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)

Chemotherapeutic anti-cancer drugs induce cell death by the process of apoptosis. Efflux of potassium ions (K(+)) is necessary for cell volume reduction during apoptosis and increased inward pumping of K(+) thus counteracts apoptosis. Potassium flux modulation could therefore interact with apoptosis and affect the efficiency of cancer chemotherapeutics. We explored if the K(+) efflux stimulator amphotericin B, with or without the Na(+), K(+), 2Cl(-)-cotransport (K(+) influx) blocker bumetanide, could affect cisplatin- and carboplatin-induced apoptosis and cytotoxicity in the pulmonary mesothelioma cell line (P31). Apoptosis was determined by quantifying free nucleosomes and caspase-3 activity, and cytotoxicity was determined by clone formation and a fluorometric assay. The pan-caspase enzyme inhibitor Boc-D-FMK was used to further determine the role of caspase activity in K(+)-flux-modulated cisplatin-/carboplatin-induced apoptosis and cytotoxicity. Amphotericin B (3.2 micromol/L) combined with bumetanide (100 micromol/L) potentiated cisplatin-induced free nucleosome and caspase-3 activity. The combination of the K(+) modulators did not, however, increase cisplatin cytotoxicity. The caspase inhibitor Boc-D-FMK, but unexpectedly also bumetanide, markedly reduced cisplatin cytotoxicity and annihilated the augmented cytotoxicity of cisplatin in the presence of amphotericin B. Carboplatin cytotoxicity was reduced by bumetanide, but not affected by amphotericin B. Carboplatin and carboplatin/bumetanide cytotoxicity was further reduced by Boc-D-FMK. We conclude that the ability of cisplatin, and to a lesser extent carboplatin, to induce apoptosis is indeed influenced by cellular potassium flux modulators. We suggest that K(+) ionophores such as amphotericin B, and K(+) influx blockers such as bumetanide, alone or in combination, should be further evaluated for their potential clinical usefulness in influencing tumor cell apoptosis induced by cisplatin and other cancer chemotherapeutics.
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PMID:Cisplatin-induced apoptosis of mesothelioma cells is affected by potassium ion flux modulator amphotericin B and bumetanide. 1147 63

Mesothelioma is a fatal tumor resistant to all treatment modalities for reasons that are still unresolved. Glutathione (GSH)-associated pathways are induced by oxidants and cytotoxic drugs, and they are also involved in the progression and resistance of some tumor cells in vitro. The rate-limiting enzyme in GSH biosynthesis is gamma-glutamylcysteine synthetase (gamma GCS). However, the expression of this enzyme has not been systematically investigated in malignant tumors, and there are no studies of gamma GCS in biopsy specimens of malignant mesothelioma. We investigated the immunohistochemical distribution and expression of both subunits of gamma GCS in healthy pleural mesothelium, pleural mesothelioma tumor biopsy samples (34 cases), and mesothelioma cells in culture (7 cell lines). Nonmalignant mesothelium showed no immunoreactivity for either subunit in any of the cases. The heavy (catalytic) subunit of gamma GCS was highly immunostained in 29 and weakly positive in 5 cases. High-moderate and weak immunoreactivity of the light (regulatory) subunit of gamma GCS was found in 15 and 7 tumors, respectively, whereas 12 cases showed no reactivity. There was no correlation with either catalytic or regulatory subunit expression and patient survival. There was, however, a significant correlation between the heavy chain and multidrug resistance protein (MRP) 2 (P =.048), whereas no correlation was observed between the light chain and MRP1 or MRP2. Treatment of cultured mesothelioma cells with buthionine sulfoximine (BSO), to inhibit gamma GCS, significantly potentiated cisplatin-induced cytotoxicity mainly by nonapoptotic mechanism when assessed by counting the living cells, TUNEL (terminal deoxytransferase-mediated dUTP nick-end labeling) assay, and caspase-3 cleavage. In conclusion, gamma GCS is highly positive in most cases of malignant mesothelioma and may play an important role in the primary drug resistance of this tumor in vivo.
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PMID:Overexpression of gamma-glutamylcysteine synthetase in human malignant mesothelioma. 1219 27

Our study was designed to investigate the role of the anti-apoptotic proteins Bcl-2 and Bcl-xL in the chemoresistance of cells derived from malignant pleural mesothelioma. First, we determined the basal expression levels of Bcl-2 and Bcl-xL in mesothelioma cells and examined the effect of their downregulation by antisense oligonucleotides. Bcl-xL mRNA and protein could be readily detected in mesothelioma cell lines, whereas only low levels of Bcl-2 mRNA and protein were found. Preferential downregulation of either Bcl-xL alone or of Bcl-xL and Bcl-2 simultaneously was achieved by treatment with antisense oligonucleotides 4259 and 4625, respectively, whereas the expression of other apoptosis-relevant genes remained unaffected. Treatment with oligonucleotides 4259 or 4625 lowered the apoptosis threshold in ZL34 mesothelioma cells, as indicated by an increase in cell death accompanied by increased caspase-3-like activity, a decrease of the mitochondrial transmembrane potential and the cleavage of procaspase-7 and ICAD. In addition to the direct induction of apoptosis, antisense treatment sensitized ZL34 cells to the cytostatic effect of cisplatin and gemcitabine, with the combination of 4625 and cisplatin being the most effective. Our results demonstrate that Bcl-2 and Bcl-xL antisense treatment facilitates apoptosis in mesothelioma cells and suggest the use of Bcl-2/Bcl-xL bispecific antisense treatment in combination with cisplatin or gemcitabine for therapy of malignant pleural mesothelioma.
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PMID:Induction of apoptosis and chemosensitization of mesothelioma cells by Bcl-2 and Bcl-xL antisense treatment. 1280 Jan 89

Diffuse malignant mesothelioma of the peritoneum is a rare diagnosis. Despite many histopathologic similarities between peritoneal and pleural tumors, clinical and prognostic features may be quite different. There is a paucity of data evaluating molecular features of peritoneal mesotheliomas. Therefore, we compared the results of a battery of immunohistochemical markers, some with therapeutic implications, in patients with primary peritoneal or pleural mesotheliomas. We examined 24 peritoneal and nine pleural malignant mesotheliomas with a battery of immunohistochemical markers (cytokeratin AE1/3, calretinin, c-kit/CD117, desmin, epidermal growth factor receptor (EGFR), estrogen receptors (ER), progesterone receptors (PR), MIB-1, and cleaved caspase-3) in an attempt to distinguish any differences in this tumor arising in these two distinct locations. The results indicate that the only marker to show a significant difference in its staining pattern between these two sites was EGFR (P=0.0004). In all, 92% (22/24) of peritoneal tumors demonstrated 3+ or 4+ immunoreactivity with EGFR, opposed to only 33% (3/9) pleural tumors. There was no significant difference in immunoreactivity between the pleural and peritoneal tumors with c-kit, ER, PR, cleaved caspase 3, calretinin, and desmin. There was a trend toward increased cytokeratin (P=0.07) and MIB-1 (P=0.08) expression in the peritoneal group. There was no significant difference in age, sex, or histologic subtype between the two locations. In conclusion, despite similarities between peritoneal and pleural mesothelioma, there are differences between this neoplasm arising in these two sites. The EGFR expression is more pronounced in peritoneal tumors compared to pleural tumors. The increased expression of EGFR in the peritoneal lesions may be of clinical significance with the recent emergence of epidermal growth factor receptor-targeted therapies.
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PMID:Diffuse malignant mesothelioma of the peritoneum and pleura, analysis of markers. 1497 33

Apoptosis plays an important role in cancer biology. We investigated the expression of caspases 3 and 8 in malignant mesothelioma and malignant mesothelioma cell lines and putative changes in their ultrastructural expression prior and after exposure to epirubicin. Further studies were conducted to compare these changes to the localization and expression of the bcl-2 group of proteins bcl-X, bax and mcl-1, and Fas-Fas ligand in the same cells. In the histological samples, caspase 3 and 8 immunoreactivity was seen in 27/37 (73%) and 16/37 (43%) of the mesotheliomas. The immunostaining was cytoplasmic diffuse, granular, and occasionally nuclear. All six mesothelioma cell lines expressed caspases 3 and 8 by immunoblotting. After exposure to epirubicin the extent of apoptosis was increased in all cell lines investigated, being weakest in the most resistant M38K cell line. Immunoelectron microscopy revealed immunogold labeling for caspases 3 and 8 in the mitochondria with the accumulation of caspase 3 in the apoptotic bodies, while the mitochondrial localization of the bcl-2 proteins appeared to be very stable. Fas receptor could be detected by flow cytometry, whereas the most resistant cell line (M38K) lacked Fas ligand when assessed by RT-PCR. These results suggest the importance of caspase 3 during the apoptotic process of mesothelioma cells and indicate that epirubicin-induced apoptosis is independent of the mitochondrial pathway.
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PMID:Activation and relocalization of caspase 3 during the apoptotic cascade of human mesothelioma cells. 1599 60

Malignant mesothelioma (MM) is an aggressive and highly chemo-resistant tumour. In this study, we examined cisplatin-induced apoptosis in mouse models of this disease and investigated the role of constitutive and inducible expression of apoptosis related genes in this process. All of the four mouse MM cell lines examined expressed Bax, Bcl-xL, c-Myc, and caspase-3 but not Bcl-2. Cisplatin-induced apoptosis characterised by DNA fragmentation and cell death while caspase-3/7 was activated in 3 of 4 cell lines. Quantitation of basal gene expression showed significant differences but there was no correlation between single genes and cisplatin sensitivity. In the AC29 and AB1 models, both cisplatin and TNF-alpha downregulated Bcl-xL gene expression, indicating that this gene was a common transcriptional target in these cells. The findings of the present study provide insights into apoptotic mechanisms in mesothelioma cells and show similar patterns of gene expression to that reported in the human disease.
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PMID:Cisplatin and TNF-alpha downregulate transcription of Bcl-xL in murine malignant mesothelioma cells. 1622 50

Malignant mesothelioma is an increasingly common tumor with an almost 100% mortality rate. It is refractory to conventional treatment. We have previously shown with SSH and microarray that the mRNA expression level of proteasome is higher in epithelioid mesothelioma cell lines than in sarcomatoid ones. This study evaluates the differential apoptotic effect of proteasome inhibitors on both of these mesothelioma sub-lines. Proteasome inhibitors show substantial anti-tumor activity in some tumor cells in vitro and in vivo, but the effects on mesothelioma cells has not been studied. The viability of mesothelioma cells was reduced in a dose- and time-dependent manner by the proteasome inhibitors tested; PSI was effective with a low dose, but higher concentrations were needed for calpain inhibitor I. The epithelioid mesothelioma cells are more sensitive to the inhibitors than the sarcomatoid ones, their IC50 after 24 h of treatment with PSI being 4 and 16 microm, respectively. Other mesothelioma cell lines show similar sensitivity. PSI seemed to decrease mesothelioma viability by inducing apoptosis, as verified by cell morphology, Western blotting analysis of caspase 3 cleavage, and flow-cytometric analysis. In conclusion, PSI, a representative agent that reduces viability and induces apoptosis of mesothelioma cells, might be useful in the treatment of patients with mesothelioma, especially of epithelioid phenotype.
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PMID:Proteasome inhibitor PSI induces apoptosis in human mesothelioma cells. 1645 12

Depletion of intracellular potassium ions (K+) is necessary for cells to shrink, activate caspases and induce DNA fragmentation, events which are features of apoptosis. Here we describe a 96-well plate method using the cell permeable form of K+ binding benzofuran isophtalate (PBFI-AM) to measure intracellular K+ content in relation to untreated control. Cultured human pulmonary mesothelioma cells (P31) and small-cell lung cancer cells (U1690) were treated with K+ flux modulators in order to deprive the cells of intracellular K+. The combination of K+ influx inhibition with 10 micromol/L bumetanide plus 10 micromol/L ouabain and K+ efflux stimulation with 3 mg/L amphotericin B or 5 micromol/L nigericin efficiently reduced the intracellular K+ content after 3 h. Manipulation of K+ fluxes with subsequent intracellular K+ depletion induced apoptosis of lung cancer cells, as detected by caspase-3 activity after 3 h K+ depletion followed by 24 h proliferation and TUNEL positive staining after 48 h proliferation. We concluded that the PBFI-AM assay was a useful tool to determine intracellular K+ content in relation to untreated control, and that intracellular K+ depletion of lung cancer cells by clinically used drugs of relevant concentrations induced apoptosis. These findings may lead to novel therapeutic strategies in the treatment of lung cancer.
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PMID:Induction of apoptosis by intracellular potassium ion depletion: using the fluorescent dye PBFI in a 96-well plate method in cultured lung cancer cells. 1648 38

Solid tumors such as mesothelioma exhibit a stubborn resistance to apoptosis that may derive from survival pathways, such as PI3K/Akt/mTOR, that are activated in many tumors, including mesothelioma. To address the role of PI3K/Akt/mTOR, we used a novel approach to study mesothelioma ex vivo as tumor fragment spheroids. Freshly resected mesothelioma tissue from 15 different patients was grown in vitro as 1- to 2-mm-diameter fragments, exposed to apoptotic agents for 48 hours with or without PI3K/Akt/mTOR inhibitors, and doubly stained for cytokeratin and cleaved caspase 3 to identify apoptotic mesothelioma cells. Mesothelioma cells within the tumor spheroids exhibited striking resistance to apoptotic agents such as TRAIL plus gemcitabine that were highly effective against monolayers. In a majority of tumors (67%; 10 of 15), apoptotic resistance could be reduced by more than 50% by rapamycin, an mTOR inhibitor, but not by LY294002, a PI3K inhibitor. Responsiveness to rapamycin correlated with staining for the mTOR target, p-S6K, in the original tumor, but not for p-Akt. As confirmation of the role of mTOR, siRNA knockdown of S6K reproduced the effect of rapamycin in three rapamycin-responsive tumors. Finally, in 37 mesotheliomas on tissue microarray, p-S6K correlated only weakly with p-Akt, suggesting the existence of Akt-independent regulation of mTOR. We propose that mTOR mediates survival signals in many mesothelioma tumors. Inhibition of mTOR may provide a nontoxic adjunct to therapy directed against malignant mesothelioma, especially in those with high baseline expression of p-S6K.
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PMID:mTOR mediates survival signals in malignant mesothelioma grown as tumor fragment spheroids. 1851 8

Human malignant pleural mesothelioma (MPM) is a dreadful disease and there is still no standard therapy available for a consistent therapeutic approach. This research is aimed at the evaluation of the potential therapeutic effect of a specific nicotinic receptor (nAChR) antagonist, namely alpha-Cobratoxin (alpha-CbT). Its effectiveness was tested in mesothelioma cell lines and in primary mesothelioma cells in vitro, as well as in vivo, in orthotopically xenotransplanted NOD/SCID mice. Cells showed alpha7-nAChR expression and their growth was significantly inhibited by alpha-CbT. Severe induction of apoptosis was observed after exposure to alpha-CbT [IC(80-90)]. Apoptosis was characterised by: change in mitochondrial potential, caspase-3 cleavage, down-regulation of mRNA and protein for survivin, XIAP, IAP1, IAP2 and Bcl-XL, inhibition by caspase-3 inhibitor. In vivo, the alpha-CbT acute LD(50) was 0.15 mg/kg. The LD(100) [0.24 mg/kg] induced fatal respiratory failure and massive kidney necrosis. Phase II experiments with 0.12 ng/kg alpha-CbT (1/1000 of LD(10)) were done in 53 xenotransplanted mice, inhibiting tumour development as confirmed by chest X-ray examinations, autopsy and microscopical findings. The growth of human proliferating T lymphocytes and of mesothelial cells in primary culture was not affected by alpha-CbT. Non-immunogenic derivatives of the alpha-CbT molecule need to be developed for possible human use.
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PMID:Targeting alpha7-nicotinic receptor for the treatment of pleural mesothelioma. 1872 10


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