首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 29 毫秒
1.
Cardiotoxin (CTX) III, a basic polypeptide with 60 amino acid residues isolated from Naja naja atra venom, has been reported to have anticancer activity. In the present study, we investigated the mechanisms underlying the anticancer activity of CTX III in human leukaemia (HL-60 cells). Cardiotoxin III activated the endoplasmic reticulum (ER) pathway of apoptosis in HL-60 cells, as indicated by increased levels of calcium and glucose-related protein 78 (Grp78), and triggered the subsequent activation of micro-calpain and caspase 12. In addition, CTX III initiated the mitochondrial apoptotic pathway in HL-60 cells, as evidenced by an increased Bax/Bcl-2 ratio, the release of cytochrome c and activation of caspase 9. In the presence of 50 micromol/L Z-ATAD-FMK (a caspase 12 inhibitor) and 100 micromol/L Z-LEHD-FMK (a caspase 9 inhibitor), the CTX III-mediated activation of caspase 9 and caspase 3 was significantly reduced. There was no significant effect of the caspase 12 inhibitor Z-ATAD-FMK on mitochondrial cytochrome c release. Cardiotoxin III-mediated activation of caspase 12 was not abrogated in the presence of the caspase 9 inhibitor Z-LEHD-FMK, indicating that caspase 12 activation was not downstream of caspase 9. These results indicate that CTX III induces cell apoptosis via both ER stress and a mitochondrial death pathway.  相似文献   

2.
1. Cardiotoxin (CTX) III is a basic polypeptide with 60 amino acid residues isolated from Naja naja atra venom. This is the first report on the mechanism of the anticancer effect of CTX III on human leukaemia K562 cells. 2. Cardiotoxin III was found to inhibit the growth of K562 cells in a time- and dose-dependent manner, with an IC(50) value of 1.7 mug/mL, and displayed several features of apoptosis, including apoptotic body formation, an increase in the sub-G(1) population, DNA fragmentation and poly (ADP-ribose) polymerase (PARP) cleavage. 3. Investigation of the mechanism of CTX III-induced apoptosis revealed that treatment of K562 cells with CTX III resulted in the loss of mitochondrial membrane potential, cytochrome c release from mitochondria into the cytosol and activation of caspase-9 and caspase-3 and the subsequent cleavage of the caspase-3 substrate PARP; however, CTX III did not generate reactive oxygen species (ROS). 4. Taken together, the results indicate that CTX III induces apoptosis in K562 cells through an ROS-independent mitochondrial dysfunction pathway.  相似文献   

3.
Cardiotoxin III (CTX III), a basic polypeptide with 60 amino acid residues isolated from Naja naja atra venom, has been reported to have anticancer activity. Exposure of MDA-MB-231 cells with 0.03, 0.09, and 0.15 μM of CTX III for 18 h, CTX III-induced cell apoptosis, as evidenced by accumulation of sub-G1 population, externalization of phosphatidylserine, loss of mitochondrial membrane potential (ΔΨm) with subsequent release of cytochrome c, and activation of both capases-9 and caspase-3. This correlated with up-regulation in Bax and Bad, and down-regulation of various anti-apoptotic proteins, including Bcl-2, Bcl-XL, and survivin in CTX III-treated cells. Mechanistic studies showed that CTX III suppressed the phosphorylation of JAK2, STAT3, Akt, and activation of PI3K. Moreover, the PI3K inhibitor wortmannin blocked activation of STAT3 and Akt without affecting the JAK2 activation, whereas JAK2 inhibitor AG490 suppressed the levels of phospho-STAT3, phospho-Akt, and PI3K, suggesting that PI3K activation occurs after JAK2 phosphorylation, and both PI3K and JAK2 kinases cooperate to mediate STAT3 and Akt phosphorylation. Both AG490 and wortmannin also led to up-regulation in Bax and Bad, and down-regulation of Bcl-2, Bcl-XL, and survivin in MDA-MB-231 cells. Taken together, these results indicate that CTX III induces apoptosis in MDA-MB-231 cells via concomitant inactivation of the JAK2, STAT3, PI3K, and Akt signaling pathways.  相似文献   

4.
Cardiotoxin III (CTX III), a basic polypeptide with 60-amino acid residues isolated from Naja naja atra venom, has been reported to have cytotoxic activity. CTX III exerted cytotoxicity with the S-phase cell cycle arrest, correlated with a marked decrease in the expression levels of cyclin A, cyclin B, and cyclin-dependent kinase 1 (CDK1), and apoptosis, accompanied with Bax and Bad up-regulation, and the down-regulation of Bcl-2, p-Bad, and X-linked inhibitor of apoptosis (XIAP) with cytochrome c release and sequential activation of caspase-9 and caspase-3 in Ca9-22 cells. Mechanistic studies showed that CTX III suppressed the phosphorylation of Src, EGFR, STAT3, STAT5, Akt, and activation of PI3 K (p110). Moreover, Src inactivation was observed earlier than that of the EGFR and the Src inhibitor PP2 suppressed the levels of phospho-EGFR, phospho-STAT3, phospho-STAT5, phospho-Akt, and PI3 K(p110). The PP2 also caused the S-phase arrest and apoptosis, and led to down-regulation of Bcl-2, p-Bad, XIAP, cyclin A, cyclin B, and CDK1, and up-regulation of Bax and Bad, similar to that observed in CTX III treatment. Taken together, these results indicate that CTX III induces apoptosis and S-phase arrest in Ca9-22 cells via concomitant inactivation of the Src, EGFR, STAT3, STAT5, PI3 K(p110), and Akt signaling pathways.  相似文献   

5.
AIM: To investigate the effect of astilbic acid (3β, 6β-dihydroxyolean-12-en-27-oic acid, AA) on human colorectal carcinoma COLO 205 cell proliferation and apoptosis. METHODS: Proliferation of COLO 205 cells was measued by MTT assay. Content of DNA in COLO 205 cell was measued by modified diphenylamine assay. AA-induced morphological changes was observed with fluorescence microscope and transmission electron microscope. DNA fragmentation was visualized by agarose gel electrophoresis. Apoptosis rate and cell cycle distribution were determined by flow cytometric analysis. Expressions of Bcl-2 and Bax proteins were visioned by immunohistochemical analysis. The change of relative mitochondral transmembrane potential (MTP) in COLO 205 cell was analyzed with FCM after rhodamine 123 staining. RESULTS: The IC50 (96 h) of AA for inhibiting COLO 205 cell proliferation was 61.56 0.34 μmol/L. AA induced a marked concentration- and time-dependent inhibition of COLO 205 cell proliferation and reduced the DNA content in COLO 205 cell. Cells treated with AA 64 μmol/L showed typical morphological changes of apoptosis and DNA “ladder“ pattern. The cell cycle was arrested in G0/G1 phase, and the apoptosis rate was 28.25 % for COLO 205 cells treated with AA 64 μmol/L for 48 h. Meanwhile the expression of Bcl-2 protein was decreased while that of Bax was increased and relative MTP was decreased as well. DEVD-CHO1 μmol/L could increase the viability of COLO 205 cells treated with AA for 48 h. CONCLUSION: AA showed potent inhibitory activity on COLO 205 cells proliferation, and could induce COLO 205 cells apoptosis through disturbing DNA replication, down-regulating Bcl-2 expression, and up-regulating Bax expression, lowering relative MTP, and activating caspase-3 pathway.  相似文献   

6.
Cardiotoxin III (CTX III), a basic polypeptide with 60 amino acid residues isolated from Naja naja atra venom, has been reported to have anticancer activity. CTX III inhibited the growth of T24 cells in a time‐ and dose‐dependent manner with an IC50value of 1.7 µg/mL and displayed several features of apoptosis including apoptotic body formation, increase of sub G1 population, DNA fragmentation, and poly (ADP‐ribose) polymerase (PARP) cleavage. Using apoptosis analysis, measurement of reactive oxygen species (ROS) and assessment of mitochondrial membrane potentials (ΔΨm), CTX III was found to be a potent inducer of apoptosis, transducing apoptotic signals via a decrease in mitochondrial membrane potential (ΔΨm) and release of cytochrome c from mitochondria into cytosol. However, CTX III did not generate reactive oxygen species (ROS). Taken together, the present data indicate that CTX III induces apoptosis in T24 cells through an ROS‐independent mitochondrial dysfunction pathway and resultant cytochrome c release. This is the first report on the mechanism of the anticancer effect of CTX III on T24 cells. Drug Dev. Res. 63:219–224, 2004. © 2004 Wiley‐Liss, Inc.  相似文献   

7.
It has been reported that sorbitol induces apoptosis in several cancer cell lines. However, the molecular mechanism underlying the sorbitol-induced apoptotic process is not yet clearly understood. In the present study, the intracellular signaling pathways of sorbitol-induced apoptosis in human K562 cells were investigated using both morphological analysis and DNA fragmentation technique. In this study, we demonstrated that sorbitol-induced apoptosis in human K562 cells is a concentration- and time-dependent manner. This sorbitol-induced apoptosis in human K562 cells was also accompanied by the up-regulation of Bax, and down-regulation of p-Bcl-2, but no effect on the levels of Bcl-X(L). Moreover, the sorbitol treatment resulted in a significant reduction of mitochondria membrane potential, increase in the release of mitochondrial cytochrome c (cyt c), and activation of caspase 3. Furthermore, treatment with caspase 3 inhibitor (z-DEVD-fmk) was capable of preventing the sorbitol-induced caspase 3 activity and cell death. These results clearly demonstrate that the induction of apoptosis by sorbitol involves multiple cellular/molecular pathways and strongly suggest that pro- and anti-apoptotic Bcl-2 family proteins, mitochondrial membrane potential, mitochondrial cyt c, and caspase 3, they all participate in sorbitol-induced apoptotic process in human K562 cells.  相似文献   

8.
Cardiotoxin III (CTX III), a basic polypeptide with 60 amino acid residues isolated from Naja naja atra venom, may have a potentiality as a structural template for rational drug design in killing cancer cells. Treatment of K562 cells with 0.3 microM of CTX III resulted in G2/M phase cell cycle arrest that was associated with a marked decline in protein levels of G2/M regulatory proteins including cyclin A, cyclin B1, Cdk2 and Cdc25C. In contrast to no effect on the phosphorylation of ERK, p38 MAPK and Akt, an activation of JNK was noted when K562 cells were exposed to CTX III. CTX III-mediated G2/M phase arrest and apoptosis were reduced by treatment with the JNK-specific inhibitor SP600125, but not by ERK and p38MAPK inhibitors. Further investigation showed that the specific JNK inhibitor, SP600125, reduced the activation of caspase-3, caspase-9, and reversed the decline in the expression of cyclin B1. Taken together, our data show for the first time that JNK, but not ERK, p38MAPK or Akt signaling, plays an important role in CTX III-mediated G2/M arrest and apoptosis in K562 cancer cells.  相似文献   

9.
10.
We investigated the mechanism by which 4-hydroxynonenal (HNE), a major aldehydic product of lipid peroxidation, induces apoptosis in tumor cells. Treatment of human colorectal carcinoma (RKO) cells with HNE-induced poly-ADP-ribose-polymerase (PARP) cleavage and DNA fragmentation in a dose- and time-dependent manner. The induction of PARP cleavage and DNA fragmentation paralleled caspase-2, -3, -8, and -9 activation. Pretreatment of cells with an inhibitor of caspase-3, z-DEVD-fmk, or a broad spectrum caspase inhibitor, z-VAD-fmk, abolished caspase activation and subsequent PARP cleavage. Constitutive expression of high levels of Bcl-2 protected cells from HNE-mediated apoptosis. In addition, Bcl-2 overexpression inhibited cytochrome c release from mitochondria and subsequent caspase-2, -3, and -9 activation. These findings demonstrate that HNE triggers apoptotic cell death through a mitochondrion-dependent pathway involving cytochrome c release and caspase activation. Bcl-2 overexpression protected cells from HNE-induced apoptosis through inhibition of cytochrome c release.  相似文献   

11.
Garlic (Allium sativum) is a popular spice, a remedy for a variety of ailments and is also known for its medicinal uses as an antibiotic, antithrombotic and antineoplastic agent. Epidemiological and animal studies have shown that garlic consumption reduces the incidence of cancer e.g. in the stomach, colon, breast and cervix. The aim of this study was to investigate whether garlic extract has any influence on caspase-3 activity and gene expression and on the signal induction of apoptosis in vitro. As an assay system, the flow cytometry assay, Western blotting and cDNA microarray were applied in human colon cancer colo 205 cells. Our results indicated that garlic extract, when administered to the colo 205 cell cultures, reduced the percetange of viable cells, induced apoptosis, increased the levels of Bax, cytochrome c and caspase-3, but decreased the level of Bcl-2. The results also showed that raw extract of garlic decreased the mitochondrial membrane potential and increased the caspase-3 activity and gene expression. We conclude that crude extract of garlic can induce apoptosis in colo 205 cells through caspase -3 activity, by means of a mitochondrial-dependent mechanism.  相似文献   

12.
2,3,5-tris(Glutathion-S-yl)hydroquinone (TGHQ), a metabolite of benzene, induces apoptosis in human promyelocytic leukemia (HL-60) cells. However, the mechanisms by which TGHQ induces apoptosis are unclear, and they were the focus of the present investigation. TGHQ stimulated the rapid formation (30 min) of reactive oxygen species (ROS) in HL-60 cells, and co-treatment with catalase or the antioxidant N-acetylcysteine (NAC) completely blocked TGHQ-induced apoptosis, implicating a causative role for ROS in HL-60 cell death. Western blot analysis revealed the complete disappearance of pro-caspase 9 between 1 and 2 hours after exposure of HL-60 cells to TGHQ, concomitant with the appearance of cleaved caspase 9 and increases in caspase 9 activity. The appearance of two cleaved forms of caspase 3 occurred subsequent to increases in caspase 9 activity. Levels of the anti-apoptotic Bcl-2 protein remained constant during TGHQ-induced apoptosis of HL-60 cells, but Bcl-2 S70 phosphorylation decreased. In contrast, changes in the subcellular localization of the pro-apoptotic molecule Bax were observed, with a rapid (15-60 min) increase in the ratio of cytosolic to mitochondrial Bax. Cytochrome c release from mitochondria to the cytosol occurred after Bax translocation and the dephosphorylation of pS70 Bcl-2. However the mitochondrial inner transmembrane potential (deltapsi(m)) was maintained, even after cytochrome c was released from the mitochondria. Cyclosporin A, an inhibitor of the mitochondrial membrane permeability transition pore (PTP), did not completely rescue HL-60 cells from apoptosis. Taken together, we conclude that TGHQ facilitates ROS production, alters the post-translational modification of Bcl-2 and subcellular localization of Bax, culminating in the release of cytochrome c and caspase activation.  相似文献   

13.
目的 观察胡椒碱对人胰腺癌PANC-1细胞增殖、凋亡的影响,探讨其诱导凋亡的Caspase 3/Bax/Bcl-2信号通路机制。方法 将人胰腺癌PANC-1细胞分为阴性对照组和40,20,10 μmol·L-1胡椒碱组,采用MTT、台盼蓝染色计数及平板克隆形成试验法检测胡椒碱对PANC-1细胞增殖、生长曲线及克隆形成的影响;采用Hoechst 33258染色法观察胡椒碱对PANC-1细胞凋亡形态学的影响;采用RT-PCR和Western blotting法检测胡椒碱对PANC-1细胞Caspase 3、cleaved-Caspase 3、Bax及Bcl-2 mRNA及蛋白表达的影响。结果 MTT、台盼蓝染色计数和平板克隆形成实验结果显示40,20 μmol·L-1胡椒碱可明显抑制PANC-1增殖、细胞生长曲线和克隆形成;Hoechst 33258染色实验显示40,20,10 μmol·L-1胡椒碱有诱导PANC-1细胞凋亡作用;RT-PCR和Western blotting实验结果显示40,20 μmol·L-1胡椒碱可上调PANC-1细胞Caspase 3、Bax mRNA表达水平,上调cleaved-Caspase 3和Bax蛋白表达水平,下调Bcl-2 mRNA和蛋白表达水平。结论 胡椒碱可抑制人胰腺癌PANC-1细胞生长、增殖,并诱导其凋亡,其机制可能与调控Caspase 3/Bax/Bcl-2凋亡信号通路有关。  相似文献   

14.
Meclizine (MEC), a histamine H1 antagonist, is used for the treatment of motion sickness and vertigo. In this study, we demonstrate that MEC dose-dependently induced apoptosis in human colon cancer cell lines (COLO 205 and HT 29 cells). Results of a DNA ladder assay revealed that DNA ladders appeared with MEC treatment in COLO 205 cells at dosage of >50 microM. In addition, the total cell number decreased dose-dependently after treatment with MEC in COLO 205 and HT 29 cells. Using flow cytometry, the percentage of COLO 205 cells arrested at G0/G1 phase increased dose-dependently. Analysis of changes in cell-cycle arrest-associated proteins with Western blotting showed that p53 and p21 were upregulated after treatment with MEC. The kinase activities of cyclin-dependent kinase 2 (CDK2) and CDK4 were suppressed in MEC-treated cells. As for apoptosis, MEC may induce upregulation of p53 and downregulation of Bcl-2, thus causing the release of cytochrome C from mitochondria and the translocation of apoptosis-inducing factor (AIF) to the nucleus. This resulted in the activation of caspase 3, 8, and 9. Our results provide the molecular basis of MEC-induced apoptosis and cell-cycle arrest in human colon cancer cells.  相似文献   

15.
Nanoscale hydroxyapatite (nano-HAP) has been reported to exhibit anti-cancer effect on several human cancers, but the molecular mechanism of which remains unclear. The aim of this study was to explore the mechanisms by investigating the effects of nano-HAP on human gastric cancer SGC-7901 cells. Our results showed that nano-HAP significantly reduced cell viability, and induced apoptosis in SGC-7901 cells characterized by hypodiploid DNA contents, morphological changes and DNA fragmentation. The increase in apoptosis was accompanied with the increased expression of Bax, a pro-apoptotic protein, and decreased expression of Bcl-2, an anti-apoptotic protein, the decrease of mitochondrial membrane potential and the release of cytochrome c from mitochondria into cytosol. Furthermore, the activation of caspases-3, and -9, but not activation of caspases-8 was induced by nano-HAP. Z-VAD-fmk, a universal caspase inhibitor, dose-dependently inhibited nano-HAP-induced apoptosis. This study demonstrates that nano-HAP inhibits the proliferation of SGC-7901 cells by inducing apoptosis, and the apoptotic pathway of nano-HAP-induced apoptosis is mediated through the mitochondrial-dependent and caspase-dependent pathway.  相似文献   

16.
目的 研究三氧化二砷(As2O3)对人大肠癌细胞株LoVo中的生长及三氧化二砷对Bcl-2、Bax表达的影响.方法 采用不同浓度的As2O3处理LoVo细胞,MTT法测定细胞的生长抑制效应;免疫细胞化学法检测人结肠癌细胞LoVo中Bcl-2、Bax的表达.结果 MTT结果示As2O3对大肠癌LoVo细胞的生长有抑制作用,且有时间-剂量依赖性(P<0.05或P<0.01);免疫细胞化学法结果示As2O3可使LoVo细胞中Bcl-2表达下降,Bax表达升高(P<0.01).结论 三氧化二砷对大肠癌细胞生长有抑制作用,且呈时间、剂量依赖性;其机制可能与改变Bcl-2和Bax的表达水平有关.  相似文献   

17.
Although isothiocyanates have been shown to inhibit carcinogen-induced tumorigenesis, no studies have been made to determine their therapeutic potential for the treatment of breast cancer. In the present study, we evaluated the apoptotic activities of phenethyl isothiocyanate (PEITC) in human breast cancer MCF-7 cells. Exposure to PEITC potently reduced cell viability. In addition, DNA fragments and TUNEL positive nuclei were detected in PEITC-treated cells. Furthermore, PEITC induced apoptosis via activation of caspases 7 and 9 and the cleavage of PARP, and these effects were reversed by treatment with the caspase inhibitor, Z-VAD-fmk. PEITC also caused a decrease in the levels of Bcl-2 with a concomitant increase in Bax levels, which resulted in the release of cytochrome c. XIAP suppression and Smac translocation also contributed to the PEITC-induced apoptosis. However, PEITC did not increase the expressions of p53 and p21. Taken together, the results of this study demonstrate that PEITC significantly induces apoptosis via a mitochondrial pathway. Specifically, PEITC induced a change in the Bax/Bcl-2 ratios, XIAP levels and Smac translocation that was conjunction with the release of cytochrome c and following caspase activation. Therefore, PEITC has the potential for use as a therapeutic agent for the treatment of breast cancer.  相似文献   

18.
SC-1, the aqueous phase of soybean fermentation products by bacteria (Bacillus subtilis and Bacillus brevis), significantly inhibited the growth and clonogenesity of human hepatocellular (Hep 3B), mouse hepatocellular (ML-1), and human colorectal (HCT 116 and HT-29) carcinoma cells. Cytotoxicity of SC-1 in Hep 3B cells was through the process of apoptosis characterizing by increase in cell population of sub-G(1) phase, fragmentation of DNA, and change of nuclear morphology. Treatment of Hep 3B cells with SC-1 activated caspase 8 and caspase 3. Elevation of nuclear DNA fragmentation factor 40 (DFF40) and cleavage form of poly(ADP-ribose) polymerase (PARP) were also observed. SC-1 also activated intrinsic pathway via increase of pro-apoptotic (tBid, Bak and Bax) and decrease of anti-apoptotic (Bcl-2 and Bcl-x(L)) proteins on mitochondria, disruption of mitochondrial membrane potential, release of cytochrome c and Smac (second mitochondria-derived activator of caspase/direct IAP binding protein with low PI) from mitochondria, and activation of caspase 9. Inhibition on protein expression of Ku70 in cytosol and cyclooxygenase (COX)-2, but not COX-1, in whole cell lystes were revealed in SC-1-treated Hep 3B cells. These results suggest caspase 8, Ku70 and mitochondria are involved in the antitumor mechanism of SC-1 in Hep 3B cells.  相似文献   

19.
20.
目的 研究藤黄酸对人卵巢透明细胞癌ES-2细胞增殖和凋亡的影响及其潜在分子机制。方法 采用CCK-8检测藤黄酸对不同类型人卵巢癌细胞增殖的影响;克隆形成实验检测藤黄酸对ES-2细胞克隆形成的影响;细胞划痕愈合实验及Transwell实验分别检测藤黄酸对ES-2细胞迁移与侵袭的影响;Caspase-Glo 3/7试剂盒检测藤黄酸对ES-2细胞内Caspase 3/7活性的影响;Annexin V-FITC/PI双染色法分析藤黄酸对ES-2细胞凋亡的影响;Western blotting检测不同浓度藤黄酸对ES-2细胞中Bcl-2、Bax、PTEN、PI3K、p-AKT、p-mTOR水平的影响。结果 人卵巢癌ES-2、HO8910、SKOV3、OVCAR3细胞中,藤黄酸对卵巢透明细胞癌ES-2细胞的增殖抑制作用最明显,且随着藤黄酸浓度和作用时间的增加而增强;藤黄酸可抑制ES-2细胞的克隆形成、迁移及侵袭、增强Caspase 3/7活性并促进细胞凋亡,且呈浓度依赖性;藤黄酸可下调ES-2细胞中Bcl-2、PI3K、p-AKT及p-mTOR的表达,上调Bax、PTEN的表达,且呈浓度依赖性。结论 藤黄酸能够抑制卵巢透明细胞癌ES-2细胞的增殖、迁移和侵袭,并诱导其凋亡,其作用机制可能与调控PI3K/AKT/mTOR信号通路相关。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号