Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.56 (caspase-3)
 35,750 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using a cell-free system, we show that rat liver mitochondria, but not mitochondrial extracts, potentiated apoptosis triggered by cytosols derived from apoptotic cells. Apoptosis potentiated by mitochondria appeared to be inhibited by caspase 3 but not by caspase 1 inhibitors. A cytosolic caspase-3-like activity was increased by the addition of mitochondria to apoptotic cytosols; the latter activation was inhibited by the addition of bcl-2. Chelation of calcium by EGTA significantly and specifically inhibited the apoptosis potentiated by mitochondria as well as the increase of caspase-3-like activity. The incubation of mitochondria with apoptotic cytosols led to the release of cytochrome c, this latter phenomenon being inhibited by EGTA. Calcium or cytochrome c and dATP, however, did not reproduce the mitochondrial potentiation in the absence of the organelle. Thus, mitochondria can initiate and potentiate apoptosis through similar but not identical mechanisms.
 ...
PMID:Potentiation of apoptosis by mitochondria in a cell-free system. 987 42

In this study, we first demonstrated that the widely used oral antifungal drug, ketoconazole (KT), can induce apoptosis in various type of human cancer cells and in a primary culture of rat liver cells. We further investigated the molecular mechanisms of KT-induced apoptosis. It was found that KT induced nuclear accumulation of p53 protein in a dose- and time-dependent manner. The level of p53 protein was elevated approximately three times as much in treated cells 24 h after KT (5 microM) exposure as in cells receiving mock treatment. We found that cells containing wild-type p53 (COLO 205 and Hep G2) were more sensitive to KT exposure. The bax protein was induced and the bcl-2 protein was inhibited by KT in cells containing wild-type p53 (Hep G2, COLO 205) but not in cells without p53 (Hep 3B). The caspase-3 was activated 24 h after KT treatment. The Poly-(ADP ribose) polymerase (PARP) and the lamin A degradation was induced by KT, which promoted nuclear membrane disassembly and eventually caused apoptosis. Our results also indicated that none of the PKC gene family was involved in KT-induced apoptosis.
 ...
PMID:Ketoconazole-induced apoptosis through P53-dependent pathway in human colorectal and hepatocellular carcinoma cell lines. 987 98

Although p53 has been shown to directly activate transcriptional bax gene and to inhibit expression of bcl-2 gene during radiation-induced apoptosis, it is poorly understood how the Bcl-2 family changes in p53-deficient cells during radiation-induced apoptosis. The present work describes the effect of X-irradiation on the apoptosis of p53-deficient HL-60 cells as assessed by means of several methods. Apoptosis of HL-60 cells was induced by X-irradiation in a dose- and time-dependent manner. 18 h after 5 Gy irradiation, G2 cells underwent apoptosis, while 15 Gy X-irradiation induced the death of G1/S cells by 6 h. After X-irradiation, expression of Bcl-2 was elevated, while Bax expression was unchanged. We have isolated a clonal HL-60 variant following twice 5 Gy irradiation of HL-XR3 cells. These cells highly expressed Bcl-2 (about 2-fold), showed a reduced activation of caspase-3, and were not only more resistant to X-irradiation-induced apoptosis but also more radioresistant. These results suggest that HL-60 cells may resist apoptosis and radiation by increasing Bcl-2 expression, and that this elevated Bcl-2 expression might be one of the causes of the phenomenon, often seen clinically, that tumor cells gradually acquire radioresistance during fractionated radiation therapy.
 ...
PMID:X-irradiation enhances the expression of Bcl-2 in HL-60 cells: the resulting effects on apoptosis and radiosensitivity. 991 21

One of the main problems in the culture of Chinese Hamster Ovary (CHO) cells continues to be the inability to maintain the viability of the cultures over an extended period of time. The rapid decline in viability at the end of the culture is exacerbated by the absence of serum. In trying to reduce the extent of death in these cultures, we first tried to determine the mode of death. We found that more than 80% of the cells in a standard serum-free batch culture of CHO cells in suspension died via apoptosis--as evidenced by condensed chromatin and the appearance of a characteristic DNA ladder. Furthermore, when protein synthesis was inhibited using cycloheximide, the cells underwent rapid apoptosis indicating that death proteins were present in greater abundance than survival proteins in our CHO cells. Cell lysate from CHO cells showed evidence of cysteine protease (caspase) activity. Caspases of the Interleukin-1-beta-Converting Enzyme (ICE) family, e.g., CPP32, Mch-1, etc., have been implicated in the apoptotic process. Surprisingly, a caspase peptide inhibitor, N-benzyloxycarbonyl-Val-Ala-Asp-fluoro-methyl-ketone (z-VAD.fmk), was unable to substantially extend the life of a serum-free batch culture of CHO cells. In addition, z-VAD.fmk was only marginally able to extend viability in response to withdrawal of growth and survival factors, insulin and transferrin. In both these instances, z-VAD.fmk was able to prevent cleavage of caspase substrates, but not protect cells from death. However, we found that bcl-2 expression was able to significantly extend viabilities in CHO batch culture. Bcl-2 expression also substantially extended the viability of cultures in response to insulin and transferrin withdrawal. These results provide interesting insights into the pathways of death in a CHO cell.
 ...
PMID:Apoptosis in batch cultures of Chinese hamster ovary cells. 995 21

The occurrence of metastatic spread depends on many factors both the condition of the patient and the properties of the tumor. In this investigation the association between proliferation and apoptosis and the incidence of lymph node involvement of patients with non-small cell lung carcinomas was analysed (n=215 patients). In order to analyse the relationship between lymph node metastasis and proliferative activity of the carcinomas, the distribution of cell cycle phases (flow cytometry), the expression of PCNA and cyclin A (immunohistochemistry) was determined. Fas, Fas-ligand, caspase-3 and Bcl-2 were determined by immunohistochemistry. In this retrospective analysis no association between proliferative activity of the tumors and lymph node status was found. In contrast, there existed a correlation between the apoptotic factors and lymph node metastasis. Higher expression of the pro-apoptic factors Fas, Fas-ligand and caspase-3 correlated with a lower incidence of lymph node involvement (Fas-ligand, p=0.004; caspase-3, p=0.007). The trend of an inverse correlation between the anti-apoptotic factor Bcl-2 and metastasis fits well into the present knowledge about the function of the bcl-2 gene. The results obtained from all the patients could be confirmed in patients with squamous cell lung carcinomas.
 ...
PMID:The implications of proliferation and apoptosis for lung cancer metastasis. 1002 8

We have previously shown that nitric oxide (NO) stimulates apoptosis in different human neoplastic lymphoid cell lines through activation of caspases not only via CD95/CD95L interaction, but also independently of such death receptors. Here we investigated mitochondria-dependent mechanisms of NO-induced apoptosis in Jurkat leukemic cells. NO donor glycerol trinitrate (at the concentration, which induces apoptotic cell death) caused (1) a significant decrease in the concentration of cardiolipin, a major mitochondrial lipid; (2) a downregulation in respiratory chain complex activities; (3) a release of the mitochondrial protein cytochrome c into the cytosol; and (4) an activation of caspase-9 and caspase-3. These changes were accompanied by an increase in the number of cells with low mitochondrial transmembrane potential and with a high level of reactive oxygen species production. Higher resistance of the CD95-resistant Jurkat subclone (APO-R) cells to NO-mediated apoptosis correlated with the absence of cytochrome c release and with less alterations in other mitochondrial parameters. An inhibitor of lipid peroxidation, trolox, significantly suppressed NO-mediated apoptosis in APO-S Jurkat cells, whereas bongkrekic acid (BA), which blocks mitochondrial permeability transition, provided only a moderate antiapoptotic effect. Transfection of Jurkat cells with bcl-2 led to a complete block of apoptosis due to the prevention of changes in mitochondrial functions. We suggest that the mitochondrial damage (in particular, cardiolipin degradation and cytochrome c release) induced by NO in human leukemia cells plays a crucial role in the subsequent activation of caspase and apoptosis.
 ...
PMID:Nitric-oxide-induced apoptosis in human leukemic lines requires mitochondrial lipid degradation and cytochrome C release. 1009 Sep 45

Apoptosis is a cell death process morphologically distinct from necrosis. Cells undergoing apoptosis shrink, the plasma membrane forms blebs, and the nucleus condenses. The nuclear DNA is degraded into oligonucleosomal fragments. Apoptosis plays regulatory and protective roles by eliminating unnecessary and dangerous cells, respectively. Many factors involved in apoptosis have been identified, their roles and interactions being understood at the molecular level. The bcl-2 family regulates apoptosis, and its members are classified into two groups: anti-apoptotic that inhibits apoptosis and pro-apoptotic that induces or accelerates it. The members form dimers to inactivate each other. Caspases cleave other members of the caspase family to activate their proteolytic activity in a cascade-like fashion, and the final target proteins prosecute apoptosis. In the case of Fas or tumor necrosis factor receptors, apoptotic signals are transmitted to the caspases via protein-protein interactions, whereas in other cases they originate from mitochondria. In the early process of apoptosis, cytochrome c, which usually is involved in the respiratory chain, is released from mitochondria into the cytosol, then bind to Apaf-1, a homologue of CED-4 of nematoda, to process pro-caspase-9. The resulting activated caspase-9 cleaves pro-caspase-3 into an activated form, which is responsible for the later process of apoptosis.
 ...
PMID:[Molecular mechanism of apoptosis]. 1019 33

A murine erythroleukemic cell line (1-2-3) which expresses only the temperature-sensitive mutant p53 gene (Ala-to-Val substitution at codon 135) was established. These cells showed typical characteristics of apoptosis, when they were cultured at 32 degrees C. In this process, p53 recovered the wild-type p53 function and the expression of the p21 (waf1/cip1/sdi1), cyclin G1 and gadd45 genes was increased. However, no significant changes were detected in the expression of the mdm2, bcl-2, bax, fas and fasl genes, suggesting the existence of other genes associated with apoptosis. Genes up-regulated by p53 were screened by the mRNA differential display method. One of the up-regulated genes was identified as the elongation factor 1 alpha (EF-1 alpha) gene. EF-1 alpha is also a microtubule-severing protein. Upon the temperature-shift, the cells developed the morphology and the localization of alpha-tubulin similar to those of the cells treated with vincristine, a drug that affects microtubules. The microtubule-severing associated with up-regulation of EF-1 alpha by p53 may be a cause of the cell death. On the other hand, the function of cyclin G1 is not so clear despite the fact that 1-2-3 cells showed a significant increase of the cyclin G1 gene during the early stage of apoptosis. The yeast two-hybrid system was used to identify cyclin G1-associated proteins. One is a cytochrome c (Cyt c) oxidase subunit II (COXII). Cyclin G1 and COXII were co-immunoprecipitated from an extract of human osteosarcoma cell line that expressed high levels of cyclin G1. COX activity was also increased by temperature-shift in this cell line. The pattern of changes in COX activity was closely reflected by the expression of the cyclin G1 gene. Cyclin G1 and COXII associate physically with each other in vivo and that activation of COXII by binding to cyclin G1 upregulated by p53 may be associated with apoptosis. These two new pathways, p53-EF-1 alpha-microtubule-severing (-distortion of cytoskeleton) and p53-cyclin G1-COXII (-CytC, ATP-caspase-3 activation), may cooperate to induce apoptosis in this cell line.
 ...
PMID:The mechanisms of death of an erythroleukemic cell line by p53: involvement of the microtubule and mitochondria. 1019 36

Recent data support a role for apoptosis, under tight regulatory control by bcl-2, oxidative stress response, tumor suppressor, and CASP gene family members, in mediating granulosa cell demise during follicular atresia in the rodent and avian ovary. Herein we evaluated the occurrence of apoptosis in the human and baboon ovary relative to follicular health status, and analyzed expression of several cell death genes in these tissues. In situlocalization of DNA strand breaks in fixed human and baboon ovarian tissue sections indicated that apoptosis was essentially restricted to granulosa cells of atretic antral follicles. Biochemical analysis of DNA oligonucleosomes in individual follicles isolated from baboon ovaries during the ovulatory phase revealed the presence of apoptotic DNA fragments in subordinate but not dominant follicles, thus substantiating the in situ labeling studies. Messenger RNA transcripts encoded by the bax death susceptibility gene, the bcl-xlong survival gene, the bcl-xshort pro-apoptosis gene, the p53 tumor suppressor gene, and two members of the CASP gene family (CASP-2/Ich-1, CASP-3/CPP32), were detected by Northern blot analysis of total RNA prepared either from human ovaries or from Percoll-purified granulosa-lutein cells obtained from patients undergoing assisted reproductive technologies. Lastly, immunohistochemical localization of the BAX death-susceptibility protein in the human ovary revealed abundant expression in granulosa cells of early atretic follicles, whereas BAX protein was extremely low or non-detectable in healthy or grossly-atretic follicles. We conclude that apoptosis occurs during, and is probably responsible for, folicular atresia in the human and baboon ovary. Moreover, apoptosis in the human ovary is likely controlled by altered expression of the same cohort of cell death regulatory factors recently implicated as primary determinants of apoptosis induction or suppression in the rodent ovary.
 ...
PMID:Analysis of apoptosis and expression of bcl-2 gene family members in the human and baboon ovary. 1020 Apr 47

The execution phase of apoptosis is comprised of those processes that commit cells to apoptotic death. Many independent studies have implicated mitochondria as playing a critical role in apoptotic execution. The activation of caspase-3 and subsequent late stage degradative events are probably triggered by the release of proteins (such as cytochrome c) from the intermembrane space of mitochondria. The mechanisms responsible for this release are controversial but may include mitochondrial permeability transition and bcl-2-regulated swelling of the mitochondrial matrix. Two theoretical models of execution are discussed. It is important to note that some critical features of these models are largely based on data acquired from cell-free studies. Further studies with intact cells are urgently needed to test the physiological validity of these models.
 ...
PMID:Apoptosis: unmasking the executioner. 1020 May 19


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>