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Query: UNIPROT:P08758 (
annexin V
)
9,383
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
alpha-Santalol, an active component of sandalwood oil, has been studied in detail in recent years for its skin cancer preventive efficacy in murine models of skin carcinogenesis; however, the mechanism of its efficacy is not defined. Two major biological events responsible for the clonal expansion of transformed/initiated cells into tumors are uncontrolled growth and loss of apoptotic death. Accordingly, in the present study, employing human epidermoid carcinoma A431 cells, we assessed whether alpha-santalol causes cell growth inhibition and/or cell death by apoptosis. Treatment of cells with alpha-santalol at concentrations of 25-75 microM resulted in a concentration- and a time-dependent decrease in cell number, which was largely due to cell death. Fluorescence-activated cell sorting analysis of
Annexin V
/propidium iodide (PI) stained cells revealed that alpha-santalol induces a strong apoptosis as early as 3 h post-treatment, which increases further in a concentration- and a time-dependent manner up to 12 h. Mechanistic studies showed an involvement of caspase-3 activation and poly(ADP-ribose) polymerase cleavage through activation of upstream
caspase-8
and -9. Further, the treatment of cells with alpha-santalol also led to disruption of the mitochondrial membrane potential and cytochrome c release into the cytosol, thereby implicating the involvement of the mitochondrial pathway. Pre-treatment of cells with
caspase-8
or -9 inhibitor, pan caspase inhibitor or cycloheximide totally blocked alpha-santalol-caused caspase-3 activity and cleavage, but only partially reversed apoptotic cell death. This suggests involvement of both caspase-dependent and -independent pathways, at least under caspase inhibiting conditions, in alpha-santalol-caused apoptosis. Together, this study for the first time identifies the apoptotic effect of alpha-santalol, and defines the mechanism of apoptotic cascade activated by this agent in A431 cells, which might be contributing to its overall cancer preventive efficacy in mouse skin cancer models.
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PMID:Skin cancer chemopreventive agent, {alpha}-santalol, induces apoptotic death of human epidermoid carcinoma A431 cells via caspase activation together with dissipation of mitochondrial membrane potential and cytochrome c release. 1552 19
Triptolide has been reported to be effective in the treatment of auto-immune diseases. This study investigates the cytotoxic function of triptolide on multiple myeloma (MM) cells. We found that triptolide inhibited the proliferation of both RPMI8226 and U266 cells in a dose-dependent manner (10-80 ng/mL). Triptolide induced apoptosis in MM cells through activation of the cystein protease
caspase 8
, 9 and 3, and subsequent cleavage of the DNA repair enzyme poly (ADP-ribose) polymerase. Apoptosis was confirmed with cell-cycle analysis and
annexin V
staining. Moreover, triptolide down-regulated nuclear factor (NF)-kappaB activity in MM cell lines. In addition, triptolide also induced chemosensitivity to doxorubicin and suppressed cell proliferation of fresh MM cells. Therefore, triptolide appears to be a potent inducer of apoptosis in myeloma cells, and might have some benefit in the treatment of myeloma patients.
...
PMID:Triptolide inhibits transcription factor NF-kappaB and induces apoptosis of multiple myeloma cells. 1554 81
Extracts from European mistletoe or Viscum album L. have been reported to exert cytotoxic and immunomodulatory effects in vitro and in vivo. The mechanism of this anti-tumoral activity is however, largely unknown. In this study we tested the hypothesis that IscadorQu, an aqueous fermented extract from the European mistletoe grown on oaks, induces tumor regression by cell cycle inhibition and/or interference with apoptotic signaling pathways in cancer cells. Also a possible effect on angiogenesis, which is a prerequisite for tumor growth in vivo, is studied in endothelial cell cultures. Furthermore, we examined which apoptotic signaling route is activated by staining cells for specific pro-apoptotic proteins. To characterize these properties, 6 different human cancer cell lines, one epidermis derived cell line and 2 endothelial cell cultures were incubated with different concentrations of IscadorQu. Cell cycle kinetics parameters were measured by bromodeoxyuridine (BrdU) pulse labeling and tubulin staining. Apoptotic responses were detected by M30 CytoDeath or
Annexin V
/propidium iodide assays. Characterization of the apoptotic pathway was performed by staining cells for active caspase 3, active
caspase 8
, cytochrome C and chloromethyl-X-rosamine. The results of this study show that sensitivity to IscadorQu treatment varies strongly between different cell lines. In sensitive cell lines, including tumor and endothelial cell cultures, IscadorQu caused early cell cycle inhibition followed by apoptosis in a dose-dependent manner. Apoptosis was induced by activating the mitochondrial but not the death receptor-dependent pathway.
...
PMID:Differential effects of Viscum album extract IscadorQu on cell cycle progression and apoptosis in cancer cells. 1554 86
Apoptosis occurs during the isolation and even short-term storage and culture of hepatocytes, and in the pathogenesis of liver diseases, such as hepatic failure and hepatitis. Therapeutic hypothermia has beneficial effects in experimental models of fulminant hepatic failure. The mechanisms underlying the potential benefits of mild hypothermia on the liver have not been well investigated. We examined the effects of temperature on soluble Fas ligand-induced apoptosis in freshly isolated mouse hepatocytes. Decreasing the culture temperature from 37 degrees C to 32 degrees C produced significant suppression of Fas-mediated apoptosis in cultured hepatocytes over a 12-h period. This observation was supported by cell morphology, flow cytometry analysis of cellular DNA content, and
Annexin V
-FITC staining of membrane phosphatidylserine translocation. In hypothermic conditions, Fas-mediated cytochrome c release from mitochondria of hepatocytes and the proximate downstream activation of caspase-9 were suppressed under mild hypothermic conditions. Effector caspase-7 activity was also inhibited at 32 degrees C. In contrast, the activation of initiator
caspase-8
and cleavage of Bid were not affected after Fas-ligand stimulation. These findings suggest that mild hypothermia suppresses Fas-mediated apoptosis of liver cells by the partial inhibition of signaling events including mitochondrial damage, cytochrome c release, and subsequent apoptosome formation and effector caspase activation.
...
PMID:Hypothermia inhibits Fas-mediated apoptosis of primary mouse hepatocytes in culture. 1564 37
In a previous study, we showed that G3139, an antisense phosphorothioate oligonucleotide that down-regulates the expression of Bcl-2 protein, did not cause chemosensitization of 518A2 melanoma cells. In this work, we show that G3139, and the 2-base mismatch, G4126, can initiate apoptosis in this and other melanoma cell lines as shown by increased cell surface
Annexin V
expression, typical nuclear phenotypic changes as assessed by 4',6-diamidino-2-phenylindole staining, activation of caspase-3 (but not
caspase-8
) and Bid, appearance of DEVDase (but not IETDase) activity, and cleavage of poly(ADP-ribose)-polymerase 1. Depolarization of the mitochondrial membrane occurs as a relatively late event. All of these processes seem to be substantially, but perhaps not totally, Bcl-2 independent as shown by experiments employing an anti-Bcl-2 small interfering RNA, which as shown previously down-regulated Bcl-2 protein expression but did not produce apoptosis or chemosensitization in melanoma cells. In fact, these G3139-induced molecular events were not dramatically altered in cells that forcibly overexpressed high levels of Bcl-2 protein. Addition of irreversible caspase inhibitors (e.g., the pan-caspase inhibitor zVAD-fmk) to G3139-treated cells almost completely blocked cytotoxicity. Examination of the time course of the appearance of caspase-3 and cleaved poly(ADP-ribose)-polymerase 1 showed that this could be correlated with the release of cytochrome c from the mitochondria, an event that begins only approximately 4 hours after the end of the oligonucleotide/LipofectAMINE 2000 5-hour transfection period. Thus, both G3139 and cytotoxic chemotherapy activate the intrinsic pathway of apoptosis in these cells, although Bcl-2 expression does not seem to contribute strongly to chemoresistance. These findings suggest that the attainment of G3139-induced chemosensitization in these cells will be difficult.
...
PMID:Phosphorothioate oligodeoxynucleotides and G3139 induce apoptosis in 518A2 melanoma cells. 1571 1
Bovine lactoferricin (LfcinB) is a cationic, amphipathic peptide that is cytotoxic for human and rodent cancer cells. However, the mechanism by which LfcinB causes the death of cancer cells is not well understood. Here, we show that in vitro treatment with LfcinB rapidly induced apoptosis in several different human leukemia and carcinoma cell lines as determined by DNA fragmentation assays and phosphatidylserine headgroup inversion detected by
Annexin V
binding to the surface of cancer cells. Importantly, LfcinB treatment did not adversely affect the viability of untransformed human lymphocytes, fibroblasts, or endothelial cells. Studies with different LfcinB-derived peptide fragments revealed that the cytotoxic activity of LfcinB resided within the amino acid sequence FKCRRWQWRM. Treatment of Jurkat T leukemia cells with LfcinB resulted in the production of reactive oxygen species followed by caspase-2-induced dissipation of mitochondrial transmembrane potential and subsequent activation of caspase-9 and caspase-3. Selective inhibitors of caspase-2 (Z-VDVAD-FMK), caspase-9 (Z-LEHD-FMK), and caspase-3 (Z-DEVD-FMK) protected both leukemia and carcinoma cells from LfcinB-induced apoptosis. Conversely, a
caspase-8
inhibitor (Z-IETD-FMK) had no effect, which argued against a role for
caspase-8
and was consistent with the finding that death receptors were not involved in LfcinB-induced apoptosis. Furthermore, Jurkat T leukemia cells that overexpressed Bcl-2 were less sensitive to LfcinB-induced apoptosis, which was characterized by mitochondrial swelling and the release of cytochrome c from mitochondria into the cytosolic compartment. We conclude that LfcinB kills cancer cells by triggering the mitochondrial pathway of apoptosis at least in part through the generation of reactive oxygen species.
...
PMID:Bovine lactoferricin selectively induces apoptosis in human leukemia and carcinoma cell lines. 1582 35
We have directly assessed the ability of interferon regulatory factor-1 (IRF-1) to act as a tumor suppressor gene in human breast cancer cells and explored whether this suppressor function is mechanistically conferred by affecting cell cycle transition, apoptosis and/or caspase activation. We have used a dual approach, measuring whether overexpression of wild-type IRF-1 or a dominant negative IRF-1 (dnIRF-1) produce opposing effects on breast cancer cell proliferation in vitro or tumorigenicity in athymic nude mice. Mechanistic studies determined the effects of blocking endogenous IRF-1 expression on cell cycle transition by flow cytometry, on apoptosis by
Annexin V
staining, and on caspase activation by fluorescent substrate cleavage. IRF-1 mRNA (P < or = 0.001) and protein (P < or = 0.001) are highly expressed in non-tumorigenic, normal, mammary epithelial cells, with intermediate expression in tumorigenic, but non-metastatic, cells and very low expression in metastatic cell lines. In MCF-7 cells transfected with a wild-type IRF-1 (MCF-7/IRF-1), IRF-1 mRNA expression inversely correlates with the rate of cell proliferation (r = -0.91; P = 0.002). Conversely, expression of dnIRF-1 in both MCF-7 (MCF-7/dnIRF-1; p53 wild-type) and T47D cells (T47D/dnIRF-1; p53 mutant) increases cell proliferation (P < or = 0.001). In athymic nude mice, the incidence of MCF-7/IRF-1 xenografts is reduced (P = 0.045), whereas MCF-7/dnIRF-1 xenografts exhibit a significantly higher tumor incidence (P < or = 0.001). Effects of IRF-1/dnIRF-1 are mediated through changes in the rates of apoptosis and not through cell cycle regulation. MCF-7/dnIRF-1 cells exhibit a 50% decrease in basal apoptosis (P = 0.007) and a significant reduction in
caspase 8
activity (P = 0.03); similar effects occur in T47D/dnIRF-1 cells, where the effects on apoptosis appear to be mediated through inhibition of caspases 3/7 (P < 0.001) and
caspase 8
(P = 0.03). These data establish a functional role for IRF-1 in the growth suppression of breast cancer cells and strongly implicate IRF-1 as a tumor suppressor gene in breast cancer that acts, independent of p53, to control apoptosis.
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PMID:Interferon regulatory factor-1 (IRF-1) exhibits tumor suppressor activities in breast cancer associated with caspase activation and induction of apoptosis. 1587 12
Cinnamaldehyde (Cin) has been shown to be effective in inducing apoptotic cell death in a number of human cancer cells. However, the intracellular death signaling mechanisms by which Cin inhibits tumor cell growth are poorly understood. In this study, we investigated the effect of mitogen-activated protein kinases (MAPKs) inhibitors [namely SP600125 (a specific JNK inhibitor), SB203580 (a specific p38 inhibitor) and PD98059 (a specific ERK inhibitor)] on the stress-responsive MAPK pathway induced by Cin in PLC/PRF/5 cells. Trypan blue staining assay indicated that Cin was cytotoxic to PLC/PRF/5 cells. Cin caused cell cycle perturbation (S-phase arrest) and triggered apoptosis as revealed by the externalization of
annexin V
-targeted phosphatidylserine and accumulation of sub-G1 peak. It down-regulated the Bcl-2 and Mcl-1 expression, and up-regulated Bax protein in a time-response manner. Treatment with 1 microM Cin resulted in an activation of
caspase-8
and cleavage of Bid to its truncated form in a time-dependent pattern. JNK, ERK and p38 kinases in cells were activated and phosphorylated after Cin treatment. Pre-incubation with SP600125 and SB203580 markedly suppressed the effect of Cin-induced apoptosis, but not PD98059. Both SP600125 and SB203580 significantly prevented the phosphorylation of JNK and p38 proteins, but not ERK. These results conclude that Cin triggers apoptosis in PLC/PRF/5 cells could be through the activation of pro-apoptotic Bcl-2 family (Bax and Bid) proteins and MAPK signaling pathway.
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PMID:Cinnamaldehyde-induced apoptosis in human PLC/PRF/5 cells through activation of the proapoptotic Bcl-2 family proteins and MAPK pathway. 1596 11
The mechanism of cell death in A2780 human ovarian carcinoma cells induced by free doxorubicin (DOX) and N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-bound DOX [P-(GFLG)-DOX] was investigated. In particular, the involvement of the Fas receptor system in drug-induced apoptosis was evaluated. P-(GFLG)-DOX was shown to effect apoptosis-induced tumor cell death as manifested by positive
Annexin V
-FITC staining, cleavage of procaspase 3 and its physiological substrate, poly(ADP-ribose) polymerase (PARP), and cleavage of procaspase 8. Using the fluorochrome-labeled caspase inhibitor assay, it was found that both free DOX and P-(GFLG)-DOX activated caspases 3 and 9, but both forms of DOX did not have an effect on the activity of
caspase 8
, when compared to untreated cells. It was shown that free DOX and P-(GFLG)-DOX upregulated Fas receptor expression at the cell membrane in a time-dependent manner. Triggering the drug-induced Fas receptor with an exogeneous soluble Fas ligand (sFasL) resulted in an increase in the extent of apoptotic cell death, indicating that the Fas signaling pathway remained functionally active. Also, antagonistic anti-Fas ZB4 antibody blocked the increase in the level of apoptosis following the application of sFasL, but did not interfere with drug-induced apoptosis. The study of the functional activity of the Fas receptor and of the activation of the most proximal effector of the caspase cascade,
caspase 8
, indicated that the Fas receptor pathway was not decisive in the induction of cell death by free DOX and P-(GFLG)-DOX in A2780 cells. This study suggests further investigation of the involvement of the mitochondrial pathway in A2780 cell apoptotic death, induced by free and HPMA copolymer-bound DOX.
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PMID:HPMA copolymer-bound doxorubicin induces apoptosis in human ovarian carcinoma cells by a Fas-independent pathway. 1598 20
During atresia of bovine follicles, granulosa cells are lost through the controlled form of cell death, apoptosis. The purpose of this study was to characterize the regulation of apoptotic death of granulosa cells in dominant bovine follicles during the first wave of follicular development. Dominant follicles were collected from Holstein heifers on days 4, 6 or 8 of the first follicular wave (n = 5/day). Regulation of apoptosis in granulosa cells was examined by
annexin V
and propidium iodide staining; measurement of relative levels of mRNA encoding Bcl-2, Bcl-xL and Bax; and activity of caspase-3, -8 and -9. Steady-state levels of mRNA encoding four oxidative stress-response proteins were determined. Compared with day 4, the incidence of apoptotic and nonviable granulosa cells tended to increase on day 6, and numbers of nonviable cells were higher on day 8. The ratios of relative levels of mRNA encoding Bcl-2 to Bax and Bcl-xL to Bax were higher on day 6 than days 4 and 8. Activity of caspases-3 and -9 in granulosa cells did not change among the 3 days, while
caspase-8
activity decreased on day 8 compared with days 4 and 6. Amounts of GSHPx, MnSOD and Cu/ZnSOD mRNA in granulosa cells were higher on day 8 than day 6. In theca interna, amounts of Cu/ZnSOD mRNA decreased between days 4 and 6. From the decreased production of estradiol and increased numbers of apoptotic and nonviable granulosa cells, we conclude that atresia of the dominant follicle is initiated between days 4 and 6 of the first follicular wave. However, apoptosis of granulosa cells does not appear to be initiated by changes in expression of oxidative stress-response proteins.
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PMID:Regulation of apoptosis in the atresia of dominant bovine follicles of the first follicular wave following ovulation. 1598 33
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