Down-regulation of lung resistance related protein by RNA interference targeting survivin induces the reversal of chemoresistances in hepatocellular carcinoma

Background Both survivin and lung resistance related protein （LRP） are hepatocellular carcinoma （HCC）. But the relationship between survivin and LRP is investigate the effects of down-regulation of survivin on LRP expressions and the both in vitro and in vivo. related to the chemoresistances in ndefinite. The aim of this study was to reversal of chemoresistances in HCC Methods The expressions of survivin were detected by RT-PCR and Western blotting in HCC cell line SMMC-7721 and SMMC-7721/ADM. The sensitivities of these two cell lines to ADM were evaluated by MTT assays. SiRNA which targeted survivin was transfected into SMMC-7721/ADM cells, then the sensitivity of SMMC-7721/ADM cells to ADM and the expressions of survivin and LRP were detected respectively. SMMC-7721/ADM cells were transplanted subcutaneously into nude mice to establish xenograft tumors. Antitumor activities of RNA interference （RNAi） targeting survivin, various doses of ADM and combination therapies were observed respectively. Possible toxicities were evaluated. LRP expression changes were tested. Student＇s ttest was used for evaluating statistical significance. Results The expressions of survivin in SMMC-7721/ADM cell line showed significant elevation compared to those in SMMC-7721 cell line （P 〈0.05）. Positive siRNA down-regulated the expressions of survivin significantly （P 〈0.05）. SiRNA targeting survivin could sensitize SMMC-7721/ADM cells to ADM and down-regulate the expressions of LRP significantly （P 〈0.05）. Growths of the tumors were significantly inhibited in positive siRNA group as compared with those in the control group from the 8th day （P 〈0.05）. Combination therapies caused significant tumor inhibitions compared with tumors of nude mice in the other three groups respectively （P 〈0.05）. No toxicities were found in nude mice treated by siRNA and combination therapies. The expressions of LRP were markedly reduced in tumors treated with siRNA targeting survivin （P 〈0.05）. Conclusions Down regulation of survivin gene by RNAi can increase chemosensitivity of HCC both in vitro and in vivo. The reversal of drug resistance may be reduced through the inhibitions of LRP.     

Effect of siRNA Targeting Survivin Gene on the Biological Behavior of Hepatocellular Carcinoma

To study the influence of siRNA targeting survivin gene on the biological behavior of hepatocellular carcinoma (HCC), one pair of 21bp reverse repeated motifs of survivin target sequence with 9 spacers were synthesized and inserted into plasmid psilencer2.1 to generate siRNA eukaryotic expression vector. After stable transfection into HepG2 cells, the biological behaviors of the survivin siRNA transfected HCC cells were observed. After the recombinant plasmid Psilence( )-survivin was successfully constructed, survivin mRNA and protein expression inhibition ratio reached 73% and 75% respectively compared to control groups. Transfected cells with survivin siRNA demonstrated significantly inhibited cell growth and increased apoptosis. Subsequent study in nude mouse model demonstrated lower succeeding rate in cells transfected with survivin siRNA and slow growth rate. The results elucidated the siRNA targeting survivin gene could specially suppress its expression in HepG2 cells and inhibit tumor cells growth both in vivo and in vitro. This provides a theoretical basis to turn the drug resistance in tumor cells.     

Effects of Livin gene RNA interference on apoptosis of cervical cancer Hela cells and enhanced sensitivity to cisplatin

The recombinant plasmids pGenesil-1-BIRC71 and pGenesil-1-BIRC72 were transfected into Hela cells and cisplatin was added with different concentrations in order to study the inhibitory effects of Livin gene, increase the apoptosis induced by cisplatin, and detect the expression ofBcl-2, Bax, caspase-3, and survivin genes. The pGenesil-1-BIRC71 and pGenesil-1-BIRC72 were transfected into Hela cells, and the expression levels of Livin, Bcl-2, Bax, caspase-3, and survivin genes were detected by using fluorescence quantitative real-time PCR. Then cisplatin at different concentrations （3.0, 6.0 and 9.9 μg/mL） was added into the transfected Hela cells, and 24, and 48 h later, the apoptosis rate was measured by flow cytometry. After transfection of pGenesil-l-BIRC71 and pGenesil-1-BIRC72 into Hela cells, the expression level of Livin gene was obviously reduced, and the apoptosis rate was significantly increased in transfection group as compared with control group （P〈0.05）. Cisplatin could increase the apoptosis rate in a dose- and time-dependent manner. After cisplatin was added, the expression levels of Bcl-2 mRNA were reduced, and those of Bax, caspase-3, and survivin mRNA were increased in transfection group as compared with those in control group （P〈0.05）. It was concluded that shRNA expression vector targeting Livin gene could inhibit the expression of Livin gene in Hela cells and enhance the apoptosis induced by cisplatin, which was related to the decreased expression of Bcl-2 and activation of Bax and caspase-3. Survivin might play an important role as an antagonist in the process of apoptosis induction.     

Genistein sensitizes ovarian carcinoma cells to chemotherapy by switching the cell cycle progression in vitro

Objective： To address how genistein sensitizes the chemotherapy-resistant ovarian carcinoma cells and promotes apoptosis in the respect of cell cycle and the regulation of survivin expression in the process. Methods： Ovarian SKOV-3 carcinoma cell line was treated with genistein or cisplatin either alone or in combination. Cell viability was showed by MTT method. Cell cycle and apoptosis were detected by flow cytometry. Survivin mRNA and protein were revealed by RT-PCR and immunocytochemistry, respectively. Results： Genistein could reduce the cell viability in a dose-dependent manner, while cisplatin did so at a much higher level. In contrast, if the two agents were treated in combination, half growth inhibition （IC50） value for cisplatin was reduced remarkably and the effect was synergistic as analyzed by isobologram. In particular, the reduced cell viability was exhibited by a switch in cell cycle progression, as the cells were arrested in G2/M phase and the G0/G1 phase- fraction was significantly decreased. The reduced cell viability appeared to involve apoptosis, based on our results from flow cytometry and Hoechst 33258 staining. In the meanwhile, genistein performed the inhibitory effect on cisplatin-induced survivin expression. Conclusion： Genistein can sensitize ovarian carcinoma cells to cisplatin therapy with the inhibition of survivin expression as the potential mechanism.     

Effect of small interfering RNA targeting survivin gene on biological behaviour of bladder cancer

Background Bladder cancer is the most common type of urinary system tumours. It is frequently associated with genetic mutations that deregulate the cell cycle and render these tumours resistant to apoptosis. Survivin, a newly discovered member inhibitor of apoptosis protein （IAP） family in several human cancers, by inducing cell proliferation and inhibiting apoptosis is frequently activated in bladder cancer. We studied the influence of small interfering RNA （siRNA） targeting survivin on the biological behaviour of bladder cancer cells. Methods A double strand survivin target sequence specific siRNA was designed and synthesized. After transfection of bladder cancer cell line T24 by siRNA/liposome complex with increasing concentrations （50-200 nmol/L）, the transfectant cells were intratumourally injected at different doses （5 μg or 50 μg）. The effects were measured in vitro and in vivo. Results The selected siRNA efficiently down-regulated survivin mRNA expression in a dose and time dependent manner. The maximal effect was achieved at the concentration of 100 nmol/L, at which survivin expression level was down-regulated by 75.91%. The inhibition rate of cell growth was 55.29% （P〈0.01） and the markedly increased apoptotic rate was 45.70% （P〈0.01）. In vivo intratumoural injection of 50 μg siRNA-survivin could notably orevent the growth of bladder cancer （P〈0.01） in xenografted animals. Conclusion The application of siRNA-survivin could markedly inhibit survivin expression in bladder cancer cell line by inducing apoptosis and inhibiting the growth of the tumour. It may become a new gene therapy tool for bladder cancer.     

Growth suppression of human lung cancer cells and implanted tumors by adenovirus-mediated transfer of the PTEN gene

This study examined the effects of a recombinant adenovirus AdTEN-EGFP on the proliferation of A549 cells, a human lung carcinoma cell line, in vitro and on the growth of the implanted tumors in the nude mice in vivo, explored the underlying mechanisms and evaluated the in vitro transfection efficiency of Ad-PTEN-EGFP into A549 cells. The expression of Ad-PTEN-EGFP in the A549 cells was determined. The proliferation and the apoptosis rates of the A549 cells with Ad-PTEN-EGFP transfection or not was detected by MTT and flow cytometry. Ad-PTEN-EGFP at different doses was injected intratumorally to the tumor-bearing mice induced by the A549 cells. Tumor sizes were measured on an alternate day. After all the mice were sacrificed, the implanted tumors were removed for routine histological examination, weight test, HE staining and immunohistochemical staining. The expressions of Bax, P16 and P53 in the tumor tissues and those of caspase-3, CD34 and VEGF in the mouse sera were detected. Tumor cell apoptosis was measured by TUNEL method. The results showed that the vitality of the A549 cells after transfection with Ad-PTEN-EGFP declined. The expression of green fluorescent protein was observed under fluorescent microscope. The transfection rate was in excess of 50%. The mRNA and protein expression of PTEN in the transfected cells was confirmed. The proliferation rate of the transfected cells was significantly decreased when compared with that of the non-transfected cells （P〈0.05）. The number of the apoptosi＇s cells was increased in the transfected cells （P〈0.05）. The models of implanted tumors were successfully estab- lished by injection of the A549 cells in the flank of Balb/c nude mice. Administration of Ad-PTEN-EGFP to the tumor-bearing nude mice resulted in a suppression of tumor growth. There were statistically significant differences in the tumor weight and tumor volume between the Ad-PTEN-EGFP-treated group and the control groups （P〈0.05）. In contrast to those in the control groups, tumor tissues in the Ad-PTEN-EGFP-treated group were shown to have typical extensive vacuolar degeneration and massive hemorrhagic necrosis. Apoptotic bodies were also observed in the tumor cells. The expressions of Bax, caspase-3 and P16 were increased （P〈0.05） while those of CD34, VEGF and P53 decreased （P〈0.05） in the Ad-PTEN-EGFP-treated group. It is concluded that Ad-PTEN-EGFP could induce the apoptosis of the A549 cells and inhibit their proliferation. And it could also substantially suppress the tumor growth in the tumor-bearing nude mice and induce apoptosis of the tumor cells as well. These findings carry significant implications for adenovirus vector-based PTEN gene therapies for lung cancers.     

Enhanced Chemotherapy Sensitivity of Human Colon Cancer Cells to 5-Fluorouracil by siRNA Recombinant Expression Vector Targeting Survivin Gene

Objective To investigate the effects of small interfering RNA （siRNA） recombinant expression vector targeting survivin gene on chemotherapy sensitivity of human colon cancer cells to 5-fluorouracil. Methods siRNA recombinant expression vector targeting survivin gene was constructed and transfected into human colon cancer cell lines LOVO. After 48 hours of transfection, cells were harvested for analysis of survivin mRNA and protein expressions using RT-PCR and Western blot. In addition, after human colon cancer cell lines were treated with Survivin siRNA and/or 5-fluorouracil, MTT assay and flow cytometry were used to analyze cell proliferation and apoptosis. Results Restriction endonuclease analysis confirmed that siRNA recombinant expression vector targeting survivin gene was successfully constructed. Inhibitory ratios of survivin mRNA and protein expressions by Survivin siRNA were 36.33% and 44.65%, respectively. Survivin siRNA combined with 5-fluorouracil significantly increased the cell proliferation inhibitory ratio and apoptosis ratio compared with 5-fluorouracil treatin~ alone （P〈0.05）. Conclusion The siRNA recombinant expression vector targeting survivin gene can inhibit the expression of survivin gene, and enhance chemotherapy sensitivity of human colon cancer cells to 5- fluorouracil.     

Effect of all-trans retinoic acid on drug sensitivity and expression of survivin in LoVo cells

Background All-trans retinoic acid （ATRA） can influence the tumor cell proliferation cycle, and some chemotherapeutic drugs are cycle specific. In this study, we hypothesize that ATRA can enhance chemotherapeutic drug sensitivity by affecting the cell cycle of tumor cells.
Methods The cell cycle of LoVo cells was evaluated using flow cytometry （FCM）. Cell viability was analyzed using the MTT assay. The morphologic changes in the treated LoVo cells were measured with acridine orange （AO）/ethidium bromide （EB） staining. Expression of survivin in LoVo cells was analyzed by immunofluorescence assay.
Results After LoVo cells were treated with ATRA, the G0/G1 ratio of the tumor cells increased and the cell ratio of S-and G2/M-phase decreased. Viability of the cells decreased significantly after combined treatment with ATRA and 5-fluorouracil （5-FU） or mitomycin c （MMC） and was evaluated by fluorescence microscopy. Expression level of survivin in the tumor cells decreased after ATRA combination treatment.
Conclusions ATRA enhances drug sensitivity of the LoVo cell line to cell cycle-specific agents and inhibits the expression of survivin in LoVo cells. The combination of ATRA and 5-FU or MMC promoted cell apoptosis, and the mechanism involved in apoptosis may be related to inhibition of survivin gene expression.     

贝伐单抗对荷耐顺铂人肺腺癌A549/DDP裸鼠皮下移植瘤生长的影响

目的 探讨贝伐单抗联合或不联合顺铂对耐顺铂肺腺癌A549/DDP移植瘤生长的抑制作用.方法 建立裸鼠移植瘤模型,随机分成空白对照组(A组)、单药贝伐单抗组(B组)、单药顺铂组(C组)、联合用药组(D组)和联合半剂量组(E组)5组,连续用药4周.观察肿瘤生长情况,计算抑瘤率;免疫组化法检测肿瘤组织微血管密度(MVD);RT-PCR分析各组经治疗后凋亡基因bcl-2及耐药基因(LRP、GST-Π)mRNA表达情况.结果 与空白对照组比较,经贝伐单抗治疗组(B、D、E组)抑瘤率分别为20.96%、51.67%、50.95%,联合用药组(D、E组)效果最佳.经贝伐单抗治疗组微血管密度分别为18.6±1.14、13.6±1.14、14.4±0.55,联合用药组最为显著,而单药顺铂组与对照组在抑瘤率和微血管密度表达上均无差异(P=0.632).经贝伐单抗治疗组bcl-2 mRNA表达较对照组有显著差异(P＜0.001),但三组之间无差异(P＞0.05);五组之间在LRP、GST-Π mRNA表达上无明显差异(P＞0.05).结论 贝伐单抗对荷A549/DDP裸鼠移植瘤有抑制作用,联合顺铂用药有显著协同作用,同时提高A549/DDP耐药细胞对顺铂的敏感性,其作用机制可能与抑制肿瘤微血管形成、诱导细胞凋亡增加有关.     

Survivin siRNA提高人结肠癌HT-29细胞对顺铂化疗敏感性的实验研究

目的 以siRNA抑制结肠癌HT-29细胞内survivin的表达,探讨HT-29细胞对顺铂(cisplatin,cDDP)的增敏效果.方法 转染siRNA于HT-29,检测survivin siRNA处理对survivin、Bax、Bcl-2蛋白表达及胱天蛋白酶-3(caspase-3)活性的影响.cDDP处理后,...     

Ad-PTEN对人小细胞肺癌NCI-H446细胞生长的抑制作用

目的研究重组腺病毒第10号染色体同源丢失性磷酸酶张力蛋白基因（PTEN）对小细胞肺癌的抑癌增效和化疗增敏效应及其分子机制。方法采用重组腺病毒载体PTEN（简称Ad-PTEN）感染QBI-293A细胞,并用该细胞进行病毒扩增和效价测定。将Ad-PTEN感染NCI-H446小细胞肺癌细胞。分为5组：PBS组、空载体Ad组、Ad-PTEN组、顺铂（DDP）组和Ad-PTEN＋DDP组,Western blot鉴定PTEN基因表达,MTT法和流式细胞仪（FCM）检测Ad-PTEN对NCI-H446小细胞肺癌细胞的生长抑制和诱导凋亡的增效作用,用RT-PCR检测细胞凋亡相关基因p53、bax、caspase-3、bcl-2、和survivin的转录。结果 Ad-PTEN可在QBI-293A细胞中增殖。Ad-PTEN感染NCI-H446细胞后,Western blot检测到了PTEN基因的表达。Ad-PTEN组、DDP组、Ad-PTEN＋DDP组体外能明显抑制人NCI-H446小细胞肺癌细胞的生长和诱导凋亡,且Ad-PTEN＋DDP组效应较Ad-PTEN组、DDP组更为显著（均P〈0.05）。Ad-PTEN组、DDP组、Ad-PTEN＋DDP组的NCI-H446细胞中的p53、bax及caspase-3基因表达均上调,而Bcl-2和Survivin基因表达均下调,这些凋亡相关基因的上调或下调的表达趋势以Ad-PTEN＋DDP组最显著（均P〈0.05）。结论 Ad-PTEN体外可抑制NCI-H446小细胞肺癌细胞生长,Ad-PTEN对DDP的细胞毒作用具有增敏效应,其机制可能与上调p53、bax及caspase-3基因表达和下调bcl-2和survivin基因表达有关。     

CTR1和ATP7B在人肺腺癌细胞A549的表达及其与顺铂耐药的关系

目的  探讨人肺腺癌细胞株A549和肺腺癌顺铂耐药细胞株A549/DDP对顺铂的耐药机制。方法  利用噻唑蓝法检测顺铂对A549/DDP及其亲代细胞株的细胞毒作用和生长曲线的影响,探讨A549/DDP细胞株凋亡敏感性的变化规律。采用Western blot检测该细胞株铜离子转运蛋白1（CTR1）、铜离子转运磷酸化ATP酶（ATP7B）及聚腺苷二磷酸-核糖聚合酶（PARP）剪切蛋白表达,分析A549细胞对顺铂耐药与CTR1、ATP7B及PARP剪切蛋白表达量的相关性。结果  A549/DDP较其亲代细胞株对顺铂引起的细胞毒性和凋亡敏感性下降;较其亲代细胞株A549/DDP中ATP7B表达增加,CTR1表达降低。结论  人肺腺癌细胞株A549对顺铂耐药的产生与细胞凋亡敏感性降低有关,且细胞内ATP7B表达增加,CTR1表达降低,或可作为细胞对顺铂的增敏靶点。

     

共抑制RAD18和REV1基因显著增加顺铂对肺癌细胞的毒性

目的: 探讨采用基因敲减技术抑制跨损伤合成（translesion synthesis,TLS）通路和范可尼贫血（Fanconi anemia,FA)通路上游的RAD18基因与TLS通路的REV1基因后增加顺铂对人肺腺癌耐药细胞株（A549/DDP）细胞毒性的可行性及其机制。方法: 蛋白质印迹法测定顺铂诱导的A549和A549/DDP细胞RAD18和REV1蛋白表达;应用脂质体转染试剂转染针对RAD18基因的siRNAs (RAD18 siRNA),检测A549/DDP细胞转染前后顺铂诱导的FANCD2和PCNA蛋白单泛素化水平;CCK 8法检测分别转染RAD18 siRNA、REV1 siRNA以及两者共转染前后经顺铂处理的A549/DDP细胞的增殖率;流式细胞术检测转染前后A549/DDP细胞凋亡率和细胞周期。结果： A549/DDP细胞转染RAD18 siRNA和REV1 siRNA后,RAD18和REV1蛋白表达明显降低,表明转染有效,基因敲减成功。转染RAD18 siRNA后顺铂诱导的FANCD2和PCNA蛋白的单泛素化水平明显下降,提示FA通路和TLS通路的激活受到抑制。分别转染RAD18 siRNA或REV1 siRNA均可增强顺铂对A549/DDP的细胞毒性,增加顺铂诱导的细胞凋亡率,并增强细胞周期S/G2期的阻滞效应。共转染RAD18 siRNA和REV1 siRNA后,顺铂对A549/DDP细胞的毒性增强作用较单转染更为显著,顺铂诱导的细胞凋亡进一步增加。 结论： 敲减A549/DDP细胞的RAD18和REV1基因可通过抑制FA通路和TLS通路的DNA损伤修复功能,增加A549/DDP细胞对顺铂的敏感性;RAD18和REV1基因共敲减对顺铂的这一增敏作用更加明显,显示出A549/DDP细胞对顺铂耐药的逆转效应。     

MT1X siRNA对肺癌A549/DDP细胞顺铂敏感性的影响

目的探讨金属硫蛋白1X（MT1X）在肺癌耐药细胞株（A549／DDP）顺铂耐药中的作用。方法通过化学合成针对MT1X的siRNA段抑制其在A549／DDP中的表达,实时定量聚合酶链反应（PCR）及WB检测干扰效果,M1Tr及平板克隆形成实验检测干扰前后细胞对顺铂的药物敏感性变化;流式细胞术检测细胞周期和细胞凋亡情况。结果针对MT1X的siRNA片段能在RNA及蛋白水平有效抑制其在A549／DDP中的表达;与对照组相比,MT1X表达被抑制后,肿瘤细胞对顺铂的敏感性明显升高;增殖被抑制,平板克隆形成率明显降低（P〈O．05）,细胞凋亡率显著增高（P〈0．05）。结论针对MT1X的siRNA片段可部分逆转肺癌细胞（A549／DDP）对顺铂的耐受,为提高肺癌的化疗效率提供了一种新方法。     

RNA干扰技术抑制EC-109细胞survivin基因表达及其促凋亡研究

目的:应用RNA干扰技术(RNAi)研究针对survivin基因的siRNA,抑制survivin基因的表达并诱导食管癌细胞系EC-109细胞的凋亡. 方法:构建针对survivin的siRNA表达质粒,转染至EC-109细胞,荧光显微镜判断转染效率,蛋白质印迹和半定量RT-PCR检测survivin蛋白表达及基因转录水平的变化,并在不同时间点收集转染细胞,利用流式细胞术及基因组DNA凋亡检测试剂盒,观察siRNA抑制survivin基因表达后诱导细胞凋亡的情况. 结果:荧光显微镜结果表明,重组质粒转染效率达46.70%. 半定量RT-PCR检测到pSIREN/S质粒在EC-109细胞内对survivin基因的转录抑制率为74.04%;蛋白质印迹结果表明,转染重组质粒pSIREN/S的EC-109细胞survivin蛋白表达量仅为正常组的41.64%,而对照质粒pSIREN/CN对survivin基因的蛋白表达及转录均没有抑制作用. 经pSIREN/S转染的EC-109细胞基因组DNA出现明显的DNA ladder,流式细胞仪分析结果也显示凋亡细胞为60.78%. 结论:survivin特异性siRNA可明显抑制survivin基因的转录和表达,并能有效地诱导EC-109细胞的凋亡,为下一步在体内利用pSIREN/S重组质粒沉寂survivin基因,促肿瘤细胞的凋亡提供实验基础.     

人肺腺癌亲代与耐顺铂细胞系耐药与凋亡相关基因表达差异及其相关性

目的 探讨人肺腺癌亲代与耐顺铂细胞系A549和A549^DDP耐药及凋亡相关基因表达的差异，以及多药耐药的发病机制。方法 采用逆转录-PCR及免疫细胞化学方法检测A549和A549^DDP细胞多药耐药相关蛋白(MRP)、肺耐药蛋白(LRP)、bcl-2及C-erbB-2的表达水平。结果 逆转录-PCR结果显示：A549细胞表达MRP、bcl-2及C-erbB-2mRNA，无LRP mRNA表达，A549^DDP细胞亦表达MRP、bcl-2及C-erbB-2mRNA，且表达LRP mRNA，耐药细胞MRP及C-erbB-2mRNA表达水平较亲代显增高，bcl-2mRNA表达水平与亲代无显性差异(P=0．731)；A549^DDP细胞血管生成因子及耐药相关基因mRNA表达水平较A549细胞显增高，差异有显性(P=0．007)。免疫细胞化学结果显示：亲代和耐药细胞bcl-2蛋白表达呈强阳性，亲代C-erbB-2及LRP呈阴性，MRP轻度阳性，耐药细胞MRP蛋白呈中度阳性，C-erbB-2及LRP轻度阳性。结论 A549细胞的原发耐药与耐药及凋亡相关基因MRP、C-erbB-2和Bcl-2的异常表达和协同作用有关。A549^DDP细胞MRP和C-erbB-2的表达增强，且表达LRP，可能是继发耐药的产生机制。     

RNA干扰沉默IGF-I R表达对非小细胞肺癌细胞生物学特性及化疗敏感性的影响

目的:评价RNA干扰(RNA interference,RNAi)技术,对人肺癌A549细胞系中胰岛素样生长因子Ⅰ类受体(IGF-I R)表达的阻断效应,和IGF-I R基因沉默后细胞增殖、凋亡等生物学特性及肿瘤细胞对化疗药物敏感性的改变.方珐:应用U6启动子,介导DNA模板转录生成短发夹样RNA(shRNA),并转染人肺癌A549细胞株,从而产生IGF-I R特异性小干扰RNA(siRNA),经RT-PCR和Western blot检测IGF-I R表达的改变;联合应用化疗药物顺铂(DDP),通过MTT法和流式细胞技术等,观察细胞生长、细胞周期、细胞凋亡及DDP半数致死量(IC50)的变化.结果:IGF-I R表达水平明显下降(抑制率高达89.8%),肿瘤细胞增殖能力明显减弱,细胞滞留于G0期的比例上升;DDP对肿瘤细胞24 h、48 h、72 h的IC50均明显减少,IGF-I R siRNAl组DDP作用72h的IC50为0.92 mg/L,明显低于control-siRNA组的3.77 mg/L,0.5 mg/L DDP联合IGF-I R siRNAl作用48 h后,A549细胞的生长抑制率达32.1%,明显高于control-siRNA组的18.9%,细胞凋亡率从27.8%上升至44.2%.结论:运用RNAi技术能有效抑制A549细胞IGF-I R的表达,使细胞增殖能力减弱,化疗敏感性增加.