ALK基因融合。     

Notch3信号通路介导SAHA诱导的小细胞肺癌H446细胞凋亡

目的:观察辛二酰苯胺异羟肟酸(suberoylanilide hydroxamic acid,SAHA)对人小细胞肺癌H446细胞凋亡的影响,并探讨其分子机制。方法:选取人小细胞肺癌H446细胞作为研究对象,采用CCK-8法检测SAHA的细胞毒作用并测定IC50,采用流式细胞术检测细胞凋亡,转染N3ICD真核表达质粒构建高表达N3ICD的H446细胞系,采用RT-PCR法检测Notch3的mRNA水平,采用Western blot法检测Notch3、N3ICD、Puma和cleaved caspase-3的蛋白水平。结果:SAHA可显著降低H446细胞存活率且呈剂量依赖性(P0.05),SAHA作用48 h的IC50为1.91μmol/L;SAHA可诱导H446细胞凋亡且具有剂量依赖性(P0.05);H446细胞中Notch3基因表达呈阴性,SAHA可使H446细胞Notch3基因恢复表达并激活Notch3信号通路(P0.05);沉默Notch3基因可抑制SAHA对H446细胞的促凋亡作用(P0.05);N3ICD高表达使H446细胞中Puma和cleaved caspase-3蛋白水平升高(P0.01)。结论:在体外SAHA可激活人小细胞肺癌H446细胞Notch3信号通路,上调Puma蛋白表达水平,诱导H446细胞凋亡。     

TLR4通路对polyI:C诱导肝癌细胞凋亡的影响

目的:研究TLR4信号通路活化对polyI:C诱导人肝癌细胞系H7402凋亡的影响,并分析其可能的作用机制。方法:用TLR4激动剂LPS处理H7402细胞24 h后,转染polyI:C刺激24 h,然后利用流式细胞术检测细胞凋亡,荧光定量PCR检测凋亡基因及胞内RNA模式识别受体TLR3、MDA5、RIG-I和LGP2的表达,Western blot检测识别受体的蛋白表达水平。结果:LPS预处理,减弱了polyI:C诱导H7402细胞凋亡的作用。同时,促凋亡基因Noxa的表达水平降低。在此过程中polyI:C的胞内识别受体RIG-I、MDA5的基因和蛋白水平表达下调。结论:LPS可能通过降低H7402细胞内dsRNA识别受体的表达,抑制了polyI:C诱导H7402细胞凋亡的作用。     

mTOR信号通路与细胞凋亡

哺乳类动物雷帕霉素靶蛋白(mTOR)主要通过上游信号转导通路磷脂酰肌醇3-激酶(PI3K)/蛋白激酶B(PKB/Akt)/mTOR信号通路及下游信号通路mTOR/ eIF4E结合蛋白1(4EBP1)、mTOR/p70S6激酶(p70S6K)在细胞生长、增值与分化和在血管再生、蛋白合成与降解中发挥作用.细胞凋亡是细胞的一种程序性死亡,在机体发育、组织代谢中有着重要作用,而细胞凋亡的异常调节与许多疾病的发生和发展紧密相连.近年研究发现,mTOR信号通路在细胞凋亡过程中扮演了重要角色,并已被作为新的药物治疗靶点.     

EGFR/HER2基因敲减对SPC-A-1细胞株细胞生物学特性及相关信号通路的影响

目的： 探讨EGFR/HER2基因沉默对非小细胞肺癌细胞株EGFR酪氨酸激酶信号转导通路的交互影响及其与细胞增殖、凋亡和周期改变的关系。方法： 设计并合成EGFR、HER2及 EGFR/HER2共干扰序列,构建含干扰序列的载体,进行瞬时转染;应用实时荧光定量、蛋白印迹法检测基因沉默效果;用四甲基偶氮唑盐比色法、流式细胞仪检测基因沉默后生物学特性改变;蛋白印迹法检测EGFR下游信号通路蛋白Akt、p-Akt、p-Erk1/2、p-p38表达水平变化;采用SPSS13.0软件分析结果。结果： 在SPC-A-1细胞系中,EGFR干扰组、HER2干扰组、EGFR联合HER2干扰组和EGFR-HER2共干扰组体外细胞增殖率均有下降趋势;除EGFR干扰外,其余各组均可诱发凋亡;各组的细胞周期G1期和S期细胞比例有显著改变;基因沉默效果检测显示EGFR和HER2基因蛋白水平被下调。下游信号通路蛋白检测示EGFR下游信号通路蛋白Akt、p-Akt、p-Erk1/2、p-p38表达水平和细胞增殖、凋亡以及细胞周期改变之间未发现明显相关规律。结论： 单纯EGFR干扰SPC-A-1细胞不能诱发显著凋亡,HER2和EGFR/HER2基因共沉默后诱发的人肺腺癌SPC-A-1细胞凋亡比阴性对照显著增加。EGFR/HER2基因沉默后诱发的细胞增殖、凋亡和细胞周期改变与EGFR家族下游信号通路蛋白之间未发现显著相关关系。     

Zeste基因增强子同源物2通过调控Wnt/β-catenin信号通路影响脑胶质瘤细胞凋亡

目的:探讨zeste基因增强子同源物2(EZH2)通过调控Wnt/β-catenin信号通路对脑胶质瘤细胞凋亡的影响。方法:以RT-q PCR和Western blot检测胶质瘤U87、H4和U251细胞及正常人脑星形细胞(NHA)中EZH2的表达水平。在H4细胞中转染EZH2 siRNA和siRNA control,MTT测定细胞活力,流式细胞术测定细胞凋亡,分光光度计法检测caspase-3的活性,Western blot检测Wnt/β-catenin信号通路中关键蛋白β-连环蛋白(β-catenin)和下游靶分子c-Myc的蛋白表达。用Wnt/β-catenin信号通路激活剂处理转染EZH2 siRNA的H4细胞,流式细胞术测定细胞凋亡,Western blot测定β-catenin和c-Myc的表达。结果:胶质瘤U87、H4和U251细胞中EZH2的mRNA和蛋白水平均明显高于NHA(P0.05),并且H4细胞中EZH2 mRNA和蛋白水平高于U87和U251细胞(P0.05)。EZH2 siRNA可以明显下调H4细胞中EZH2的mRNA和蛋白水平。EZH2表达下调后的H4细胞从48 h开始细胞活力降低,并且细胞凋亡率也明显升高,细胞中caspase-3活性也明显升高(P0.05),同时EZH2表达下调还可以抑制β-catenin和c-Myc的表达。Wnt/β-catenin信号通路的激活剂可以减少EZH2诱导的H4细胞凋亡,降低细胞中caspase-3的活性。结论:EZH2在脑胶质瘤细胞中过度表达,下调其表达可以通过抑制Wnt/β-catenin信号通路的激活而诱导胶质瘤细胞凋亡。     

Xaf1调节TNFR信号转导而诱导细胞凋亡的机制研究

目的： 利用基因开关调节的Xaf1-Saos诱导细胞株， 检测Xaf1对TNFR信号转导通路的影响，探索Xaf1与TNF-α协同诱导细胞凋亡的机制。方法： 以免疫印迹法和RT-PCR检测Xaf1对TNFR1 表达的影响，细胞周期 DNA 含量流式细胞术检测NF-κB对Xaf1诱导细胞凋亡的影响，gel mobility shift assay 检测NF-κB的DNA结合活性， luciferase 活性检测法及RT-PCR检测NF-κB的转录活性，激酶分析法检测SAPK/JNK 激酶的活性。结果： Xaf1不影响TNFR1蛋白及mRNA水平的表达，细胞内诱导活性的NF-κB可抑制Xaf1诱导的细胞凋亡， Xaf1的表达抑制TNF-α所介导的NF-κB的DNA结合活性和转录活性，也抑制了SAPK/JNK 激酶的活性。结论： Xaf1 对TNFR信号转导的抑制是Xaf1协同TNF-α诱导细胞凋亡的机制之一。     

IHC、FISH和RT-PCR检测对EML4-ALK重排的一致性

棘皮动物微管结合蛋白-间变性淋巴瘤激酶(echinoderm microtubule-associated protein-like4-anaplastic lymphoma kinase,EML4-ALK)在肺癌中已成为第二个最重的驱动致癌基因,在4%~6%的肺腺癌中EML4-ALK已经成为第一个可以靶向治疗的融合基因位点.伴随着ALK分离探针荧光原位杂交(fluorescent in situ hybridization,FISH)试剂盒的上市,克唑替尼已经被批准治疗ALK阳性的进展期非小细胞肺癌(non-smallcelllungcancer,NSCLC).然而,一种靶向药物的成功主取决于一种敏感且特异的筛选实验方法来检测分子药物作用的靶点.以作者的经验看,用RT-PCR来检测EML4-ALK,比用FISH和免疫组化(immunohistochemistry,IHC)方法更敏感,结果更可靠.尽管通过FISH检测ALK已经经过大量的临床实验验证,然而该方法在技术层面仍存在许多具有挑战性的问题,而通过IHC和RT-PCR方法检测ALK仍需临床进一步的探索.     

EML4-ALK fusion gene in Korean non-small cell lung cancer

A fusion gene between echinoderm microtubule-associated protein-like 4 (EML4) and the anaplastic lymphoma kinase (ALK) has been identified in non-small cell lung cancers (NSCLCs). Although a few studies have evaluated EML4-ALK fusion genes in Korean NSCLCs, the prevalence of different EML4-ALK fusion variants has yet to be clearly assessed. Herein, we have examined the profiles of EML4-ALK fusion gene variants in Korean patients of NSCLCs. EML4-ALK fusion genes have been detected in 10 (6.0%) of 167 patients of NSCLCs and in 9 (7.4%) of 121 patients of adenocarcinoma. Of the 10 patients with fusion genes identified, 8 (80%) were E13;A20 (variant 1) and 2 (20%) were E6;A20, with an additional 33-bp sequence derived from intron 6 of EML4 (variant 3b). These results indicate that the profiles of EML4-ALK fusion gene variants in Korean patients of NSCLC may differ from those in other ethnic populations. Herein, we describe for the first time the profiles of EML4-ALK fusion variants of Korean patients with NSCLCs.     

EGFR突变的非小细胞肺癌患者EML4-ALK融合基因的检测及其临床特征分析

目的: 检测EML4-ALK融合基因在表皮生长因子受体(epidermal growth factor receptor, EGFR)突变的非小细胞肺癌(non-small-cell lung cancer, NSCLC)人群中的突变率,并分析其与临床特征的关系。方法: 入选的102例NSCLC患者均为中国人,且至少满足以下1个入选条件:女性、不吸烟/少吸烟和肺腺癌。将102例患者的组织标本采用多重逆转录聚合酶链反应 (multiplex RT-PCR)的方法检测其EML4-ALK融合基因的突变率;对EML4-ALK阳性患者的组织标本采用DNA扩增后直接测序的方法来检测其EGFR(18~21号外显子)及Kirsten鼠肉瘤基因(Kirsten rat sarcoma,KRAS)(1、2号外显子)的突变情况。结果: 102例非小细胞肺癌患者的组织标本,有8例(7.8%)存在EML4-ALK融合基因突变,其中7例为突变体1(variant 1,V1),1例为突变体2(variant 2,V2);这8例EML4-ALK阳性患者组织标本的EGFR(18~21号外显子)及KRAS(1、2号外显子)均为野生型。8例阳性患者中,5例患者的年龄小于总体患者的平均年龄(59±10)岁,占62.5%(5/8);女性患者6例,占75%(6/8);不吸烟患者7例,占87.5%(7/8);腺癌患者5例,占62.5%(5/8)。结论: EML4-ALK融合基因突变代表了NSCLC的一个新的分子亚型,EML4-ALK突变与EGFR及KRAS突变是不共存的。     

京尼平对缺氧/复氧损伤后大鼠心肌细胞凋亡及自噬的影响

目的 探讨京尼平对缺氧/复氧(H/R)损伤后大鼠心肌细胞凋亡及自噬的影响。方法 建立H/R损伤模型,体外培养的大鼠H9c2心肌细胞行缺氧12 h、复氧4 h。实验分为对照组（Con）、京尼平组(GE)、缺氧/复氧组(H/R)、缺氧/复氧+京尼平组(H/R+GE)。细胞计数试剂盒-8（CCK-8）检测细胞存活率,流式细胞仪检测细胞凋亡,透射电子显微镜观察自噬体,Western blotting检测Bax、Bcl-2、P62、Beclin1、LC3-Ⅱ、蛋白激酶B(Akt)、p-Akt、哺乳动物雷帕霉素靶蛋白（mTOR）和p-mTOR蛋白的表达。结果 京尼平预处理增强了H/R损伤后的H9c2心肌细胞活力,抑制细胞凋亡及自噬体累积,降低自噬结构断面积与细胞质断面积的比值。Western blotting结果显示,京尼平预处理减少了H/R损伤后Bax、LC3-Ⅱ和Beclin1蛋白表达,增加Bcl-2、P62、p-Akt和p-mTOR蛋白表达。结论 京尼平可以抑制H/R损伤后心肌细胞凋亡及自噬,其机制可能与上调Akt/mTOR信号通路有关。     

Activation of mammalian target of rapamycin signaling promotes cell cycle progression and protects cells from apoptosis in mantle cell lymphoma

Mantle cell lymphoma (MCL) is characterized by the t(11;14) and cyclin D1 overexpression. However, additional molecular events are most likely required for oncogenesis, possibly through cell cycle and apoptosis deregulation. We hypothesized that mammalian target of rapamycin (mTOR) is activated in MCL and contributes to tumor proliferation and survival. In MCL cell lines, pharmacological inhibition of the phosphoinositide 3-kinase/AKT pathway was associated with decreased phosphorylation (activation) of mTOR and its downstream targets phosphorylated (p)-4E-BP1, p-p70S6 kinase, and p-ribosomal protein S6, resulting in apoptosis and cell cycle arrest. These changes were associated with down-regulation of cyclin D1 and the anti-apoptotic proteins cFLIP, BCL-XL, and MCL-1. Furthermore, silencing of mTOR expression using mTOR-specific short interfering RNA decreased phosphorylation of mTOR signaling proteins and induced cell cycle arrest and apoptosis. Silencing of eukaryotic initiation factor (eIF4E), a downstream effector of mTOR, recapitulated these results. We also assessed mTOR signaling in MCL tumors using immunohistochemical methods and a tissue microarray: 10 of 30 (33%) expressed Ser473p-AKT, 13 of 21 (62%) Ser2448p-mTOR, 22 of 22 (100%) p-p70S6K, and 5 of 20 (25%) p-ribosomal protein S6. Total eIF4E binding protein 1 and eukaryotic initiation factor 4E were expressed in 13 of 14 (93%) and 16 of 29 (55%) MCL tumors, respectively. These findings suggest that the mTOR signaling pathway is activated and may contribute to cell cycle progression and tumor cell survival in MCL.     

DICER activates autophagy and promotes cisplatin resistance in non-small cell lung cancer by binding with let-7i-5p

ObjectiveDrug resistance is the main obstacle in the treatment of non-small cell lung cancer (NSCLC). This study aimed to explore the mechanism of DICER in NSCLC resistance and its downstream signaling pathways.MethodsThe A549 cisplatin (DDP)-resistant strain A549/DDP was established. A549/DDP cells were transfected with DICER- and let-7i-5p-related vectors, and treated with autophagy activator rapamycin. The cell viability and apoptosis were tested by CCK-8 assay and flow cytometry, respectively. The formation of autophagosomes was observed with a transmission electron microscopy. RT-qPCR and Western blot assay were conducted to detect expression levels of DICER, let-7i-5p, autophagy-related proteins, and the PI3K/AKT/mTOR pathway-related proteins. The dual luciferase reporter gene assay was implemented to confirm the targeted binding of DICER and let-7i-5p.ResultsDICER was highly expressed in DDP-resistant NSCLC tissues and cells, and DICER could target and negatively regulate the expression of let-7i-5p. DDP treatment could inhibit the viability and promote cell apoptosis of A549/DDP cells. Downregulation of DICER in A549/DDP cells exhibited a decrease of cell viability, a decreased ratio of LC3-II/LC3-I and autophagosomes, together with an elevation of cell apoptosis rate and the phosphorylation levels of PI3K/AKT/mTOR. Treatment of rapamycin and let-7i-5p inhibitor reversed the effects of downregulated DICER in cell viability, ratio of LC3-II/LC3-I, autophagosomes, cell apoptosis rate and the phosphorylation levels of PI3K/AKT/mTOR in A549/DDP cells.ConclusionOur research suggests that DICER promotes autophagy and DDP resistance in NSCLC through downregulating let-7i-5p, and inhibits the activation of PI3K/AKT/mTOR pathway.     

EML4-ALK mutations in lung cancer that confer resistance to ALK inhibitors

The EML4 (echinoderm microtubule-associated protein-like 4)-ALK (anaplastic lymphoma kinase) fusion-type tyrosine kinase is an oncoprotein found in 4 to 5% of non-small-cell lung cancers, and clinical trials of specific inhibitors of ALK for the treatment of such tumors are currently under way. Here, we report the discovery of two secondary mutations within the kinase domain of EML4-ALK in tumor cells isolated from a patient during the relapse phase of treatment with an ALK inhibitor. Each mutation developed independently in subclones of the tumor and conferred marked resistance to two different ALK inhibitors. (Funded by the Ministry of Health, Labor, and Welfare of Japan, and others.).     

Mir-30a抑制自噬及上皮细胞间质化增强肺腺癌细胞对克唑替尼的敏感性

目的探索上调肺腺癌细胞中Mir-30a的表达水平能否增强细胞对克唑替尼的敏感性,观察细胞增殖率的变化及克唑替尼IC50等的变化,并探索相关的机制。方法使用Lipofectamine2000携带Mir-30a对H3122细胞进行瞬时转染,并与克唑替尼共同作用。将肺腺癌H3122细胞分为对照组、克唑替尼与联合组。MTT法检测各组细胞增殖率变化,Transwell检测细胞侵袭性。Western blot检测ALK、c-MET、Beclin-1、E-cadherin及Vimentin蛋白的表达。结果在H3122细胞中Mir-30a转染与克唑替尼共同作用较克唑替尼单独作用有更显著的细胞杀伤作用。转染后的细胞较单独应用克唑替尼组侵袭力减弱。转染与克唑替尼联合组Beclin1、ALK、c-MET及Vimentin的蛋白的表达有明显下降,E-cadherin稍有增强。结论 Mir-30a增强肺腺癌细胞对克唑替尼的敏感性,可能与过量表达的Mir-30a抑制癌细胞的自噬及上皮细胞间质化相关。