三氧化二砷诱导人肝癌细胞株HepG2凋亡的机制研究

目的：探讨三氧化二砷（As2O3）诱导人肝癌细胞株HepG2凋亡的作用机制。方法：采用MTT法观察不同浓度的As2O3对人类肝癌细胞株HepG2生长的抑制作用;以流式细胞术观察细胞的凋亡率;以Westernblot法检测JNK、p-JNK、Caspase-3及PARP蛋白在As2O3作用下及SP600125阻断JNK信号转导通路情况下的表达。结果：As2O3对体外生长的肝癌细胞HepG2具有明显抑制作用,并可诱导细胞凋亡。Westernblot结果显示,As2O3诱导肝癌细胞HepG2凋亡伴随着Caspase-3和PARP的活化;AS2O3作用于HepG2细胞10min后p-JNK蛋白表达开始增加,20min达到高峰,30min开始减少,总JNK蛋白的含量无明显改变,JNK的激活早于细胞凋亡;用SP600125预处理HepG2细胞株后,可以明显减少Caspase-3和PARP的活化。结论：As2O3通过诱导细胞凋亡抑制肝癌细胞株HepG2的增殖,细胞凋亡通过Caspase-3途径实现。JNK信号转导通路参与了As2O3诱导的HepG2凋亡反应,并位于Cas-pase-3的上游。     

JNK抑制剂对D-氨基葡萄糖衍生物诱导Eca-109细胞Caspase-3活化的影响

目的:观察特异性c-Jun氨基末端激酶(JNK)抑制剂SP600125对D-氨基葡萄糖衍生物(COPADG)诱导的Eca-109细胞Caspase-3激活及细胞凋亡的影响,并探讨COPADG诱导Eca-109细胞凋亡的潜在分子机制。方法:体外培养Eca-109细胞,以COPADG及SP600125与细胞作用,细胞间接免疫荧光染色观察P-JNK蛋白表达的改变,流式细胞术检测细胞凋亡率及Caspase-3活性的变化。结果:经SP600125处理后,COPADG诱导的Eca-109细胞P-JNK蛋白表达明显减弱,凋亡率明显减低,Caspase-3活性显著下调,与COPADG单作用组之间有显著性差异。结论:SP600125能够显著抑制COPADG诱导Eca-109细胞Caspase-3激活以及COPADG诱导Eca-109细胞凋亡,并间接证明JNK信号转导通路在COPADG诱导Eca-109细胞凋亡过程中发挥着重要作用。     

SP600125对D-氨基葡萄糖衍生物诱导Eca-109细胞凋亡的影响

目的:观察特异性JNK抑制剂[specificc-junNH2terminalproteinkinase(JNK)inhibitor]SP600125对D-氨基葡萄糖衍生物2-(3-羧基-1-丙酰氨基)-2-脱氧-D-葡萄糖{[2-(3-carboxy-1-oxopropyl)a-mino-2-deoxy-D-Glucose],COPADG}诱导Eca-109细胞凋亡的影响并探讨COPADG诱导Eca-109细胞凋亡的潜在分子机制。方法:体外培养Eca-109细胞,用COPADG及SP600125对细胞进行处理。细胞间接免疫荧光染色观察P-JNK蛋白表达的改变,倒置相差显微镜观察细胞形态学变化;MTT检测不同时间点的细胞活性;流式细胞术检测细胞凋亡率。结果:经SP600125处理后,COPADG诱导的Eca-109细胞P-JNK蛋白表达明显减弱,同时,COPADG诱导的Eca-109细胞凋亡率明显减低,细胞增殖抑制率下降明显,与COPADG单独作用组之间比较差异有统计学意义。结论:SP600125对D-氨基葡萄糖衍生物CO-PADG诱导Eca-109细胞凋亡具有抑制作用,并间接证明JNK信号转导通路在COPADG诱导Eca-109细胞凋亡过程中发挥着重要作用。     

Studies on the mechanism of arsenic trioxide-induced apoptosis in HepG<Subscript>2</Subscript> human hepatocellular carcinoma cells

OBJECTIVE To study the anti-tumor effect of arsenic trioxide on the HepG2 human hepatocellular carcinoma cell line, and to explore its mechanism of action. METHODS The MTT assay was used to determine the inhibitory effect of As2O3 on HepG2 cells at various As2O3 concentrations. The expression of p-JNK, caspase-3 and PARP was detected by Western blots. RESULTS As2O3 markedly inhibited the growth of the HepG2 cells and induced apoptosis. The results of Western blot analysis showed that the As2O3-induced apoptosis was accompanied by caspase-3 and PARP activation. p-JNK was detected at 10 min following As2O3 treatment, and preceded to peak at 20 min, and decreased by 30 min. The total protein content did not obviously change. The activation of JNK occurred prior to cell apoptosis. SP600125, a JNK inhibitor, suppressed the As2O3-induced activation of caspase-3 and PARP cleavage. CONCLUSION As2O3 inhibits the proliferation of human HepG2 hepatocellular carcinoma cells by inducing apoptosis in vitro. As2O3-induced apoptosis is accessed through the caspase-3 pathway. The JNK signal-transduction pathway and caspase-3 are involved upstream in the As2O3 induced HepG2 apoptotic response.     

As2O3联合L-OHP对HepG2肝癌细胞株的体外抑制作用

目的探讨As2O3联合L-OHP对HepG2肝癌细胞株的体外抑制作用。方法采用MTT法（四唑盐比色法）动态观察As2O3联合L-OHP对HepG2肝癌细胞的生长抑制作用,并采用两药相互作用系数（CDI）来评价两药相互作用的性质;应用流式细胞术（FCM）检测凋亡率和细胞周期分布。结果 As2O3与L-OHP联合应用,对HepG2肝癌细胞株的生长抑制、诱导凋亡作用均较相应的单药增强。流式细胞直方图上可见明显的＂凋亡峰＂,且As2O3使肝癌细胞周期阻滞于G2/M期,L-OHP使细胞周期阻滞于S期和G2/M期,两药合用使细胞周期阻滞于S期和G2/M期。结论中低浓度As2O3与L-OHP联合作用具有显著的协同效益,其主要机制可能是As2O3联合L-OHP诱导肝癌细胞凋亡作用及增强细胞周期阻滞作用。     

槐定碱通过JNK/MAPK信号通路介导前列腺癌PC3细胞的凋亡

目的:探究槐定碱对前列腺癌PC3细胞凋亡的影响,及其促进细胞凋亡可能的作用机制。方法:采用MTT法分析槐定碱对前列腺癌PC3细胞增殖的抑制作用;台盼蓝染色实验检测槐定碱对前列腺癌PC3细胞生长增殖的影响;Hoechst 33342染色法和流式细胞术检测槐定碱对前列腺癌PC3细胞凋亡的影响;Western blot检测槐定碱对前列腺癌PC3细胞凋亡相关蛋白Caspase-3、Bax、Bcl-2及凋亡信号通路蛋白p-JNK、p-p38、p-ERK表达的影响。结果:随着槐定碱浓度的升高,PC3细胞抑制率逐渐升高,作用呈剂量依赖性,细胞增殖受到明显抑制作用(P<0.05);槐定碱组的细胞凋亡率显著升高,Caspase-3、Bax促凋亡蛋白表达显著增高,而Bcl-2抑凋亡蛋白表达则显著降低(P<0.05);MAPK信号通路蛋白p-JNK表达显著升高(P<0.05),p-p38、p-ERK表达无显著性差异(P>0.05);JNK抑制剂SP600125逆转槐定碱对前列腺癌PC3细胞凋亡的促进作用(P<0.05);槐定碱能下调裸鼠瘤体体积、瘤体质量(P<0.05)。...     

醋酸甲地孕酮联合三氧化二砷对肝癌HepG2细胞株体外抑制作用的研究

目的 探讨醋酸甲地孕酮（MA）联合三氧化二砷（As2O3）对肝癌HepG2细胞株体外增殖的影响及其可能机制。方法 将对数生长期HepG2细胞分为4组：MA单药组、As2O3单药组、MA+As2O3联合组和对照组,根据前期研究结果确定药物剂量分别为75.0 μmol/L MA、1.0 μg/ml As2O3,对照组加入等量细胞培养液。24 h后采用CCK-8方法、流式细胞学检测及Western blotting检测MA单药组、As2O3单药组及MA+As2O3联合组对HepG2细胞增殖、细胞凋亡及X连锁凋亡抑制蛋白（XIAP）表达的影响。结果CCK-8法显示MA+As2O3组较MA或As2O3单药组均能够明显抑制HepG2细胞生长;流式细胞仪结果显示MA+As2O3联合组的细胞凋亡率高于MA或As2O3单药组。MA+As2O3作用后XIAP表达较MA或As2O3单药组降低。结论MA联合As2O3能够发挥对HepG2细胞协同抑制作用,其中诱导细胞凋亡可能是其机制之一。     

蛋白酶体抑制剂对肝癌HepG2细胞BAG3表达影响及其机制探讨

目的：探讨4种蛋白酶体抑制剂硼替佐米（bortezome,BZ）、环氧甲酮四肽（epoxomycin,Epox）、乳孢素（1actacystin,Lacta）和MG132单独作用或者联合JNK特异性抑制剂SP600125,对肝癌HepG2细胞内BAG3蛋白表达的影响及分子机制。方法：空白对照、100nmol／LBZ、100nmol／LEpox、500nmol／LLacta和2umol／LMG132单独或联合50μmol／LSP600125处理HepG2细胞;实时定量RT-PCR检测蛋白酶体抑制剂对肝癌HepG2细胞内BAG3基因mR—NA表达水平影响,蛋白质印迹法检测蛋白酶体抑制剂单独或者联合JNK激酶特异性抑制剂对BAG3蛋白表达水平的影响;利用MTT试剂盒检测蛋白酶体抑制剂细胞存活率,Hoechest33258染色检测细胞凋亡率。结果：蛋白酶体抑制剂BZ、Epox、Lacta和MG132均不同程度上调BAG3基因的mRNA和蛋白表达水平,而SP600125显著抑制蛋白酶体抑制剂引起的BAG3表达上调。MTT结果显示,SP600125显著抑制HepG2细胞对蛋白酶体抑制剂的敏感性;进一步Hoechst33258染色结果显示,4种蛋白酶体抑制剂联合SP600125作用引起HepG2细胞的凋亡率分别为（49．2±3．2）％、（58．7±3．5）％、（56．8±3．4）％和（53．4±3．3）％,明显高于蛋白酶体抑制剂单独作用组的（7．2±2．8）％、（16．7±3．2）％、（12．3±2．9）％和（11．4±3．0）％,P〈0．05。结论：蛋白酶体抑制剂通过JNK信号通路上调BAG3的表达,抑制JNK活性增加了HepG2细胞对蛋白酶体抑制剂的敏感性。     

敲除人乳腺癌MCF-7细胞中PTEN基因对JNK通路活性的影响

背景与目的:PTEN与多种肿瘤发生发展密切相关,大量研究表明PTEN基因通过直接或间接作用整合复杂的信号网络系统,并影响靶分子及其下游信号级联反应.本研究探讨敲除MCF-7细胞中PTEN基因对JNK通路活性的影响.方法:PTEN反义寡核苷酸转染后,激光共聚焦显微镜检测MCF-7细胞内PTEN蛋白表达:流式细胞术、四甲基偶氮唑蓝(MTT)及Western blot法分别检测SP600125诱导的细胞早期凋亡和细胞周期改变、细胞增殖抑制、细胞中JNK及其下游底物ATF-2、C-Jun的磷酸化水平.结果:FTEN反义寡核苷酸有效封闭MCF-7细胞中PTEN蛋白表达:SP600125(10 μmol/L)诱导已敲除PTEN的MCF-7细胞发生早期凋亡.凋亡率达(32.4±2.4)%,细胞发生G1期阻滞、细胞增殖明显受抑制,与SP600125组、反义组细胞相比差异有显著性(P<0.05);反义+SP600125组MCF-7细胞中磷酸化JNK及其下游底物ATF-2及C-Jun磷酸化水平下调.结论:MCF-7细胞中JNK通路激活与PTEN表达水平相关,PTEN缺失使MCF-7细胞中JNK通路活化,细胞对JNK相关抑制剂的敏感性增加.     

JNK/FOXO3信号通路介导黄连素促人肺腺癌PC-9细胞凋亡的研究

  目的  探讨黄连素（berberine,Ber）诱导肺腺癌PC-9细胞凋亡及c-Jun氨基末端激酶（c-Jun N-terminal kinase,JNK）/转录因子叉头蛋白3（forkhead box protein O3,FOXO3）信号通路的作用机制。  方法  实验采用完全随机化的分组方法,分为对照组、Ber组（30、60 μM）,分别检测各组PC-9细胞活力值、凋亡率、ROS含量、caspase 3活性、线粒体膜电位,以及JNK/FOXO3通路和凋亡相关蛋白含量的变化。SP600125特异性抑制JNK（磷酸化）激活后,Ber（0、60 μM）处理细胞24 h,重复上述检测。  结果  Ber有效抑制PC-9细胞活力,促进细胞凋亡（P < 0.05）,显著降低PC-9细胞线粒体膜电位,增加ROS含量和caspase 3活性（P < 0.05）,并呈浓度依赖效应;Western blot检测结果显示Ber上调p-JNK、FOXO3和Bax的含量（P < 0.05）,下调p-FOXO3和Bcl-2的含量（P < 0.05）;SP600125特异性抑制JNK激活后,拮抗Ber下调p-FOXO3含量及其促PC-9细胞凋亡作用（P < 0.05）。  结论  Ber可有效抑制肺腺癌PC-9细胞活力、促进细胞凋亡和氧化应激损伤,作用机制可能与上调p-JNK、FOXO3含量和抑制FOXO3磷酸化有关。      

Arsenic trioxide induces apoptosis in human gastric cancer cells through up-regulation of p53 and activation of caspase-3

Arsenic trioxide (As(2)O(3)) can induce clinical remission in patients suffering from acute promyelocytic leukemia, through induction of apoptosis and activation of caspases. We investigated the potential use of As(2)O(3) in human gastric cancer and its possible mechanisms. Human gastric cancer cell lines AGS and MKN-28 were treated with various concentrations (0.1 to 100 microM) of As(2)O(3) for 24 to 72 hr. Apoptosis was determined by acridine orange staining, flow cytometry and DNA fragmentation. Protein levels of p53, p21(waf1/cip1), c-myc, bcl-2 and bax were detected by Western blotting. Effects of As(2)O(3) on caspase-3 protease activity, its protein concentration and cleavage of poly(ADP)-ribose polymerase (PARP) were also studied. As(2)O(3) inhibited cell growth and induced apoptosis in both cell lines, though AGS cells were more sensitive. As(2)O(3) induced apoptosis in AGS cells in a concentration- and time-dependent manner. Treatment resulted in a marked increase in p53 protein levels as early as 4 hr. Co-incubation with p53 anti-sense oligo-nucleotide suppressed As(2)O(3)-induced intracellular p53 over-expression and apoptosis. As(2)O(3) increased the activity of caspase-3, with appearance of its 17 kDa peptide fragment, and cleavage of PARP, with appearance of the 85 kDa cleavage product, both in parallel with the induction of apoptosis. Both the tripeptide caspase inhibitor zVAD-fmk and the specific caspase-3 inhibitor DEVD-fmk partially suppressed As(2)O(3)-induced caspase-3 activation and apoptosis. As(2)O(3) inhibits cell growth and induces apoptosis in gastric cancer cells, involving p53 over-expression and activation of caspase-3. The potential use of this compound in the treatment of gastric cancer is worth further investigation.     

Buthionine sulfoximine enhancement of arsenic trioxide-induced apoptosis in leukemia and lymphoma cells is mediated via activation of c-Jun NH2-terminal kinase and up-regulation of death receptors

The mechanism of apoptosis induced by treatment with As(2)O(3) alone or in combination with buthionine sulfoximine (BSO) was studied in NB4, U937, Namalwa, and Jurkat cells. As(2)O(3) at concentrations <2 micromol/L induced apoptosis in NB4 cells and Namalwa cells but not in U937 and Jurkat cells. As(2)O(3)-induced apoptosis in NB4 cells and Namalwa cells correlated with increase of H(2)O(2) and caspase activation without activation of c-Jun NH(2)-terminal kinase (JNK). BSO (10 micromol/L) depleted the reduced form of intracellular glutathione without inducing apoptosis but synergized with 1 micromol/L As(2)O(3) to induce apoptosis in all four cell lines. This synergy correlated with JNK activation. Treatment with As(2)O(3) plus BSO, but not with As(2)O(3) alone, increased the levels of death receptor (DR) 5 protein and caspase-8 cleavage. The JNK inhibitor SP600125 inhibited the increase in DR5 protein and attenuated apoptosis induced by treatment with As(2)O(3) plus BSO. These observations suggest that a DR-mediated pathway activated by JNK is involved in apoptosis induced by treatment with As(2)O(3) plus BSO.     

Platycodin D,a triterpenoid saponin from Platycodon grandiflorum,induces G2/M arrest and apoptosis in human hepatoma HepG2 cells by modulating the PI3K/Akt pathway

Platycodin D (PD) is one of triterpenoid saponins isolated from the roots of Platycodon grandiflorum. In the present study, we aimed at examining the antitumor activity of PD against human hepatoma HepG2 cancer cells and investigated the underlying molecular mechanisms of PD-induced apoptosis in HepG2 cells. PD significantly inhibited the proliferation of HepG2 cells in a concentration- and time-dependent manner as assessed by MTT assay. Besides, flow cytometry revealed that PD treatment obviously induced G2/M arrest and apoptosis in HepG2 cells. Moreover, Western blot analysis demonstrated that PD induced downregulation of protein expression of PI3K, P-Akt, and Bcl-2, whereas cleaved products of caspase-3 and ?9 and PARP were upregulated by PD treatment. Furthermore, the protein level of P-p38, p-38, and Bax in PD-treated HepG2 cells was kept unchanged. In addition, the inhibitors of z-DEVD-fmk (a specific caspase-3 inhibitor) and z-LEHD-fmk (a specific caspase-9 inhibitor), but not z-IETD-fmk (a specific caspase-8 inhibitor), could significantly block PD-triggered apoptosis, whereas LY294002 (Akt inhibitor) could significantly enhance PD-induced apoptosis in HepG2 cells. Thus, the increasing ratio of Bax to Bcl-2, activation of caspase-3 and ?9 and PARP, and inactivation of the PI3K/Akt signaling pathway significantly enhanced PD-induced apoptosis in HepG2 cells. Our results suggest that PD induced cell cycle G2/M arrest and apoptosis in HepG2 cells by decreasing PI3K/Akt pathway. Therefore, we propose that PD has potential as a liver cancer chemotherapeutic agent.     

YM155对肝癌HepG2细胞增殖和凋亡的影响

目的:探讨YM155对肝癌HepG2细胞增殖和凋亡的影响及可能的机制。方法:采用CCK-8法检测细胞生长抑制率；应用流式细胞仪检测细胞凋亡率的变化；Western blot法检测细胞中蛋白表达的变化，实时定量RT-PCR检测survivin mRNA表达的变化。结果:YM155对人肝癌HepG2细胞的生长抑制作用呈现剂量和时间依赖性。流式细胞术结果显示，HepG2细胞凋亡率明显升高,呈现剂量依赖性。YM155可引起survivin mRNA及蛋白表达下降，而caspase-3、caspase-9和PARP蛋白表达上升。结论:YM155可以抑制人肝癌HepG2细胞的增殖并促进其凋亡，其机制可能是通过激活caspase凋亡途径来实现。     

Arsenic trioxide induces regulated, death receptor-independent cell death through a Bcl-2-controlled pathway

Arsenic trioxide (As2O3, arsenite) efficiently kills cells from various hematologic malignancies and has successfully been employed especially for the treatment of acute promyelocytic leukemia. There and in lymphoid cells, we demonstrated that As2O3 induces cell death in a caspase-2- and -9-independent fashion. Here, we address a potential role of death receptor signaling through the FADD/caspase-8 death-inducing signaling complex in As2O3-induced cell death. In detail, we demonstrate that As2O3 induces cell death independently of caspase-8 or FADD and cannot be blocked by disruption of CD95/Fas receptor ligand interaction. Unlike in death receptor ligation-induced apoptosis, As2O3-induced cell death was not blocked by the broad-spectrum caspase inhibitor z-VAD-fmk or the caspase-8-specific inhibitor z-IETD-fmk. Nevertheless, As2O3-induced cell death occurred in a regulated manner and was abrogated upon Bcl-2 overexpression. In contrast, As2O3-induced cell demise was neither blocked by the caspase-9 inhibitor z-LEHD-fmk nor substantially inhibited through the expression of a dominant negative caspase-9 mutant. Altogether our data demonstrate that As2O3-induced cell death occurs independently of the extrinsic death receptor pathway of apoptosis. Cell death proceeds entirely via an intrinsic, Bcl-2-controlled mitochondrial pathway that does, however, not rely on caspase-9.     

Tumor growth inhibition by arsenic trioxide (As2O3) in the orthotopic metastasis model of androgen-independent prostate cancer.

Arsenic trioxide (As2O3) induces clinical remission of patients with acute promyelocytic leukemia. As a novel anticancer agent for treatment of solid cancers, As2O3 is promising, but no in vivo experimental investigations of its efficacy on solid cancers have been done at clinically obtained concentrations. In addition, the cell death mechanism of As2O3 has yet to be clarified, especially in solid cancers. In this study, human androgen-independent prostate cancer cell lines, PC-3, DU-145, and TSU-PR1 were examined as cellular models for As2O3 treatment, and As2O3-induced cell death and inhibition of cell growth and colony formation were evaluated. The involvement of p38, c-Jun NH2-terminal kinase (JNK), caspase-3, and reactive oxygen species (ROS) were investigated in As2O3-induced cell death. Finally, As2O3 was administered to severe combined immunodeficient mice inoculated orthotopically with PC-3 cells to estimate in vivo efficacy. In all three of the cell lines, at high concentrations, As2O3 induced apoptosis and, at low concentrations, growth inhibition. As2O3 activated p38, JNK, and caspase-3 dose dependently. Treatment with the p38 inhibitor and over-expression of dominant-negative JNK did not guard against As2O3-induced cell death. In contrast with partial protection by the caspase-3 inhibitor, the antioxidant N-acetyl-L-cysteine gave marked protection from As2O3-induced apoptosis and eliminated the activation of p38, JNK, and caspase-3, and the generation of ROS. The orthotopic murine metastasis model showed in vivo tumor growth inhibition in orthotopic and metastatic lesions with no signs of toxicity. This study establishes that As2O3 provides a novel, safe approach for treatment of androgen-independent prostate cancer. Generation of ROS as a therapeutic target for the potentiation of As2O3-induced apoptosis also was shown.     

Therapeutic effect of arsenic trioxide (As2O3) on cervical cancer in vitro and in vivo through apoptosis induction

Arsenic trioxide (As2O3) induces apoptosis in certain types of cancer cells. But the detailed mechanisms of As2O3 efficacy are not completely known. Here we demonstrate that As2O3 has a therapeutic effect on cervical cancer in vitro and in vivo. We investigated the As2O3-induced apoptosis in various cervical cancer cells. The apoptosis was triggered by mitochondrial pathway and associated with dissociation of Bcl-2 from Bax and VDAC, then the release of cytochrome c from Bax and VDAC channel, resulting in the activation of caspase-9 and caspase-3. The overexpression of Bcl-2 counteracted the As2O3-mediated apoptosis. The As2O3 treatment also resulted in an increased M phase cell cycle distribution by inducing microtubule polymerization. Two independent death-signaling pathways in cervical cancer cells were activated, one dominated by JNK/p38/GADD45 and one by p53 signals. Further investigation involving assessment of As2O3 on tumor cell growth in mice indicated that As203 also inhibited in vivo tumor growth. As2O3 as an inhibitor of cervical cancer proliferation both in vitro and in vivo suggests a potential clinical application in cervical cancer therapies.     

Potential role of caspase-3 and -9 in arsenic trioxide-mediated apoptosis in PCI-1 head and neck cancer cells

Arsenic trioxide (As2O3) has been shown to inhibit the proliferation of hematologic malignant cells. Previously, we reported that As2O3 had an antitumoral effect in head and neck cancer. Here, we investigated the induction of apoptosis and its mechanism in PCI-1 head and neck squamous carcinoma cells, after treatment with As2O3. Treatment with 2 microM of As2O3 caused apoptosis in PCI-1 cells following 3 days of exposure, which was detected by the annexin V-PI and DAPI staining methods. The cell death population was markedly increased, being 88% larger than the As2O3-untreated control cells. To address the mechanism of apoptosis, a Western blot assay was performed, showing that Bax was up-regulated without a change in Bcl-2. Activation of caspase-9 during As2O3-induced apoptosis was substantiated by monitoring the proteolysis of the caspase-9, which was associated with an increase of Apaf-1 and cytochrome c protein. PCI-1 cells rapidly changed the mitochondria membrane potential (DeltaPsim) after addition of As2O3. Furthermore, activation of caspase-3 was demonstrated by monitoring the proteolysis of the caspase-3 and by measuring caspase-3 activity with a fluorogenic substrate, which was associated with the cleavage of poly(ADP-ribose) polymerase. To examine the in vivo effect of As2O3, C3H mouse inoculated with syngenic SCC7 cells was treated by intratumoral injection of As2O3 (300 microg) every day, demonstrating that tumor mass was dramatically reduced on day 4, and revealed induction of apoptosis by TUNEL assay. These results suggest that apoptosis of PCI-1 cells by As2O3 is induced by activation of caspase-3 via cytochrome c, caspase-9 and Apaf-1 complex.     

TSA对肺腺癌细胞株A549细胞凋亡的影响

目的：探讨组蛋白脱乙酰化酶抑制剂曲古抑菌素A（trichostatin A，TSA）对A549肺腺癌细胞凋亡的影响。方法：Annexin V和Hoechst染色法检测细胞凋亡；流式细胞仪分析细胞周期；Western blot检测凋亡信号通路中caspas-8、caspase-9活化及多聚ADP核糖聚合酶（PARP）裂解情况。结果：TSA可诱导细胞凋亡，主要使细胞积聚在G2／M期，且呈浓度依赖性。Western blot检测表明TSA诱导了A549肺腺癌细胞caspase-8、caspase-9裂解活化及PARP裂解，且随TSA作用时间延长而逐步升高。结论：TSA诱导A549细胞凋亡中caspase-8、caspase-9介导caspas-3的活化，TSA通过caspase级联反应诱导A549细胞凋亡。