参麦注射液对肺腺癌耐药细胞株的逆转作用

本研究探讨了参麦注射液对人肺腺癌耐药细胞株A549/DTX(多西他赛)的耐药逆转作用,并初步分析其作用机制。以MTT法检测参麦注射液、多西他赛及联合应用对耐药细胞株的增殖抑制率,并计算耐药逆转倍数。用流式细胞术测定参麦注射液联合多西他赛对A549/DTX细胞株的促凋亡作用;用Western blotting分析参麦注射液对A549/DTX细胞株的凋亡相关蛋白Bax和Bcl-2表达水平的影响。研究表明,参麦注射液增加耐药细胞株对DTX的敏感性,耐药逆转倍数为3.92,并明显增强DTX对A549/DTX细胞株的促凋亡作用。同时抑制了Bcl-2和P-gp蛋白表达,与对照组相比差异显著(p0.05)。故参麦注射液能部分逆转A549/DTX细胞株耐药性,其作用通过诱导细胞凋亡及降低P-gp表达实现。     

多西他赛固体脂质纳米粒抗乳腺癌效果及机制研究

目的:探讨多西他赛固体脂质纳米粒抗乳腺癌效果及机制研究。方法:本实验采用MTT法考察了多西他赛固体脂质纳米粒对人乳腺癌MCF-7细胞增殖的抑制作用,采用流式细胞术检测多西他赛固体脂质纳米粒对MCF-7肿瘤细胞凋亡作用,并进一步应用Western-Blot印迹法观察多西他赛固体脂质纳米粒对MCF-7细胞中Src、E-cadherin、β-catenin蛋白表达的影响,探索了其抗乳腺肿瘤的作用机制。结果:多西他赛固体脂质纳米粒能够显著抑制人乳腺癌MCF-7肿瘤细胞的增殖,且浓度越高,抑制率越大(P0.05)。经25、50、100μg/m L多西他赛固体脂质纳米粒制剂作用24 h后,人乳腺癌细胞MCF-7的凋亡率分别为14.56%、21.21%、29.94%,细胞凋亡率随着药物浓度的增加而增加,且各实验组间比较有显著性差异(P0.05)。人乳腺癌MCF-7肿瘤细胞经不同浓度的多西他赛固体脂质纳米粒处理后,细胞中E-cadherin蛋白表达显著升高,Src、β-catenin蛋白表达显著降低,且呈现出明显的剂量依赖性。结论:多西他赛固体脂质纳米粒能够抑制人乳腺癌MCF-7细胞增殖,促进其凋亡,可能与下调β-catenin蛋白的表达,上调E-cadherin蛋白表达以及抑制Src激酶活性有关。     

PRMT5调控三阴性乳腺癌对多西他赛敏感性的研究

目的:探讨蛋白质精氨酸甲基转移酶5(protein arginine methyltransferase 5,PRMT5)对三阴性乳腺癌对多西他赛敏感性的影响,为三阴性乳腺癌的治疗提供新的思路。方法:通过包装慢病毒构建PRMT5过表达稳转细胞系和PRMT5敲除细胞系。采用平板克隆测定不同浓度下多西他赛对于MDA-MB-231细胞和PRMT5过表达细胞增殖的影响。采用流式周期和凋亡检测不同浓度多西他赛对PRMT5过表达和PRMT5敲除以及MDA-MB-231亲本细胞的周期以及凋亡的影响。采用Western Blot方法检测PARP以及p21、p27及LC3等表达。结果:成功构建PRMT5过表达及敲除稳转系。与对应对照组(MDA-MB-231细胞)比较,4nM和8nM的多西他赛处理的PRMT5过表达细胞系(MDA-MB-231-PRMT5细胞)形成克隆率明显降低(P0.05),细胞凋亡率明显增加(P0.05),细胞周期p21分子表达增多(P0.05),但未随浓度增加增高(P0.05),cycling D1、PARP剪切体、LC3-Ⅱ的表达均明显增加(P0.05)。4nM和8nM的多西他赛处理的PRMT5敲除稳转系(MDA-MB-231-sh PRMT5)细胞凋亡率、p21、p27、cyclin D1、LC3-Ⅱ的表达均较对应对照组(MDA-MB-231细胞)明显降低(P0.05),LC3-Ⅱ表达水平较亲本低(P0.05)。结论:PRMT5高表达可增加MDA-MB-231细胞对多西他赛的敏感性,PRMT5有望成为多西他赛临床治疗敏感性预测和方案选择的关键分子,并有望成为调控多西他赛等化疗药物耐药的新靶点。     

合成的哌啶并噻吩类化合物抑制肺癌细胞生长的初步研究

为了发现新的可用于肺癌治疗的小分子药物,从实验室现有的小分子化合物库中,选取13个未见报道的新型哌啶并噻吩类化合物,对其抑制肺癌A549细胞生长的作用进行初步评价。通过体外培养A549细胞,应用WST-1法检测小分子化合物(终浓度为10μmol/L)处理后细胞存活率的变化,发现化合物11(噻吩并[2,3-c]哌啶-3-甲酰胺-2-[(3-甲氧基-萘-2-羰基)-氨基]-6-苄基-,盐酸盐)能显著抑制A549细胞的生长,抑制率可达到(71.34±0.96)%。对小分子化合物结构与活性关系的分析发现苯并结构可能是增强化合物对A549细胞生长的抑制作用的关键结构基团。随后,进一步分析了化合物11(终浓度分别为1、2.5、5、10μmol/L)对A549细胞和正常人胚肺成纤维MRC-5细胞生长的抑制作用。结果表明,随着该化合物浓度增加,对A549细胞生长的抑制率逐渐增大,用GraphPad Prism软件计算出该化合物的IC50为2.407μmol/L;而该化合物对MRC-5细胞生长的抑制率显著低于对A549细胞生长的抑制率,当作用终浓度为10μmol/L时,其对MRC-5细胞生长的抑制率也只有30.41%。这些研究结果初步显示化合物11是一种新的较为理想的治疗肺癌药物先导化合物的候选分子。     

盐酸埃克替尼与多西他赛、培美曲塞不同联合方式对非小细胞肺癌PC-9细胞系作用的实验研究

目的:探讨盐酸埃克替尼以不同次序联合多西他赛、培美曲塞对非小细胞肺癌细胞系PC-9的作用。方法:运用xCELLigence系统检验多西他赛、培美曲塞、盐酸埃克替尼单药作用于PC-9细胞系的半数抑制浓度(Half maximal inhibitory concentration,IC50),用流式细胞仪检测埃克替尼与多西他赛/培美曲塞联合的不同组合方式对PC-9细胞系的细胞周期影响及凋亡。结果:1埃克替尼对PC-9细胞作用60 h后的IC50值为5.3μM;多西他赛对PC-9细胞作用36 h后的IC50为21.5 mg·m L-1;培美曲塞对PC-9细胞作用36 h后的IC50为30μM。2Annexin V-FITC凋亡实验观察到化疗药先于埃克替尼应用对靶细胞的体外杀伤作用均明显高于其他各组,先用多西他赛组细胞凋亡率为(23±0.2)%,高于先用埃克替尼组(10.2±0.1)%和两药同时用药组(15.8±0.4)%;先用培美曲塞组细胞凋亡率为(36.3±0.03)%,高于先用埃克替尼组(14.7±0.1)%和两药同时用药组(30.6±0.03)%,差异有统计学意义(P0.05)。3流式细胞仪周期检测结果显示埃克替尼先于多西他赛(或培美曲塞)用药或两药同时应用时PC-9细胞G0/G1期比例比多西他赛(或培美曲塞)先于埃克替尼用药组高。结论:多西他赛、培美曲塞先于埃克替尼应用方案对肿瘤细胞杀伤作用优于晚用埃克替尼或同时应用埃克替尼。     

人参皂苷Rh2对肺癌A549细胞miR-16和Bcl-2表达与生长的影响研究

目的探讨人参皂苷Rh2(G-Rh2)诱导人肺癌细胞A549凋亡作用及机制研究。方法采用2.5、5.0、10.0、20.0、40.0μmol/L的G-Rh2处理A549细胞,MTT法于不同时间点测定G-Rh2对A549的生长抑制作用;倒置显微镜观察G-Rh2对A549细胞作用后的形态改变;Annexin-FITC/PI双染法检测细胞凋亡情况;Real-time PCR和Western-blot法分别检测G-Rh2对A549细胞中miR-16和Bcl-2蛋白表达的影响。结果与阴性对照组相比,不同浓度G-Rh2能够抑制A549肺癌细胞增殖并呈时间-浓度依赖性;GRh2作用后,A549细胞凋亡率明显增加,miR-16的表达显著增加,而Bcl-2蛋白表达显著降低。结论G-Rh2能够显著抑制A549肺癌细胞增殖并通过上调miRNA-16,下调Bcl-2的表达发挥治疗肺癌的作用。     

microRNA-3163靶向乳腺癌耐药蛋白逆转肺癌细胞多药耐药作用

目的:验证microRNA-3163(miR-3163)在肺癌细胞中是否靶向乳腺癌耐药蛋白(BCRP),探索逆转肺癌细胞抗肿瘤药物多药耐药(MDR)的干预策略。方法:检测BCRP在肺癌细胞A549和耐药细胞系A549/ADR中的表达,利用系列浓度梯度的抗肿瘤药物处理细胞,计算其作用的IC50值;在A549/ADR细胞中转染miR-3163的模拟物或抑制剂,用Western印迹检测BCRP的表达水平;在此基础上检测miR-3163对抗肿瘤药物杀伤A549/ADR细胞的影响。结果:与A549细胞相比,A549/ADR细胞具有对抗肿瘤药物的MDR特性,BCRP在A549/ADR细胞中的表达显著上调。转染miR-3163的模拟物能够上调A549/ADR细胞对抗肿瘤药物阿霉素、紫杉醇、吉西他滨和吉非替尼的敏感性,逆转其MDR作用。这些抗肿瘤药物作用的IC50值分别从4.86±0.33、0.41±0.05、3.79±0.26和5.51±0.25μmol/L下调至0.30±0.05、0.07±0.01、0.67±0.10和1.58±0.42μmol/L。特异性实验结果表明,miR-3163的模拟物能够在A549/ADR细胞中下调BCRP的表达水平,转染miR-3163的抑制剂能够阻断miR-3163模拟物的作用。结论:miR-3163有可能通过靶向耐药蛋白BCRP逆转肺癌细胞的MDR作用。     

SETD8基因表达对乳腺癌细胞周期、活性氧及药物敏感性的影响

目的:构建SETD8重组慢病毒载体,探讨SETD8对人乳腺癌细胞周期、氧化应激的影响,并观察稳定敲低SETD8后对乳腺癌细胞多西他赛敏感性的影响。方法:构建含SETD8基因的重组慢病毒载体,经转染,荧光显微镜观察感染效率;采用RT-qPCR和Western blot检测SETD8 m RNA和蛋白相对表达量;采用流式细胞技术检测细胞周期及活性氧水平,通过CCK-8试剂检测稳定敲低SETD8基因的乳腺癌细胞对多西他赛的敏感性变化。结果:成功包装慢病毒,荧光观察慢病毒感染效率在85%左右,通过PCR和WB验证SETD8过表达及敲低稳转细胞系的效率显著(P0.01)。低表达SETD8的乳腺癌细胞周期停滞在G2/M和S期,细胞内ROS水平高于对照组。不同浓度多西他赛处理的SETD8敲低稳转细胞系的细胞活性较对照组明显降低(P0.01)。结论:慢病毒介导下调SETD8表达,使得乳腺癌细胞周期阻滞在G2/M期,细胞内ROS增多,与多西他赛发生协同作用,从而增加了药物敏感性。     

澳洲茄边碱通过Caspase3蛋白诱导人肺腺癌A549细胞的凋亡作用

运用中药龙葵提取物澳洲茄边碱处理人肺腺癌A549细胞,研究其对A549细胞的抑制及凋亡作用,探讨澳洲茄边碱对肺腺癌的作用机制。通过细胞增殖抑制实验检测不同浓度澳洲茄边碱对A549细胞增殖的影响,采用蛋白印迹法(Western blot)检测凋亡蛋白Caspase3的表达水平,采用流式细胞术测定处理后A549细胞的凋亡水平及细胞周期变化。结果显示,不同浓度澳洲茄边碱均能抑制A549的增殖,呈浓度效应;用不同浓度澳洲茄边碱处理A549细胞24h后,Western blot结果显示,随药物浓度增大,凋亡蛋白Caspase3水解程度增高,对A549凋亡作用明显增强;流式细胞术检测细胞凋亡的结果显示,20μmol·L-1澳洲茄边碱处理A549细胞后,细胞发生明显凋亡,其中早期凋亡细胞比例为25.35%,晚期凋亡细胞比例为11.47%;流式细胞术检测细胞周期的结果显示,20μmol·L-1澳洲茄边碱处理A549细胞后,细胞周期阻滞于G2/M期。本研究结果表明,澳洲茄边碱通过激活细胞凋亡通路中的Caspase3蛋白触发细胞凋亡,同时将A549细胞阻滞在细胞周期的G2/M期,抑制人肺腺癌细胞A549的生长。     

肺癌脑转移型A549／GFP-2细胞的筛选及其条件液对脑微血管内皮细胞的作用

目的：建立肺癌脑转移模型,筛选脑转移倾向细胞A549／GFP-2,探讨A549和A549／GFP-2条件液对脑微血管内皮细胞的作用,揭示肺癌脑转移的机制。方法：利用胸腔原位注射法筛选出A549脑转移细胞亚型A549／GFP-2,原代培养大鼠脑微血管内皮细胞,观察A549和A549／GFP-2细胞条件液对脑微血管内皮细胞增殖的影响和细胞内HIF-1α和VEGF表达的改变。结果：胸腔内原位种植较好地反应了临床肺癌脑转移的过程。不同浓度的A549和A549／GFP-2细胞条件液对脑微血管内皮细胞增殖的影响不同,低浓度（〈30％）对脑微血管内皮细胞有促进的作用;高浓度（〉60％）对脑微血管内皮细胞的增殖有不同程度的抑制作用,且有随浓度增加抑制作用增强的趋势。A549和A549／GFP-2细胞条件液能提高脑微血管内皮细胞内HIF-1α和VEGF的表达。结论：胸腔内原位种植是建立肺癌脑转移的稳定模型。肺癌脑转移与肺癌细胞在生长过程中分泌的HIF-1α和VEGF等细胞因子破坏了脑微血管内皮细胞的结构有关。     

Alteration in the Balance of Prosurvival and Proapoptotic Signalling Pathways Leads to Sequence-Dependent Synergism Between Docetaxel and Sorafenib in Human Non-small Cell Lung Cancer Cell Lines

To examine the antiproliferative effect of the combination of docetaxel and sorafenib, applied to the representative non-small cell lung cancer cell line A549 cells either wild type or with acquired resistance to docetaxel (A549/D). The aim of this study is to evaluate the synergistic effect of combination treatment on cell growth inhibition and to elucidate the involved molecular mechanisms. A549 cells with acquired resistance to docetaxel were established by continuous exposure to docetaxel. We examined the effect of different combinatorial treatment on cell proliferation and cell cycle distribution. In addition, the effect of combinatorial treatments on proliferative and apoptotic signalling pathway were studied. Our results showed that the synergistic effect presented when A549 cells were treated with docetaxel followed by sorafenib or when A549/D cells were treated in reverse sequence. Furthermore, we suggested that synergistic effect in A549/D cells was caused by inhibiting P-gp function and altering in the balance of growth and apoptotic signalling pathways. Our data suggested a potential role of sorafenib in chemosensitizing docetaxel-resistant cancer cells. This study also provides molecular evidence for applying different therapeutic strategies for patients with different genetic and proteomic profile.     

The impact of hyperglycemia on adhesion between endothelial and cancer cells revealed by single‐cell force spectroscopy

The impact of hyperglycemia on adhesion between lung carcinoma cells (A549) and pulmonary human aorta endothelial cells (PHAEC) was studied using the single‐cell force spectroscopy. Cancer cells were immobilized on a tipless Atomic Force Microscopy (AFM) cantilever and a single layer of endothelial cells was prepared on a glass slide. The measured force‐distance curves provided information about the detachment force and about the frequency of specific ligand‐receptor rupture events. Measurements were performed for different times of short term (up to 2 h) and prolonged hyperglycemia (3 h ‐ 24 h). Single‐cell force results were correlated with the expression of cell adhesion molecules (intercellular adhesion molecule, P‐selectin) and with the length and density of the PHAECs glycocalyx layer, which were measured by AFM nanoindentation. For short‐term hyperglycemia, we observed a statistically significant increase of the adhesion parameters that was accompanied by an increase of the glycocalyx length and expression of P‐selectin. Removal of hyaluronic acid from PHAECs glycocalyx significantly decreased the adhesion parameters, which indicates that hyaluronic acid has a strong impact on adhesion in A549/PHAEC system in short term of hyperglycemia. For prolonged hyperglycemia, the most significant increase of adhesion parameters was observed for 24 hours and this phenomenon correlated with the expression of adhesion molecules and a decrease of the glycocalyx length. Taking together, presented data indicate that both mechanical and structural properties of the endothelial glycocalyx strongly modulate the adhesion in the A549/PHAEC system.     

Metformin attenuates adhesion between cancer and endothelial cells in chronic hyperglycemia by recovery of the endothelial glycocalyx barrier

BackgroundEpidemiologic studies suggest that diabetes is associated with an increased risk of cancer. Concurrently, clinical trials have shown that metformin, which is a first-line antidiabetic drug, displays anticancer activity. The underlying mechanisms for these effects are, however, still not well recognized.MethodsMethods based on atomic force microscopy (AFM) were used to directly evaluate the influence of metformin on the nanomechanical and adhesive properties of endothelial and cancer cells in chronic hyperglycemia. AFM single-cell force spectroscopy (SCFS) was used to measure the total adhesion force and the work of detachment between EA.hy926 endothelial cells and A549 lung carcinoma cells. Nanoindentation with a spherical AFM probe provided information about the nanomechanical properties of cells, particularly the length and grafting density of the glycocalyx layer. Fluorescence imaging was used for glycocalyx visualization and monitoring of E-selectin and ICAM-1 expression.ResultsSCFS demonstrated that metformin attenuates adhesive interactions between EA.hy926 endothelial cells and A549 lung carcinoma cells in chronic hyperglycemia. Nanoindentation experiments, confirmed by confocal microscopy imaging, revealed metformin-induced recovery of endothelial glycocalyx length and density. The recovery of endothelial glycocalyx was correlated with a decrease in the surface expression of E-selectin and ICAM-1.ConclusionOur results identify metformin-induced endothelial glycocalyx restoration as a key factor responsible for the attenuation of adhesion between EA.hy926 endothelial cells and A549 lung carcinoma cells.General significanceMetformin-induced glycocalyx restoration and the resulting attenuation of adhesive interactions between the endothelium and cancer cells may account for the antimetastatic properties of this drug.     

Mechanics in human fibroblasts and progeria: Lamin A mutation E145K results in stiffening of nuclei

The lamina is a filamentous meshwork beneath the inner nuclear membrane that confers mechanical stability to nuclei. The E145K mutation in lamin A causes Hutchinson‐Gilford progeria syndrome (HGPS). It affects lamin filament assembly and induces profound changes in the nuclear architecture. Expression of wild‐type and E145K lamin A in Xenopus oocytes followed by atomic force microscopy (AFM) probing of isolated oocyte nuclei has shown significant changes in the mechanical properties of the lamina. Nuclei of oocytes expressing E145K lamin A are stiffer than those expressing wild‐type lamin A. Here we present mechanical measurements by AFM on dermal fibroblasts obtained from a 4‐year‐old progeria patient bearing the E145K lamin A mutation and compared it to fibroblasts obtained from 2 healthy donors of 10 and 61 years of age, respectively. The abnormal shape of nuclei expressing E145K lamin A was analyzed by fluorescence microscopy. Lamina thickness was measured using electron micrographs. Fluorescence microscopy showed alterations in the actin network of progeria cells. AFM probing of whole dermal fibroblasts did not demonstrate significant differences in the elastic moduli of nuclear and cytoplasmic cell regions. In contrast, AFM measurements of isolated nuclei showed that nuclei of progeria and old person's cells are significantly stiffer than those of the young person, indicating that the process of aging, be it natural or abnormal, increases nuclear stiffness. Our results corroborate AFM data obtained using Xenopus oocyte nuclei and prove that the presence of E145K lamin A abnormally increases nuclear stiffness.     

Psoralen reverses docetaxel-induced multidrug resistance in A549/D16 human lung cancer cells lines

Chemotherapy is the recommended treatment for advanced-stage cancers. However, the emergence of multidrug resistance (MDR), the ability of cancer cells to become simultaneously resistant to different drugs, limits the efficacy of chemotherapy. Previous studies have shown that herbal medicine or natural food may be feasible for various cancers as potent chemopreventive drug. This study aims to explore the capablility of reversing the multidrug resistance of docetaxel (DOC)-resistant A549 cells (A549/D16) of psoralen and the underlying mechanisms. In this study, results showed that the cell viability of A549/D16 subline is decreased when treated with psoralen plus DOC, while psoralen has no effect on the cell proliferation on A549 and A549/D16 cells. Furthermore, mRNA and proteins levels of ABCB1 were decreased in the presence of psoralen, while decreased ABCB1 activity was also revealed by flow cytometry. Based on these results, we believe that psoralen may be feasible for reversing the multidrug resistance by inhibiting ABCB1 gene and protein expression. Such inhibition will lead to a decrease in ABCB1 activity and anti-cancer drug efflux, which eventually result in drug resistance reversal and therefore, sensitizing drug-resistant cells to death in combination with chemotherapeutic drugs.     

Effect of selenite combined with chemotherapeutic agents on the proliferation of human carcinoma cell lines

Selenite is frequently used in combination with cancer chemotherapeutic agents to reduce side effects. However, the cytoprotective activity of selenite may also reduce the efficacy of chemotherapeutic drugs on tumor cells. This study was designed to examine the effects of selenite combined with cytotoxic agents used in clinical protocols [e.g., doxorubicine, docetaxel, 5-fluorouracil (5-FU), methotrexate (MTX), mafosphamide, mitomycin C, gemcitabine, etoposide, cisplatin, irinotecan, and oxaliplatin] on the proliferation of various carcinoma cell types. The data demonstrated that selenite had no marked effects on the antiproliferative activity of docetaxel, doxorubicine, 5-FU, MTX, and mafosphamide in MDA-MB-231 breast cancer cells. Likewise, no consistent changes were observed in A549 lung cancer cell proliferation when selenite was combined with cisplatin, etoposide, gemcitabine, or mitomycin C. On the other hand, selenite potentiated the cytotoxicity of 5-FU, oxaliplatin, and irinotecan in HCT116 colon cancer cells by approx 1.1-fold, 2.7-fold, and 2.6-fold, respectively. In SW620 colon cancer cells, selenite induced a 1.5-fold and 4.3-fold increase of the antiproliferative activity of 5-FU and oxaliplatin, respectively. Whereas irinotecan showed no effects on SW620 cell growth, a combination with selenite resulted in 23% inhibition. Our results indicate that selenite did not reduce the antiproliferative activity of chemotherapeutic agents in vitro. In addition, selenite was able to increase the inhibitory activity of docetaxel in A549 lung cancer cells, and of 5-FU, oxaliplatin, and irinotecan in HCT116 and SW620 colon cancer cells implying selenite is potentially useful as an adjuvant chemotherapeutic agent.     

Sequence-Dependent Antiproliferative Effects of Gefitinib and Docetaxel on Non-Small Cell Lung Cancer (NSCLC) Cells and the Possible Mechanism

Purpose

Recent clinical trials showed that the sequential combination of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) and chemotherapy could prolong the PFS and/or OS of advanced non-small cell lung cancer (NSCLC) patients with EGFR mutation. The aim of present study was to assess the optimal combination sequence and to explore its possible mechanism.

Methods

PC-9 cells and A549 cells, the lung adenocarcinoma cells with mutant and wide-type EGFR respectively, were treated with docetaxel/gefitinib alone or in different combination schedules. The EGFR and K-ras gene status was determined by qPCR-HRM technique. Cell proliferation was detected by MTT assay. The expression and phosphorylation of EGFR, ERK, Akt and IGF-1R were detected by western blot. Cell cycle distribution was observed by flow cytometry.

Results

Only sequential administration of docetaxel followed by gefitinib (D→G) induced significant synergistic effect in both cell lines (Combination Index<0.9). The reverse sequence (G→D) resulted in an antagonistic interaction in both cell lines (CI>1.1), whereas the concurrent administration (D+G) showed additive (0.9<CI<1.1)-synergistic effect in PC-9 cells and antagonistic-additive effect in A549 cells. Mechanism studies showed that docetaxel-induced phosphorylation of EGFR and ERK was repressed by subsequently used gefitinib, but not by concurrent exposure of gefitinib. The gefitinib-repressed phosphorylation of EGFR and ERK was reversed neither by concurrent nor by subsequent administration of docetaxel. D+G reinforced their inhibition on the phosphorylation of IGF-1R in PC-9 cells.

Conclusions

The cytotoxic drugs followed by EGFR-TKIs may be the optimal combination for antiproliferative effects in EGFR-mutant NSCLC cells, and the phosphorylation of EGFR and ERK might contribute to this effect.     

miR-126增加非小细胞肺癌细胞A549对顺铂的敏感性

miR-126在多种恶性肿瘤中存在表达下调并显示抑癌基因的功能,然而其在肿瘤敏感性中的作用仍不明确.为了探讨miR-126在非小细胞肺癌细胞A549对顺式铂氨(cis-diammine dichloroplatoum, cisplatin, CDDP)敏感性中的作用及可能机制,本研究用MTS法检测非小细胞肺癌细胞A549及其衍生的CDDP耐受细胞A549/DDP对CDDP的敏感性.结果表明,A549/DDP细胞对CDDP的耐受性是A549细胞的4.05倍(P=0.0078)|用qRT-PCR检测发现,相比于A549细胞,A549/DDP细胞中miR-126的表达下调了8.45倍(P=0.0063),而survivin和Bcl-2的表达明显上调|通过MTS、qRT-PCR及Western印迹实验发现,miR-126 mimics使A549/DDP细胞中miR-126的表达上调了12.63倍(P=0.0013),并明显增加A549/DDP细胞对CDDP的敏感性及下调survivin和Bcl-2的表达;相反,miR-126 inhibitor能明显增加A549细胞对CDDP的耐受性及增加survivin和Bcl-2的表达.本研究结果提示,miR-126在非小细胞肺癌CDDP耐受细胞中的表达下调,上调miR-126的表达能增加耐药细胞对CDDP的敏感性. miR-126是逆转肺癌CDDP耐受的可能潜在靶标.     

Highly efficient system to deliver taxanes into tumor cells: docetaxel-loaded chitosan oligomer colloidal carriers

Chitosan (CS) colloidal carriers, which consist of an oily core and a CS coating, were developed to facilitate a controlled intracellular delivery of docetaxel. The systems presented a particle size of <200 nm and a positive surface charge. As shown by the flow cytometry analysis, fluorescent CS carriers were rapidly internalized by human tumor cells. Fluorescence was observed in more than 80% of MCF7 (human breast adenocarcinoma) and almost 100% of A549 (human lung carcinoma) cells when a 2 h treatment with fluorescent CS carriers was given. A total of 24 h after treatment, docetaxel-loaded CS carriers had an effect on cell proliferation that was significantly greater than that of free docetaxel. These results indicate that docetaxel remains fully active upon its encapsulation into the colloidal carriers and that these systems actively transport docetaxel into cancer cells and, thus, result in a significant increase in its antiproliferative effect.     

Sensing Biophysical Alterations of Human Lung Epithelial Cells (A549) in the Context of Toxicity Effects of Diesel Exhaust Particles

Diesel exhaust particles (DEP) in urban air are associated with numerous respiratory diseases. The role of underlying biomechanics in cytotoxicity of individual lung cells relating to DEP exposure is unclear. In this study, atomic force microscopy (AFM), confocal Raman microspectroscopy (RM), and fluorescence (FL) microscopy were used to monitor alterations of single A549 cells exposed to DEP. Results revealed a significant decrease in membrane surface adhesion force and a significant change in cell elasticity as a function of DEP–cell interaction time, and the dynamic changes in cellular biocomponents which were reflected by changes of characteristic Raman bands: 726 cm^?1 (adenine), 782 cm^?1 (uracil, cytosine, thymine), 788 cm^?1 (O–P–O), 1006 cm^?1 (phenylalanine), and 1320 cm^?1 (guanine) after DEP exposure. These findings suggest that the combination of multi-instruments (e.g., AFM/FL) may offer an exciting platform for investigating the roles of biophysical and biochemical responses to particulate matter-induced cell toxicity.