Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P42574 (caspase-3)
 45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The antineoplastic agent paclitaxel (TaxolTM), a microtubule stabilizing agent, is known to arrest cells at the G2/M phase of the cell cycle and induce apoptosis. We and others have recently demonstrated that paclitaxel also activates the c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) signal transduction pathway in various human cell types, however, no clear role has been established for JNK/SAPK in paclitaxel-induced apoptosis. To further examine the role of JNK/SAPK signaling cascades in apoptosis resulting from microtubular dysfunction induced by paclitaxel, we have coexpressed dominant negative (dn) mutants of signaling proteins of the JNK/SAPK pathway (Ras, ASK1, Rac, JNKK, and JNK) in human ovarian cancer cells with a selectable marker to analyze the apoptotic characteristics of cells expressing dn vectors following exposure to paclitaxel. Expression of these dn signaling proteins had no effect on Bcl-2 phosphorylation, yet inhibited apoptotic changes induced by paclitaxel up to 16 h after treatment. Coexpression of these dn signaling proteins had no protective effect after 48 h of paclitaxel treatment. Our data indicate that: (i) activated JNK/SAPK acts upstream of membrane changes and caspase-3 activation in paclitaxel-initiated apoptotic pathways, independently of cell cycle stage, (ii) activated JNK/SAPK is not responsible for paclitaxel-induced phosphorylation of Bcl-2, and (iii) apoptosis resulting from microtubule damage may comprise multiple mechanisms, including a JNK/SAPK-dependent early phase and a JNK/SAPK-independent late phase.
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PMID:Microtubule dysfunction induced by paclitaxel initiates apoptosis through both c-Jun N-terminal kinase (JNK)-dependent and -independent pathways in ovarian cancer cells. 1007 25

We investigated the intracellular mechanisms of retinoic acid (9-cis-RA, 13-cis-RA or all-trans-RA) and a cyclic AMP analog 8-Cl-cAMP on growth-inhibition and apoptosis in human ovarian cancer NIH: OVCAR-3 and OVCAR-8 cells. The cyclic AMP analog, 8-Cl-cAMP, acted synergistically with RA in inducing and activating retinoic acid receptor beta (RARbeta) which correlated with the growth inhibition, cell cycle arrest, and apoptosis in both cell types. In addition, combined treatment of cells with RA plus 8-Cl-cAMP resulted in the release of cytochrome c, loss in mitochondrial membrane potential and activation of caspase-3 followed by cleavage of anti-poly(ADP-ribose)polymerase and DNA-dependent protein kinase (catalytic subunit). Interestingly, inhibition of caspase-3 activation blocked RA plus 8-Cl-cAMP induced apoptosis. Furthermore, mutations in a CRE-related motif within the RARbeta promoter resulted in loss of both transcriptional activation of RARbeta and synergy between RA and 8-Cl-cAMP. Thus, RARbeta can mediate RA and/or cyclic AMP action in ovarian cancer cells by promoting apoptosis. Loss of RARbeta expression, therefore, may contribute to the tumorigenicity of human ovarian cancer cells. These findings suggest that RA and 8-Cl-cAMP act in a synergistic fashion in inducing apoptosis via caspase-3 activation, and may have potential for combination biotherapy for the treatment of malignant disease such as ovarian cancer.
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PMID:Synergistic effects of retinoic acid and 8-Cl-cAMP on apoptosis require caspase-3 activation in human ovarian cancer cells. 1020 36

We have assessed in detail the effect of cisplatin-activated programmed cell death in the cisplatin-sensitive human ovarian cancer cell line A2780 and two drug-resistant subclones, CP70 and C30. To determine whether the differential extent of apoptosis observed between the sensitive and resistant ovarian cancer cell lines was the result of dissimilar upstream signaling events, we assessed the execution of apoptotic events that precede target protein proteolysis and subsequent chromosomal DNA degradation. Proteolytic degradation of procaspase-3 was observed in both the CP70 and C30 cells following IC50 cisplatin treatment, whereas no proteolyzed caspase-3 subunits were detected in the A2780 cells. However, using a direct enzymatic assay measuring cleavage of the synthetic peptide substrate (N-acetyl-Asp-Glu-Val-Asp-p-nitroanilide), activity was detected in extracts prepared from A2780 cells treated at the IC90 level of cisplatin and was 2-3-fold less than that of extracts prepared from CP70 and C30 cells. Because the activation of procaspase-3 by caspase-9 requires the release of cytochrome c into the cytoplasm, we determined the level of cytoplasmic cytochrome c in each cell line in response to cisplatin treatment. Consistent with the caspase-3 activation data, a very small increase in cytoplasmic cytochrome c was observed in A2780 cells following cisplatin treatment, whereas dramatic increases were evident in both the CP70 and C30 cell lines. The expression of the mitochondrial factors Bcl-2, Bcl-x, and Bax was determined because each has been implicated in the regulation or release of cytochrome c at the level of the mitochondria. Bcl-2 and Bcl-xL proteins remained relatively unchanged in expression for over 48 h after exposure to cisplatin in the A2780 cell lines. However, within the same time period, expression of Bcl-2 decreased in the CP70- and C30-resistant cell lines, whereas an increase in Bcl-xL expression was observed. Expression of the proapoptotic Bcl-xS protein was observed in only the resistant CP70 and C30 cell lines independent of cisplatin treatment. A change in the expression of Mr 24,000 Bax to a Mr 21,000 isoform was evidenced in the A2780 cells within 48 h of cisplatin treatment and, to a greater extent, in the CP70 and C30 cells, which also expressed a Mr 16,000 Bax variant. Evidence for an alternative apoptotic pathway in A2780 cells was obtained by demonstrating increased FADD expression in response to cisplatin treatment. These results support a model in which cisplatin-induced programmed cell death in the cisplatin-sensitive A2780 and -resistant CP70 and C30 cells proceeds via caspase-3-independent and -dependent pathways, respectively.
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PMID:Cisplatin-induced apoptosis proceeds by caspase-3-dependent and -independent pathways in cisplatin-resistant and -sensitive human ovarian cancer cell lines. 1039 48

HER-2/neu-overexpressing breast cancer cells are more resistant to the chemotherapeutic agent paclitaxel (Taxol) than low-HER-2/neu-expressing breast cancer cells, and the adenoviral type 5 EIA can down-regulate HER-2/neu overexpression. Therefore, in this study, we asked (a) whether EIA might sensitize response to paclitaxel in human HER-2/neu-overexpressing ovarian cancer cells, and, if so, what is the mechanism responsible; and (b) whether this enhanced chemosensitivity would translate into a therapeutic effect in an ovarian cancer xenograft model. Consequently, we demonstrated that: (a) adenovirus type 5 E1A could enhance the sensitivity of paclitaxel in paclitaxel-resistant HER-2/neu-overexpressing human ovarian cancer cells in vitro by inducing apoptosis, (b) this induction was heavily dependent on activation of the caspase-3 pathway, and (c) nude mice bearing i.p. HER-2/neu-overexpressing human ovarian cancer cells and treated with both paclitaxel and E1A gene therapy survived significantly longer than did mice treated only with paclitaxel or E1A gene therapy. Thus, we concluded that the E1A gene enhanced both the in vitro and in vivo sensitivity of paclitaxel in paclitaxel-resistant HER-2/ neu-overexpressing ovarian cancer SKOV3.ipl cells. Because a Phase I clinical trial using E1A gene targeted to HER-2/neu down-regulation has recently been completed, the current study also provided a scientific basis to further develop a novel therapy that combines paclitaxel and E1A gene therapy and its testing in a Phase II trial.
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PMID:E1A-mediated paclitaxel sensitization in HER-2/neu-overexpressing ovarian cancer SKOV3.ip1 through apoptosis involving the caspase-3 pathway. 1065 56

Both cAMP and retinoids play a role in cell differentiation and the control of cell growth. A site-selective cAMP analog, 8-Cl-cAMP and retinoic acid synergistically inhibit growth and induce apoptosis in certain cancer cells. In advanced or recurrent malignant diseases, retinoic acid (RA) is not effective even at doses that are toxic to the host. The objective of our present study was to examine the mechanism(s) of synergistic effects of retinoic acid (9-cis, 13-cis or all-trans RA) and 8-Cl-cAMP on apoptosis in human ovarian cancer NIH: OVCAR-3 and OVCAR-8 cells. RA induced growth inhibition and apoptosis in OVCAR-3 and OVCAR-8 cells. 8-Cl-cAMP acted synergistically with RA in inducing and activating retinoic acid receptor beta (RARbeta) which correlates with growth inhibition and apoptosis in both cell types. In addition, induction of apoptosis by RA plus 8-Cl-cAMP requires caspase-3 activation followed by cleavage of anti-poly(ADP-ribose) polymerase. Furthermore, mutations in CRE-related motif within the RARbeta promoter resulted in loss of both transcriptional activation of RARbeta and synergy between RA and 8-Cl-cAMP. RARbeta expression appears to be associated with induction of apoptosis. Introduction of the RARbeta gene into OVCAR-3 cells resulted in gain of RA sensitivity. Loss of RARbeta expression, therefore, may contribute to the tumorigenicity of human ovarian cancer cells. Thus, combined treatment with RA and 8-Cl-cAMP may provide an effective means for inducing RARbeta expression leading to apoptosis in ovarian cancer cells.
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PMID:Synergistic effects of 8-Cl-cAMP and retinoic acids in the inhibition of growth and induction of apoptosis in ovarian cancer cells: induction of retinoic acid receptor beta. 1071 18

Several endogenous or viral inhibitors of apoptosis, including Bcl-2, Bcl-xL, FLIP, p35, and CrmA, have been shown to be cleaved by caspases during apoptosis. In this study, we demonstrate that the endogenous inhibitor of apoptosis, hILP/XIAP, is also cleaved in apoptotic T lymphocytes, generating at least one prominent fragment of 29 kDa. This p29 cleaved fragment was detected in Jurkat cells induced to apoptose by anti-Fas antibody, staurosporin, or VP-16. The cleavage of hILP appears to be caspase mediated because the production of the p29 protein was inhibited by the pan-caspase peptide inhibitor, Z-VAD.FMK. In Jurkat cells engineered to overexpress CrmA, cleavage of hILP in response to anti-Fas antibody or staurosporin was inhibited, whereas overexpression of Bcl-2 abrogated the cleavage in response to VP-16. Cleavage of hILP was also observed in cell-free reactions using in vitro translated hILP and recombinant caspase-3 or -7. Moreover, we found that the p29 hILP fragment retained the ability to bind caspase-3 and -7, as shown previously for full-length or BIR-2 hILP. The p29 cleavage product was also detected during T-cell receptor-mediated apoptosis in peripheral blood lymphocytes from normal donors. Furthermore, tumor-associated T lymphocytes purified from ascites of patients with ovarian cancer expressed fragmented hILP, which was not detected in control T cells purified from peripheral blood of normal donors. Our results suggest that the cleavage of hILP represents an important event in apoptosis of T lymphocytes in both normal and pathological in vivo settings.
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PMID:Inhibitor of apoptosis protein hILP undergoes caspase-mediated cleavage during T lymphocyte apoptosis. 1076 65

Cisplatin-centered chemotherapy is a key treatment for ovarian cancer, but resistance to chemotherapeutic agents remains a major cause of treatment failure. Multiple factors are known to contribute to the development of this chemoresistance. Although it has been demonstrated that X-linked inhibitor of apoptosis protein (Xiap) prevents apoptosis by inhibiting effector caspases, if and how it is important in chemoresistance in ovarian cancer has not been studied. The effects of Xiap down-regulation and/or restoration of wild type p53 by recombinant adenovirus infection were examined on four ovarian epithelial cancer cell lines [C13*, A2780-s (wild type p53), A2780-cp (mutant p53), and SKOV3 (null p53)]. Apoptosis and protein expression (e.g., Xiap, caspase-3, p53, MDM2, and p21waf1) were assessed by Hoechst 33258 stain and Western blot, respectively. We demonstrated that Xiap down-regulation following adenoviral antisense expression induces apoptosis in the wild-type p53 cells, but not in the mutated or null cells. Xiap down-regulation resulted in caspase-3 activation, caspase-mediated MDM2 processing, and p53 accumulation. Restoration of wild type p53 in the p53-mutated or -null cells significantly enhanced the proapoptotic effect of Xiap antisense expression. Down-regulation of Xiap induced apoptosis in chemoresistant ovarian cancer cells, a process dependent on p53 status.
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PMID:Down-regulation of X-linked inhibitor of apoptosis protein induces apoptosis in chemoresistant human ovarian cancer cells. 1105 57

The 2',5'-oligoadenylate (2-5A) system is an interferon (IFN)-regulated RNA decay pathway that provides innate immunity against viral infections. The biologic action of the 2-5A system is mediated by RNase L, an endoribonuclease that becomes enzymatically active after binding to 2-5A. RNase L is also implicated in mediating apoptosis in response to both viral and nonviral inducers. To study the cellular effects of RNase L activation directly, 2-5A was transfected into the human ovarian cancer cell line, Hey1B. Activation of RNase L by 2-5A resulted in specific 18S rRNA cleavage and induction of apoptosis, as measured by TUNEL and annexin V binding assays. In contrast, the dimeric form of 2-5A, ppA2'p5'A, neither activated RNase L nor caused apoptosis. Treatment with IFN-beta prior to 2-5A transfection enhanced cellular RNase L levels (< or = 2.2-fold) and increased the proportion of cells undergoing apoptosis (by < or =40%). However, rRNA cleavages after 2-5A transfections were not enhanced by IFN-beta pretreatments, indicating that basal levels of RNase L were sufficient for this activity. Apoptosis in response to RNase L activation was accompanied by cytochrome c release from mitochondria. Induction of apoptosis by either 2-5A alone or by the combination of 2-5A and IFN-beta was effectively blocked with either the pancaspase inhibitor, Z-VAD-fmk, or with the caspase 3 inhibitor, DEVD-fmk. Therefore, activation of RNase L by 2-5A leads to cytochrome c release into the cytoplasm and then to caspase activation and apoptosis. These results suggest potential uses for 2-5A in augmenting the anticancer activities of IFN.
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PMID:Caspase-dependent apoptosis by 2',5'-oligoadenylate activation of RNase L is enhanced by IFN-beta. 1115 76

Cytotoxic drugs commonly used in cancer therapy promote tumor cell death by inducing apoptosis, but the cell death pathway(s) is likely dependent on the mechanism of drug action. In the present study, we investigated the mechanisms of cell death induced by doxorubicin (DXR) and the novel disaccharide anthracycline MEN 10755, in a human ovarian cancer cell line (A2780). Exposure to either anthracycline induced the up-regulation of several genes known to promote cell cycle arrest and DNA repair (WAF1/p21, GADD45) or apoptosis (bax, Fas). Although the expression of Fas was increased, an antagonistic anti-Fas antibody ZB4 did not inhibit anthracycline-induced apoptosis, suggesting that the stimulation of the Fas receptor did not play a critical role in the induction of apoptosis in this cell line. We also observed that neither MEN 10755 nor DXR were able to induce apoptosis in A2780 cells deprived of the nucleus but retaining an intact mitochondrial function (cytoplasts) and that apoptosis induced by either anthracycline was inhibited by cycloheximide, indicating that it is an active process requiring new protein synthesis. Both the caspases inhibitors, ZVAD-fmk and DEVD-cho, inhibited at similar extent apoptosis induced by either DXR or MEN 10755, suggesting an involvement of caspase-3 in this response. We conclude that, in a tumor cell line of epithelial origin, the apoptosis following exposure to anthracyclines is an active process requiring protein synthesis and drug interaction with nuclear structures. The pathway was Fas-independent but likely involved bax and caspase-3 as effectors of the cascade culminating in apoptosis.
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PMID:Apoptotic events in a human ovarian cancer cell line exposed to anthracyclines. 1116 Jun 8

Resistance to chemotherapy commonly compromises the treatment of many advanced cancers. Evidence suggests a correlation between chemoresistance and more aggressive tumor growth, possibly through accumulation of additional genetic defects in drug-treated or resistant cells. To study this process in a human ovarian cancer model, we examined OVCAR-3 cells for acute sensitivity to cisplatin (cDDP) and subsequent emergence of drug-resistant clones following chronic cDDP exposure. Clonal cells (OVCAR-3/C-1) that displayed 20-fold reduced sensitivity to cisplatin but retained equivalent sensitivity to paclitaxel, as compared with the parental population, were isolated. The cDDP-resistant clone had growth kinetics similar to those of parental population, but when transplanted into the peritoneal cavity of nude mice, they acquired the ability to grow with the development of both ascites and solid tumor masses; such growth was not detectable after transplantation of the drug-sensitive parental cell line. C-1 cells had a p53 gene mutation (codon 266) that was not detected in the parental OVCAR-3 cell line, and infection of C-1 cells with p53-adenovirus (rAd-p53) caused greater apoptosis and gene transduction than that observed in the similarly infected parental population. rAd-p53 induced high levels of p21WAF1, p27Kip1, activated caspase 3 and apoptosis in C-1 cells, without causing major changes in bax or bcl-XL levels. Together, the results suggest that alterations in tumor growth and gene mutations characterize cDDP-resistance in OVCAR-3 cells, and viral replacement of one of these defective genes (p53) may provide an effective treatment for elimination of drug-resistant cells.
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PMID:Emergence of cisplatin-resistant cells from the OVCAR-3 ovarian carcinoma cell line with p53 mutations, altered tumorigenicity, and increased apoptotic sensitivity to p53 gene replacement. 1124 Jun 61


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