共查询到20条相似文献,搜索用时 545 毫秒
1.
Luiz H. Rosa Elaine M. Souza-Fagundes Kátia M.G. Machado Tânia M. A. Alves Olindo A. Martins-Filho Alvaro J. Romanha Rodrigo C. Oliveira Carlos A. Rosa Carlos L. Zani 《World journal of microbiology & biotechnology》2006,22(6):539-545
Summary The ethyl acetate extract from the culture of the fungus Agrocybe perfecta (Rick) Singer was selected for further study in a screening of Brazilian basidiomycetes for bioactivity. The extract showed
significant activity against the recombinant enzyme trypanothione reductase (TryR) from Trypanosoma cruzi, lymphocyte proliferation in human peripheral mononuclear cells (PBMC) stimulated with phytohemaglutinin (PHA), and the human
cancer cell lines UACC-62 (melanoma), MCF-7 (mammary), and TK-10 (kidney). The chromatographic fractionation of the extract
was monitored by the above bioassays and showed that agrocybin was the active component. Agrocybin, a known polyacetylene
amide, showed an IC50 of 2 μM in the TryR assay but killed only 60% of the trypomastigote form of T. cruzi in infected murine blood even at 680 μM. This weaker activity could be due to the low temperature used to mimic banked blood
or as a consequence of its inactivation by blood, already reported in the literature. On the other hand, it inhibited the
proliferation of PBMC by 50% at 3.4 μM and the growth of the cancer cell lines at concentrations between 9 and 24.5 μM. Measurements
of DNA fragmentation using flow cytometry suggest that agrocybin promotes cell death via apoptosis. 相似文献
2.
S. K. Arepalli V. Sridhar J. Venkateswara Rao P. Kavin Kennady Y. Venkateswarlu 《Apoptosis : an international journal on programmed cell death》2009,14(5):729-740
Bioassay directed fractionation and purification led to the successful isolation of a furano sesquiterpene, Methyl 5-[(1E,5E)-2,6-Dimethyl
octa-1,5,7-trienyl] furan-3-carboxylate (MDTFC), a bioactive component from a soft coral, Sinularia kavarittiensis. Its structure was determined by analyzing 1H, 13C NMR and FAB-MS. The results show that MDTFC could efficiently and selectively inhibit the proliferation of several human
cancer cell lines. Among all the cell lines, THP-1 was found to be most sensitive (IC50 29.59 μM), whereas the peripheral blood mononuclear cells were least effected (IC50 464.16 μM). The molecular mechanism of MDTFC mediated apoptosis was investigated for the first time. Induction of apoptosis
in THP-1 cells was characterized by cell membrane blebbing, chromatin condensation, DNA fragmentation, and decrease in level
of pro-caspases 3, 9 and increase in Bax/Bcl-2 ratio. Our results were further strengthened through cleavage of poly (ADP-ribose)
polymerase, reduction of mitochondrial membrane potential (Ψm) and cytosolic release of cytochrome c, which are key events during apoptosis. Moreover, phosphatidyl serine exposure and appearance of sub-G1 peak also demonstrated
cell death, when analyzed by flow cytometry. DNA fragmentation was prevented moderately when pretreated with caspase-9 inhibitor
(Z-LEHD-FMK) and largely with caspase-3 inhibitor (Z-DEVD-FMK). In summary, MDTFC mediated apoptosis involves mitochondria-dependent
pathway and the present compound of marine origin might have a therapeutic value against human cancer cell lines and especially
on leukemia cells. 相似文献
3.
Arsenic trioxide (ATO; As2O3) can induce apoptotic cell death in various cancer cells including lung cancer cells. However, little is known about the
toxicological effects of ATO on normal primary lung cells. In this study, we investigated the cellular effects of ATO on human
pulmonary fibroblast (HPF) cells in relation to cell growth inhibition and death. ATO inhibited HPF cell growth with an IC50 of approximately 30–40 μM at 24 h and induced cell death accompanied by the loss of mitochondrial membrane potential (MMP;
ΔΨm). Thus, HPF cells were considered to be very resistant to ATO insults. ATO increased the expression of p53 protein and decreased
that of Bcl-2 protein. This agent activated caspase-8 but not caspase-3 in HPF cells. Z-VAD (a pan-caspase inhibitor; 15 μM)
did not significantly decrease cell growth inhibition, death and MMP (ΔΨm) loss by ATO. Moreover, administration of Bax or casase-8 siRNA attenuated HPF cell death by ATO whereas p53 or caspase-3
siRNAs did not affect cell death. In conclusion, HPF cells were resistant to ATO and higher doses of ATO induced the growth
inhibition and death in HPF cells via the regulation of Bcl-2 family and caspase-8. 相似文献
4.
Bhushan S Kumar A Malik F Andotra SS Sethi VK Kaur IP Taneja SC Qazi GN Singh J 《Apoptosis : an international journal on programmed cell death》2007,12(10):1911-1926
A triterpenediol (TPD) comprising of isomeric mixture of 3α, 24-dihydroxyurs-12-ene and 3α, 24-dihydroxyolean-12-ene from
Boswellia serrata induces apoptosis in cancer cells. An attempt was made in this study to investigate the mechanism of cell death by TPD in
human leukemia HL-60 cells. It inhibited cell proliferation with IC50 ∼ 12 μg/ml and produced apoptosis as measured by various biological end points e.g. increased sub-G0 DNA fraction, DNA ladder
formation, enhanced AnnexinV-FITC binding of the cells. Further, initial events involved massive reactive oxygen species (ROS)
and nitric oxide (NO) formation, which were significantly inhibited by their respective inhibitors. Persistent high levels
of NO and ROS caused Bcl-2 cleavage and translocation of Bax to mitochondria, which lead to loss of mitochondrial membrane
potential (Δψm) and release of cytochrome c, AIF, Smac/DIABLO to the cytosol. These events were associated with decreased expression of
survivin and ICAD with attendant activation of caspases leading to PARP cleavage. Furthermore, TPD up regulated the expression
of cell death receptors DR4 and TNF-R1 level, leading to caspase-8 activation. These studies thus demonstrate that TPD produces
oxidative stress in cancer cells that triggers self-demise by ROS and NO regulated activation of both the intrinsic and extrinsic
signaling cascades. 相似文献
5.
The aim of the present studies was to characterise cell death following inhibition of mitochondrial complex I with rotenone
in a transformed cell line (RGC-5 cells) and to examine the neuroprotective properties of the flavonoids genistein, epigallocatechin
gallate (EGCG), epicatechin (EC) and baicalin. Rotenone-induced cell death of RGC-5 cells results in a generation of reactive
oxygen species, a breakdown of DNA, the translocation of membrane phosphatidylserine, an up-regulation of haemoxygenase-1
and is unaffected by necrostatin-1 (inhibitor of necroptosis), z-VAD-fmk (pan caspase inhibitor) or NU1025 (PARP inhibitor)
but attenuated with SP600125 (JNK inhibitor). Rotenone-induced toxicity of RGC-5 cells also caused an activation of mitogen-activated
kinases indicated by an up-regulation and translocation into mitochondria of p-c-Jun, pJNK and pp38. Exposure of RGC-5 cells
to rotenone does not affect apoptosis inducing factor or significantly stimulate caspase-3 activity. EGCG and EC both significantly
blunt rotenone toxicity of RGC-5 cells at concentrations of 50 μM while genistein and baicalin were without effect. Significantly,
genistein is approximately 20 times less efficacious than EGCG (IC50 2.5 μM) and EC (IC50 1.5 μM) at inhibiting sodium nitroprusside-induced lipid peroxidation. These studies show that rotenone toxicity of RGC-5
cells is neither necroptosis nor caspase-dependent apoptosis but involves the activation of mitogen-activated kinases and
is inhibited by a JNK inhibitor, EGCG and EC. Genistein attenuates lipid peroxidation less efficaciously than EC and EGCG
and does not affect rotenone toxicity of RGC-5 cells. 相似文献
6.
Malik F Kumar A Bhushan S Khan S Bhatia A Suri KA Qazi GN Singh J 《Apoptosis : an international journal on programmed cell death》2007,12(11):2115-2133
Induction of apoptosis in cancer cells has become the major focus of anti-cancer therapeutics development. WithaferinA, a
major chemical constituent of Withania somnifera, reportedly shows cytotoxicity in a variety of tumor cell lines while its molecular mechanisms of action are not fully understood.
We observed that withaferinA primarily induces oxidative stress in human leukemia HL-60 cells and in several other cancer
cell lines. The withanolide induced early ROS generation and mitochondrial membrane potential (Δψmt) loss, which preceded release of cytochrome c, translocation of Bax to mitochondria and apoptosis inducing factor to cell
nuclei. These events paralleled activation of caspases −9, −3 and PARP cleavage. WA also activated extrinsic pathway significantly
as evidenced by time dependent increase in caspase-8 activity vis-à-vis TNFR-1 over expression. WA mediated decreased expression
of Bid may be an important event for cross talk between intrinsic and extrinsic signaling. Furthermore, withaferinA inhibited
DNA binding of NF-κB and caused nuclear cleavage of p65/Rel by activated caspase-3. N-acetyl-cysteine rescued all these events suggesting thereby a pro-oxidant effect of withaferinA. The results of our studies
demonstrate that withaferinA induced early ROS generation and mitochondrial dysfunction in cancer cells trigger events responsible
for mitochondrial -dependent and -independent apoptosis pathways. 相似文献
7.
Lasfer M Vadrot N Aoudjehane L Conti F Bringuier AF Feldmann G Reyl-Desmars F 《Cell biology and toxicology》2008,24(1):55-62
The heavy metal cadmium, an environmental pollutant, has been widely demonstrated to be toxic, in particular for liver. In
murines, cadmium induces apoptosis of hepatocytes and hepatomas. In human cells, apoptosis induced by cadmium has been exclusively
demonstrated in tumoral cell lines. Nothing was known in normal liver, in vitro or in vivo. In the present study, we examined the effects of cadmium in nonmalignant human hepatocytes. For that purpose, we investigated
whether cadmium was able to induce apoptosis of normal human hepatocytes (NHH) in primary culture and of a SV40-immortalized
human hepatocyte (IHH) cell line. Treatment of IHH and NHH with cadmium induced the presence of a sub-G1 population at 10 and 100 μmol/L, respectively. DAPI staining of both cell types treated with cadmium 100 μmol/L revealed
the induction of nuclear apoptotic bodies, supporting the hypothesis of apoptosis. In IHH and NHH, cadmium 100 μmol/L induced
PARP cleavage into a 85 kDa fragment. In order to investigate the involvement of mitochondria in cadmium-induced apoptosis,
we measured the mitochondrial membrane potential (ΔΨm). We observed that in IHH and NHH, cadmium 100 μmol/L induced a decrease of ΔΨm. As expected, cadmium under the same conditions enhanced caspase-9 and caspase-3 activities. In addition, cadmium from 1
to 100 μmol/L induced the expression of p53 and phosphorylation of its Ser15 in IHH and NHH. In conclusion, we showed in this
study that human hepatocytes were sensitive to cadmium and apoptosis induced at concentrations suggested in the literature
to inhibit p53 DNA-binding and DNA repair. 相似文献
8.
Kim BM Rode AB Han EJ Hong IS Hong SH 《Apoptosis : an international journal on programmed cell death》2012,17(2):200-216
In the present study, we investigated the signaling pathways implicated in the induction of apoptosis by two modified nucleosides,
5-phenylselenyl-methyl-2′-deoxyuridine (PhSe-T) and 5-methylselenyl-methyl-2′-deoxyuridine (MeSe-T), using human cancer cell
lines. The induction of apoptosis was associated with proteolytic activation of caspase-3 and -9, PARP cleavage, and decreased
levels of IAP family members, including c-IAP-1 and c-IAP-2, but had no effect on XIAP and survivin. PhSe-T and MeSe-T also
enhanced the activities of caspase-2 and -8, Bid cleavage, and the conformational activation of Bax. Additionally, nucleoside
derivative-induced apoptosis was inhibited by the selective inhibitors of caspase-2, -3, -8, and -9 and also by si-RNAs against
caspase-2, -3, -8, and -9; however, inhibition of caspase-2 and -3 was more effective at preventing apoptosis than inhibition
of caspase-8 and -9. Moreover, the inhibition of caspase-2 activation by the pharmacological inhibitor z-VDVAD-fmk or by the
knockdown of protein expression using siRNA suppressed nucleoside derivative-induced caspase-3 activation, but not vice versa.
PhSe-T and MeSe-T also induced a Δψm loss via a CsA-insensitive mechanism, ROS production, and DNA damage, including strand breaks. Moreover, ROS scavengers such
as NAC, tiron, and quercetin inhibited nucleoside derivative-induced ROS generation and apoptosis by blocking the sequential
activation of caspase-2 and -3, indicating the role of ROS in caspase-2-mediated apoptosis. Taken together, these results
indicate that caspase-2 acts upstream of caspase-3 and that caspase-2 functions in response to DNA damage in both PhSe-T-
and MeSe-T-induced apoptosis. Our results also suggest that ROS are critical regulators of the sequential activation of caspase-2
and -3 in nucleoside derivative-treated cancer cells. 相似文献
9.
Romorini L Scassa ME Richardson GV Blüguermann C de Giusti CJ Questa M Fernandez Espinosa DD Gómez RM Sevlever GE Miriuka SG 《Apoptosis : an international journal on programmed cell death》2012,17(2):132-142
Human embryonic stem cells (hESCs) are self-renewing pluripotent cells that can differentiate to a wide range of specialized
cells and hold great promise as models for human development and disease, as well as for drug discovery and cell-replacement
therapies. Group B Coxsackie viruses (CVBs) produce acute myocarditis, pancreatitis, non-septic meningitis and encephalitis
in neonates, children and young adults. Moreover, CVBs can produce spontaneous miscarriage after early embryo infection. It
was reported that hESCs express CVBs receptors and are susceptible to CVB3 infection. Apoptosis is one of the hallmarks of
CVBs infection although details regarding CVB3 involvement in the apoptotic processes remain elusive. In order to evaluate
the mechanisms of cell death induced by CVB3 in these pluripotent cells, we infected HUES-5 (H5) and WA01 (H1) hESC lines
with CVB3. After validating the maintenance of stemness in these hESC lines when grown as confluent monolayers in feeder-free
conditions, we analysed several aspects of programmed cell death triggered by CVB3. In all cases, we detected chromatin condensation,
DNA fragmentation and caspase-9 and 3 cleavages. Moreover, we observed the presence of cleaved PARP product which was preceded
by the appearance of p17, the catalytically active fragment of caspase-3. Mitochondrial function assays revealed a MOI dependent
decrease in cell viability at 24 h post-infection (pi). No appreciable modifications in Bcl-2, Bcl-XL and Bax protein levels were observed upon CVB3 infection during 5–24 h observation period. However, a marked decrease in
pro-apoptotic Bad abundance was detected without changes in its mRNA levels. In this study we found that the hESCs are highly
susceptible to CVB3 infection and display elevated apoptosis rates, thus emerging as suitable human non-transformed in vitro
models to study CVB3-induced apoptosis and resulting relevant to understand CVBs pathogenesis. 相似文献
10.
Antiproliferative activity of sulfated polysaccharide isolated from an enzymatic digest of Ecklonia cava on the U-937 cell line 总被引:1,自引:0,他引:1
Yasantha Athukorala Gin Nae Ahn Young-Heun Jee Gi-Young Kim Soo-Hyun Kim Jin-Hwan Ha Jung-Sook Kang Ki-Wan Lee You-Jin Jeon 《Journal of applied phycology》2009,21(3):307-314
A sulfated polysaccharide purified from a brown alga Ecklonia cava, having high anticoagulant activity was investigated for its antiproliferative effect on murine colon carcinoma (CT-26),
human leukemic monocyte lymphoma (U-937), human promyelocytic leukemia (HL-60), and mouse melanoma (B-16) cell lines. The
sulfated polysaccharide isolated and purified from an enzymatic extract of E. cava had a good selective tumor cell growth inhibition effect; its effect on HL-60 and U-937 was especially promising. The IC50 value for the sulfated polysaccharide from E. cava (ECSP) on U-937 was 43.9 μg mL−1. The presence of the sample in the cell culture media stimulated the induction of apoptosis, revealed by nuclear staining
with Hoechst 33342. The apoptosis induction was confirmed by the cell cycle analysis, while pronounced sub-G1 phase arrests
of 9.5% and 13.8% were also clearly observed when the cells were treated at 15 and 30 μg mL−1 of ECSP in the U-937 cell line, respectively. After a 24-h incubation period, ECSP dose-dependently enhanced the DNA fragmentation
on the U-937 cell line as observed in the agarose gel electrophoresis assay. To rule out the action mechanism of ECSP for
its anticancer activity, some western blot analyses were conducted with several antibodies (caspase-7, caspase-8, Bax, Bcl-xL,
and PARP) and ECSP had a clear effect on the caspase -7 and 8 which cleave protein substrates, including PARP, an inducer
of apoptosis responsible for DNA cleavage. Moreover, ECSP controlled the cellular transmembrane molecules like Bax and Bcl-xL.
Taken together, the above results demonstrate that the apoptosis for antiproliferative effect of ECSP was clearly induced
on U-937 cells. 相似文献
11.
Garlic compounds induced calpain and intrinsic caspase cascade for apoptosis in human malignant neuroblastoma SH-SY5Y cells 总被引:12,自引:1,他引:11
Karmakar S Banik NL Patel SJ Ray SK 《Apoptosis : an international journal on programmed cell death》2007,12(4):671-684
Malignant (N-type) neuroblastoma continues to defy current chemotherapeutic regimens. We tested the garlic compounds diallyl
sulfide (DAS) and diallyl disulfide (DADS) for induction of apoptosis in human malignant neuroblastoma SH-SY5Y cells. Viability
of human primary neurons was unaffected after 24 h treatment with 50 and 100 μM DAS and 50 μM DADS but slightly affected with
100 μM DADS. Treatment with 50 and 100 μM DAS or DADS significantly decreased viability in SH-SY5Y cells. Wright staining
showed morphological features of apoptosis in SH-SY5Y cells treated with 50 and 100 μM DAS or DADS for 24 h. ApopTag assay
demonstrated DNA fragmentation in apoptotic cells. Apoptosis was associated with an increase in [Ca2+]i, increase in Bax:Bcl-2 ratio, mitochondrial release of cytochrome c, increase in cytosolic Smac/Diablo, and down regulation of inhibitor-of-apoptosis proteins and nuclear factor kappa B (NFκB).
Activation of caspase-9 and caspase-3 indicated involvement of intrinsic pathway of apoptosis. Calpain and caspase-3 activities
produced 145 kD spectrin break down product (SBDP) and 120 kD SBDP, respectively. Also, caspase-3 activity cleaved inhibitor
of caspase-activated DNase (ICAD). Results strongly suggested that the garlic compounds DAS and DADS suppressed anti-apoptotic
factors and activated calpain and intrinsic caspase cascade for apoptosis in SH-SY5Y cells. 相似文献
12.
Bodo J Jakubikova J Chalupa I Bartosova Z Horakova K Floch L Sedlak J 《Apoptosis : an international journal on programmed cell death》2006,11(8):1299-1310
The effect of synthetic isothiocyanate ethyl-4-isothiocyanatobutanoate (E-4IB) on survival of mismatch repair-proficient TK6
and -deficient MT1 cell lines as well as the influence of proteasomal inhibitor MG132, caspase inhibitor Z-VAD-fmk, and ATM
inhibitor caffeine on E-4IB modulation of cell cycle and apoptosis was evaluated. Flow cytometric analyses of DNA double strand
breaks (γ-H2AX), mitotic fraction (phospho-histone H3), cell cycle modulation, apoptosis induction (sub-G0 fraction and fluorescein diacetate staining), and dissipation of transmembrane mitochondrial potential (JC-1 staining) were
performed. Western blotting was used for the evaluation of ERK activation, expression of p53, p21cip1/waf1 and GADD45α proteins, as well as PARP fragmentation. Analysis of mitotic nuclei was performed for chromosomal aberrations assessment.
MT1 cells were more resistant to E-4IB treatment then TK6 cells (IC50 8 μM vs. 4 μM). In both cell lines E-4IB treatment induced phosphorylation of H2AX, increase of p53 protein level, phospho-histone
H3 staining, and G2/M arrest. The sub-G0 fragmentation was accompanied by PARP degradation, decreased mitochondrial transmembrane potential, and diminished p21cip1/waf1 protein expression in TK6 cells. Caspase inhibitor Z-VAD-fmk decreased E-4IB induced sub-G0 fragmentation and extent of apoptosis in TK6 cells, while proteasome inhibitor MG132 increased number of apoptotic cells
in both cell lines tested. A number of aberrant metaphases and clastogenic effect of high E-4IB concentration was observed.
The synthetic isothiocyanate E-4IB induced DNA strand breaks, increased mitotic fraction and apoptosis potentiated by MG132
inhibitor in both mismatch repair-proficient and -deficient cell lines.
This work was supported in part by Slovak Governmental Research and Development sub-program Food-quality and safety No. 2003SP270280E010280E01,
National Program “Use of Cancer Genomics to Improve the Human Population Health”, project 2003 SP 510280800/0280801, European
Commission project (QLG1-CT-2000-01230), and VEGA projects 2/4069 and 2/3161/23. 相似文献
13.
Programmed cell death (PCD), now known as apoptosis, is accompanied by specific morphological features. In this study, fusaric acid, a fusarium mycotoxin, was used to examine cell death in saffron (Crocus sativus Linnaeus) roots, using several apoptosis assays. Our results show that moderate FA doses (50–100 μM) induce apoptotic features while high FA doses (> 200 μM) stimulate necrosis. The apoptotic-like features induced by moderate doses of FA include chromatin condensation, formation of condensed chromatin spheres which bud from the nucleus, fragmentation of nucleosomal DNA into ∼ 180 bp fragments, exposure of phosphatidyl serine to the external membrane leaflet, delivery of cytochrome c to cytosol, and generation of H2O2. These apoptotic alterations in root cells are not observed in the presence of serine protease, caspase-1 or caspase-3 inhibitors. It is proposed that production of H2O2 and release of cytochrome c into the cytosol may activate caspase-like proteases and thus establish the apoptotic pathway. As nuclei budding spheres formed in plant root cells after exposure to 50–100 μM FA doses seem to be digested inside the cytosol, we suggest labeling them as internal apoptotic bodies (IAB) that may be more informative than previously used term, apoptotic-like bodies.Electronic Supplementary Material Supplementary material is available to authorised users in the online version of this article at . 相似文献
14.
Fang EF Zhang CZ Fong WP Ng TB 《Apoptosis : an international journal on programmed cell death》2012,17(4):377-387
Ribonucleases (RNases) are ubiquitously distributed nucleases that cleave RNA into smaller pieces. They are promising drugs
for different cancers based on their concrete antitumor activities in vitro and in vivo. Here we report for the first time
purification and characterization of a 14-kDa RNase, designated as RNase MC2, in the seeds of bitter gourd (Momordica charantia). RNase MC2 manifested potent RNA-cleavage activity toward baker’s yeast tRNA, tumor cell rRNA, and an absolute specificity
for uridine. RNase MC2 demonstrated both cytostatic and cytotoxic activities against MCF-7 breast cancer cells. Treatment
of MCF-7 cells with RNase MC2 caused nuclear damage (karyorrhexis, chromatin condensation, and DNA fragmentation), ultimately
resulting in early/late apoptosis. Further molecular studies unveiled that RNase MC2 induced differential activation of MAPKs
(p38, JNK and ERK) and Akt. On the other hand, RNase MC2 exposure activated caspase-8, caspase-9, caspase-7, increased the
production of Bak and cleaved PARP, which in turn contributed to the apoptotic response. In conclusion, RNase MC2 is a potential
agent which can be exploited in the worldwide fight against breast cancer. 相似文献
15.
Acharya BR Bhattacharyya S Choudhury D Chakrabarti G 《Apoptosis : an international journal on programmed cell death》2011,16(9):924-939
Naphthazarin (DHNQ, 5,8-dihydroxy-l,4-naphthoquinone) is a naturally available 1,4-naphthoquinone derivatives. In this study,
we focused on elucidating the cytotoxic mechanism of naphthazarin in A549 non-small cell lung carcinoma cells. Naphthazarin
reduced the A549 cell viability considerably with an IC50 of 16.4 ± 1.6 μM. Naphthazarin induced cell death in a dose- and time-dependent manner by activating apoptosis and autophagy
pathways. Specifically, we found naphthazarin inhibited the PI3K/Akt cell survival signalling pathway, measured by p53 and
caspase-3 activation, and PARP cleavage. It also resulted in an increase in the ratio of Bax/Bcl2 protein levels, indicating
activation of the mitochondrial apoptotic pathway. Similarly naphthazarin triggered LC3II expression and induced autophagic
flux in A549 cells. We demonstrated further that naphthazarin is a microtubule inhibitor in cell-free system and in A549 cells. Naphthazarin treatment depolymerized interphase microtubules and disorganised spindle microtubules and
the majority of cells arrested at the G2/M transition. Together, these data suggest that naphthazarin, a microtubule depolymerizer which activates dual cell death
machineries, could be a potential novel chemotherapeutic agent. 相似文献
16.
This report is designed to explore the molecular mechanism by which dihydroartemisinin (DHA) and ionizing radiation (IR) induce apoptosis in human lung adenocarcinoma A549 cells. DHA treatment induced a concentration- and time-dependent reactive oxygen species (ROS)-mediated cell death with typical apoptotic characteristics such as breakdown of mitochondrial membrane potential (Δψm), caspases activation, DNA fragmentation and phosphatidylserine (PS) externalization. Inhibition of caspase-8 or -9 significantly blocked DHA-induced decrease of cell viability and activation of caspase-3, suggesting the dominant roles of caspase-8 and -9 in DHA-induced apoptosis. Silencing of proapoptotic protein Bax but not Bak significantly inhibited DHA-induced apoptosis in which Bax but not Bak was activated. In contrast to DHA treatment, low-dose (2 or 4 Gy) IR induced a long-playing generation of ROS. Interestingly, IR treatment for 24 h induced G2/M cell cycle arrest that disappeared at 36 h after treatment. More importantly, IR synergistically potentiated DHA-induced generation of ROS, activation of caspase-8 and -3, irreparable G2/M arrest and apoptosis, but did not enhance DHA-induced loss of Δψm and activation of caspase-9. Taken together, our results strongly demonstrate the remarkable synergistic efficacy of combination treatment with DHA and low-dose IR for A549 cells in which IR potentiates DHA-induced apoptosis largely by enhancing the caspase-8-mediated extrinsic pathway. 相似文献
17.
The mechanisms of protective effect of N-methyl-D-aspartate (NMDA) receptor stimulation on apoptosis of neurons at their early
stage of development are poorly understood. In the present study, we investigated the effects of NMDA on staurosporine (St)-
and low-potassium (LP)-evoked apoptotic cell death in primary cerebellar granule cell (CGC) cultures at 7 days in vitro (DIV).
We found that NMDA (200 μM) attenuated the St (0.5 μM)- and LP (5 mM KCl)-induced neuronal cell death in 7 but not 12 DIV
CGC as confirmed by LDH release and MTT reduction assays. Moreover, NMDA attenuated St-and LP-evoked DNA fragmentation and
cytosolic apoptosis inducing factor (AIF) protein level but not caspase-3 activation induced by both pro-apoptotic factors.
Neuroprotective effects of NMDA on St-induced apoptosis in CGC were attenuated by inhibitors of ERK/MAPK-signaling, PD 98059
and U0126 but not by NMDA receptor antagonists, AP-5 (100 μM) and MK-801 (1 μM) or by inhibitors of PI3-K/Akt pathway (LY
294002 and wortmannin). In contrast to staurosporine model of apoptosis, AP-5 and MK-801 but not inhibitors of PI3-K/Akt and
MAPK/ERK1/2 prevented the NMDA-mediated neuroprotection in LP-induced apoptosis of CGC. In separate experiments, we observed
also the anti-apoptotic action of NMDA on St (0.5 μM)- and salsolinol (250 μM)-evoked cell death in human neuroblastoma SH-SY5Y
cells without its influence on caspase-3 activity, induced by these pro-apoptotic factors. These data indicate that neuroprotection
evoked by NMDA in CGC strongly depends on used pro-apoptotic agent and could engage NMDA channel function or be connected
with the activation of pro-survival MAPK/ERK1/2 pathway. It is also suggested that anti-apoptotic effects of NMDA is connected
with inhibition of fragmentation of DNA via caspase-3-independent mechanism. 相似文献
18.
The oxysterol 7beta-hydroxycholesterol (7beta-OH) has been shown to induce apoptosis in a number of cell lines. Though not fully elucidated, the mechanism through which this oxysterol induces cell death is thought to involve the generation of an oxidative stress leading to perturbation of the mitochondrion and release of cytochrome c into the cytosol. Cytochrome c together with Apaf-1 causes activation of the initiator caspase, caspase-9, which in turn activates caspase-3 ultimately leading to the degradation of poly(ADP-ribose) polymerase (PARP). The objective of the present study was to investigate the signalling pathway in 7beta-OH-induced apoptosis in U937 cells, a human monocytic blood cell line known to undergo apoptosis upon treatment with 7beta-OH, over a time course of 48 h. Apoptosis was evident after 24 h incubation. Glutathione levels were decreased after 6 h and this was coupled with an increase in SOD activity. Through western blot analysis we examined expression of caspase-3, -8, and -9 and cleavage of the caspase-3 substrate PARP. The sequence proceeded with activation of caspase-9 after 9 h, caspase-3 at the 12 h timepoint, and cleavage of PARP after 24 h treatment with 7beta-OH. Caspase-8 did not appear to play a major role in this particular apoptotic pathway. 相似文献
19.
20.
Kallio A Zheng A Dahllund J Heiskanen KM Härkönen P 《Apoptosis : an international journal on programmed cell death》2005,10(6):1395-1410
Tamoxifen (Tam) is widely used in chemotherapy of estrogen receptor-positive breast cancer. It inhibits proliferation and
induces apoptosis of breast cancer cells by estrogen receptor-dependent modulation of gene expression, but recent reports
have shown that Tam (especially at pharmacological concentrations) has also rapid nongenomic effects. Here we studied the
mechanisms by which Tam exerts rapid effects on breast cancer cell viability. In serum-free medium 5–7 μM Tam induced death
of MCF-7 and MDA-MB-231 cells in a time-dependent manner in less than 60 min. This was associated with release of mitochondrial
cytochrome c, a decrease of mitochondrial membrane potential and an increase in production of reactive oxygen species (ROS). This suggests
that disruption of mitochondrial function has a primary role in the acute death response of the cells. Accordingly, bongkrekic
acid, an inhibitor of mitochondrial permeability transition, was able to protect MCF-7 cells against Tam. Rapid cell death
induction by Tam was not associated with immediate activation of caspase-9 or cleavage of poly (ADP-ribose) polymerase. It
was not blocked by the caspase inhibitor z-Val-Ala-Asp-fluoromethylketone either. Diphenylene ionodium (DPI), an inhibitor
of NADPH oxidase, was able to prevent Tam-induced cell death but not cytochrome c release, which suggests that ROS act distal to cytochrome c. The pure antiestrogen ICI 182780 (1 μM) could partly oppose the effect of Tam in estrogen receptor positive MCF-7 cells,
but not in estrogen receptor negative MDA-MB-231 cells. Pre-culturing MCF-7 cells in the absence of 17β-estradiol (E2) or in the presence of a low Tam concentration (1 μM) made the cells even more susceptible to rapid death induction by 5
or 7 μM Tam. This effect was associated with decreased levels of the anti-apoptotic proteins Bcl-XL and Bcl-2. In conclusion, our results demonstrate induction of a rapid mitochondrial cell death program in breast cancer
cells at pharmacological concentrations of Tam, which are achievable in tumor tissue of Tam-treated breast cancer patients.
These mechanisms may contribute to the ability of Tam therapy to induce death of breast cancer cells. 相似文献