p53N15融合肽转染肺腺癌细胞系H1299的抗肿瘤作用

目的 探讨p53N15融合肽转染对肺腺癌细胞H1299体外生长的抑制作用.方法 通过腺体相关病毒(adeno-associated virus AAV)载体把p53N15融合肽高效导入p53缺失肺腺癌H1299细胞系,应用相差倒置显微镜观察、MTT细胞活性试验及流式细胞仪技术分析p53N15对肺癌细胞的抑制作用.结果 p53N15融合肽在H1299细胞中得到了高效表达并发挥明显效应,表现为显微镜下,重组病毒转染72 h可见大片细胞死亡.MTT试验分析,重组病毒转染组细胞活性明显降低.流式细胞仪技术显示,重组病毒转染组可见大量死亡细胞.结论 p53N15融合肽转染可明显抑制肺腺癌细胞H1299的体外生长.     

p53N15融合肽转染肺腺癌细胞系H1299的抗肿瘤作用

目的 探讨p53N15融合肽转染对肺腺癌细胞H1299体外生长的抑制作用.方法 通过腺体相关病毒(adeno-associated virus AAV)载体把p53N15融合肽高效导入p53缺失肺腺癌H1299细胞系,应用相差倒置显微镜观察、MTT细胞活性试验及流式细胞仪技术分析p53N15对肺癌细胞的抑制作用.结果 p53N15融合肽在H1299细胞中得到了高效表达并发挥明显效应,表现为显微镜下,重组病毒转染72 h可见大片细胞死亡.MTT试验分析,重组病毒转染组细胞活性明显降低.流式细胞仪技术显示,重组病毒转染组可见大量死亡细胞.结论 p53N15融合肽转染可明显抑制肺腺癌细胞H1299的体外生长.     

p53~(mut)、p53~(wt)、p16基因转染对肺腺癌H1299细胞Samd4蛋白表达的影响

目的探讨外源性p53mut、p53wt和p16基因转染人肺癌细胞株H1299后对其Smad4蛋白表达的影响。方法运用PCR方法扩增p53mut、p53wt及p16基因,构建真核表达载体p IRES2-EGFP-p53mut、p IRES2-EGFP-p53wt及p IRES2-EGFP-p16,脂质体法单独或共转染H1299细胞。荧光显微镜下观察细胞中表达的带绿色荧光的增强型荧光蛋白(EGFP),使用RT-PCR验证质粒载体转染效果,使用Western blot检测转染后各组细胞Smad4蛋白表达水平的变化。结果转染72小时后在荧光显微镜下观察到被转染的H1299细胞发绿色荧光。经RT-PCR证实转染后的H1299细胞成功表达目的基因。Western blot法显示空载体组与空白对照组在Smad4蛋白表达上无明显差异(P0.05),p53mut组Smad4蛋白表达较空载体组下调(P0.05),而p53wt转染组或p53wt、p16联合转染组Smad4表达增强,且以后者的上调作用更为明显(P0.05)。结论 p53mut转染可抑制H1299细胞的Samd4蛋白表达,而单独转染p16或共转染p16、p53wt可使Smad4蛋白表达上调,且以后者的上调作用更为显著。p53mut的促癌作用及p53wt和p16的抑癌作用可能与TGF-β/Smad4相关信号通路有关。     

以白细胞介素4-受体为靶标的胰腺癌靶向治疗研究

目的 检测白细胞介素4受体(IL-4R)在胰腺癌组织及人胰腺癌细胞株中的表达,观察以抗白细胞介素-4受体单抗(MAIL4R)为载体构建的免疫毒素MAIL4R-CTX对胰腺癌细胞的靶向杀伤作用.方法 应用免疫组织化学检测IL-4R在26例胰腺癌组织、15例胰腺正常组织中的表达;免疫细胞化学染色检测IL-4R在人胰腺癌PANC-1、BxPC-3细胞和人肺腺癌H1299细胞中的表达;采用噻唑蓝(MTT)法观察MAIL4R、眼镜蛇毒细胞毒素(CTX)、免疫毒素MAIL4R-CTX对体外培养PANC-1,BxPC-3细胞和H1299细胞生长的影响.结果 IL-4R在26例胰腺癌组织中均呈不同程度的阳性表达,而15例胰腺正常组织中仅1例呈弱阳性表达,余均为阴性表达;人胰腺癌PANC-1,BxPC-3细胞均表达IL-4R,H1299细胞不表达IL-4R;CTX对PANC-1,BxPC-3和H1299细胞均有明显抑制作用,但对3株细胞的抑制率差异无统计学意义(P＞0.05);MAIL4R对PANC-1、BxPC-3和H1299细胞均无明显抑制作用;MAIL4R-CTX对过表达IL-4R的BxPC-3和PANC-1细胞的生长具有显著的抑制作用,并且为剂量依赖性,而对低表达IL-4R的H1299细胞不敏感,在浓度为18.75 mg/L,作用4h时PANC-1和BxPC-3细胞分别有86.4%和95.2%被杀伤,H1299细胞仅死亡26.8%(P＜0.01).结论 IL-4R过表达于胰腺癌组织和胰腺癌细胞株,而低表达于正常胰腺组织中,免疫毒素MAIL4R-CTX在体外对过表达IL-4R的细胞株PANC-1、BxPC-3有靶向性杀伤作用.     

125I粒子照射与60Co放射治疗对肺腺癌细胞的生物学效应

目的探讨~(125)I粒子和~(60)Co照射两种不同照射方式对肺腺癌细胞生物学效应的影响。方法对肺腺癌细胞株A549、H1299及人正常肺上皮细胞BEAS-2B分别行~(125)I粒子和~(60)Co照射。~(125)I粒子组和~(60)Co照射组的照射剂量分别为2、4、6、8Gy,将不进行照射的细胞设定为对照组。分别检测细胞存活分数、细胞周期、细胞凋亡率及凋亡相关蛋白的表达水平。结果与对照组相比,~(125)I粒子组和~(60)Co照射组的细胞存活分数明显降低。在照射剂量为4、6、8Gy时,A549细胞表达较明显的G1期阻滞,H1299和BEAS-2B表达较明显的G2/M期阻滞。同时在照射剂量为4、6、8Gy时,两种照射方式均能导致肺腺癌细胞凋亡率明显升高。在照射剂量为4、8Gy时,两种照射方式都能显著上调Bax、Cleaved-caspase-3和Cleaved-PARP蛋白的表达并下调Bcl-2蛋白的表达。与~(60)Co照射组相比,~(125)I粒子组的A549、H1299细胞有更低的细胞存活分数、更明显的细胞周期阻滞效应及更高的细胞凋亡率,且对凋亡相关蛋白的调节效应更明显。对于BEAS-2B细胞株,细胞凋亡率和凋亡相关蛋白的表达基本未发生改变。结论 ~(125)I粒子照射和~(60)Co照射均有抑制肺腺癌细胞增殖、促进凋亡的作用,~(125)I粒子照射作用更明显。A549细胞较H1299细胞对放射治疗敏感性高。Bcl-2/Bax蛋白比的失衡和Caspase-3、PARP蛋白的激活在~(125)I粒子照射抑制肿瘤细胞增殖的效应中可能发挥重要的作用。     

腺病毒介导p53基因对胰腺癌细胞抑制作用的体外实验研究

目的 探讨腺病毒介导p53基因(adenovirus-mediated p53 gene,Ad-p53)对人胰腺癌细胞株PANC-1的生长抑制作用.方法 以Western Blot方法 检测加入Ad-p53后PANC-1细胞在48h 、72h p53表达情况以及未处理组细胞48h 、72h p53的表达.采用四甲基偶氮唑盐(MTT)比色实验检测不同MOI值的Ad-p53感染后,PANC-1细胞的生长情况并绘制生长曲线,用PI、annexin V-FITC双重染色并用流式细胞技术检测受感染细胞的凋亡比例.结果 Western Blot结果 显示,处理组细胞内48h 、72h p53蛋白表达明显高于相同时间点对照组细胞;MTT结果 显示不同MOI值细胞生长抑制情况不同,MOI值越高,对细胞生长的抑制程度也越高;流式检测细胞在MOI值为150时,0h、48h、72h凋亡比例分别为(7.5±0.8)%、(22.5±2.3)%和(34.4±2.7)%,对照组细胞为(5.8±0.4)%、(8.3±1.7)%和(9.7±2.1)%.结论 Ad-p53能有效感染胰腺癌细胞,导致胰腺癌细胞凋亡.     

新型增殖性腺病毒的构建及对肝癌细胞的抑制

目的 构建携带p53基因新型增殖性腺病毒CNHK600-p53,研究其对肝癌细胞株抑制效应是否优于Ad-p53.方法 PCR扩增p53基因,利用酶切连接方法 将其插入CNHK600载体,PCR鉴定.经293细胞包装成病毒,抽提病毒DNA,PCR鉴定.氯化铯密度梯度离心法纯化病毒,TCID50 方法 测病毒滴度.病毒增殖实验检测病毒在不同细胞增殖能力.四甲基偶氮唑盐(methyl-thiazolyl tetrazolium assay,MTT)法观察CNHK600-p53、Ad-p53两种病毒分别对肝癌细胞株的抑制率.结果 成功构建新型增殖性腺病毒载体CNHK600-p53;293细胞包装成病毒,PCR方法 鉴定无野生型病毒存在;病毒滴度为1.99×10~（10）pfu/ml;CNHK600-p53在肝癌细胞HepG2、SMMC-7721内复制能力明显高于正常肝细胞HEL-1和L02.对6种肝癌细胞(PLC/PRF5、SMMC7721、HepaG2、BEL-7402、BEL-7404、QGY-7703)而言,随着MOI值的不断增高.其对肝癌细胞的抑制作用也不断增强;在相同MOI情况下,CNHK600-p53组较Ad-p53组的细胞抑制率高(P＜0.05).当细胞抑制率达到80%以上时.两组之间差异无统计学意义(P＞0.05).结论 利用新型增殖性腺病毒CNHK600一p53较 Ad-p53能更有效的抑制肝癌细胞,可能成为肝癌的基因治疗更有效的一种基因治疗手段.     

腺病毒介导p53基因联合肿瘤坏死因子对H22腹水瘤的协同作用

目的评价p53腺病毒注射液（AD-p53）与肿瘤坏死因子（TNF）联合腹腔给药对H22腹水瘤模型的协同抑制作用。方法建立H22腹水瘤的昆明小鼠模型，48h后以AD-p53、TNF、生理盐水等腹腔注射，治疗周期为1周，治疗后测量腹围、体重，计量腹水，计数瘤细胞数，以流式细胞分析检测瘤细胞凋亡、死亡比例及细胞周期。结果AD-p53腹腔给药1周，出现瘤细胞G0／G1期阻滞；其和TNF联用后，未生成腹水的小鼠增多；在生成腹水的小鼠，腹水量和瘤细胞数均较单用时明显减少。结论AD-p53可阻滞瘤细胞周期，抑制增殖，联合TNF腹腔给药，在抑制腹水瘤时具有协同作用。     

GADD45β基因表达诱导对不同p53状态的肝癌细胞作用

目的：体外合成GADD45β基因全序列表达质粒后，研究GADD45β基因表达诱导对呈不同p53状态的肝癌细胞的作用及可能机制。方法：采用RT-PCR法获得GADD45β基因全序列，插入pDrive穿梭克隆载体和pIRES2-EGFP荧光表达载体后大量扩增获得DNA，结合p53全基因表达质粒pp53-EGFP转染HepG2、Hep3B细胞后，以[^3H]胸腺嘧啶脱氧核苷掺入法(^3H—Tdr)和细胞克隆形成法分析DNA合成变化及细胞生长能力；以双抗体夹心ELISA法测定TGF-β1表达变化。结果：成功合成GADD45β基因全序列和表达质粒，通过流式细胞仪收集转染阳性的荧光表达细胞能显著提高转染效率；转染GADD45β后．具有野生型p53基因的HepG2细胞的细胞克隆形成能力和DNA合成能力明显受到抑制，细胞凋亡明显增加，TGF-β1的表达亦明显受抑。与之相反，缺失p53基因的Hep3B需要同时共转染p53基因后，方出现抑制效应。结论：GADD45β基因能够有效抑制肝癌细胞的生长．其功能需要完整p53基因的辅助和(或)调控。GADD45表达和（或)功能异常，导致p53介导的DNA损伤修复途径异常或阻断，是肝脏细胞恶性转化及形成肿瘤的可能机制。     

导入野生型p53基因对人胶质瘤细胞生长及化疗敏感性的影响

目的 研究野生型p53基因对人胶质瘤细胞生长及化疗敏感性的影响。方法 将载有野生型p53基因的表达质粒PC53-SN3导入U251细胞。通过逆转录-聚合酶链反应(RT-PCR)检测p53基因在转染细胞中的表达,用四甲基偶氮唑盐微量酶反应比色法(MTT法)和流式细胞仪检测p53基因对U251细胞生长抑制及凋亡的影响以及它与顺铂联合作用后的效果。结果 通过RT-PCR证实了野生型p53基因在U251细胞中的表达。MTT检测发现p53基因对U251细胞的生长有明显的抑制作用,抑制率为(79.60±5.69)％。顺铂对 U251细胞的抑制作用随着顺铂浓度的增加(1、2、4、8 mg/L)而增强,抑制率分别为(19.40±6.69)％、(24.41±2.68)％、(51.84±13.38)％、(66.22±5.02)％,但不如 p53基因的抑制作用强。当野生型 p53基因与顺铂联合作用于 U251细胞时,抑制率明显增加,分别为(91.64±1.00)％、(94.98±1.67)％、(95.32±2.01)％、(95.65±1.00)％。p53基因转染所产生的 U251细胞凋亡率为 17.38％。顺铂引起的细胞凋亡率随着顺铂浓度的增加(1、2、4、8mg/L)而增加,分别为5.71％、5.93％、6.27％、6.81％。当p53基因与不同浓度的顺铂(1、2、4、8mg/L)联合作用于U251细胞时,凋亡率也明显增加,分别为23.50％、23.54％、23.89％、28.88％。结论 野生型p53基因与     

Aberrant Expression and Mutation-Inducing Activity of AID in Human Lung Cancer

Background

Activation-induced cytidine deaminase (AID) is expressed in B lymphocytes and triggers antibody diversification. Recent reports have indicated that the constitutive expression of AID in mice causes not only lymphomas, but also cancers of some organs including the lung, prompting us to investigate the expression and effect of AID on human lung cancer.

Materials and Methods

We examined AID mRNA expression in 17 lung cancer cell lines and 51 primary lung cancers using a quantitative RT-PCR analysis. Next, we established H1299 lung cancer cells stably overexpressing AID and performed a supF forward mutation assay. We then examined AID protein expression and p53 mutation in 129 primary lung cancers by an immunohistochemical analysis and PCR-SSCP and sequencing analyses, respectively.

Results

Aberrant mRNA expression of AID was detected in 29% (5 of 17) of the lung cancer cell lines and 31% (16 of 51) of the primary lung cancers. AID-overexpressing H1299 clones showed a 5.0- to 6.1-fold higher mutation frequency than an empty vector-transfected H1299 clone, and about half of the AID-induced mutations were base substitutions, indicating that AID induces gene mutations in lung cancer cells. Furthermore, an association was found between the AID protein expression level and the p53 mutation status in an analysis of 129 primary lung cancers. A further expression analysis revealed that a portion of AID is localized at the centrosomes.

Conclusion

Our current findings suggest that the aberrant expression of AID may be involved in a subset of human lung cancers as a result of its mutation-inducing activity.

     

Checkpoint kinase 1 protein expression indicates sensitization to therapy by checkpoint kinase 1 inhibition in non–small cell lung cancer

Background

When presenting with advanced stage disease, lung cancer patients have <5% 5-y survival. The overexpression of checkpoint kinase 1 (CHK1) is associated with poorer outcomes and may contribute to therapy resistance. Targeting CHK1 with small-molecule inhibitors in p53 mutant tumors might improve the effectiveness of chemotherapy and radiotherapy in non–small cell lung cancer (NSCLC).

Methods

We evaluated CHK1 messenger RNA and protein levels in multiple NSCLC cell lines. We assessed cell line sensitization to gemcitabine, pemetrexed, and radiotherapy by CHK1 inhibition with the small molecule AZD7762 using proliferation and clonogenic cell survival assays. We analyzed CHK1 signaling by Western blotting to confirm that AZD7762 inhibits CHK1.

Results

We selected two p53 mutant NSCLC cell lines with either high (H1299) or low (H1993) CHK1 levels for further analysis. We found that AZD7762 sensitized both cell lines to gemcitabine, pemetrexed, and radiotherapy. Chemosensitization levels were greater, however, for the higher CHK1 protein expressing cell line, H1299, when compared with H1993. Furthermore, analysis of the CHK1 signaling pathway showed that H1299 cells have an increased dependence on the CHK1 pathway in response to chemotherapy. There was no increased sensitization to radiation in H1299 versus H1993.

Conclusions

CHK1 inhibition by AZD7762 preferentially sensitizes high CHK1 expressing cells, H1299, to anti-metabolite chemotherapy as compared with low CHK1 expressing H1993 cells. Thus, CHK1 inhibitors may improve the efficacy of standard lung cancer therapies, especially for those subgroups of tumors harboring higher expression levels of CHK1 protein.     

Adenoviral melanoma differentiation-associated gene 7 induces apoptosis in lung cancer cells through mitochondrial permeability transition-independent cytochrome c release

OBJECTIVE: Melanoma differentiation-associated gene 7 is a novel tumor suppressor gene that induces apoptosis in lung cancer cells when delivered by adenoviral gene transfer as Ad-mda7. The mechanisms of action are not well defined but may involve release of cytochrome c from the mitochondria with subsequent caspase activation. METHODS: The lung cancer cell lines A549 and H1299 were transduced with Ad-mda7, adenovirus containing the gene for p53 (Ad-p53), and control adenoviral luciferase vectors. Staurosporine was used as a positive control to induce cytochrome c release through mitochondrial permeability transition-dependent pores, whereas cyclosporine (INN: ciclosporin) was used to specifically inhibit these mitochondrial permeability transition-dependent pores. Apoptosis was evaluated with fluorescence-activated cell sorting analysis of subdiploid populations and mitochondrial membrane potential changes with tetramethylrhodamine ethylester perchlorate. RESULTS: Melanoma differentiation-associated gene 7, transduced by Ad-mda7 into H1299 and A549 lung cancer cells, resulted in sharp increases in cytosolic cytochrome c levels followed by induction of apoptosis and cellular death. The release of cytochrome c from the mitochondria occurred without changes in the mitochondrial membrane potential. Unlike staurosporine treatment, transduction with Ad-p53 and Ad-mda7 caused releases of cytochrome c and apoptosis that were not blocked by cyclosporine, suggesting a mitochondrial permeability transition pore-independent pathway. CONCLUSIONS: Ad-mda7 induces apoptosis in lung cancer cells through mitochondrial cytochrome c release in a process that is not dependent on mitochondrial membrane potential changes and occurs through mitochondrial permeability transition-independent pores. This unique mechanism of action may allow treatment of patients with lung cancer resistant to mitochondrial permeability transition-dependent cell death processes.     

丁酸钠对人胰腺癌细胞ASPC-1生长的影响及其机制的研究

目的 探讨丁酸钠对人胰腺癌ASPC-1细胞生长的影响并探讨其作用机制.方法 使用不同浓度丁酸钠处理ASPC-1细胞.MTT法观察肿瘤细胞的增殖;流式细胞仪检测细胞凋亡和细胞周期的变化;Western印迹法检测细胞内p21、p53、bcl-2、bax蛋白表达的变化,实时定量PCR检测p21和bcl-2的表达.结果 丁酸钠能明显抑制ASPC-1细胞的增殖,其作用具有明显的时间和剂量依赖性.丁酸钠处理24 h后ASPC-1细胞凋亡率明显提高(P＜0.05),S期细胞比例显著降低(P＜0.05),G0/G1期细胞比例显著升高(P＜0.05).p21、bax蛋白表达明显上调(P＜0.05);bcl-2蛋白的表达显著降低(P＜0.05);p53蛋白表达无明显变化(P＞0.05).结论 丁酸钠可以通过诱导胰腺癌细胞的凋亡和周期阻滞而抑制癌细胞生长;其发生机制可能与下调抗凋亡基因bcl-2、上调促凋亡基因bax和肿瘤抑制基因p21的表达有关.

Abstract：

Objective To investigate the effects of sodium butyrate(NaBT) on proliferation of human pancreatic cancer cell line ASPC-1 and explore the possible mechanism. Methods The methylthiazolyl tetrazolium assay (MTT) method was used to detect cell proliferation and draw a curve. The cell apoptosis and cell cycle were determined with flow cytometry. Western blot was used to study the effect NaBT on the pancreatic cancer cells and explore its mechansim. Real-time PCR was employed to assess the expression levels of p53, p21, bcl-2 and cell cycle regulation gene p21. Results After incubation with different concentrations of NaBT for 24 to 72 h, ASPC-1 cell proliferation was inhibited dramatically. NaBT induced an increase of G0/G1 phase cells and a significant decrease in the ratio of S phase cells. The expression of p21 and bax was up-regulated at protein and mRNA level. The expression of bcl-2 was down-regulated at protein and mRNA level. There was no significant difference in the expression of p53 at protein and mRNA level. Conclusion TSA-induced growth inhibition is associated with a block in the G0/G1 phase and apoptosis, which may occur through down-regulating the expression of apoptosis gene bcl-2 and up-regulating the expression of cell cycle regulation gene p21and pro-apoptotic gene bax.     

腺病毒载体介导的早幼粒细胞白血病基因生长抑制因子诱导胃癌细胞凋亡的机制研究

目的 探讨腺病毒载体介导的早幼粒细胞白血病基因（PML）生长抑制因子诱导胃癌细胞凋亡作用的机制。方法 将人PML全长cDNA插入穿梭质粒pSGCMV，再与腺病毒骨架质粒pPE3共转染293细胞后获得重组病毒。用重组病毒感染胃癌细胞系SGC-7901，采用噻唑蓝比色法、流式细胞术以及免疫细胞化学法对p53和bcl-2在肿瘤细胞内的表达以及细胞凋亡的定性与定量指标进行检测。结果 经腺病毒介导的PML处理的SGC-7901细胞生长受到明显抑制，凋亡细胞发生率升高，且与MOI值呈正相关，MOI值由5增加到20，细胞的生长抑制率从22．4％增加到38．5％，而细胞凋亡率从37．2％增加到49．8％。经腺病毒介导的PML处理的SGC-7901细胞内p53蛋白表达较对照组明显增加，bel-2蛋白的表达则无明显变化。结论 腺病毒介导的PML对胃癌细胞的杀伤主要是通过诱导细胞凋亡，p53蛋白高表达为其诱发胃癌细胞凋亡的机制之一。