Silencing of Bcl-XL Expression in Human MGC-803 Gastric Cancer Cells by siRNA

To investigate the inhibitory effect of the Bcl-XL small interfering RNA(siRNA)on BcI-XLgene expression in the human gastric cancer cell line MGC-803,green fluorescent protein(GFP)siRNAwas constructed and transfected into MGC-803 ceils,together with GFP expression vector pTrace SV40.GFP expression levels were observed using fluorescence microscopy.Bcl-XL siRNA and negative siRNAwere then constructed and stably transfected into MGC-803 cells.RT-PCR and immunofluorescence wereused to detect the expression of Bcl-XL.Spontaneous apoptosis was detected by acridine orange(AO)andflow cytometry.Results were as follows:(1)48 h after GFP expression vector and GFP siRNA co-transfection,the expression level of GFP in the GFP siRNA group was much lower than the negative siRNA group,according to fluorescence microscopy results.The mRNA and protein levels of Bcl-XL in Bcl-XL siRNAstable transfectants were reduced to almost background level compared with negative siRNA transfectantsor untreated cells.(2)Changes in nucleus morphology was observed by AO staining nucleic and flowcytometry analysis,which showed that stable Bcl-XL siRNA transfectants have an increased spontaneousapoptosis (21.17%+1.26% vs.1.19%+0.18% and 1.56%+0.15% respectively,P<0.05 vs.negative siRNAor untreated control),siRNA targeting GFP or Bcl-XL genes can specifically suppress GFP or BcI-XLexpression in MGC-803 cells,and Bcl-XL siRNA can increase spontaneous apoptosis.Bcl-XL siRNA maybe a beneficial agent against human gastric adenocarcinoma.     

Silencing of Bcl-XL expression in human MGC-803 gastric cancer cells by siRNA

To investigate the inhibitory effect of the Bcl-XL small interfering RNA （siRNA） on Bcl-XL gene expression in the human gastric cancer cell line MGC-803, green fluorescent protein （GFP） siRNA was constructed and transfected into MGC-803 cells, together with GFP expression vector pTrace SV40.GFP expression levels were observed using fluorescence microscopy. Bcl-XL siRNA and negative siRNA were then constructed and stably transfected into MGC-803 cells. RT-PCR and immunofluorescence were used to detect the expression of Bcl-XL. Spontaneous apoptosis was detected by acridine orange （AO） and flow cytometry. Results were as follows： （1） 48 h after GFP expression vector and GFP siRNA co-transfection,the expression level of GFP in the GFP siRNA group was much lower than the negative siRNA group,according to fluorescence microscopy results. The mRNA and protein levels of Bcl-XL in Bcl-XL siRNA stable transfectants were reduced to almost background level compared with negative siRNA transfectants or untreated cells. （2） Changes in nucleus morphology was observed by AO staining nucleic and flow cytometry analysis, which showed that stable Bcl-XL siRNA transfectants have an increased spontaneous apoptosis （21.17%± 1.26% vs. 1.19%±0.18% and 1.56%±0.15% respectively, P〈0.05 vs. negative siRNA or untreated control）, siRNA targeting GFP or Bcl-XL genes can specifically suppress GFP or Bcl-XL expression in MGC-803 cells, and Bcl-XL siRNA can increase spontaneous apoptosis. Bcl-XL siRNA may be a beneficial agent against human gastric adenocarcinoma.     

A morphometric tool applied to angiogenesis research based on vessel segmentation

To investigate the relationship between P-glycoprotein (Pgp), glutathione S-transferase π (GST-π) and topoisomerase II (Topo II) expression and human gastric cancer chemoresistance in vitro. Primary single-cell suspensions were prepared from fresh specimens of primary gastric cancer and exposed to hydroxycamptothecin (HCPT), cisplatin (CDDP), 5-fluorouracil (5-FU), adriamycin (ADM) and mitomycin (MMC) for 48 h. Cell metabolic activity and rate of inhibition were evaluated using tetrazolium (MTT) assay. Pgp, GST-π and Topo II expression was determined in gastric carcinoma tissue samples using immunohistochemistry. Chemosensitivity of the gastric cancer cells varied; the rates of inhibition of cells exposed to HCPT, CDDP and 5-FU were significantly higher than that of cells exposed to ADM and MMC (p?相似文献   

Carcinoembryonic antigen expression level as a predictive factor for response to 5-fluorouracil in colorectal cancer

Carcinoembryonic antigen (CEA) expression has been shown to protect cancer cell lines from apoptosis and anoikis. The aim of this study was to further elucidate the role of CEA expression on resistance to anticancer drugs in human colorectal cancer (CRC). We transfected CEA negative CRC cell line SW742 as well as CHO cells to overexpress CEA and their chemoresistance were assessed by MTT assay. In comparison to the parental cell lines, transfected cells had significantly increased resistance to 5-fluorouracil (5-FU). The results also showed a direct correlation between the amount of cellular CEA protein and 5-FU resistance in CEA expressing cells. We found no significant difference in sensitivity to cisplatin and methotrexate between CEA-transfected cells and their counter parental cells. We also compared the association between CEA expression and chemoresistance of 4 CRC cell lines which differed in the levels of CEA production. The CEA expression levels in monolayer cultures of these cell lines did not correlate with the 5-FU resistance. However, 5-FU treatment resulted in the selection of sub-populations of resistant cells that displayed increased CEA expression levels by increasing drug concentration. We analyzed the effect of 5-FU in a 3D multicellular culture generated from the two CRC cell lines, LS180 and HT29/219. Compared with monolayer culture, CEA production and 5-FU resistance in both cell lines were stimulated by 3D growth. In comparison to the 3D spheroids of parental CHO, we observed a significantly elevated 5-FU resistance in 3D culture of the CEA-expressing CHO transfectants. Our findings suggest that the CEA level may be a suitable biomarker for predicting tumor response to 5-FU-based chemotherapy in CRC.     

靶向survivin 的siRNA 联合5-FU 转染抑制肝细胞株HepG2 增殖的研究

目的:研究靶向survivin的(小分子干扰RNA)siRNA和(氟尿嘧啶)5-FU联用对肝癌细胞HepG2的增殖抑制及凋亡的影响。方法:将HepG2细胞分为空白对照组、阴性对照组、5-FU处理组、siRNA转染组、5-FU+siRNA转染组。转染采用脂质体法。RT-PCR法检测HepG2细胞survivin mRNA转录水平;MTT法检测靶向survivin的siRNA和5-FU对HepG2细胞增殖的抑制作用;流式细胞术检测HepG2细胞凋亡情况。结果:空白对照组、阴性对照组、5-FU处理组survivin mRNA表达无明显变化(P>0.05),siRNA转染组、5-FU+siRNA转染组survivin mRNA表达明显下降(F=280.326,q=4.72~7.34,P<0.05)。5-FU+siRNA转染组增殖抑制率为51.58%±1.35%,与其它各组相比抑制率明显增高(F=280.326,q=5.27~9.84,P<0.05)。5-FU+siRNA组与其它各组相比细胞凋亡率明显增高(F=13568.68,q=110.47～327.16,P<0.01)。结论:将靶向survivin的siRNA和5-FU联合应用可以显著抑制肝癌细胞survivin基因表达,并协同抑制HepG2细胞增殖,共同发挥诱导细胞凋亡作用。     

靶向survivin的siRNA联合5-Fu转染抑制肝细胞株HepG2增殖的研究

目的：研究靶向survivin的（小分子干扰RNA）siRNA和（氟尿嘧啶）5-FU联用对肝癌细胞HepG2的增殖抑制及凋亡的影响。方法：将HepG2细胞分为空白对照组、阴性对照组、5-FU处理组、siRNA转染组、5-FU＋siRNA转染组。转染采用脂质体法。RT-PCR法检测HepG2细胞survivinmRNA转录水平;MTT法检测靶向survivin的siRNA和5．FU对HepG2细胞增殖的抑制作用;流式细胞术检测HepG2细胞凋亡情况。结果：空白对照组、阴性对照组、5-FU处理组survivinmRNA表达无明显变化（P〉0．05）,siRNA转染组、5-FU＋siRNA转染组survivinmRNA表达明显下降（F=280．326,q=4．72-7．34,P〈0．05）。5-FU＋siRNA转染组增殖抑制率为51．58％±1-35％,与其它各组相比抑制率明显增高（F=280．326,q=5．27-9．84,P〈0．05）。5-Fu＋siRNA组与其它各组相比细胞凋亡率明显增高（F=13568．68,q=110．47-327．16,P〈0．01）。结论：将靶向survivin的siRNA和5一Fu联合应用可以显著抑制肝癌细胞survivin基因表达,并协同抑制HepG2细胞增殖,共同发挥诱导细胞凋亡作用。     

MEKK3稳定表达细胞株的建立及其对A549细胞增殖的影响

目的 构建人MEKK3基因编码区序列（cDNA）的真核表达载体、建立其稳定表达细胞株并观察其对肺腺癌细胞增殖的影响.方法 从A549细胞中提取总RNA,应用RT-PCR扩增MEKK3 cDNA的全长序列后克隆入pcDNA3.1/hygro（＋）质粒中,构建成MEKK3基因的真核表达载体,然后转染入人肺腺癌A549细胞中,潮霉素筛选稳定转染克隆,通过MTT实验,研究转染MEKK3基因前后细胞增殖的变化.结果 重组载体经酶切鉴定和测序证实目的 基因正确无误,Western印迹检测结果显示MEKK3基因在A549细胞中具有良好的表达;荧光实时定量PCR结果表明MEKK3基因在其稳定转染的A549细胞克隆中表达上调,与空载体稳定转染及未转染细胞比较,差异具有统计学意义（P＜0.05）;MTT结果显示MEKK3表达上调的稳定克隆组,A549细胞的增殖活性显著增强（A570=0.876 1±0.074 5）,明显高于空载体稳定转染组（A570=0.582 8±0.070 3）及未转染亲代细胞组（A570=0.584 9±0.035 2）,差异具有统计学意义（P＜0.01）,而后两者之间差异无统计学意义（P＞0.05）.结论 MEKK3表达上调可导致肺腺癌细胞的增殖增强.     

RNA干扰沉默缺氧诱导因子1α逆转肺癌细胞耐药性

目的：观察RNA干扰沉默缺氧诱导因子1α（HIF-1α）对肺癌细胞耐药性的影响。方法：构建靶向HIF-1α小干扰RNA基因,并转染到人肺腺癌耐顺铂细胞株A549／DDP细胞中。逆转录聚合酶链反应RT—PCR）检测细胞的HIF-1α、多药耐药基因-（MDR-1）以多药耐药相关蛋白基因（MRP）mRNA变化,免疫细胞化学法观察干扰后HIF-1α、P-糖蛋白以及MRP蛋白的变化。MTT法检测不同浓度的顺铂作用下细胞死亡率。结果：HIF-1αsiRNA组中H1F-1α、MDR—1、MRPmRNA水平显著降低（P〈0．05）。且蛋白水平也显著下降（P〈0．05）。HIF-1αsiRNA组细胞死亡率较未转染组均明显增高（P〈0．05）,转染siRNA阴性组不影响肿瘤细胞的耐药性。结论：HIF-1αsiRNA可显著降低A549／DDP细胞中H1F-1α、MDR-1、MRP表达,从而起到逆转肺腺癌A549／DDP细胞的耐药作用。     

H18杂交瘤抗凋亡能力的改造

利用PCR从pGEMTbcl-X_L质粒中获得bcl-X_L基因,构建真核表达载体pEF-bcl-X^{L,脂质体法转染杂交瘤细胞,G418筛选稳定表达株,Western blotting检测目的蛋白表达,流式细胞仪检测Bcl-X_L提高杂交瘤抗正丁酸钠诱导凋亡的功能。 将构建的编码鼠bcl-X_L基因的真核表达载体pEF-bcl-X_L,转染H18细胞后,获得稳定的表达株细胞;稳定表达Bcl-X_L的细胞具有抗正丁酸钠诱导凋亡的功能。鼠bcl-X_L基因在杂交瘤细胞中稳定表达,提高了杂交瘤抗凋亡的能力,对高密度大规模培养杂交瘤细胞具有重要意义。}     

Enhanced sensitivity of human hepatoma cells to 5-fluorouracil by small interfering RNA targeting Bcl-2

This study was designed to reveal whether the apoptosis induced in human hepatocellular carcinoma (HCC) cell lines by 5-fluorouracil (5-FU) could be enhanced by transfecting Bcl-2 small interfering RNA (siRNA). Bcl-2 siRNA and control siRNA were transfected into cells following treatment with or without 5-FU. Suppression of Bcl-2 expression was confirmed by Western blotting; cell viability was evaluated by MTS assay, and the occurrence of apoptosis in cells was evaluated by apoptosis assay. Expression of Bcl-2 protein after transfection of 20 nM Bcl-2 siRNA was significantly lower than that of control. Incubation of all cell lines with Bcl-2 siRNA reduced cell viability 96 h after 5-FU treatment compared with all other controls: Huh-7 (P < 0.01), Huh-7 with hepatitis C replicon (P < 0.01), HepG2 (P < 0.01), HLE (P < 0.05). Moreover, the proportion of apoptosis in control siRNA, Bcl-2 siRNA, control siRNA prior to 5-FU treatment, and Bcl-2 siRNA prior to 5-FU treatment groups were (4.6 +/- 2.3)%, (7.5 +/- 0.5)%, (6.0 +/- 2.1)%, and (19.5 +/- 0.86)%, respectively. The Bcl-2 siRNA prior to 5-FU treatment group showed the strongest effect of inducing apoptosis. In conclusion, the combination Bcl-2 siRNA and 5-FU might represent a new therapeutic option for HCC.     

单纯疱疹病毒2型潜伏相关转录体ORF2的表达及其抗凋亡作用

本文探讨了单纯疱疹病毒2型 (HSV-2)潜伏相关转录体 (LAT)的开放读码框2 (ORF2)在细胞中的表达, 及其对5-氟尿嘧啶 (5-FU)诱导的非洲绿猴肾细胞 (Vero)凋亡的影响。通过将重组质粒pEGPF-ORF2转染Vero细胞, 绿色荧光蛋白检测转染效率, RT-PCR验证目的基因的表达, 5-FU 诱导细胞凋亡, 通过荧光显微镜观察凋亡小体, Gimesa染色检测细胞核形态, MTT法检测细胞的存活率, DNA ladder片段分析, 结果表明, 转染后绿色荧光蛋白表达效率很高, RT-PCR验证有目的基因的转录。凋亡诱导后的细胞形态正常, MTT法分析活性率与正常无差异, 而显著高于空质粒组, DNA ladder未见凋亡条带。由此我们认为HSV-2 LAT ORF2 基因在Vero细胞中得到了高效表达, 并且具有抗5-FU诱导的凋亡作用。     

Regulatory mechanism of ZNF139 in multi-drug resistance of gastric cancer cells

Our previous study found increased zinc finger protein 139 (ZNF139) expression in gastric cancer (GC) cells. Purpose of the study is to further clarify the role and mechanism of ZNF139 in multi-drug resistance (MDR) of GC cells. MTT assay, RT-PCR, Western blotting were employed to detect susceptibility of GC cells to chemotherapeutic agents (5-FU, L-OHP) in vitro, and expressions of ZNF139 and MDR associated genes MDR1/P-gp, MRP1, Bcl-2, Bax were also detected. siRNA specific to ZNF139 was transfected into MKN28 cells, then chemosensitivity of GC cells as well as changes of ZNF139 and MDR associated genes were detected. It’s found the inhibition rate of 5-FU, L-OHP to well-differentiated GC tissues and cell line was lower than that in the poorly differentiated tissues and cell line; expressions of ZNF139 and MDR1/P-gp, MRP1 and Bcl-2 in well-differentiated GC tissues and cell line MKN28 were higher, while Bax expression was lower. After ZNF139-siRNA was transfected into MKN28, ZNF139 expression in GC cells was inhibited by 90 %; inhibition rate of 5-FU, L-OHP to tumor cells increased, and expressions of MDR1/P-gp, MRP1 and Bcl-2 were down-regulated, while Bax was up-regulated. ZNF139 was involved in GC MDR by promoting expressions of MDR1/P-gp, MRP1 and Bcl-2 and inhibiting Bax simultaneously.     

Akt3稳定表达细胞株的建立及其对MDA-MB-231细胞增殖的影响

目的 构建人蛋白激酶Bγ（Akt3）基因编码区序列（cDNA）的真核表达载体、建立其稳定表达细胞株并观察其对MDA-MB-231细胞增殖的影响.方法 从流产胎儿脑组织中提取总RNA,采用RT-PCR方法扩增Akt3 cDNA的全长序列后克隆入pEGFP-N2质粒中,构建成Akt3基因真核表达载体,然后转染入MDA-MB-231细胞中,新霉素筛选稳定转染细胞克隆,通过MTT实验,研究转染Akt3基因前后细胞增殖的变化.结果 重组载体经酶切鉴定和测序证实目的 基因正确无误.Western印迹检测结果显示AKT3融合蛋白在MDA-MB-231细胞中表达良好,而转染空载体及未转染细胞对照中未见有此融合蛋白质条带;MTT结果显示AKT3表达上调的稳定克隆组,其增殖活性显著高于空载体稳定转染细胞组及未转染亲代细胞组,差异具有统计学意义（P＜0.01）,而后两者差异无统计学意义（P＞0.05）.结论 Akt3过表达可增强MDA-MB-231细胞的增殖.     

Fhit protein inhibits cell growth by attenuating the signaling mediated by nuclear factor-kappaB in colon cancer cell lines

Fragile histidine triad (FHIT) gene is involved in the deletions at the 3p14.2 region in various cancers. We investigated the role of Fhit protein in cell growth by examining the signaling pathway affected by Fhit. We used 3 human colon cancer cell lines, SW480, DLD-1 and COLO201, in the study. SW480 cells, in which the expression of Fhit is completely absent, were transfected with pIRES1neo vector (SW/IRES cells), wild-type FHIT vector (SW/FHIT cells) or mt-FHIT (codon 96, His changed to Asn) vector (SW/mt-FHIT cells). The growth of SW/FHIT or SW/mt-FHIT cells was suppressed in comparison with that of parent or SW/IRES cells. Especially, the growth of SW/FHIT cells was considerably suppressed. On the other hand, the silencing of FHIT by an siRNA for it in SW/FHIT or DLD-1 cells harboring Fhit demonstrated that the growth of FHIT siRNA-treated cells was significantly enhanced in comparison with that of the vector control or nonspecific siRNA control. Thus, we found that Fhit negatively contributed to cell growth in the colon cancer cell lines. Moreover, SW/FHIT cells exhibited a higher sensitivity to oxidative stress evoked by inhibitors of mitochondrial electron transport or proteasomes compared with any of the control transfectants. The base line amount of phospho-IkappaB-alpha (p-IkappaB-alpha) was reduced in SW/FHIT cells compared with that in the other transfectants. On the contrary, the FHIT siRNA-treated SW/FHIT and DLD-1 cells exhibited an elevated p-IkappaB-alpha level in an RNAi experiment on FHIT. Perturbation of nuclear factor (NF)-kappaB signaling was strongly suggested by the fact that the wild-type Fhit expressants of SW480 cells tended to be sensitive to sulfasarazine or parthenolide, which are inhibitors of NF-kappaB. The time course of the level of IkappaB kinase (IKK) complex (IKKalpha/beta, phospho-IKKalpha/beta and IKKgamma) after the treatment with TNF-alpha was similar between the transfectants. Although p-IkappaB-alpha and phospho-NF-kappaB p65 (p-NF-kappaB) in SW/FHIT cells responded to TNF-alpha as those in other transfectants, the increase in the levels of p-IkappaB-alpha and p-NF-kappaB after a 5-min treatment was less in SW/FHIT cells than in the other transfectants. These results altogether suggest that Fhit functions as an anti-oncoprotein by inhibiting the phosphorylation of IkappaB-alpha and thereby blocking NF-kappaB signaling.     

Screening and test of CD40 related signal transduction pathway in AGS cells and construction of gene silencing vector

This study is designed to screen the CD40 related signal transduction pathway in AGS cells and construction of gene silencing vector. Analysis results showed 414 differential genes expression, including upregulation of 209 genes and downregulation of 205 genes. Basing on the ratio of signal in experimental group to signal in control group, 45 genes (38 genes upregulation and seven genes downregulation) with significant (P < 0.01) change in expression levels were screened according to the screening standard (signal log ratio ≥1 or ≤?1). These genes involved into metabolism, cell cycle and apoptosis, signal transduction and stress response. Furthermore, PI3K mRNA expression level in PI3K siRNA transfected AGS cells was 0.2335 ± 0.0116 72 h after transfection. This value was significantly (P < 0.05) lower than that in blank and negative control groups. PI3K protein expression in PI3K siRNA transfected AGS cells was significantly (P < 0.05) lower than that in blank and PI3K siRNA/N transfected groups. Therefore, PI3K siRNA gene silencing vector can significantly inhibit PI3K mRNA and protein expression in AGS cells.     

应用siRNA技术探讨MCF-7乳腺癌细胞分泌的VEGF对树突状细胞的影响

为探讨MCF-7乳腺癌细胞分泌的血管内皮生长因子（ vascular endothelial growth factor, VEGF）对树突状细胞（dendritic cell, DC）功能及其分化的影响,针对VEGF基因设计siRNA（small interfering RNA, siRNA),采用脂质体转染法以100 nmol/L最佳转染浓度导入MCF-7乳腺癌细胞（siRNA组）,以脂质体Lipofectamine　2000TM转染MCF-7 乳腺癌细胞培养上清培养正常DC作为对照（对照组）,采用ELISA法检测经siRNA 干扰VEGF基因后的MCF-7 乳腺癌细胞分泌的VEGF因子含量, Western 印迹检测VEGF蛋白表达,以探讨siRNA的基因沉默效果;以siRNA组和对照组培养上清分别培养外周血单个核细胞,用流式细胞仪检测所诱导DC表型CD1a、CD80、CD83、CD86和HLA-DR的表达,用MTT法检测转染前后两组DC 诱导的细胞毒性T淋巴细胞（cytotoxic T lymphocyte, CTL）对MCF-7细胞的细胞毒作用.结果显示,MCF-7 乳腺癌细胞培养上清能明显抑制正常DC分化成熟及抗原递呈能力,干扰VEGF基因后MCF-7 乳腺癌细胞培养上清对DC的影响明显降低,CD80、CD83、CD86和HLA-DR的表达较对照组显著升高,而CD1a表达下降（P＜0.01）.转染前后DC 诱导的CTL对MCF-7细胞的杀伤活性有明显差异（P＜0.01）.由此可见,siRNA可靶向抑制MCF-7乳腺癌细胞VEGF的表达,下调VEGF后的MCF-7 细胞上清对DC分化成熟及功能的抑制作用明显降低,从而推测VEGF在肿瘤的发生、发展和免疫抑制方面可能起着重要的作用.