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 effects of reactive oxygen species (ROS) on tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in solid cancers have yet to be clearly defined. In this study, we found that the classic uncoupler of oxidative phosphorylation, carbonyl cyanide m-chlorophenylhydrazone (CCCP), induced a reduction in DeltaPsim and generation of ROS. This uncoupling effect enhanced TRAIL-induced apoptosis in TRAIL-resistant human colon carcinoma cell lines (RKO, HT29, and HCT8). Sensitization was inhibited by benzyloxycarbonyl-valine-alanine-aspartate fluoromethylketone, indicating the requirement for caspase activation. CCCP per se did not induce apoptosis or release of proapoptotic factors from mitochondria. Generation of ROS by CCCP was responsible for TRAIL-induced Bax and caspase activation because scavenging ROS completely abrogated apical caspase-8 activation and further downstream events leading to cell death. Overexpression of Bcl-2 did not prevent the initial loss of DeltaPsim and ROS generation following CCCP treatment, but did prevent cell death following TRAIL and CCCP exposure. Uncoupling of mitochondria also facilitated TRAIL-induced release of proapoptotic factors. X-linked inhibitor of apoptosis overexpression abrogated TRAIL-induced apoptosis in the presence of CCCP and decreased initiator procaspase-8 processing, indicating that additional processing of caspase-8 required initiation of a mitochondrial amplification loop via effector caspases. Of interest, depletion of caspase-9 in RKO cells did not protect cells from TRAIL/CCCP-induced apoptosis, indicating that apoptosis occurred via a caspase-9-independent pathway. Data suggest that in the presence of mitochondrial-derived ROS, TRAIL induced mitochondrial release of Smac/DIABLO and inactivation of X-linked inhibitor of apoptosis through caspase-9-independent activation of caspase 3.
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PMID:Reactive oxygen species regulate caspase activation in tumor necrosis factor-related apoptosis-inducing ligand-resistant human colon carcinoma cell lines. 1610 97

Effect of varying extracellular pH on mode of cell death induced by photodynamic action of chlorin p6 was investigated in human colon carcinoma (Colo-205) cells. At an extracellular pH of 7.4, compared to cells treated with chlorin p6 in dark, the photodynamically treated cells showed reduction in mitochondrial membrane potential, an increase in ADP/ATP ratio (1:2) and a large percentage of cells with chromatin condensation. In contrast, when photodynamic treatment and post irradiation incubation was carried out in acidic medium (pH 6.5), total loss of mitochondrial membrane potential, a marked increase in ADP/ATP ratio (1:33) and increased damage to plasma membrane were observed. Further, cells subjected to photodynamic treatment in a medium of pH 7.4 showed twofold increase in caspase-3 activity as compared to photodynamic treatment at pH 6.5. These results suggest that chlorin p6 mediated photodynamic action induces apoptotic cell death when extracellular pH is 7.4 whereas necrosis is more predominant under condition when extracellular pH is 6.5.
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PMID:Extracellular pH influences the mode of cell death in human colon adenocarcinoma cells subjected to photodynamic treatment with chlorin p6. 1615 55

The role of the product in the treatment of colorectal cancer is reviewed in the light of experimental and clinical results to date. The fermented wheat germ extract (code name: MSC, trade name: Avemar) registered as a dietary food for special medical purposes for cancer patients to complement the active oncotherapy, exerted a growth inhibitory effect in HCR-25 human colon carcinoma xenograft, and had a synergistic effect with 5-FU in mouse C-38 colorectal carcinoma. The product is capable of chemoprevention of colon carcinoma in F-344 rats. One of the most significant underlying mechanism is a highly cancer cell specific induction of caspase-3 mediated cleavage of PARP. In the frame of supportive therapy, fermented wheat germ extract proved to be efficient in the treatment of colorectal cancer in humans. 30 patients following radical operation were treated with standard postoperative therapy, 12 of them were given fermented wheat germ extract as additive treatment: following a 9 month long administration, no new distant metastases were detected, in contrast to 4 out 18 treated with standard therapy alone. Out of 34 patients following radical surgery and treated with chemotherapy, 17 who were given fermented wheat germ extract, achieved an improved survival rate. In the frame of a controlled multicenter open label cohort study, 170 colorectal cancer patients received anticancer therapies (chemo/radiotherapy) completed with fermented wheat germ extract in 66 of them. Results (fermented wheat germ extract vs. control): new recurrences: 3.0% vs. 17.3% (p < 0.01); new metastases: 7.6% vs. 23.1% (p < 0.01); deaths: 12.1% vs. 31.7% (p < 0.01), progression-related events in total: 16.7% vs. 42.3% (p < 0.001). Survival analysis showed significant improvements in the fermented wheat germ extract group, regarding progression-free (p = 0.0184) and overall survival probabilities (p = 0.0278). Strong predictors of survival determined by Cox's proportional hazards were UICC stage and fermented wheat germ extract treatment. Mild gastrointestinal side effects were observed in 9 cases. Supportive application of fermented wheat germ extract in colorectal cancer is highly recommended.
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PMID:[Fermented wheat germ extract in the supportive therapy of colorectal cancer]. 1625 77

The combination of irinotecan (CPT-11) and 5-fluorouracil (5-FU) is currently used in the treatment of advanced colorectal carcinoma. When compared to both agents alone, CPT-11 followed by 5-FU treatment demonstrated a synergistic effect. This observation can be related to increased in apoptosis induction after caspase activation. Several studies have demonstrated that changes in mitochondrial membrane potential occur earlier in apoptosis. In this study, we verified whether the collapse in mitochondrial membrane and the activation of caspases is responsible for increased apoptosis observed with CPT-11/5-FU treatment. Thus, HT-29 and SNU-C4 human colon carcinoma cell lines were exposed for 24 h to each drug alone, and to various combinations and treatment sequences, and assessed for colony formation, changes in the mitochondrial membrane potential, and the activities of caspase-3, -8, and -9. The CPT-11/5-FU treatment induced apoptosis in both cell lines; however, the most pronounced effect was observed in HT-29 cells. In these cells, both caspase-3 and -9 were involved in the activation of apoptosis after CPT-11/5-FU treatment. Moreover, in these cells, a reduction of 50% in mitochondrial membrane potential was observed with this treatment. On the other hand, in the SNU-C4 cell line in addition to caspase-3 and-9, caspase-8 seems to be important to apoptosis after CPT-11/5-FU treatment. Furthermore, in this cell line we did not observe alterations in mitochondrial membrane potential. In spite of the differences among the cell lines, these results indicated that the increase in apoptosis in HT-29 cells observed with CPT-11 followed by 5-FU treatment could be explained by a disruption in mitochondria membrane potential that induced caspases activation.
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PMID:Irinotecan/5-fluorouracil combination induces alterations in mitochondrial membrane potential and caspases on colon cancer cell lines. 1649 56

Nucleoside anticancer drugs like gemcitabine (2'-deoxy-2',2'-difluorocytidine) are potent inducers of p53, and ectopic expression of wild-type p53 sensitizes cells to these agents. However, it is also known that nucleosides are efficient activators of apoptosis in tumor cells that do not express a functional p53. To clarify this issue, we examined the effects of gemcitabine and 4'-thio-beta-d-arabinofuranosylcytosine (T-ara-C) on p73, a structural and functional homologue of p53, whose activation could also account for nucleoside-induced apoptosis because no functionally significant mutations of p73 have been reported in cancers. Acute treatment of HCT 116 colon carcinoma cells with gemcitabine or T-ara-C induced marked cytotoxicity and cleavage of caspase-3 and poly(ADP-ribose) polymerase. T-ara-C and gemcitabine markedly induced p53 accumulation as well as increased levels of phospho-p53 (Ser15/Ser20/Ser46) and induced its binding to a consensus p53 response element. Despite robust activation of p53 by T-ara-C and gemcitabine, we found that wild-type and p53-/- HCT 116 cells exhibited almost equivalent sensitivity towards these nucleosides. Examination of p73 revealed that T-ara-C and gemcitabine markedly increased p73 protein levels and p73 DNA-binding activities in both p53-/- and wild-type cells. Furthermore, T-ara-C- and gemcitabine-induced increases in p73 levels occur due to a decrease in p73 protein turnover. RNA interference studies show that nucleoside-induced p73 increases are independent of c-Abl, a nucleoside-activated kinase recently implicated in p73 stabilization. HCT 116 lines, wherein the downstream p53/p73 targets Bax and PUMA (p53 up-regulated modulator of apoptosis) were deleted, were less sensitive to T-ara-C and gemcitabine. Together, these studies indicate that c-Abl-independent p73 stabilization pathways could account for the p53-independent mechanisms in nucleoside-induced apoptosis.
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PMID:c-Abl-independent p73 stabilization during gemcitabine- or 4'-thio-beta-D-arabinofuranosylcytosine-induced apoptosis in wild-type and p53-null colorectal cancer cells. 1650 15

Photodynamic therapy (PDT) typically involves systemic or topical administration of a tumor-localizing photosensitizer or prodrug and its subsequent activation by visible light. This results primarily in singlet oxygen-induced photodamage to the tumor. 5-Aminolevulinic acid (ALA) and its derivatives have recently been widely used for PDT due to their selective induction in tumor of endogenous protoporphyrin IX (PpIX), a potent photosensitizer. Although ALA-PDT has achieved successful results in the treatment of several clinical oncological and nononcological diseases, the mechanisms of this modality are still not fully elucidated. In the present study, the human colon carcinoma cell line 320DM was treated in vitro with PDT using hexaminolevulinate (HAL), a hexylester of ALA known to be 50 to 100 times more efficient at producing PpIX formation than ALA itself. PpIX production increased with increasing HAL concentrations in the cells and phototoxicity of the cells was enhanced with increasing light (450 nm) doses. HAL-PDT induced apoptotic cell death, as measured by nuclear staining of Hoechst 33342 for fluorescence microscopy, DNA electrophoresis and TdT staining for flow cytometry. PDT with 5 muM of HAL and a light dose of 640 mJ/cm2 produced a 75% apoptotic cell population 40 hr after the treatment. Furthermore, the loss of mitochondrial membrane potential coincident with the release of cytochrome c from the mitochondria into the cytosol led to a rapid activation of caspase-9 and caspase-3 (an executioner), indicating that the selective damage to the mitochondria by HAL-PDT can induce a cytochrome-c-mediated apoptotic response in the 320DM cells.
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PMID:Induction of apoptosis by hexaminolevulinate-mediated photodynamic therapy in human colon carcinoma cell line 320DM. 1656 15

A controlled balance among cell proliferation, differentiation, and apoptosis is required for the maintenance of gastrointestinal mucosa; these processes are influenced by luminal components, such as butyrate and bile acids. Using butyrate-sensitive (BCS-TC2) and butyrate-resistant (BCS-TC2.BR2) human colon carcinoma cells, we wanted to establish whether colon carcinoma cells that acquire resistance to butyrate-induced apoptosis are also resistant to the cytotoxic effect of certain bile acids, contributing, in this way, to the progression of colon carcinogenesis. The effect of bile acids on BCS-TC2 cell viability is dose and time dependent and highly stereospecific. Quantification of the relative percentage of apoptotic cells and caspase-3 activity reveals that deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA) induce apoptosis in BCS-TC2 cells. BCS-TC2.BR2 cells are consistently less sensitive to their cytotoxic effects, requiring concentrations to induce 50% inhibition (IC50) in cell viability of 740 microM and >1 mM for CDCA and DCA, respectively, compared with IC50 values of 310 and 540 microM for BCS-TC2 cells. DCA-treated BCS-TC2.BR2 cells show few apoptotic signs and no caspase-3 activation. On the other hand, CDCA-treated BCS-TC2.BR2 cells show caspase-3 activation and apoptotic features, although to a lower extent than BCS-TC2 cells. Our results, in an in vitro model system, point out that acquisition of butyrate resistance is accompanied by a partial resistance to the cytotoxic effects of bile acids, which may enhance the survival of tumorigenic cells.
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PMID:Effect of bile acids on butyrate-sensitive and -resistant human colon adenocarcinoma cells. 1657 82

Mylabris is used in clinical therapy, but is always accompanied by cystitis. The toxic effects of mylabris on bladder are attributed to its active principle: cantharidin. In the present study, we explored how cantharidin induces cytotoxicity in the bladder. Human bladder carcinoma cell line T 24 cells were used as target cells, and human colon carcinoma HT 29 cells as native cells. Cantharidin exhibited acute cytotoxicity in the T 24 cells, and IC(50) was 21.8, 11.2 and 4.6 microM after treatment for 6, 24 and 48 h, respectively. The cytotoxicity of cantharidin was not significantly enhanced when T 24 cells were treated for a longer time. Moreover, PARP proteins and pro-caspase 3, Bcl-2 were significantly inhibited after cantharidin treatment in T 24 cells. Pretreatment with the caspase 3 inhibitor markedly inhibited cantharidin-induced cell death. Therefore, we suggested that cantharidin could induce apoptosis via active caspase 3 in T 24 cells. When T 24 cells were treated with cantharidin at a low dose, the cell cycle was arrested in the G(2)/M phase. Furthermore, p21(Cip1/Waf1) was enhanced, and cyclin A, B1 and cdk1 decreased. At a high dose (more 12.5 microM), cantharidin could stimulate T 24 cells to deplete a large number of ATP and induce secondary necrosis. In addition, cantharidin also stimulated COX 2 over-expression and PGE(2) production in T 24 cells, in a dose-dependent manner. However, cantharidin also induced apoptosis and G(2)/M phase arrest in HT 29 cells, but did not induce COX 2 over-expression. Therefore, we suggest that cantharidin may induce cystitis through secondary necrosis and COX 2 over-expression.
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PMID:Cantharidin-induced cytotoxicity and cyclooxygenase 2 expression in human bladder carcinoma cell line. 1669 99

The synergistic interaction between proteasome inhibitors and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a promising approach to induce cell death in tumor cells. However, the molecular and biochemical mechanisms of this synergism have been proven to be cell type specific. We therefore focused our investigation on TRAIL-resistant colon carcinoma cells in this study. DNA fragmentation, mitochondrial membrane depolarization and increased caspase-3-like enzyme activity was exclusively induced only by combined treatment with proteasome inhibitors (epoxomicin, MG132, bortezomib/PS-341) and TRAIL. The expression level of anti-apoptotic proteins (XIAP, survivin, Bcl-2, Bcl-XL), regulated by NF-kappaB transcription factor, was not effected by any of these treatments. TRAIL alone induced only partial activation of caspase-3 (p20), while the combination of TRAIL and proteasome inhibition led to the full proteolytic activation of caspase-3 (p17). Only the combination treatment induced marked membrane depolarization and the release of cytochrome c, HtrA2/Omi and Smac/DIABLO. Apoptosis-inducing factor (AIF) was not released in any of these conditions. These results are consistent with a model where the full activation of caspase-3 by caspase-8 is dependent on the release of Smac/DIABLO in response to the combined treatment. This molecular mechanism, independent of the inhibition NF-kappaB activity, may provide rationale for the combination treatment of colon carcinomas with proteasome inhibitors and recombinant TRAIL or agonistic antibody of TRAIL receptors.
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PMID:Proteasome inhibitors sensitize colon carcinoma cells to TRAIL-induced apoptosis via enhanced release of Smac/DIABLO from the mitochondria. 1699 92

The role of the cyclin-dependent kinase (CDK) inhibitor p21 as a mediator of p53-induced growth arrest is well established. In addition, recent data provide strong evidence for new emerging functions of p21, including a role as a modulator of apoptosis. The mechanisms, however, by which p21 interferes with the death machinery, especially following ionizing radiation (IR), are largely unknown. Here, we report that IR induced caspase-9 and caspase-3 activation and subsequent apoptosis only in p21-deficient colon carcinoma cells, whereas similar treated wild-type cells were permanently arrested in the G(2)-M phase, correlating with the induction of cellular senescence. Interestingly, activation of the mitochondrial pathway, including caspase-2 processing, depolarization of the outer mitochondrial membrane, and cytochrome c release, was achieved by IR in both cell lines, indicating that p21 inhibits an event downstream of mitochondria but preceding caspase-9 activation. IR-induced p21 protein expression was restricted to the nucleus, and no evidence for a mitochondrial or cytoplasmic association was found. In addition, p21 did neither interact with caspase-3 or caspase-9, suggesting that these events are not required for the observed protection. Consistent with this assumption, we found that CDK inhibitors potently abrogated IR-induced caspase processing and activation without affecting mitochondrial events. In addition, in vitro caspase activation assays yielded higher caspase-3 activities in extracts of irradiated p21-deficient cells compared with extracts of similar treated wild-type cells. Thus, our results strongly indicate that p21 protects cells from IR-induced apoptosis by suppression of CDK activity that seems to be required for activation of the caspase cascade downstream of the mitochondria.
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PMID:p21 blocks irradiation-induced apoptosis downstream of mitochondria by inhibition of cyclin-dependent kinase-mediated caspase-9 activation. 1714 70


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