肺腺癌干细胞表达小细胞肺癌相关抗原的实验研究

肿瘤干细胞（cancerstem cells,csc）是指一类具有自我更新（self-renewal）能力的未分化细胞。在肺腺癌中,csc的自我更新调控机制类似胚胎干细胞,即高表达OCT4、Nanog和Sox2}潜能基因,但目前对其表型特征尚存争议。该文采用成球试验（sphere—formingassay）AkSPC—A1细胞株中富集CSC后进行分子表型分析。结果显示,此类肺球体细胞（pulmospheres）同时表达肺脏近端和远端呼吸上皮的多个谱系（1ineage）标志,包括纤毛柱状细胞标志FoxJl、非纤毛柱状细胞（即Clara细胞）标志CCSP、肺神经肉分泌细胞标志GRP、II型肺泡细胞标志SP-C及其转录调控因子TTF-1。这些肺球体细胞也能够被3株小细胞肺癌特异性单抗（2F7、483和E6）所识别。通过基因沉默技术使得肺球体细胞中OCT4表达转阴后,上述标志（除E6P外）均消失。研究结果揭示,肺癌CSC具有肺脏呼吸上皮多潜能细胞的表型特征。此外,初步研究结果发现,中药冬虫夏草（Hirsutella Hepialid of Cordyceps Sinensis）的被毛孢菌丝体中含有新颖抗癌成分,能够显著遏制肺球体细胞增殖,提示对其进行分离鉴定,将是研制开发肺癌CSC靶向药物的一个发展方向。     

ALDH1A1诱导肺腺癌细胞发生上皮-间质转化及化疗耐药

目的:探索醛脱氢酶1A1(aldehyde dehydrogenase 1A1,ALDH1A1)在肺腺癌细胞(lung adenocarcinoma cell,LAC)化疗耐药中的作用及机制,为肺癌临床治疗和新型药物的研发提供实验依据。方法:采用慢病毒载体构建ALDH1A1高表达肺腺癌细胞模型,并通过流式细胞术和western blot技术对该细胞模型进行验证。通过CCK8法检测ALDH1A1高表达肺腺癌细胞对肺癌治疗药物顺铂(cisplatin,DDP)、紫杉醇(paclitaxcel)、厄洛替尼(erlotinib)和吉非替尼(gefitinib)的耐药性。通过检测肿瘤干细胞(cancer stem cell,CSC)分子标志物、上皮-间质转化(Epithelial-Mesenchymal Transition,EMT)分子标志物及细胞迁移能力探讨ALDH1A1高表达对肺腺癌细胞的干性和EMT特征的影响。双硫仑(disulfiram,DSF)是ALDH的抑制剂,我们通过CCK8法和transwell细胞迁移实验探究DSF对肺腺癌细胞体外生长和迁移能力的影响,体内实验探究DSF和厄洛替尼联合用药对HCC827-ALDH1A1细胞皮下异种移植瘤生长的影响。结果:ALDH1A1高表达诱导肺腺癌细胞对厄洛替尼、吉非替尼、紫杉醇和顺铂产生不同程度的耐药,干细胞标志物CD44、CD133蛋白表达上调,EMT间充质标志物vimentin蛋白表达上调,transwell实验结果显示ALDH1A1高表达肺腺癌细胞的迁移能力增强,使用ALDH靶向抑制剂DSF能选择性抑制ALDH1A1高表达肺腺癌细胞所增高的迁移能力并克服HCC827-ALDH1A1细胞皮下异种移植瘤的生长,延缓体内耐药。结论:ALDH1A1能诱导肺腺癌细胞对多种抗肺癌药物产生耐药并发生干细胞样转化,靶向抑制ALDH酶活性可克服由ALDH1A1高表达所产生的耐药,为肺癌的临床治疗提供新的思路。     

Ad-ING4-IL-24 双基因共表达对人肺腺癌化疗的增敏效应

研究ING4 (肿瘤生长抑制因子4) 和IL-24 (人白细胞介素24) 双基因共表达腺病毒载体 (Ad-ING4-IL-24) 对肺腺癌的化疗增敏效应及分子机制。将Ad-ING4-IL-24感染A549肺癌细胞及联合顺铂 (DDP) 化疗药物作用,RT-PCR和Western blotting检测ING4和IL-24基因在A549肺癌细胞中的转录和表达,MTT法、流式细胞仪 (FCM) 和 Hoechst 染色法检测Ad-ING4-IL-24联合DDP (联合组) 对A549肺癌细胞的生长抑制和凋亡效应。采用A549细胞株建立人肺腺癌裸鼠模型,然后瘤体局部注射干预用药,动态测量肿瘤体积,并计算瘤重抑瘤率,免疫组化检测ING4、IL-24、bax、bcl-2、VEGF等基因的表达。结果表明,Ad-ING4-IL-24感染A549肺癌细胞后可获得成功转录和表达,体外联合组能明显抑制A549肺癌细胞生长和诱导细胞凋亡,呈现出典型细胞凋亡形态学变化。体内联合组同样能显著抑制肿瘤生长,瘤重抑瘤率达52.81％,免疫组化结果显示联合组能上调bax基因表达,同时下调bcl-2、VEGF等基因的表达。以上结果表明Ad-ING4-IL-24具有化疗增敏的作用,该作用机制可能与促进肿瘤细胞凋亡和抑制血管形成有关。     

PLAGL2与SP—C基因启动子相互作用的研究

目的研究PLAGL2（pleiomorphic adenoma genelike-2,PLAGL2）对SP-C基因（surfactant pro-tein—C,SP—C）启动子的结合与影响作用。方法定点诱变技术（site—directed mutagenesis）及凝胶电泳迁移实验（electrophoresis mobility shiftassay,EMSA）研究PLAGL2与SP—C基因启动子之间的相互结合作用;体外培养MLE12细胞共转染和荧光素酶报告基因活性值检测技术,研究PLAGL2对SP—C基因启动子表达活性的影响;结果EMSA及竞争性EMSA实验表明：PLAGL2能通过其核心和簇结合位点序列与同位素标记的SP—C基因启动子片段相结合形成蛋白-DNA复合物;细胞共转染及荧光素酶报告基因活性值检测结果显示：PLAGL2能明显促进SP—C基因启动子的表达。结论在肺Ⅱ型细胞中,PLAGL2能与SP—C基因启动子相互作用并促进其表达。     

ILK在肺鳞状细胞癌和肺腺癌的表达及其与临床病理特征和预后的关系

目的 探讨ILK在肺鳞状细胞癌和肺腺癌组织中的表达情况,及其与病理分型、肿瘤分化、分期、淋巴结转移及预后的关系。方法采用S-P免疫组织化学方法和Western Blot法,检测肺鳞状细胞癌和肺腺癌组织及相应癌旁肺组织中整合连接激酶（integrin-linkedkinase,ILK）的表达情况,并结合临床和病理资料进行分析。结果免疫组化结果显示：ILK在53／76（70％）的肺癌组织中阳性表达。其中鳞状细胞癌阳性率75％（33／44）,腺癌阳性率62．5％（20／32）,其表达与肺鳞状细胞癌的分化呈负相关（P〈0．01）,与临床分期（P〈0．01）、淋巴结转移（P〈0．01）呈正相关;与肺腺癌的临床分期（P〈0．01）和淋巴结转移（P〈0．01）正相关,与分化程度无相关性（P〉0．05）。同时,其表达与患者的生存时间呈负相关（P〈0．01）,与年龄、性别、肿瘤大小和组织类型等因素无关。Western Blot法进一步证实ILK在肺癌组织中的表达显著高于癌旁正常肺组织（P〈0．01）,其表达与肺癌的分化（P〈0．01）显著负相关。结论肺鳞状细胞癌和肺腺癌中,ILK与肺癌的侵袭和转移有关。ILK可作为判断肺鳞状细胞癌和肺腺癌预后的参考指标。     

新生SD大鼠岛源性胰岛祖细胞的分离培养与诱导分化

目的：分离培养新生大鼠岛源性胰岛祖细胞,观察GLP-1（7-36）NH2诱导其向成熟细胞分化作用。方法：分离与纯化胰岛,在含20μg／LEGF和20μg／LbFGF的RPMI1640培养基中分离和扩增胰岛祖细胞．用20nmol／LGLP-1（7-36）NH2诱导分化。用原位杂交、免疫细胞化学染色、二硫腙（DTZ）染色和放射免疫分析等方法对的胰岛祖细胞分化前后细胞特征进行初步鉴定。结果：胰岛祖细胞表达Nestin,不表达PDX-1、InsulinmRNA、Insulin、Somatostatin。以GLP-1（7-36）NH2诱导分化后,部分细胞表达PDX-1、胰岛素mRNA、胰岛素、生长抑素,胰岛样细胞团（Ic＆）形成,其周边细胞DTZ着色。分化3周后培养基中胰岛素释放明显增加。结论：在新生SD大鼠胰岛存在有一类胰岛祖细胞,可以被分离并在体外不断扩增。GLP-1（7-36）NH2可以诱导胰岛祖细胞形成有胰岛素分泌功能的胰岛样细胞团。     

肺干细胞和肺癌干细胞研究进展

近年来成体干细胞研究进展迅速。肺干细胞和肺癌干细胞在表面标志、分离方法和功能研究等方面也取得了一定进展。在肺组织中,肺干细胞维持着肺上皮的更新和稳定,肺脏不同解剖结构存在不同的干细胞,主要的肺干细胞有气管—支气管干细胞、细支气管干细胞、细支气管肺泡干细胞和肺泡干细胞等,不同干细胞特异表面标志也不同。根据肿瘤干细胞理论,目前研究认为肺癌的发生与肺癌干细胞有关,肺癌干细胞来源于其对应肺干细胞的恶性转化。肺癌干细胞特异标志研究主要集中在侧群细胞、CD133和醛脱氢酶等。与其他成体干细胞相似,肺癌干细胞维持自我更新以及分化能力的信号通路主要有Wnt、Hedgehog和Notch通路等。肺癌干细胞与肺癌的发生、发展、转移、治疗反应及预后关系,也取得了一定的进展。该文对肺干细胞和肺癌干细胞研究进展作简要综述。     

肿瘤干细胞对非小细胞肺癌放疗效果机制的研究进展

肿瘤干细胞 (CSC)是一类具有肿瘤起始、自我更新及无限增殖潜能的细胞亚群,与肿瘤的局部复发与远处转移密切相关,是肿瘤放射治疗抵抗的根源。非小细胞肺癌是目前发病率及致死率较高的恶性肿瘤,已证实非小细胞肺癌中具有干细胞特性的CSC亚群,目前通过分离CD133等一系列已知免疫表型阳性细胞是获得非小细胞肺癌CSC的主要手段。研究证实CSC主要是通过DNA损伤、细胞自噬和缺氧肿瘤微环境等机制介导非小细胞肺癌的放疗抵抗效应。本文主要对非小细胞肺癌CSC的生物学特性、免疫表型表达及放疗抵抗的分子机制进行综述,以期为提高非小细胞肺癌放射疗效提供线索和依据。     

Isolation of Cancer Stem Like Cells from Human Adenosquamous Carcinoma of the Lung Supports a Monoclonal Origin from a Multipotential Tissue Stem Cell

There is increasing evidence that many solid tumors are hierarchically organized with the bulk tumor cells having limited replication potential, but are sustained by a stem-like cell that perpetuates the tumor. These cancer stem cells have been hypothesized to originate from transformation of adult tissue stem cells, or through re-acquisition of stem-like properties by progenitor cells. Adenosquamous carcinoma (ASC) is an aggressive type of lung cancer that contains a mixture of cells with squamous (cytokeratin 5+) and adenocarcinoma (cytokeratin 7+) phenotypes. The origin of these mixtures is unclear as squamous carcinomas are thought to arise from basal cells in the upper respiratory tract while adenocarcinomas are believed to form from stem cells in the bronchial alveolar junction. We have isolated and characterized cancer stem-like populations from ASC through application of selective defined culture medium initially used to grow human lung stem cells. Homogeneous cells selected from ASC tumor specimens were stably expanded in vitro. Primary xenografts and metastatic lesions derived from these cells in NSG mice fully recapitulate both the adenocarcinoma and squamous features of the patient tumor. Interestingly, while the CSLC all co-expressed cytokeratins 5 and 7, most xenograft cells expressed either one, or neither, with <10% remaining double positive. We also demonstrated the potential of the CSLC to differentiate to multi-lineage structures with branching lung morphology expressing bronchial, alveolar and neuroendocrine markers in vitro. Taken together the properties of these ASC-derived CSLC suggests that ASC may arise from a primitive lung stem cell distinct from the bronchial-alveolar or basal stem cells.     

Identification of bronchioalveolar stem cells in normal lung and lung cancer

Injury models have suggested that the lung contains anatomically and functionally distinct epithelial stem cell populations. We have isolated such a regional pulmonary stem cell population, termed bronchioalveolar stem cells (BASCs). Identified at the bronchioalveolar duct junction, BASCs were resistant to bronchiolar and alveolar damage and proliferated during epithelial cell renewal in vivo. BASCs exhibited self-renewal and were multipotent in clonal assays, highlighting their stem cell properties. Furthermore, BASCs expanded in response to oncogenic K-ras in culture and in precursors of lung tumors in vivo. These data support the hypothesis that BASCs are a stem cell population that maintains the bronchiolar Clara cells and alveolar cells of the distal lung and that their transformed counterparts give rise to adenocarcinoma. Although bronchiolar cells and alveolar cells are proposed to be the precursor cells of adenocarcinoma, this work points to BASCs as the putative cells of origin for this subtype of lung cancer.     

Pleomorphic adenoma gene-like 2 regulates expression of the p53 family member,p73, and induces cell cycle block and apoptosis in human promonocytic U937 cells

The proto-oncogene, pleomorphic adenoma gene-like 2 (PLAGL2), is implicated in a variety of cancers including acute myeloid leukemia (AML), malignant glioma, colon cancer, and lung adenocarcinoma. There is additional evidence that PLAGL2 can function as a tumor suppressor by initiating cell cycle arrest and apoptosis. Interestingly, PLAGL2 has also been implicated in human myelodysplastic syndrome, a disease that is characterized by ineffective hematopoiesis and can lead to fatal cytopenias (low blood counts) as a result of increased apoptosis in the marrow, or, in about one-third of cases, can progress to AML. To gain a better understanding of the actions of PLAGL2 in human myeloid cells, we generated a stable PLAGL2-inducible cell line, using human promonocytic U937 cells. PLAGL2 expression inhibited cell proliferation which correlated with an accumulation of cells in G1, apoptotic DNA-laddering, an increase in caspase 3, 8, and 9 activity, and a loss of mitochondrial transmembrane potential. There was significant increase in the p53 homologue, p73, with PLAGL2 expression, and consistent with mechanisms of p73-regulated cell cycle control and apoptosis, there was increased expression of known p73 target genes p21, DR5, TRAIL, and Bax. PLAGL2-induced cell cycle block was abolished in the presence of p73 siRNA. Together, these data support a role for PLAGL2 in cell cycle regulation and apoptosis via activation of p73.