顺铂诱导宫颈癌Hela细胞凋亡及其作用机制的研究

目的:研究顺铂在体外诱导宫颈癌Hela细胞凋亡及其作用机制。方法:采用MTT法测定顺铂对Hela细胞增殖的影响;流式细胞仪和Hochest33258检测药物作用前后的细胞凋亡情况;RT-PCR检测HPVE6的mRNA水平表达;WesternBlot测定HPVE6、p53、p21、Bax、Bcl-2蛋白水平的表达。结果:顺铂抑制Hela细胞生长呈时效和量效关系;经10μg/ml顺铂分别在12、24、36、48小时作用Hela细胞,亚G1峰与对照组有显著性差异;RT-PCR提示顺铂作用Hela细胞后HPVE6的mRNA水平表达逐渐降低;WesternBlot提示顺铂作用Hela细胞后HPVE6的蛋白水平表达逐渐降低,p53、p21和Bax蛋白水平表达逐步升高,Bcl-2的表达无变化。结论:顺铂通过抑制HPVE6的表达,恢复p53的功能,引起细胞凋亡,起到杀伤肿瘤的作用。     

Methyl jasmonate induces cell death with mixed characteristics of apoptosis and necrosis in cervical cancer cells

In the present study the effectiveness of methyl jasmonate (MJ) against cervical cancer cell lines was investigated. We show that MJ is cytotoxic to a range of cervical cancer lines including SiHa, CaSki and HeLa that carry human papillomavirus (HPV) DNA and wild type p53, and C33A that is negative for HPV and contains mutant p53. Primary human foreskin keratinocytes were almost resistant to the drug. Cytotoxicity of MJ was dose and time dependent, and associated mainly with the induction of cell death and to a less extent with inhibition of cell growth. Cell death induced by MJ displayed features characteristic to both apoptosis and necrosis, and was associated with different changes in the levels of p53, p21, bcl-2 and bax in the various cervical cancer lines. In conclusion, MJ a novel anticancer agent, acts via multiple pathways to induce death of cervical cancer cells, thus making it a promising candidate for treatment of cervical cancer.     

新型磺酰胺类肿瘤抑制剂DHW-51诱导宫颈癌细胞HeLa凋亡的作用机制

目的从新合成的甲磺酰胺类化合物库中筛选出一种新型肿瘤抑制剂DHW-51,初步探讨DHW-51对宫颈癌细胞HeLa凋亡的影响及其作用机制。方法采用细胞增殖抑制实验检测DHW-51作用HeLa细胞12、24和48h时的细胞存活率,分为对照组和10、15、20、25、30μmol/L实验组共6组;流式细胞术检测不同浓度DHW-51诱导HeLa细胞的凋亡率及细胞周期;检测细胞内Caspase 3、Caspase 8和Caspase 9活性及细胞凋亡相关蛋白pro-Caspase 3、pro-Caspase8和poly ADP-ribose polymerase-DNA修复酶(PARP)的表达,分析DHW-51的作用机制。结果DHW-51对HeLa细胞的增殖具有良好抑制作用。当DHW-51浓度为25μmol/L作用时间为24h时,HeLa细胞的存活率仅为(27.34±1.891)%,与对照组相比差异有统计学意义,F=1.369,P<0.001;随着浓度增加,作用时间延长细胞存活率更低。DHW-51能够有效诱导HeLa细胞凋亡,呈浓度和时间依赖关系;当DHW-51浓度为25μmol/L作用时间为24h时,细胞凋亡率为(92.10±1.683)%,与对照组相比差异有统计学意义,t=43.715,P<0.001;随着时间的延长,晚期凋亡的比例逐步增加,而对细胞周期则没有影响。当DHW-51浓度为20μmol/L时,Caspase 3[(1.87±0.063)%,t=12.43,P<0.001]和Caspase 9[(2.0±0.069)%,t=9.519,P<0.05]的活性增加,与对照组相比,差异有统计学意义;Caspase 8的活性无变化。蛋白质印迹结果显示,当DHW-51浓度为20μmol/L时,pro-Caspase 3[(0.33±0.005)%,t=-89.334,P<0.001]和pro-Caspase 9[(0.19±0.009)%,t=-48.308,P<0.001]蛋白表达量下调,pro-Caspase 8蛋白表达无变化,PARP[(0.35±0.012)%,t=14.961,P<0.001]出现断裂带。结论新型磺酰胺类化合物DHW-51可以诱导宫颈癌HeLa细胞凋亡。作用机制初步推测主要是通过由线粒体介导的Caspase依赖途径诱导HeLa细胞凋亡,进而实现抑制肿瘤细胞生长,这一过程与细胞周期阻滞无关。     

Low expression of MYCN promotes cisplatin resistance by suppressing cisplatin-induced apoptosis in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is the most common cause of gynecological cancer-associated mortality. Cisplatin is one of the most effective chemotherapeutic drugs used in EOC; however, its use can lead to relapse due to cisplatin resistance. MYCN sensitizes neuroblastoma to undergo cisplatin-induced apoptosis. However, to the best of our knowledge, there have been no studies to date on the association between MYCN and cisplatin resistance in EOC. Therefore, the present study assessed this association. Datasets from The Cancer Genome Atlas database were used. The overall survival (OS) of patients receiving platin-based therapy was analyzed using Kaplan-Meier Plotter software. RNA sequencing data of 300 patients with EOC were downloaded from cBioportal. The co-expressed genes were subjected to ‘Kyoto Encyclopedia of Genes and Genomes’ analysis using DAVID software. For gene set enrichment analysis, the expression matrix was separated according to the median expression of MYCN, which was selected for hallmark gene set enrichment. Immunohistochemistry was used to assess MYCN expression in EOC tissue. Western blotting was used to evaluate MYCN, p53, Bax and Bcl-2 protein expression levels in EOC cells. Cell viability and apoptosis were assessed using Cell Counting Kit-8 and flow cytometry, respectively. The results demonstrated that MYCN upregulation was associated with increased cisplatin sensitivity and prolonged OS of patients with EOC and patients receiving platin-based therapy. Cisplatin downregulated MYCN expression in cisplatin-sensitive, but not resistant, EOC cells. The genes co-expressed with MYCN were primarily involved in pathways involved in ‘chemotherapeutic resistance’ and ‘apoptosis’. MYCN enriched the apoptosis and p53 signaling pathways in hallmark gene sets. Cells in which MYCN was knocked down demonstrated significantly increased cisplatin resistance; however, MYCN overexpression in cisplatin-resistant cells restored cisplatin sensitivity. Collectively, the present study demonstrated that MYCN downregulation promoted cisplatin resistance by suppressing cisplatin-induced apoptosis in EOC.     

Vandetanib对人卵巢癌细胞抑制作用机制探讨

目的探讨Vandetanib对人卵巢浆液性乳头状腺癌细胞株SKOV3和卵巢癌顺铂耐药细胞株SKOV3/DDP的增殖抑制作用及其机制。方法采用MTT法检测体外不同时间不同浓度的Vandetanib对SKOV3及SKOV3/DDP细胞的杀伤作用,计算半数抑制浓度（IC50）;流式细胞术检测药物对细胞凋亡及其周期分布变化;采用蛋白质印迹法分析凋亡基因Bcl-2、Bax及反映肿瘤细胞侵袭力的基因MMP-2的蛋白表达变化。结果与对照组相比,Vandetanib能明显抑制SKOV3和SKOV3/DDP生长,呈时间-剂量依赖性,IC50值均呈明显减小趋势。32μmol/L的Vandetanib作用SKOV3和SKOV3/DDP 72h后,抑制率分别为（43.21±0.92）%和（56.74±1.09）%,64μmol/L的Vandetanib作用SKOV3和SKOV3/DDP72h后,抑制率分别为（55.37±1.21）%和（79.20±0.39）%,耐药株SKOV3/DDP的抑制率明显高于敏感株SKOV3,差异有统计学意义,P〈0.05。流式细胞术结果显示,随时间浓度的增加,两种细胞凋亡明显增加,G1期细胞增加,S期和G2期细胞减少,差异有统计学意义,P〈0.05。蛋白印迹法结果显示,药物作用于SKOV3细胞株Bcl-2、MMP-2表达减少,Bax表达无明显变化;药物作用于SKOV3/DDP细胞株Bcl-2表达减少,Bax表达增加,耐药株不表达MMP-2。结论 Vandetanib对两种细胞株生长有明显的呈时间及浓度依赖性的抑制作用,可以诱导细胞凋亡并将细胞阻滞于G1期,其机制与下调Bcl-2/Bax、MMP-2表达有关,有利于降低卵巢癌细胞的侵袭力。     

1,4-苯醌致人胚肺成纤维细胞的凋亡效应与调控机制

目的:研究1,4-苯醌(1,4-benzoquinone,PBQ)对人胚肺成纤维细胞(human embryonic lung fibroblast,HELF)的凋亡效应与调控机制。方法:分别用不同浓度(10、20、40、60、80μmol/L)的PBQ处理HELF细胞24 h和40μmol/L PBQ处理HELF细胞24、48、72 h后,应用噻唑蓝(MTT)比色法检测PBQ对HELF细胞增殖的抑制作用,以PI单染法检测细胞周期的改变,用Annexin-Ⅴ/PI双染法检测细胞凋亡,以实时荧光PCR法检测Bax、Bcl-2、p53 mRNA表达水平的改变。结果:与对照组相比,不同PBQ染毒浓度下作用24 h后,随PBQ浓度增加,细胞相对增殖率显著下降(P0.05),G0/G 1期细胞下降(在40和60μmol/L时,P0.05),S期细胞增加(P0.05),以40μmol/L PBQ浓度作用于HELF细胞不同时间,随着染毒时间的增加其相对增殖率和S期细胞均下降(P0.05),而G0/G1期细胞随着染毒时间的增加呈上升趋势(P0.05);当染毒浓度大于20μmol/L时,染毒24 h可诱导HELF细胞产生凋亡,凋亡率随着染毒时间的增加而上升,与对照组相比差异具有统计学意义(P0.05);不同浓度的PBQ染毒24 h,细胞的Bax、Bcl-2、p53 mRNA表达水平均上调。40μmol/L PBQ作用不同时间后,Bax、p53 mRNA水平随着染毒时间的增加而上升,与对照组相比差异均具有统计学意义(P均0.05);Bcl-2随染毒时间增加而下降,48和72 h时与对照组相比差异具有统计学意义(P0.05);Bax/Bcl-2比值随染毒时间增加而增加,与对照组相比差异具有统计学意义(P0.05)。结论:PBQ能抑制HELF细胞增殖,影响HELF细胞周期分布,诱导细胞发生凋亡,其凋亡机制可能与Bax/Bcl-2比值的上升,及p53 mRNA表达的上调有关。     

上调2型大麻素受体诱导子宫颈癌HeLa细胞凋亡

目的:通过构建基因真核表达载体,探讨人2型大麻素受体(human cannabinoid receptor 2,hCB2R)对人子宫颈癌HeLa细胞体外凋亡的作用及机制.方法:选用人脑组织的cDNA作为模板,进行hCB2R基因的RT-PCR扩增,构建重组质粒GV230-hCB2R及其对照空质粒GV230并转染HeLa细胞,Western blotting法及免疫荧光细胞化学染色联合激光扫描共聚焦显微镜技术检测hCB2R表达及细胞内定位;流式细胞术检测HeLa细胞凋亡,Western blotting法及实时荧光定量PCR检测HeLa细胞中hCB2R、Bcl-2、Bax、Bad的表达.结果:与空质粒转染组相比,GV230-hCB2R转染HeLa细胞后表达相对分子质量40 000的hCB2R蛋白,且细胞膜和细胞质中均有hCB2R的表达;GV230-hCB2R转染组的细胞凋亡率显著高于GV230空质粒对照组[(14.51±4.51)％vs(6.29±0.57)％,t=1.72,P＜0.05];与空质粒对照组相比,hCB2R转染组细胞内Bax和Bad 的表达水平明显上调(P＜0.05),而Bcl-2的表达明显下调(P＜0.05).结论:hCB2R对子宫颈癌HeLa细胞的生长表现出明显的抑制作用,其作用机制可能与hCB2R直接参与了细胞凋亡相关蛋白的表达变化有关.     

减毒水泡性口炎病毒诱导宫颈癌HeLa细胞的凋亡及其作用机制

目的:研究减毒水泡性口炎病毒(vesicular stomatitis virus,VSV)对宫颈癌HeLa细胞的凋亡诱导作用,并探讨其可能的机制。方法:将减毒VSV以1.0 MOI的接种密度感染HeLa细胞,在6、12、18、24和30 h后收集细胞,MTT法检测HeLa细胞的增殖;AO/EB染色观察HeLa细胞凋亡形态学变化,Annexin V-FITC/PI双染法检测HeLa细胞早期凋亡率,流式细胞术分析HeLa细胞sub-G1凋亡峰,JC-1染色法测定细胞线粒体跨膜电位水平,caspase试剂盒检测HeLa细胞caspase-3、caspase-8及caspase-9的活性。结果:减毒VSV感染HeLa细胞12和24 h后,HeLa细胞增殖活力分别为(78.4±1.9)%和(63.1±5.6)%(P<0.01);早期凋亡细胞率分别为(16.88±2.48)%和(31.9±4.24)%(P<0.01),sub-G1凋亡峰分别为(14.85±1.48)%和(21.05±2.28)%(P<0.01)。随着减毒VSV感染时间的增加,HeLa细胞线粒体跨膜电位逐渐降低(P<0.05),caspase-9和caspase-3的活性显著升高(均P<0.05)。结论:减毒VSV能够抑制HeLa细胞的增殖,并通过caspase-9和caspase-3依赖的途径诱导HeLa细胞凋亡。     

Estrogen increases intracellular p26Bcl-2 to p21Bax ratios and inhibits taxol-induced apoptosis of human breast cancer MCF-7 cells

Recent studies have demonstrated that following estrogen ablation, estrogen responsive breast cancer cells undergo apoptosis. In addition, estrogen receptor (ER) expression has been strongly correlated with the expression of the bcl-2 gene product, p26Bcl-2 protein, which is known to inhibit apoptosis. In the present studies, we investigated whether estrogen affects the intracellular levels of p26Bcl-2 and thereby modulates taxol-induced apoptosis of estrogen responsive human breast cancer MCF-7 cells. Transfer of MCF-7 cells to a culture-medium without estrogens reduced their intracellular p26Bcl-2 levels by 50%. Inclusion of 0.1 M estradiol in the medium produced approximately a four-fold increase in p26Bcl-2, but not p29Bcl-xL or p21Bax levels; the expression of the c-myc and mdr-1 genes remained unchanged. Estradiol-induced four-fold increase in the ratio of the p26Bcl-2 to p21Bax levels caused a significant decline in the lethal, kilobase size DNA fragments of apoptosis, which had resulted when MCF-7 cells were cultured in a medium without estrogen. In addition, in MCF-7 cells, estradiol-induced increase in the intracellular p26Bcl-2 to p21Bax ratios was associated with a significant reduction in the large-sized DNA fragmentation induced by treatment with taxol. The increased ratios also protected MCF-7 cells against taxol-mediated cytotoxicity as assessed by the MTT assay. These results suggest that by modulating p26Bcl-2 levels, estrogens may affect the antitumor activity of taxol and potentially of other anti-breast cancer drugs against estrogen responsive human breast cancer cells.     

Escape of p53 protein from E6-mediated degradation in HeLa cells after cisplatin therapy

We previously reported that therapy of human cervical carcinoma HeLa cells with CP induced segregation of nucleoli and changes of nuclei characteristic of apoptosis. We raised the question of whether p53 can be reactivated by chemotherapy in HeLa cells despite the presence of HPV-encoded E6 activity. Cellular levels of p53 protein increased after CP treatment, reaching a maximum after 6 hr. p53 protein accumulated preferentially in the nucleoli, with a peak after 15 hr. CP-induced nucleolar targeting of p53 appears to be selective because p73, another member of the p53 gene family, accumulated primarily in nuclei in response to CP. Monitoring of the intranuclear distribution of Hdm-2, a negative regulator of p53, revealed this protein in the nucleoli of untreated controls translocated into chromatin during CP therapy. Interestingly, p14(ARF) showed an inverse intranuclear redistribution. Proteasome inhibitors were not able to mimic the effect of CP on p53 levels. Since the reduced stability of wild-type p53 protein in HeLa cells is a consequence of its enhanced ubiquitination by virally encoded E6 protein, resulting in its accelerated degradation, we checked the cellular level of E6 during CP therapy. Six hours after application of CP, E6 protein expression was markedly reduced. This coincided with the increase of cellular p53 and preceded the nucleolar accumulation of p53 protein, indicating that repression of virally coded E6 protein by CP contributes to the restoration of p53 expression.     

泛素结合酶E2A在顺铂诱导的HeLa细胞应激反应中的作用

目的：探讨泛素结合酶E2 A（UBE2A）基因在顺铂（cisplatin）诱导的HeLa细胞应激反应中的作用。方法：RT-PCR检测顺铂作用后UBE2A mRNA在HeLa细胞中的表达水平;利用针对UBE2A的特异性siRNA转染细胞后,采用qPCR检测UBE2A mRNA在HeLa细胞中的表达情况,并应用CCK-8法检测细胞在顺铂作用下的存活率。结果：UBE2A基因在HeLa细胞中表达两种转录本：U-1和U-2,U-2相比U-1缺少了外显子4的部分序列,并且顺铂作用后二者表达水平均升高。针对UBE2A的特异性siRNA可分别降低其对应转录本的表达水平,表达量分别为对照组的27.43%、15.85%。UBE2A表达受到抑制的HeLa细胞在顺铂作用后细胞存活率降低,相比对照组分别下降了14.46%和19.20%,差异均有统计学意义（P均 < 0.05）。结论：UBE2A可能参与了顺铂诱导的细胞应激反应,抑制其表达可以明显提高HeLa细胞对顺铂细胞毒性的敏感性。     

HPV16 E6蛋白与hDaxx的相互作用及其对HeLa细胞凋亡的影响

Objective: To study the interaction of human papillomavirus type 16 (HPV16 E6) protein and human death domain associated protein (hDaxx) and its effect on apoptosis of HeLa cells to provide the experimental basis for exploring the oncogenic mechanism of HPV16 E6 protein. Methods: Recombinant vector of pGADT7/E6 or pGBKT7/hDaxx was con- structed. The interaction of E6 protein and hDaxx was detected by yeast two-hybrid system. Their expression in yeast was detected by Western blotting. The eukaryotic plasmids of E6 and hDaxx were co-transfected into HeLa cells. Apoptosis was induced by 5-FU. The apoptotic rate was measured by flow cytometry (FCM). Results: E6 protein had intracellular interaction with hDaxx. The apoptotic rate was rising with the increase in the transfection quantity of pcDNA3.1 (-) / hDaxx in pcDNA3.1 (-) /E6 and pcDNA3.1 (-) / hDaxx co-transfected cells. The difference was significant ( P < 0. 01). Conclusion: There is intracellular interaction between HPV16 E6 protein and hDaxx. The over-expression of hDaxx can increase the sensitivity of E6 protein positive HeLa cells to 5-FU. The effect was in a dose dependent manner. HPV16 E6 protein inhibited the apoptosis of HeLa cells by interacting with hDaxx.     

Tetrazolium violet induces G0/G1 arrest and apoptosis in brain tumor cells

Summary Tetrazolium violet (TV), a potent anticancer agent, has been shown to induce cell growth-inhibition in tumor cells. However, the related mechanism has not been revealed yet. In this report we assessed the influence of TV on cell growth and cell cycle in brain tumor cells. Treatment of C6 tumor cells with TV (5–15 μM for 24–72 h) resulted in a growth inhibition in a dose and time-dependent manner and G0/G1 phase arrest, determined by flow cytometry analysis. These effects were accompanied by apoptosis other than necrosis, evidenced by nuclear condensation, terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay and trypan blue exclusion assay plus lactate dehydrogenase (LDH) release assay. Treatment of cells with TV at 15 μM for 24 h resulted in an increase in the activity of caspase-3, evidenced by colorimetric assay, and a dramatic up-regulation of p53, accompanied with a significant increase of Bax/Bcl-2 ratio, as evidenced by immunofluorescence assay. These results suggest that TV induces growth inhibition of C6 cells through p53-midiated apoptotic pathway and G0/G1 checkpoint mechanism. Although detailed mechanisms remain to be explored, selective blockage of tumor cells in G0/G1 phase accompanied by p53-associated apoptosis makes tetrazolium violet a promising anticancer agent, meriting further investigations.     

RhoGDI2 confers gastric cancer cells resistance against cisplatin-induced apoptosis by upregulation of Bcl-2 expression

Rho GDP dissociation inhibitor (RhoGDI)2 has been identified as a regulator of Rho family GTPase. Recently, we suggested that RhoGDI2 could promote tumor growth and malignant progression in gastric cancer. In this study, we demonstrate that RhoGDI2 contributes to another important feature of aggressive cancers, i.e., resistance to chemotherapeutic agents such as cisplatin. Forced expression of RhoGDI2 attenuated cisplatin-induced apoptosis, whereas RhoGDI2 depletion showed opposite effects in vitro. Moreover, the increased anti-apoptotic effect of RhoGDI2 on cisplatin was further validated in RhoGDI2-overexpressing SNU-484 xenograft model in nude mice. Furthermore, we identified Bcl-2 as a major determinant of RhoGDI2-mediated cisplatin resistance in gastric cancer cells. Depletion of Bcl-2 expression significantly increased cisplatin-induced apoptosis in RhoGDI2-overexpressing gastric cancer cells, whereas overexpression of Bcl-2 blocked cisplatin-induced apoptosis in RhoGDI2-depleted gastric cancer cells. Overall, these findings establish RhoGDI2 as an important therapeutic target for simultaneously enhancing chemotherapy efficacy and reducing metastasis risk in gastric cancer.     

Bcl-2基因在人膀胱癌细胞中表达对CTL凋亡诱导作用的影响

目的:探讨Bcl-2基因在人膀胱癌细胞中表达对细胞毒性T淋巴细胞(CTL)凋亡诱导作用的影响。方法:采用基因重组技术构建真核表达载体pcDNA3.1(+)/Bcl-2;应用脂质体介导的基因转染技术将pcDNA3.1(+)/Bcl-2导入膀胱癌BIU-87细胞,RT-PCR检测Bcl-2基因表达水平;不同浓度抗Fas单克隆抗体(Anti-Fasmab)模拟CTL的Fas-配体(Fas-L)处理转染与未转染Bcl-2基因的膀胱癌细胞,采用四甲基偶氮唑蓝(MTT)比色法、吖啶橙(AO)荧光染色法和流式细胞检测仪(FCM)分析细胞存活和凋亡情况。结果:酶切和核酸测序证明真核表达载体pcDNA3.1(+)/Bcl-2构建成功。将重组质粒转染膀胱癌细胞后,RT-PCR分析表明,转染Bcl-2基因的BIU-87/Bcl-2细胞的Bcl-2基因表达水平较BIU-87细胞和转染空载体的BIU-87/neo细胞显著增高,P<0.01。An-ti-Fasmab作用后,BIU87/Bcl-2细胞的存活率显著高于BIU-87和BIU-87/neo细胞,P<0.05或P<0.01。3种细胞虽均发生凋亡的形态学改变,但BIU87和BIU87/neo细胞改变更为明显,两者的凋亡率分别为(25.33±3.00)%和(27.05±1.75)%,而BIU-87/Bcl-2细胞的凋亡率为(18.06±1.41)%,显著低于前两者,P<0.01。结论:Bcl-2基因高表达通过阻断CTL杀伤膀胱癌细胞的Fas/Fas-L途径,使膀胱癌细胞能够抵御免疫系统中CTL的攻击。     

绞股蓝诱导人肝细胞瘤细胞凋亡

Objective： To identify the proapoptotic effects of Gynostemma pentaphyllum Makino （GpM） on human hepatoma cells. Methods： The effects of GpM on the cell apoptosis of human hepatoma cell line Huh-7 was assessed by flow cytomety. The expression of Bcl-2, Bcl-XL, Bax and Bad molecules in hepatoma cells treated with GpM was detected by Western blot. Results： After treatment with 20 mg/mL GpM for 24 h, 56% of Huh-7 cells were undergoing apoptosis, while cell death was only observed in 12% of humaa fibroblast cells treated with GpM. Western blot demonstrated that, Bcl-2 was markedly decreased in Huh-7 cells treated with GpM. Whereas, Bax was significantly up-regulated in Huh-7 cells treated with GpM. Conclusion： Treatment of human hepatoma cells with GpM induced apoptosis through the down-regulation of Bcl-2, and up-regulation of Bax.     

Reactive oxygen species-dependent EndoG release mediates cisplatin-induced caspase-independent apoptosis in human head and neck squamous carcinoma cells

Cisplatin is a chemotherapeutic agent that is widely used to treat cancers such as head and neck squamous cell carcinoma (HNSCC). Previously, we have reported that cisplatin induced an early caspase-dependent apoptosis (8 hr) in a HNSCC cell, HN4. In this study, we examined a late caspase-independent apoptosis as well as an early caspase-dependent apoptosis in cisplatin-treated HN4 cells. While z-VAD-fmk, a pan-caspase inhibitor, blocked the caspase activities and protected cells from the early apoptosis, it did not provide protection against delayed apoptosis occurring after extended exposure (16 hr) to cisplatin, suggesting that the delayed apoptotic response in the presence of z-VAD-fmk was caspase-independent. Cisplatin treatment induced reactive oxygen species (ROS) generation, loss of the mitochondrial membrane potential (MMP) and nuclear translocation of endonuclease G (EndoG). Small interfering RNA mediated-knockdown of EndoG significantly protected cells from the delayed apoptosis induced by cisplatin in the presence of z-VAD-fmk. Overexpression of Bcl-2 in HN4 cells prevented loss of MMP, nuclear translocation of EndoG and protected cells from the delayed apoptosis induced by cisplatin in the presence of z-VAD-fmk. Pretreatment with N-acetyl-L-cysteine (NAC), a ROS scavenger, prevented both ROS generation, loss of the MMP and nuclear translocation of EndoG. Together, our data indicate that cisplatin treatment induced ROS-mediated loss of the MMP, and, then, the nuclear translocation of EndoG, which played a crucial role in caspase-independent apoptosis of HN4 cells in the presence of z-VAD-fmk. This is the first report about the involvement of EndoG in cisplatin-induced caspase-independent apoptosis of cells.     

顺铂诱导宫颈癌SiHa细胞周期阻滞及凋亡的研究

目的:探讨顺铂在体外对宫颈癌SiHa细胞周期和凋亡的影响及其作用机制。方法:采用MTT法测定顺铂对SiHa细胞增殖的影响;DNAladder和Hoechst33258检测药物作用前后的细胞凋亡情况;流式细胞仪检测药物作用前后的周期阻滞和凋亡;Westernblot检测E6、p53和p21的表达。结果:顺铂抑制SiHa细胞生长呈时效和量效关系,10mol/L顺铂作用SiHa细胞12、24、36和48h,亚G1峰分别为(3·07±0·15)%、(5·18±0·28)%、(17·73±1·20)%和(32·55±2·74)%,与对照组比较差异均有统计学意义,t值分别为32·80、31·46、29·73和25·99,P值均为0·000;顺铂能使SiHa细胞发生G2~M期阻滞,24h达到最高(66·43±4·62)%,凋亡开始;Hoechst33258实验组可见凋亡细胞;琼脂糖凝胶电泳出现DNA梯形条带;Westernblot提示,顺铂作用SiHa细胞后HPVE6的蛋白水平表达逐渐降低,p53和p21蛋白水平表达逐步升高。结论:顺铂随着药物浓度和作用时间的增加对SiHa细胞的体外抑制效应增加,顺铂通过引起SiHa细胞G2~M周期阻滞及抑制HPVE6蛋白的表达,恢复p53功能,启动凋亡,起到杀伤肿瘤作用。     

黄芪对肺腺癌细胞凋亡及Bcl-2、Bax表达的影响

目的:探讨中药提取物黄芪(Astragalus)对人肺腺癌(lung adenocarcinoma)细胞系SPC-A-1的凋亡诱导作用及其发生机制。方法:体外培养SPC-A-1细胞,用不同浓度黄芪对体外培养的SPC-A-1细胞进行干预。分别采用MTT、免疫细胞化学染色、流式细胞仪法检测其对SPC-A-1细胞的增殖抑制和凋亡诱导作用;并对凋亡相关Bcl-2与Bax蛋白表达的变化进行定性检测。结果:经不同浓度黄芪处理后的SPC-A-1细胞,其生长受到明显的抑制,细胞凋亡指数随药物浓度增加而明显增加;黄芪作用Bax表达明显高于对照组。结论:一定浓度的黄芪能抑制SPC-A-1细胞的增殖,促进其凋亡;其机制可能与调控Bcl-2、Bax表达有关。