沉默ABCC4基因逆转人胃癌多药耐药的研究

目的 探讨胃癌耐药复发相关基因ABCC4在胃癌耐药复发中的分子机制。方法 采用免疫组织化学、Western blot、RT-PCR、流式细胞检测胃癌组织及胃癌耐药细胞中ABCC4的表达情况,利用RNA干扰技术下调ABCC4基因在胃癌耐药细胞中的表达水平。结果 ABCC4基因在多种胃癌细胞中高表达,尤其是在胃癌耐药细胞中表达增加更为显著,但在正常胃黏膜细胞中极低表达或表达缺失。RNA干扰下调ABCC4基因可导致胃癌耐药细胞发生凋亡,并且细胞周期被阻滞在G1期以内。5-Fu可以显著抑制ABCC4沉默后肿瘤细胞增殖,同时,也能明显抑制ABCC4沉默后裸鼠体内肿瘤生长。结论 ABCC4基因过度表达于胃癌耐药细胞中,下调ABCC4基因表达可抑制胃癌多药耐药细胞增殖,并且可增强其对化疗药物的敏感度。     

siRNA沉默MMP-2基因对肺癌A549细胞侵袭能力的影响

目的 探讨siRNA靶向抑制MMP-2基因的表达对肺癌A549细胞侵袭的抑制作用.方法 化学合成一对针对MMP-2基因的干扰序列siRNA和一对阴性对照的无义序列siRNA-N,转染肺癌A549细胞,同时以未转染A549细胞作为空白对照.于转染后48 h,分别采用半定量RT-PCR技术和Western blotting法从mRNA和蛋白水平检测干扰效果;采用Boyden侵袭小室检测转染MMP-2siRNA后对A549细胞侵袭能力的影响.结果 与空白对照组和转染阴性对照siRNA-N组相比,A549细胞转染MMP-2 siRNA 48 h后,MMP-2基因转录水平和蛋白水平的表达均受到抑制.转染MMP-2 siRNA组细胞穿膜数与空白对照组和转染阴性对照siRNA-N组相比明显下降.结论 靶向MMP-2的siRNA不仅能特异性抑制MMP-2 mRNA和蛋白的表达,且能有效抑制A549肺癌细胞的侵袭,为肺癌的基因治疗提供了有效的靶点.     

沉默EZH2基因表达对肾癌细胞生物学行为的影响

目的 研究RNA干扰靶向沉默EZH2基因表达对ACHN肾癌细胞株增殖、细胞周期和凋亡的影响。方法 应用Western blot法检测EZH2蛋白在人正常近端肾小管上皮细胞株HK-2和肾癌细胞株786-0和ACHN中的表达。脂质体法介导化学合成EZH2 siRNA转染ACHN细胞株,Western blot法检测转染后ACHN细胞EZH2蛋白的表达情况,CCK-8法检测转染后ACHN细胞增殖率,流式细胞术检测转染后ACHN细胞周期分布和凋亡情况。结果 肾癌细胞株786-0和ACHN中EZH2蛋白的表达水平明显高于人正常近端肾小管上皮细胞HK-2。RNA干扰EZH2基因可成功地敲减ACHN细胞EZH2蛋白的表达。EZH2-siRNA干扰后,实验组ACHN细胞生长明显受抑制,在转染后48和72 h细胞增殖受抑制效应著（P＜0.05）。细胞周期分析显示：siEZH2转染组G1期ACHN细胞比例呈增加趋势,而S期和G2期细胞比例呈减少趋势,其中在转染后48h G1期ACHN细胞比例显著增加,而S期和G2期细胞比例明显下降（P＜0.05）;凋亡分析显示：siEZH2转染组ACHN细胞凋亡率随转染后时间的延长而呈增加趋势,在转染后48和72 h细胞凋亡率增加最显著（P＜0.05）。结论 沉默EZH2基因表达可靶向肾癌ACHN细胞周期中G1/S限制点而阻滞细胞周期进展,同时可有效抑制肾癌细胞增殖和促进细胞凋亡。     

Establishment and Partial Characterization of an Epirubicin-Resistant Gastric Cancer Cell Line with Upregulated ABCB1

Multidrug resistance (MDR) is a major impediment to successful chemotherapy of gastric cancer. Our aim was to establish an epirubicin-resistant cell subline (AGS/EPI) and to elucidate the mechanisms involved in acquired EPI resistance. The AGS/EPI cell subline developed by exposing parental AGS cells to stepwise increasing concentrations of EPI demonstrated 2.52-fold resistance relative to the AGS cell line, and mRNA expression of the ATP-dependent drug-efflux pump P-glycoprotein (Pgp), more recently known as ABCB1 protein, was similarly upregulated. An AGS/EPI cell subline could thus be effectively established, and MDR mechanism of these cells was shown to be related to the overexpression of mRNA of the ABCB1 gene.     

Effect of MUC1 siRNA on Drug Resistance of Gastric Cancer Cells to Trastuzumab

Trastuzumab is the first molecular targeting drug to increase the overall survival rate in advanced gastriccancer. However, it has also been found that a high intrinsic or primary trastuzumab resistance exists in someproportion of gastric cancer patients. In order to explore the mechanism of resistance to trastuzumab, firstlywe investigated the expression of MUC1 (membrane-type mucin 1) in gastric cancer cells and its relationshipwith drug-resistance. Then using gene-silencing, we transfected a siRNA of MUC1 into drug-resistant cells.The results showed the MKN45 gastric cell line to be resistant to trastuzumab, mRNA and protein expressionof MUC1 being significantly upregulated. After transfection of MUC1 siRNA, protein expression of MUC1in MKN45cells was significantly reduced. Compared with the junk transfection and blank control groups, thesensitivity to trastuzumab under MUC1 siRNA conditions was significantly increased. These results imply thatHER2-positive gastric cancer cell MKN45 is resistant to trastuzumab and this resistance can be cancelled bysilencing expression of the MUC1 gene.     

非小细胞肺癌支气管镜活检组织中LRP和MRP表达及其临床意义

背景与目的 研究非小细胞肺癌支气管镜活检组织中肺耐药蛋白(LRP)、多药耐药相关蛋白(MRP)的表达及其临床意义,方法应用免疫组织化学S-P技术对112例非小细胞肺癌支气管镜活检组织进行LRP和MRP表达的检测,结果LRP和MRP在肺腺癌和肺鳞癌组织中的表达阳性率分别为LRP,68.3396和42.31％(P<0.025);MRP,73.33％和46.15％(P<0.005);LRP和MRP在中高分化和低分化组间的表达阳性率分别为LRP.68.42％和43.64％(P<0.05);MRP,77.19％和43.64％(P<0.025),LRP和MRP在不同组织类型和分化程度中差异有显著性(均P<0.05或P<0.025);LRP和MRP在TNM各分期中差异无显著性(均P>0.05);112例非小细胞肺癌组织中LRP和MRP表达存在高度正相关(r=-0.984,P:O.016);2种耐药基因协同表达的阳性率肺腺癌组(51.66％)和肺鳞癌组(44.23％)差异无显著性(P>0.os),结论肺癌耐药为多途径多基因参与的过程,LRP和MRP的表达水平在肺腺癌与肺鳞癌之间、在中高分化与低分化组之间均存在显著性差异,且LRP和MRP表达呈正相关,联合检测NSCLC组织中LRP和MRP的表达水平,对化疗药物的选择、预后的判断均具有重要的临床意义,     

siRNA沉默Snail基因对胃癌SGC7901细胞株增殖及侵袭能力的影响

目的探讨转录因子Snail在胃癌SGC7901细胞株增殖及侵袭转移过程中的作用,为胃癌的基因治疗提供有效靶点。方法化学合成针对Snail的靶向siRNA,同时以转染阴性对照siRNA、转染脂质体转染试剂和空白细胞作为对照。RT-PCR检测转染效率,MTT检测Snail siRNA对SGC7901细胞增殖能力的影响,Boyden chamber检测Snail siRNA对SGC7901细胞侵袭能力的影响。结果与各对照组相比,转染SnailsiRNA组SGC7901细胞Snail mRNA的表达下降,且随转染时间延长,Snail mRNA的表达下降明显(P<0.05)。MTT结果显示转染Snail siRNA组SGC7901细胞在转染后48、72 h较对照组增殖能力明显下降(P<0.05);Boyden chamber结果显示转染Snail siRNA组SGC7901细胞在转染后48、72 h较对照组穿膜细胞数明显下降(P<0.05);转染Snail siRNA组各时间点之间增殖能力和侵袭转移能力的差异也有统计学意义(P<0.05)。结论转录因子Snail在胃癌的发生、发展及侵袭转移中发挥重要作用,可作为胃癌基因治疗的有效靶点。     

A New Quinoline Derivative MS-209 Reverses Multidrug Resistance and Inhibits Multiorgan Metastases by P-glycoprotein-expressing Human Small Cell Lung Cancer Cells

Development of distant metastases and acquired multidrug resistance (MDR) are major problems in therapy for human small cell lung cancer (SCLC). MS-209 is a novel quinoline compound, which reverses P-glycoprotein (P-gp)-mediated MDR. We previously reported that MS-209 reversed in vitro MDR of human SCLC (SBC-3/ADM and H69/VP) cells expressing P-gp. In the present study, we determined the therapeutic effect of MS-209 in combination with chemotherapy against multiorgan metastases of MDR SCLC cells. SBC-3/ADM cells expressing P-gp were highly resistant to etoposide (VP-16), adriamycin (ADM), and vincristine (VCR) in vitro , compared with parental SBC-3 cells lacking P-gp expression. MS-209 restored chemosensitivity of SBC-3/ADM cells to VP-16, ADM, and VCR in a dose-dependent manner in vitro. Intravenous injection with SBC-3 or SBC-3/ADM cells produced metastatic colonies in the liver, kidneys and lymph nodes in natural killer (NK) cell-depleted severe combined immunodeficiency (SCID) mice, though SBC-3/ ADM cells more rapidly produced metastases than did SBC-3 cells. Treatment with VP-16 and ADM reduced metastasis formation by SBC-3 cells, whereas the same treatment did not affect metastasis by SBC-3/ADM cells. Although MS-209 alone had no effect on metastasis by SBC-3 or SBC-3/ADM cells, combined use of MS-209 with VP-16 or ADM resulted in marked inhibition of metastasis formation by SBC-3/ADM cells to multiple organs. These findings suggest that MS-209 reversed the MDR of SBC-3/ADM cells, but not SBC-3 cells, growing in the various organs, and inhibited metastasis formation in vivo. Therefore, this chemosensitizing agent, MS-209, may be useful for treatment of refractory SCLC patients with multiorgan metastases.     

耐药相关基因在非小细胞肺癌组织中的表达及其意义

目的:探讨耐药相关基因在非小细胞肺癌(NSCLC)组织中的表达及其临床意义.方法:应用免疫组化技术检测治疗前肺癌组织标本中P-gp、MRP、LRP、GST-π和TopoⅡ表达.结果:58例治疗前NSCLC中P-gp、MRP、LRP、GST-π和TopoⅡ阳性率分别为96.55%,67.24%,75.86%,65.52%,98.28%,并有部分共表达.癌旁正常肺组织呈阴性或弱阳性表达.性别、有无吸烟史、有无淋巴结转移及在TNM各分期中P-gp、MRP、LRP、GST-π和TopoⅡ阳性表达无明显差异(P＞0.05).比较腺癌组与鳞癌组,MRP、LRP、GST-π阳性表达有显著性差异(P＜0.05),而P-gp、TopoⅡ阳性表达无明显差异(P＞0.05);MRP、LRP、P-gp、GST-π共表达有显著性差异(χ2=21.662,P＜0.001);低分化腺癌、鳞癌与中、高分化腺癌、鳞癌P-gp、MRP、LRP、GST-π和TopoⅡ阳性表达无明显差异(P＞0.05).结论:肺癌耐药为一多途径多基因参与的过程,肺腺癌原发的多药耐药机率较肺鳞癌高,联合检测肺癌组织中耐药相关基因的表达有助于判断化疗疗效及预后.     

肺癌上皮间质转化后引发Nrf2介导的多药耐药的研究

目的 探讨肺癌中上皮间质转化通过Nrf2通路导致多药耐药的可能性。方法 TGF-β1诱导肺腺癌细胞发生上皮间质转化, Western blot法检测癌细胞发生上皮间质转化的标志分子和细胞核内Nrf2的表达变化;比色法测定GSH含量及GST活力的变化;MTT实验检测癌细胞发生上皮间质转化前后对顺铂耐药指数的变化。结果 TGF-β1使癌细胞发生了上皮间质转化：细胞失去极性,上皮标志分子E-cadherin表达下降,而间质标志分子Vimentin和Snail表达上升;细胞发生上皮间质转化后细胞核内Nrf2表达显著增加,GSH含量增高及GST活力增强,癌细胞对顺铂的耐药指数是原来的7.7倍。结论 肺癌上皮间质转化后可能通过Nrf2通路介导了癌细胞的多药耐药。     

姜黄素逆转电离辐射诱导的非小细胞肺癌A549细胞上皮间质转化

目的 探讨姜黄素对电离辐射诱导的非小细胞肺癌A549细胞上皮间质转化的影响。方法 用电离辐射诱导A549细胞发生上皮间质转化,将其命名为A549R。CCK8法检测细胞增殖;Western blot检测姜黄素对A549R上皮/间质标志物表达的影响;划痕实验及Transwell实验检测姜黄素对A549R细胞迁移能力的影响。结果 A549R细胞经姜黄素处理后,细胞形态由纺锤形转变为椭圆形上皮形态;E-cadherin表达下调,pan-Keratin表达上调,Vimentin、Twist表达显著下调,N-cadherin表达水平无明显变化;划痕愈合面积随姜黄素浓度的升高而显著下降;A549R细胞迁移能力随姜黄素浓度的升高而显著下降。结论 姜黄素通过下调E-cadherin、Vimentin、Twist的表达,并上调Keratin的表达,从而逆转电离辐射诱导A549细胞发生上皮间质转化。     

Inhibition by Fibrin Coagulation of Lung Cancer Cell Destruction by Human Interleukin-2-activated Killer Cells

We examined the effect of fibrin coagulation on tumor cytotoxicity mediated by human lymphokine (IL-2)-activated killer (LAK) cells. LAK cells were induced from peripheral blood mononuclear cells (MNC) by culture with recombinant IL-2 for 4 or 5 days, and LAK cell-mediated cytotoxicity against tumor cells was assessed by ⁵¹Cr release assay in the presence or absence of plasma from normal subjects and lung cancer patients. Plasma did not affect the phase of induction of LAK activity by IL-2, but dose-dependently inhibited the effector phase of LAK cell-mediated cytotoxicity against Daudi cells. Similar inhibition of LAK cell-mediated cytotoxicity was observed on pretreatment of Daudi cells and human lung cancer cell lines with human fibrinogen plus thrombin. A parallel relationship was found between the amount of fibrinogen in plasma of lung cancer patients and inhibition of LAK cytotoxicity. This inhibition was reduced by addition of anticoagulants (heparin or argatroban). These findings suggest that fibrin coagulation on tumor cells protects them from LAK cell-mediated tumor cytotoxicity in malignant lesions and that a combination of an anticoagulant drug and IL-2/LAK therapy may be effective for treatment of lung cancer patients.     

Silencing of Rac3 Inhibits Proliferation and Induces Apoptosis of Human Lung Cancer Cells

Background: Rac3, a member of the Rac family of small guanosine triphosphatases (GTPases), regulatesa variety of cell functions, including the organization of the cytoskeleton, cell migration, and invasion.Overexpression of Rac3 has been reported in several human cancers. However, the role of Rac3 in lung cancer(LC) has not been determined in detail. The purpose of this study was to investigate the effect of silencing of Rac3expression in human LC cells and the consequences for cell survival. Materials and Methods: Lentivirus smallhairpin RNA (shRNA) interference techniques were utilized to knock down the Rac3 gene. Gene and proteinexpression was quantified by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting.LC cell apoptosis was examined by annexin V-APC /propidium iodide staining. Results: Efficient silencing ofRac3 strongly inhibited A549 cell proliferation and colony formation ability, and significantly decreased tumorgrowth. Moreover, flow cytometry analysis showed that knockdown of Rac3 led to G2/M phase cell cycle arrestas well as an excess accumulation of cells in the G1 and S phase. Conclusions: Thus, functional analysis usingshRNAs revealed a critical role for Rac3 in the tumor growth of LC cells. shRNA silencing of Rac3 could providean effective strategy to treat LC.     

Effect of Embelin on TRAIL Receptor 2 mAb-induced Apoptosis of TRAIL-resistant A549 Non-small Cell Lung Cancer Cells

Introduction: Some non-small cell lung cancer (NSCLC) tumor cells are insensitive to tumor necrosis factorrelatedapoptosis-inducing ligand (TRAIL) -based therapy. This study was conducted to examine the effect ofembelin on the sensitivity of the A549 NSCLC cell line to TRAIL receptor2 (TRAILR2) monoclonal antibodiesand to investigate the potential mechanisms. Materials and Methods: A549 cells were treated with embelin,TRAILR2 mAb or a combination of both. Cell viability was measured using ATPlite assay and apoptosis rateswere determined by flow cytometry with AnnexinV-FITC and propidium iodide staining, with the expressionlevels of proteins analyzed by Western blotting. Results: The cell survival rate of separate treatments with 100ng/ml TRAILR2 antibody or 25 uM embelin were 81.5±1.57% and 61.7±2.84%, respectively. Their combined usemarkedly decreased cell viability in A549 cells to 28.1±1.97% (P<0.05). The general caspase inhibitor Z-VADFMKcould inhibit the embelin-enhanced sensitivity of A549 cells to TRAILR2 mAb (75.97±3.17%)(P<0.05).Both flow cytometry and cell morphological analysis showed that embelin was able to increase TRAIL-inducedapoptosis in A549 cells. Combined treatment with embelin and TRAILR2 mAb augmented the activation ofinitiator caspases and effector caspase. In addition, A549 cells showed increasing levels of TRAILR2 proteinand decreasing levels of Bcl-2, survivin and c-FLIP following the treatment with embelin+TRAILR2 mAb.Conclusions: Embelin could enhance TRAIL-induced apoptosis in A549 cells. The synergistic effect of thecombination treatment might be due to modulation of multiple components in the TRAIL receptor-mediatedapoptotic signaling pathway, including TRAILR2, XIAP, survivin, Bcl-2 and c-FLIP.     

AKT2在非小细胞肺癌中的表达及预后意义

背景与目的 AKT2是PI3K信号传导通路中重要因子,AKT2激活导致细胞生长和生存,近年来,许多研究表明AKT2在肿瘤形成、生长及转移中起着重要作用。本研究通过检测肿瘤组织中AKT2的表达水平,旨在研究AKT2在非小细胞肺癌(non-small cell lung cancer,NSCLC)中的表达及其与临床预后的关系。方法通过免疫组化方法检测80例NSCLC及10例肺良性病变的组织标本中AKT2蛋白水平。结果 NSCLC中AKT2表达的阳性率为57.50%(46/80),明显高于肺良性病变组织(1/10,10.0%)中的表达,具有统计学差异(χ2=8.038,P=0.006)。AKT2表达与NSCLC患者临床病理特征无明显关系。AKT2表达与患者无进展生存期(χ2=12.671,P=0.005)及总生存期(χ2=9.851,P=0.021)有明显关系。结论 NSCLC中AKT2是患者预后不良的生物学标志。     

非小细胞肺癌靶向治疗研究进展

目前肺癌的生物靶向药物抗表皮生长因子受体(Epidermal Growth Factor Receptor,EGFR)已成功地应用于肺癌临床治疗.但肺癌分子生物学机制十分复杂,新的生物靶点药物在临床中的重要作用日益受到关注.本文对上述分子生物学标志物在肺癌治疗中的作用及其相关临床研究进展进行综述.