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1(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HIF-1α、MDR-1、MRP mRNA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HIF-1α、MDR-1、MRP表达,从而起到逆转肺腺癌A549/DDP细胞的耐药作用。     

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。     

氧化铁磁性纳米颗粒介导缺氧诱导因子1α shRNA质粒转染逆转A549/CDDP细胞对顺铂耐药的实验研究

评价了氧化铁磁性纳米颗粒作为缺氧诱导因子1α shRNA (HIF-1α shRNA) 重组质粒载体进行体内体外转染的可行性及其逆转人肺腺癌耐药细胞株(A549/CDDP)顺铂耐性的效果,并初步探讨相关机制．在成功构建HIF-1α shRNA重组质粒后,分别利用氧化铁磁性纳米颗粒及脂质体介导质粒转染A549/CDDP细胞及其移植瘤裸鼠动物模型,荧光显微镜检测转染效率,RT-PCR及细胞免疫化学检测转染后A549/CDDP 细胞HIF-1α、多药耐药相关蛋白1(multidrug resistance 1,MRP1)、肺耐药相关蛋白(lung resistance-related protein,LRP) mRNA及蛋白质表达,免疫组化检测转染后A549/CDDP移植瘤HIF-1α、MRP1及LRP蛋白表达,MTT法检测转染HIF-1α shRNA前后A549/CDDP细胞对顺铂的耐药性,并检测转染HIF-1α shRNA后A549/CDDP细胞移植瘤的肿瘤生长指数,HE染色检测纳米颗粒转染对裸鼠肝、肾及脑的组织学毒理作用．结果显示,氧化铁磁性纳米颗粒介导转染相对效率高于脂质体介导(P < 0.01),HIF-1α shRNA转染A549/CDDP细胞后HIF-1α、MRP1、LRP mRNA及蛋白质表达下降,逆转A549/CDDP细胞对顺铂耐性82%,纳米颗粒介导HIF-1α shRNA转染A549/CDDP细胞移植瘤裸鼠动物模型后,移植瘤组织中HIF-1α、MRP1及LRP蛋白表达下降,转染HIF-1α shRNA后抑制移植瘤的生长,且与顺铂有协同效应,纳米颗粒转染后裸鼠肝、肾及脑组织无坏死．这些结果说明,纳米颗粒介导HIF-1α shRNA的体内体外转染效率高于脂质体,RNA干扰技术封闭HIF-1α基因可较大程度逆转耐顺铂人肺腺癌细胞的耐药性及其抑制瘤的生长,其作用可能与HIF-1α shRNA降低HIF-1α、MRP1及LRP表达有关,HIF-1α基因可作为逆转肺癌耐药治疗的有效靶点,磁性纳米颗粒介导HIF-1α shRNA质粒转染具有一定的生物安全性．     

干扰LRP16基因表达对人卵巢癌耐药SKOV3/DDP细胞耐药性的影响及机制研究

目的:探究干扰人白血病相关蛋白16(LRP16)基因表达对人卵巢癌耐药SKOV3/DDP细胞耐药性的影响及其相关机制。方法:采用Real-time PCR和蛋白免疫印迹(WB)检测LRP16在敏感组(SKOV3细胞)、耐药组(SKOV3/DDP细胞)、LRP16干扰组(SKOV3/DDP细胞-稳定转染LRP16 shRNA质粒)和NC组(即阴性对照组,SKOV3/DDP细胞-稳定转染阴性对照质粒)细胞中的表达情况;MTT试验检测LRP16对SKOV3/DDP细胞耐药性的影响;彗星试验检测LRP16对顺铂(DDP)诱导DNA损伤的影响;流式细胞术(FCM)试验检测细胞凋亡变化;WB试验检测PTEN、p-Akt和NF-κB蛋白表达水平。结果:LRP16干扰组细胞的耐药指数(RI)值(3.19±0.21)显著低于耐药组细胞(6.84±0.37)(P0.05)。DDP(25μmol/L)处理24 h后,LRP16干扰组DNA损伤的细胞百分比、细胞凋亡百分比均显著低于耐药组和NC组(P均0.05),而耐药组和NC组比较差异无统计学意义(P0.05);LRP16干扰组细胞PTEN蛋白相对表达量高于耐药组和NC组(P均0.05),而p-Akt和NF-κB相对表达量低于耐药组和NC组(P均0.05)。结论:干扰LRP16基因表达可逆转卵巢癌耐药SKOV3/DDP细胞的耐药性,PTEN/Akt/NF-κB可能是其中的关键信号通路。     

Wnt5a通过PI3K/Akt/GSK3β信号通路调控人卵巢癌SKOV3/VCR细胞对长春新碱的敏感性

本研究旨在探究Wnt5a对人卵巢癌SKOV3细胞长春新碱(vincristine, VCR)耐药性的影响,并探讨其分子机制。采用浓度梯度递增法构建耐药株SKOV3/VCR细胞,将人WNT5A基因的干扰质粒转染SKOV3/VCR细胞并筛选出稳定干扰Wnt5a的细胞株,用RT-PCR检测Wnt5a的mRNA表达水平,用CCK-8法检测细胞活力,用流式细胞术检测细胞凋亡,用Western blot法检测Wnt5a、MDR1、Survivin、β-catenin、Akt、p-Akt(S473)、GSK3β和p-GSK3β(Ser9)的蛋白表达水平。结果显示,SKOV3/VCR细胞中Wnt5a、MDR1、β-catenin和Survivin蛋白的表达水平、Akt和GSK3β蛋白的磷酸化水平以及Wnt5a mRNA表达水平均显著高于其亲代SKOV3细胞;WNT5A基因沉默使VCR抑制SKOV3/VCR细胞活力的IC50从38.412降至9.283 mg/L,提高SKOV3/VCR细胞凋亡率并协同增强VCR诱导的细胞凋亡(P 0.05),下调MDR1、β-catenin和Survivin蛋白的表达水平(P 0.05),抑制Akt和GSK3β蛋白磷酸化(P 0.05);此外,PI3K抑制剂LY294002也可下调SKOV3/VCR细胞中MDR1、β-catenin和Survivin蛋白表达水平,并降低Akt和GSK3β蛋白磷酸化水平(P 0.05)。以上结果提示,沉默WNT5A基因可在体外逆转人卵巢癌耐药株SKOV3/VCR细胞耐药性,作用机制可能与其抑制PI3K/Akt/GSK3β/β-catenin通路,继而下调MDR1和Survivin蛋白表达有关。     

HIF-1α 在卵巢癌中的表达及与化疗耐药相关性研究

目的:探讨缺氧诱导因子-1α(HIF-1α)在卵巢癌中的表达及其在卵巢癌化疗耐药中的作用。方法:采用免疫组化方法,检测96例卵巢癌组织,45例良性卵巢肿瘤和30例正常卵巢组织中HIF-1α的表达,分析其表达与临床病理特征及化疗耐药的相关性。结果:卵巢癌中HIF-1α的表达高于正常卵巢及良性卵巢肿瘤组织,且临床分期越晚其表达越高(P<0.001),而与肿瘤组织类型、病理分级及患者年龄无显著相关性。HIF-1α在卵巢癌化疗耐药组阳性率明显高于化疗敏感组(P<0.001)。结论:卵巢癌中HIF-1α高表达与卵巢癌的发生、发展、浸润和转移有关,与卵巢癌化疗耐药密切相关,HIF-1α可成为卵巢癌化疗新的分子治疗靶点。     

大黄素抑制胃癌细胞糖酵解并促进凋亡

目的:探讨大黄素对人胃癌BGC-823细胞凋亡及糖酵解的影响。方法:采用不同浓度大黄素(30μmol/L、90μmol/L、180μmol/L)、磷脂酰肌醇3-激酶(Phosphatidylinositol 3 kinase,PI3K)抑制剂处理人胃癌BGC-823细胞,通过四甲基偶氮唑盐(MTT)检测细胞活力,采用试剂盒检测细胞葡萄糖消耗及乳酸水平,western blotting检测细胞己糖激酶Ⅱ、Bcl-2相关蛋白(Bcl-2 Associated X Protein,Bax)、PI3K、人低氧诱导因子1α(Human Hypoxia-inducible factor 1α,HIF-α)的表达。结果:大黄素能浓度依赖性的抑制BGC-823细胞增殖、葡萄糖消耗,降低乳酸水平;并降低己糖激酶Ⅱ的表达,促进凋亡蛋白Bax表达。PI3K抑制剂可抑制胃癌细胞糖酵解水平,而将大黄素与PI3K抑制剂联合使用后,与单一抑制剂组比,对细胞糖酵解抑制水平进一步加强,大黄素可下调PI3K下游蛋白及HIF-α的表达。结论:大黄素对人胃癌BGC-823细胞的增殖抑制作用其作用机制与调节PI3K途径及HIF-α,并抑制己糖激酶Ⅱ表达降低胃癌细胞糖酵解水平相关。     

小干扰RNA靶向EGFR基因逆转卵巢癌细胞顺铂耐药的研究

目的：探讨载体表达的小干扰RNA（siRNA）影响卵巢癌耐药细胞株EGFR基因的表达并逆转其顺铂耐药的可行性。方法：体外构建EGFR小发卡状RNA（shRNA）的表达质粒,脂质体法介导将其转染入SKOV3/DDP细胞。实验分为正常对照组、空质粒转染组、非特异性转染组和特异性转染组。采用逆转录聚合酶链反应（RT-PCR）检测EGFR mRNA的表达;使用免疫细胞化学法（ICC）检测EGFR蛋白的表达;使用四甲基偶氮唑蓝法（MTT）测定各组细胞对顺铂的半数抑制浓度（IC50）。结果：EGFR shRNA转染组细胞EGFR mRNA的表达与其他两组相比明显减弱（P〈0.01）,EGFR蛋白表达明显下调（P〈0.01）;顺铂敏感性比正常对照组提高了约2.5倍。结论：针对EGFR合成的siRNA能够有效地抑制EGFR mRNA和蛋白的表达,并能恢复其对顺铂的敏感性。应用RNAi技术,能够逆转卵巢癌细胞对化疗药物的耐药性。     

卵巢癌中HMGB1、BRCA1和p62蛋白的表达与其化疗敏感性的相关性

为了探讨卵巢癌中HMGB1、BRCA1和p62蛋白的表达与化疗敏感性的相关性,培养卵巢癌顺铂化疗耐药细胞ES-2和敏感细胞SKVO3,顺铂100 mg/m2环境培养5 d,分别采用Western blotting法和RT-PCR方法检测两种细胞中的HMGB1、BRCA1和p62蛋白表达情况,采用流式细胞术测算细胞凋亡率。敏感组细胞SKOV3和耐药组细胞ES-2中,BRCA1蛋白表达率分别为(38.08±22.56)%和(45.65±22.42)%,HMGB1蛋白表达率分别为(75.13±16.45)%和(83.08±24.22)%,p62蛋白表达率分别为(52.31±25.13)%和(37.26±21.09)%;顺铂处理后,敏感组SKOV3细胞中BRCA1蛋白表达量显著提高(p0.05),耐药组ES-2细胞中p62蛋白相对表达量高于敏感组SKOV3细胞(p0.01)。卵巢癌化疗后HMGB1下调与BRCA1、p62上调共存;卵巢癌中BRCA1蛋白的不同表达与化疗敏感性相关,其水平变化有可能作为一种新的肿瘤标志物,动态观察卵巢癌病情进展,为临床治疗提供客观指标。     

上调hMLH1基因表达对卵巢癌药物敏感性的影响

构建携带错配修复基因hMLH1编码序列全长的真核表达质粒pCAN—hMLHl,并探讨其对卵巢癌细胞顺铂耐药的逆转作用。应用基因重组技术将pET28-hMLHl中的目的基因hMLHl定向克隆到真核表达载体pCAN,经酶切及测序鉴定：分别将pCAN—hMLHl和空质粒pCAN转染进卵巢癌耐药细胞SKOV3／DDP,同时以对顺铂敏感的sKOV3细胞和未转染的SKOV3／DDP细胞作为对照：应用RT-PCR和Westemblo凇测转染前后细胞内hMLHlmRNA和蛋白的表达变4Jc;四甲基偶氮唑蓝（MTT）比色法检测转染前后sKOv3／DDP细胞对顺铂敏感性的变化;Hoechst染色检测转染前后细胞的凋亡。结果提示：pCAN—hMLHl重组质粒经酶切及测序鉴定,表明真核表达质粒构建正确;采用脂质体法转染sKOv3／DDP细胞后,RT-PCR和Westernblot检测到耐药细胞内hMLHl的表达增强：MTT结果显示转染重组质粒后sKOv3／DDP细胞对顺铂的敏感性显著增加;Hoechst染色观察到转染后耐药细胞的凋亡明显增强。该研究成功构建了pCAN．hMLHl重组质粒,在sKOV3／DDP细胞中进行表达,并能增强耐药细胞对顺铂的敏感性,促进耐药细胞的凋亡。     

Curcumin reverses cis-platin resistance and promotes human lung adenocarcinoma A549/DDP cell apoptosis through HIF-1α and caspase-3 mechanisms

Curcumin, a yellow pigment derived from Curcuma longa Linn, has been favored by the Eastern as dietary ingredients for centuries. During the past decade, extensive investigations have revealed curcumin sensitized various chemotherapeutic agents in human breast, colon, pancreas, gastric, liver, brain and hematological malignant disorders in vivo and in vitro. Several pathways and specific targets including NF-κB, STAT3, COX-2, Akt and multidrug resistant protein have been identified to facilitate curcumin as a chemosensitizer. Recent studies suggest HIF-1α participated in the development of drug resistance in cancer cells and targeting HIF-1α either by RNAi or siRNA successfully overcame chemotherapeutic resistance. To investigate the mechanism basis of curcumin as a chemosensitizer in lung cancer, we examined curcumin's effects on HIF-1α in cis-platin (DDP) sensitive A549 and resistant A549/DDP cell lines by RT-PCR and Western blot. HIF-1α in A549/DDP cells was found to be overexpressed at both mRNA and protein levels together with a poor response to DDP. Results from transient transfection and flow cytometry showed the HIF-1α abnormality contributed to DDP resistance in A549/DDP lung cancer cells. Combined curcumin and DDP treatment markedly inhibited A549/DDP cells proliferation, reversed DDP resistance and triggered apoptotic death by promoting HIF-1α degradation and activating caspase-3, respectively. Expression of HIF-1α-dependent P-gp also seemed to decrease as response to curcumin in a dose-dependent manner. Our findings shed light on drug resistant reversing effect of curcumin in lung cancer cells by inhibiting HIF-1α expression and activating caspase-3.     

卵巢癌细胞与巨噬细胞共培养对B7-H1表达的影响及机制

为了探讨卵巢癌细胞与巨噬细胞共培养后对B7．H1表达的影响及其可能机制,利用佛波酯（PMA）诱导THP-1或外周血单核细胞分化为巨噬细胞后,与人卵巢癌细胞株SKOV3体外非接触共培乔24h,qRT-PCR、Western blot以及流式细胞术分别检测SKOV3与巨噬细胞B7-H1的表达：进一步利用NF-KB、JAK2／STAT3、p38MAPK信号通路的抑制剂作用于共培养体系,检测B7-H1表达的变化,以探讨其机制。结果显示,共培养24h后,SKOV37L巨噬细胞B7-H1mRNA和蛋白的表达较非共培养组均显著升高（P〈0．05）,而阻断NF-κB、JAK2／STAT3、p38MAPK信号通路后,B7-H1的上调均明显被抑制（P〈0．05）。SKOV3与巨噬细胞共培养后B7-H1的表达升高伊〈0．05）,其机制可能涉及到NF—κB、JAK2／STAT3、p38MAPK信号通路的激活。     

Aberrant expression of SIRT3 is conversely correlated with the progression and prognosis of human gastric cancer

SIRT3 is a NAD⁺-dependent histone deacetylaseand and plays a critical role in various human carcinomas. However, its precise role in the pathogenesis of gastric cancer (GC) is still unclear. Western blot and Real-Time PCR were used to detect the protein and mRNA level of SIRT3 in freshly collected samples from GC patients. Immunohistochemistry staining was adopted to determine the expression of SIRT3 in 65 formalin-fixed, paraffin-embedded samples from GC patients. In addition, western blot was used to detect the protein levels of SIRT3 and HIF-1α in gastric cancer cells MGC-803 transfected with SIRT3 or control siRNA. Western blot analysis of 25 samples from GC patients showed that 64% (16/25) of patients exhibited decreased expression of SIRT3, whereas 4.0% (1/25) of patients displayed complete loss. In addition, Real-Time PCR analysis showed that GC patients had decreased expression of SIRT3 mRNA. Furthermore, immunohistochemistry analysis of 65 formalin-fixed, paraffin-embedded samples from GC patients showed that 67.7% (44/65) had decreased SIRT3 staining in the cancer tissues. Notably, the expression level of SIRT3 was inversely correlated with clinicopathological variable, including tumor infiltration, tumor differentiation and tumor stage and 5-year survival of these patients. In vitro experiment showed that knockdown of SIRT3 in MGC-803 gastric cancer cells significantly increased the expression of HIF-1α. Our results provide the first evidence showing that an aberrantly decreased expression of SIRT3 occurred in GC patients, suggesting that SIRT3 might function as a mitochondrial tumor suppressor in GC. Furthermore, the possible mechanism by which SIRT3 affect the progress of GC is its direct control of HIF-1α.     

Hypoxia-inducible factor-1α mediates oral squamous cell carcinoma invasion via upregulation of α5 integrin and fibronectin

With progressive and rapid growth of malignant tumors, cancer cells in an ischemic condition are expected to develop an increased potential for local invasive growth. To address this hypothesis, we first examined the effect of hypoxia on the invasiveness of oral squamous cell carcinoma (OSCC) cells using the Matrigel invasion assay. We then investigated the effect of hypoxia on the protein and mRNA expression of α5 integrin and fibronectin, which are major factors involved in tumor cell invasion. We showed that (i) hypoxia increased the invasiveness of OSCC cells, (ii) α5 integrin and fibronectin protein and mRNA expression levels were increased in OSCC cells under hypoxic conditions, (iii) hypoxia stimulated autocrine secretion of fibronectin in OSCC cells, (iv) administration of siRNA_HIF-1α caused a significant decrease in α5 integrin and fibronectin protein, confirming that HIF-1α plays a role in their induction, and (v) siRNA_HIF-1α abrogated hypoxia-induced cell invasion. Collectively, these data suggest that hypoxia promotes OSCC cell invasion that is elicited by HIF-1α-dependent α5 integrin and fibronectin induction.