SOX4对非小细胞肺癌细胞A549的顺铂耐药作用的影响

背景与目的 肺癌是最严重的恶性肿瘤之一,其中非小细胞肺癌发病率在肺癌中居首位.部分患者对顺铂耐受是导致化疗失败的主要原因.SOX4是转录调节因子,在多种肿瘤的发生发展过程中发挥着重要的作用,通过调控β-catenin的表达对Wnt信号通路进行调控.本研究旨在探讨SOX4对非小细胞肺癌细胞A549的顺铂耐药作用的影响.方法 体外诱导法建立顺铂耐药的肺癌细胞株A549/DDP,CCK8法检测A549及A549/DDP细胞对顺铂的耐药性.绘制A549与A549/DDP细胞生长曲线.Western blot检测耐药细胞株中SOX4的蛋白表达水平.CCK8法检测敲减SOX4后耐药细胞株A549/DDP对顺铂耐药性.实时定量PCR和免疫印迹法检测敲减SOX4后A549/DPP细胞中β-catenin和Survivin蛋白的表达.结果 成功构建非小细胞肺癌顺铂耐药细胞株A549/DDP,其耐药性是亲本细胞的13.7倍,差异有统计学意义(P<0.001).生长曲线显示耐药细胞株与亲本细胞增殖速度没有统计学差异(P<0.05);与A549细胞相比,耐药细胞A549/DDP细胞中SOX4的表达显著增高(P<0.001).敲减SOX4后,A549/DDP细胞的耐药性显著降低;敲减SOX4后,A549/DDP细胞中β-catenin和Survivin的mRNA和蛋白表达水平显著降低.结论 SOX4的表达水平影响非小细胞肺癌细胞A549对顺铂的耐药性.     

Nrf2及其靶基因在人肺腺癌A549顺铂耐药细胞株中的表达和意义

背景与目的 NF-E2相关因子2(NF-E2-related factor 2,Nrf2)是细胞调节抗氧化应激反应的重要转录因子,已有研究表明Nrf2及其信号传导通路与卵巢癌顺铂耐药密切相关,但Nrf2与肺腺癌耐药相关性的研究罕见报道,本研究的目的是测定转录因子Nrf2及其靶基因在人肺腺癌A549顺铂耐药细胞株(A549/DDP)及其亲本细胞(A549)中的定量表达,探讨肺腺癌顺铂耐约机制.方法 采用MTT法测定A549/DDP及A549细胞对DDP的敏感性;实时荧光定量PCR检测两株细胞中转录因子Nrf2及其靶基因定量表达.结果 A549/DDP对DDP的耐药指数为12.12,属于中度耐药;与亲本细胞比较,A549/DDP细胞Keap1、Nrf2、NQO1、GSTP1、GCL、HO-1、MRP4的mRNA表达增加(P＜0.01),MRP1、MRP2及MRP3的表达降低(P＜0.01).结论 Nrf2信号传导通路可能参与了人肺腺癌A549顺铂耐药现象的产生,这一发现对从基因水平开发新的耐药拮抗剂用于肿瘤耐药的辅助治疗,避免和克服耐药具有重要意义.     

沉默CXCR4的表达逆转肺癌细胞顺铂耐药

目的:探讨沉默CXCR4对肺癌细胞顺铂耐药的影响,并研究其分子作用机制。方法:利用RT-qPCR测定肺癌耐药（A549/DDP）及药物敏感细胞株（A549）中CXCR4 mRNA的表达水平;利用LipofectamineTM 2000将siRNA-CXCR4转染至肺癌耐药细胞株中,RT-qPCR及蛋白质印迹法（Western blot）验证siRNA对CXCR4基因的靶向沉默效率;利用CCK-8法检测沉默CXCR4后肺癌耐药细胞的增殖活性;利用流式细胞仪测定沉默CXCR4后肺癌耐药细胞的凋亡率;利用MTT法测定沉默CXCR4后肺癌耐药细胞对顺铂的敏感性;利用Western blot实验测定沉默CXCR4后CYP1B1蛋白的表达水平。结果:RT-qPCR实验结果显示,肺癌耐药细胞株A549/DDP中CXCR4 mRNA的表达量显著高于药物敏感细胞株（P＜0.01）;体外转染siRNA-CXCR4可明显下调A549/DDP细胞株中CXCR4的表达（P＜0.001）;CCK-8实验结果显示,沉默CXCR4的表达抑制了A549/DDP细胞的增殖活性（P＜0.01）;流式细胞仪实验结果显示,沉默CXCR4的表达促进了A549/DDP细胞凋亡（P＜0.01）;MTT实验结果显示,沉默CXCR4的表达增加了A549/DDP细胞对顺铂的敏感性（P＜0.01）;Western blot实验结果显示,沉默CXCR4后CYP1B1蛋白的表达水平显著降低（P＜0.05）。结论:沉默CXCR4的表达抑制肺癌耐药细胞增殖、促进凋亡,逆转肺癌细胞顺铂耐药,CXCR4正向调控CYP1B1的表达,可能是CXCR4逆转肺癌细胞顺铂耐药的作用机制。     

CXCL4对非小细胞肺癌H460细胞顺铂耐药性的影响及其机制探讨

目的:探讨血小板因子4（CXCL4）对人非小细胞肺癌H460细胞顺铂耐药性的影响及其作用机制。方法:体外诱导法建立顺铂耐药的非小细胞肺癌细胞株H460/DDP,并鉴定其生物学特性。采用CCK-8法分别检测H460及H460/DDP对顺铂的耐药性。qRT-PCR及Western Blot检测亲本细胞株H460及顺铂耐药株H460/DDP中CXCL4的mRNA及蛋白表达水平。通过CCK-8法检测过表达或者敲低CXCL4后亲本细胞株H460或顺铂耐药株H460/DDP对顺铂的敏感性。最后利用Western Blot及qRT-PCR法探讨CXCL4抵抗非小细胞肺癌化疗敏感性的调控机制。结果:成功构建了非小细胞肺癌顺铂耐药株H460/DDP（H460/DDP IC50=55.005 μg/ml）,CCK-8结果提示顺铂耐药株H460/DDP与亲本细胞株H460细胞的增殖速度没有明显差异（P＞0.05）;顺铂耐药株H460/DDP中,CXCL4 mRNA及蛋白水平均显著增高（P＜0.000 1）;在亲本细胞株H460中稳定过表达CXCL4能显著降低其对顺铂的敏感性（P＜0.000 1）,而于顺铂耐药株H460/DDP中敲低CXCL4能显著增加H460/DDP对顺铂的敏感性（P＜0.000 1）;Western Blot及qRT-PCR结果显示,CXCL4能激活Wnt/β-catenin 信号通路,促进下游基因MYC、CyclinD1、MMP-7、CDK4的表达。结论:CXCL4通过调控Wnt/β-catenin 信号通路促进非小细胞肺癌对顺铂的耐药性。     

SIRT1通过调节Noxa表达影响非小细胞肺癌细胞株A549对顺铂的敏感性

背景与目的 非小细胞肺癌的顺铂耐药是常见的临床现象,严重制约了患者的化疗效果,是亟待解决的问题.SIRT1和Noxa的表达变化影响肿瘤细胞对化疗药物的敏感性.本研究旨在研究SIRT1表达对非小细胞肺癌对顺铂的敏感性的影响,并探讨其涉及Noxa表达的机制,以求为提高非小细胞肺癌细胞对顺铂敏感性提供希望.方法 利用实时荧光定量PCR和Westem blot分析A549细胞及顺铂耐药的A549/DDP细胞SIRT1及Noxa mRNA和蛋白水平的表达差异.利用siRNA干扰技术抑制A549/DDP细胞的SIRT1表达,进而使用Cell Titer Blue试验、流式细胞术从细胞增殖、细胞周期和细胞凋亡方面分析SIRT1沉默对A549/DPP细胞顺铂敏感性的影响.同时利用实时荧光定量PCR和Western blot分析SIRT1抑制对A549/DPP细胞Noxa表达的影响.结果 A549细胞和A549/DDP细胞对顺铂的敏感性有显著差异,与A549细胞相比,A549/DDP细胞的SIRT1表达较高,但Noxa表达较低.使用siRN抑制A549/DPP细胞的SIRT1表达后,与未抑制SIRT1细胞相比,4μg/mL顺铂处理后的细胞存活率降低,G2期/M期阻滞比例增加,凋亡率提高.同时,SIRT1沉默导致A549/DPP细胞的Noxa表达增加.结论 较高的SIRT1可能引起A549细胞对顺铂的耐药性,抑制SIRT1可以提高A549/DDP细胞对顺铂的敏感性,其机制可能涉及SIRT1对Noxa的调节.     

N-乙酰半胱氨酸对耐顺铂人肺腺癌细胞A549/DDP耐药逆转及其与多药耐药蛋白表达的关系

目的:研究N-乙酰半胱氨酸(NAC)时人肺腺癌细胞A549/DDP耐顺铂的逆转作用,探讨其与多药耐药蛋白表达的关系.方法:以MTT法检测不同浓度NAC处理A549/DDP细胞及顺铂联合对A549/DDP细胞的细胞毒性作用,采用RT-PCR检测NAC作用前后A549/DDP细胞MRP mRNA的表达水平.结果:NAC在10、20及50μg/L浓度时其可以增加A549/DDP对顺铂的敏感性,而在NAC浓度为0.1和1μg/L时未见明显的药物逆转作用.NAC在10、20和50 μg/L时其作用后的A549/DDP细胞中MRPmRNA的表达水平低于作用前.结论:NAC可以逆转A549/DDP耐药,由于体外实验中缺乏可能让NAC转为谷胱甘肽(GSH)的微环境,其在另一方面可以通过下调MRP1 mRNA的表达,从而导致细胞对DDP的敏感性增加.     

长链非编码RNA-FENDRR提高非小细胞肺癌细胞对顺铂的化疗敏感性

目的:研究长链非编码RNA-FENDRR基因对非小细胞肺癌(NSCLC)细胞的顺铂(DDP)化疗敏感性的调节作用.方法:实时定量PCR检测FENDRR基因在DDP耐药的NSCLC组织及细胞系中的表达.应用脂质体将FENDRR基因表达载体转染入顺铂耐药的NSCLC细胞系A549/DDP.MTT法明确A549/DDP细胞对DDP的半数抑制浓度(IC50).结果:与DDP化疗敏感的NSCLC组织相比,FENDRR基因在DDP不敏感的NSCLC组织中的表达明显降低.与A549细胞相比,A549/DDP细胞呈现出对DDP的IC50显著增高,其对化疗药物DDP的耐药性更高.FENDRR基因在DDP耐药的A549/DDP细胞中表达显著低于其在A549细胞中的表达.转染表达载体pc-FENDRR能够显著上调A549/DDP细胞中FENDRR基因的表达.FENDRR高表达能够降低A549/DDP细胞对DDP的IC50,提高化疗敏感性.FENDRR高表达能够显著地促进DDP诱导的A549/DDP细胞的凋亡.结论:长链非编码RNA-FENDRR基因与NSCLC的化疗耐药相关,能够提高NSCLC细胞对DDP的敏感性.     

RNA干扰ERCC1基因表达对肺腺癌细胞A549/DDP顺铂耐药的影响

背景与目的核苷酸切除修复机制可修复顺铂(DDP)造成的DNA损伤,作为其中的关键酶之一,切除修复交叉互补基因1(excision repair cross-complementing gene 1,ERCC1)的表达可能与DDP耐药有关.本研究旨在探讨小干扰RNA沉默ERCC1基因表达对肺腺癌耐药细胞A549/DDP药物敏感性的影响.方法将体外设计合成针对ERCC1的小分子RNA(siRNA)转染A549/DDP细胞,RT-PCR检测ERCC1 mRNA水平;Western blot检测ERCC1蛋白表达的变化;MTT检测RNA干扰后细胞药物敏感性改变.结果 ERCC1 RNAi干扰后ERCC1 mRNA表达指数降低,明显低于对照组,干扰后ERCC1 mRNA表达抑制率为90.4%.转染ERCC1 siRNA降低TERCC1蛋白的表达水平.MTT显示分别用2μg/mL、4μg/mL、8μg/mL、16μg/mL、32μg/mL顺铂处理细胞48 h,转染ERCC1 siRNA细胞组较对照组敏感性明显增高,干扰前A549/DDP细胞IC50为12.49μg/mL,干扰后A549/DDP细胞IC50下降为9.27 μg/mL.结论 ERCC1siRNA干扰可以降低ERCC1的表达水平,并可提高A549/DDP细胞对顺铂的敏感性.     

蛋白激酶C抑制剂对人非小细胞肺癌细胞株药物敏感性的影响

背景与目的 蛋白激酶C(PKC)在癌变过程中的作用使其成为肿瘤治疗的潜在重要靶点.非小细胞肺癌(NSCLC)中存在PKC-α的异常表达和活性增高,PKC抑制剂能通过诱导肿瘤细胞凋亡、增强细胞毒作用及下调多药耐药基因的表达而发挥其抗肿瘤作用.通过观察PKC抑制剂白屈菜红碱(CH)对四种人NSCLC细胞株药物敏感性的影响,初步探讨其作用机制.方法 以PKC抑制剂CH分别处理四种NSCLC细胞株H1299、H460、A549及耐顺铂A549细胞株,逆转录聚合酶链式反应法(RT-PCR)及蛋白印迹法(Western blot)检测PKC-α的mRNA及蛋白表达水平,流式细胞仪检测细胞凋亡率,四甲基偶氮唑蓝(MTT)法检测细胞株对顺铂药物敏感性.结果 用药前A549/DDP细胞株中PKC-α mRNA及蛋白的表达水平高于NSCLC细胞株H1299、H460及亲本A549细胞株(P＜0.05),CH处理后四种NSCLC细胞株中PKC-αmRNA及蛋白的表达水平均有不同程度的下降,CH处理4 h及24 h后H1299、H460、A549细胞株的凋亡率无明显增加,仅A549/DDP细胞株的凋亡率明显增加,用药后NSCLC细胞株对顺铂的药物敏感性即IC50值有不同程度的下降,以A549/DDP细胞株降低更为明显(P＜0.05).结论 四种NSCLC细胞株中存在PKC-αmRNA及蛋白的高表达.通过抑制NSCLC细胞株中PKC-α mRNA及蛋白的表达,PKC抑制剂CH能增加其对顺铂的药物敏感性.与亲本A549细胞株相比,PKC抑制剂CH能通过抑制耐顺铂A549细胞株中PKC-α蛋白的表达及增加细胞凋亡率,而更有效地增加其对顺铂的药物敏感性.     

The change of intracellular pH is involved in the cisplatin-resistance of human lung adenocarcinoma A549/DDP cells

We had reported that the intracellular pH (pHi) of human lung adenocarcinoma A549 cells, which is sensitive to cisplatin, was more acidic than that of cisplatin-resistant A549/DDP cells. The correlation between the change of the pHi and cisplatin-resistance of A549/DDP cells was further studied by altering pHi in consequence of the change of CO2 concentration of the incubator. The pHi alterations of the cells were monitored by using the fluorescence probe of BCECF-AM. The results indicated that the pHi was more alkaline at lower CO2 concentration (2% CO2 in the incubator) and more acidic at higher CO2 concentration (8% CO2 in the incubator) for both A549 and A549/DDP cells compared with those of both A549 and A549/DDP cells cultured at 5% CO2 as the normal condition. Accumulation of bodipy-cisplatin, a fluorescence probe used for drug resistance assays, in A549 cells incubated at 2%, 5%, and 8% CO2 was increased 8.4%, 17.4%, and 23.5% compared to A549/DDP cells, respectively. Intracellular sequestration and distribution of bodipy-cisplatin imaged by laser scanning confocal microscopy indicated that bodipy-cisplatin was more encapsulated in acidic compartments of A549/DDP cells as shown with acridine orange, a dye that specifically labels acidic organelles in the cells. These results can be further confirmed in liposome systems with different pH gradients. It is proposed from the above results that the change of pHi in especially more acidic compartments in A549/DDP cells involves their cisplatin resistance.     

Simultaneous targeting of ATM and Mcl-1 increases cisplatin sensitivity of cisplatin-resistant non-small cell lung cancer

Development of cisplatin-resistance is an obstacle in non-small cell lung cancer (NSCLC) therapeutics. To investigate which molecules are associated with cisplatin-resistance, we analyzed expression profiles of several DNA repair and anti-apoptosis associated molecules in parental (A549P and H157P) and cisplatin-resistant (A549CisR and H157CisR) NSCLC cells. We detected constitutively upregulated nuclear ATM and cytosolic Mcl-1 molcules in cisplatin-resistant cells compared with parental cells. Increased levels of phosphorylated ATM (p-ATM) and its downstream molecules, CHK2, p-CHK2, p-53, and p-p53 were also detected in cisplatin-resistant cells, suggesting an activation of ATM signaling in these cells. Upon inhibition of ATM and Mcl-1 expression/activity using specific inhibitors of ATM and/or Mcl-1, we found significantly enhanced cisplatin-cytotoxicity and increased apoptosis of A549CisR cells after cisplatin treatment. Several A549CisR-derived cell lines, including ATM knocked down (A549CisR-siATM), Mcl-1 knocked down (A549CisR-shMcl1), ATM/Mcl-1 double knocked down (A549CisR-siATM/shMcl1) as well as scramble control (A549CisR-sc), were then developed. Higher cisplatin-cytotoxicity and increased apoptosis were observed in A549CisR-siATM, A549CisR-shMcl1, and A549CisR-siATM/shMcl1 cells compared with A549CisR-sc cells, and the most significant effect was shown in A549CisR-siATM/shMcl1 cells. In in vivo mice studies using subcutaneous xenograft mouse models developed with A549CisR-sc and A549CisR-siATM/shMcl1 cells, significant tumor regression in A549CisR-siATM/shMcl1 cells-derived xenografts was observed after cisplatin injection, but not in A549CisR-sc cells-derived xenografts. Finally, inhibitor studies revealed activation of Erk signaling pathway was most important in upregulation of ATM and Mcl-1 molcules in cisplatin-resistant cells. These studies suggest that simultaneous blocking of ATM/Mcl-1 molcules or downstream Erk signaling may recover the cisplatin-resistance of lung cancer.     

Proliferation rate but not mismatch repair affects the long-term response of colon carcinoma cells to 5FU treatment

Cisplatin (DDP) is widely used in lung cancer chemotherapy. However, cisplatin resistance represents a major obstacle in effective clinical treatment. This study aims to investigate whether Newcastle disease virus (NDV) exhibits an oncolytic effect on cisplatin-resistant A549 lung cancer cells. We found that NDV induced A549/DDP cell apoptosis via the caspase pathway, particularly involving caspase-9, while the mitogen-activated protein kinase (MAPK) and Akt pathways also contributed to apoptotic induction. Furthermore, NDV displayed oncolytic effects in a mouse A549/DDP lung cancer model. Collectively, our data indicate that NDV could overcome the cisplatin resistance in lung cancer cells in vitro and in vivo.     

GSK-3β及β-catenin的表达定位与肺腺癌顺铂耐药作用机制研究

目的 研究人肺腺癌细胞系A549和其顺铂耐药细胞系A549/DDP中GSK-3β及β-catenin的表达定位差异,以探讨其与肺腺癌顺铂耐药的作用机制。方法 MTT法检测A549和A549/DDP细胞对顺铂的IC50 ;免疫细胞荧光法检测顺铂处理前后两种细胞GSK-3β及β-catenin的定位表达。结果 顺铂对A549/DDP细胞的IC₅₀值为（28.984±1.404）μmol/L高于A549细胞的（5.888±0.338）μmol/L（t=27.696,P<0.001）;A549/DDP细胞中的GSK-3β表达主要在胞质,顺铂处理后GSK-3β定位在胞质和胞核;β-catenin表达主要在胞膜、胞质,顺铂处理后定位转移至胞核。而A549细胞中GSK-3β及β-catenin表达定位无变化。结论 肺腺癌顺铂耐药的机制可能与GSK-3β胞质和胞核共同定位、β-catenin核转移定位相关。     

Relationship between epithelial to mesenchymal transition and chemoresistance of lung cancer

Objective： The aim of this study was to explore the correlation between epithelial to mesenchymal transition （EMT） and chemoresistance of non-small-cell lung cancer （NSCLC）. Methods： In vitro, the drug resistance index of cisplatin resistant lung adenocarcinoma cell line （A549/DDP） was detected by CCK-8 assay; the morphological change between A549/ DDP cells and lung adenocarcinoma cells （A549） was observed by phase contrast microscope; expression of EMT markers （including E-cadherin and vimentin） and resistance protein, excision repair cross-complementing 1 （ERCC1） was detected by immunocytochemistry. The expression of E-cadherin, vimentin and ERCC1 was investigated by immunohistochemistry in 120 cases of NSCLC, half of that were treated with pre-operative neoadjuvant chemotherapy （neoadjuvant chemotherapy group）, and the other underwent surgery alone （simple surgery group）. Results： There was a significant difference between the ICso （half maximal inhibitory concentration） of A549/DDP cells （5.20） and A549 cells （1.88） （P 〈 0.05）, and the drug resistance index of A549/DDP cells was 2.77. Compared with A549 cells, A549/DDP cells increased expression of ERCC1 （P 〈 0.05）. Moreover, A549/DDP cells showed morphological and phenotypic changes consistent with EMT： with spindle-shaped morphology, and decreased expression of E-cadherin and increased expression of vimentin. Immunohistochemistry showed significant positive correlation between the expression of ERCCI and vimentin （r = 0.496, 0.332, P 〈 0.05）, and significant negative correlation between the ERCCI and E-cadherin （r = -0.403, -0.295, P 〈 0.05） in neoadjuvant chemotherapy group and simple surgery group. In addition, compared with simple surgery group, the expression of ERCC1 （P = 0.003） and vimentin （P = 0.004） was significantly increased, and the expression of E-cadherin was decreased in neoadjuvant chemotherapy group （P = 0.032）. Cenclusion： A549/DDP cells acquired cisplatin-resistance and occurred EMT simultaneously; the phenomenon of chemoresistance and EMT was caused more easily in neoadjuvant chemotherapy group. As such, we further confirmed the close correlation between chemoresistance and EMT of NSCLC, and provided theoretical basis for the targeting therapy with EMT regulatory factor for chemoresistant NSCLC patients.     

细胞色素c 介导的半胱天冬氨酸蛋白酶-3活性改变与人卵巢癌顺铂耐药的关系

目的：探讨人卵巢癌顺铂耐药细胞株A2780／DDP、COC1／DDP中抗凋亡基因bcl-XL、细胞色素c的表达和半胱天冬氨酰蛋白酶－3（caspase-3)活性对人卵巢癌顺铂耐药的影响。方法：采用逆转录聚合酶链反应（RT－PCR）和Western blot检测人卵巢癌顺铂敏感细胞株A2780、COC1和顺铂耐药株A2780／DDP、COC1／DDP中bcl-XL的表达,以及顺铂作用后细胞色素c的含量和caspase-3活性的变化,并应用流式细胞仪测定顺铂作用后A2780、COC1、A2780／DDP、COC1／DDP细胞的凋亡率。结果：bcl-XL在A2780/DDP、COC1／DDP细胞中的表达明显高于A2780、COC1细胞;顺铂作用后,细胞色素c在A2780／DDP、COC1／DDP细胞中的表达明显减少,caspase-3活性和凋亡率也较A2780和COC1细胞明显降低（P＜0．05）。结论：人卵巢部细胞对顺铂产生耐药可能与细胞内bcl-XL过度表达、细胞色素c释放受抑制和caspase-3活性下降有关。     

5-氮-2'-脱氧胞苷逆转人非小细胞肺癌A549/DDP细胞对顺铂的耐药性

目的 探讨5-氮-2'-脱氧胞苷(5-Aza-dc)逆转耐顺铂(DDP)的A549/DDP细胞对DDP的耐药性及其可能的机制.方法 以耐DDP的人非小细胞肺癌(NSCLC)细胞系A549/DDP为研究对象,采用四甲基偶氮唑蓝(MTT)法检测5-Aza-de对A549/DDP细胞的毒性作用和对A549/DDP细胞的耐药逆转指数(RI);采用甲基化特异性聚合酶链反应(MSP)、逆转录聚合酶链反应(RT-PCR)和Western blot法检测5-Aza-de干预前后的A549/DDP细胞hMLH1基因启动子甲基化状态和基因表达情况.结果 20 μmol/L 5-Aza-dc(无毒剂量组)和40 μmol/L5-Aza-dc(低毒剂量组)干预A549/DDP细胞48 h后,其R1分别为1.82和4.42.MSP结果显示,A549/DDP细胞中,hMLH1基因启动子区呈部分甲基化状态;经无毒和低毒剂量5-Aza-dc处理A549/DDP细胞48 h后,hMLH1基因启动子区发生DNA去甲基化.无毒剂量组和低毒剂量组的hMLH1 mRNA相对表达量分别为2.05±0.08和2.00±0.03,hMLHl蛋白相对表达鼍分别为1.74±0.14和1.65±0.11.结论 5-Aza-dc能部分逆转A549/DDP细胞的DDP耐药,其机制可能与去除hMLH1基因启动子甲基化、上调其基因表达有关.

Abstract：

Objective The aim of this study was to investigate the effect of 5-aza-2'-deoxycytidine (5-Aza-dc), a methylation inhibitor, on cisplatin-resistance in non-small cell lung cancer cell line A549/ DDP and to explore its possible mechanism. Methods MTT assay was used to test the cytotoxicity of 5-Aza-dc on A549/DDP cells, and the IC50, and cisplatin resistance index of A540/DDP cells at 48 hours after 5-Aza-dc (0 μmol/L, 20 μmol/L, 40 μmol/L) treatment at different concentrations. MSP, fluorescence quantitative RT-PCR (real-time RT-PCR) and Western blot were used to detect the hMLH1 methylation status,mRNA and protein expressions, espectively. Results The IC50 value of cisplatin in AS49/DDP cells was 30.15 ±0.76 μmol/L. The MTT assay results demonstrated that during the 5-Aza-dc treatment for 48 hours, the dose of 20 μmol/L was non-toxic and 40 μmol/L was low-toxic. 5-Aza-dc at those two doses reduced IC50 value of cisplatin to 16. 54 ±0. 35 μmol/L (RI = 1. 82) and 6. 82 ±0. 16 μmol/L ( RI = 4.42) , respectively. MSP, real-time RT-PCR and Western blot showed that 5-Aza-dc at non-toxic and low-toxic doses removed the partial hMLH1-hypermethylation, and up-regulated hMLH1 mRNA and protein expressions. Conclusions Low dose 5-Aza-dc can partially reverse the cisplatin-resistance in A549/DDP cells, which may be achived through removal of hMLH1 hypermethylation and increased expression of hMLH1 gene. 5-Aza-dc may have a role in increasing the efficacy of chemotherapy for patients whose tumors are lack of hMLHl expression because of hMLHl promoter hypermethylation.     

FTY720对耐顺铂非小细胞肺癌细胞增殖及凋亡的影响

目的:检测芬戈莫德（fingolimod,FTY720)对耐顺铂非小细胞肺癌细胞株A549增殖及凋亡的影响。方法:应用CCK-8检测耐顺铂A549细胞株在FTY720不同浓度（5 μmol/L、10 μmol/L、15 μmol/L和20 μmol/L）作用不同时间（24 h和48 h）后的增殖活性。流式细胞仪检测不同浓度（5 μmol/L、10 μmol/L和20 μmol/L）作用不同时间（24 h和48 h）后耐顺铂A549细胞凋亡情况,Western blot 法检测细胞凋亡相关蛋白的表达。结果:耐顺铂A549细胞的增殖抑制程度和促进凋亡的程度均与FTY720呈时间依赖及剂量依赖性。结论:FTY720以时间依赖及剂量依赖模式对耐顺铂A549细胞呈现出抑增殖及促凋亡作用。     

Regulatory Mechanisms of Annexin-Induced Chemotherapy Resistance in Cisplatin Resistant Lung Adenocarcinoma

Adenocarcinoma of lung has high incidence and a poor prognosis, woith chemotherapy as the main therapeutictool, most commonly with cisplatin. However, chemotherapy resistance develops in the majority of patientsduring clinic treatment. Mechanisms of resistance are complex and still unclear. Although annexin play importantroles in various tumor resistance mechanisms, their actions in cisplatin-resistant lung adenocarcinoma remainunclear. Preliminary studies by our group found that in cisplatin-resistant lung cancer A549 cells and lungadenocarcinoma tissues, both mRNA and protein expression of annexins A1, A2 and A3 is increased. Using alibrary of annexin A1, A2 and A3 targeting combined molecules already established by ourselves we found thatspecific targeting decreased cisplatin-resistance. Taken together, the underlined effects of annexins A1, A2 and A3on drug resistance and suggest molecular mechanisms in cisplatin-resistant A549 cells both in vivo and in vitro.Furthermore, the study points to improved research on occurrence and development of lung adenocarcinoma,with provision of effective targets and programmes for lung adenocarcinoma therapy in the clinic.