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 most active metabolite of vitamin D, calcitriol, is growth inhibitory for various tumor types in vitro and in vivo and inhibits the growth of endothelial cells freshly isolated from tumors [tumor-derived endothelial cells (TDEC)]. We compared the effects of calcitriol on Matrigel-derived endothelial cells (MDEC) and TDEC isolated from Matrigel plugs and squamous cell carcinoma tumors, respectively. TDEC and MDEC expressed vitamin D receptor (VDR) and responded to calcitriol by increasing VDR protein expression. Although no mutations were found in VDR from either cell type, Scatchard plot analysis revealed a higher ligand-binding affinity in TDEC (K(d), 0.26 nmol/L) than MDEC (K(d), 0.65 nmol/L). The VDR signaling axis in both cells was intact as shown using nuclear translocation and 24-hydroxylase promoter-luciferase reporter assays. However, unlike TDEC, MDEC were resistant to calcitriol-induced growth inhibition. Calcitriol (10 nmol/L) resulted in a 12.3% growth inhibition of MDEC compared with 47% in TDEC. In TDEC, calcitriol resulted in induction of G(0)/G(1) arrest (10.75%) and reduction of S-phase cells (6.8%) with induction of p27 and down-regulation of p21 protein expression. Apoptotic effects, determined by Annexin V staining were also observed in calcitriol-treated TDEC (38.6%). Calcitriol caused reduced expression of p-Erk and p-Akt and an increase of poly(ADP-ribose) polymerase and caspase-3 cleavage in TDEC. By contrast, none of these effects on cell cycle or apoptosis were seen in calcitriol-treated MDEC. These results show that TDEC were more sensitive than MDEC to the antiproliferative effects of calcitriol despite apparently normal VDR content and structure of signaling axis in both cell types.
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PMID:Differential antiproliferative effects of calcitriol on tumor-derived and matrigel-derived endothelial cells. 1695 Nov 69

1,25-Dihydroxyvitamin D(3) and vitamin D(3) analogues, such as EB 1089, potentiate the response to ionizing radiation in breast tumor cells. The current studies address the basis for this interaction by evaluating DNA damage and repair, the effect of interference with reactive oxygen generation, the involvement of p53 and caspase-3, signaling through c-myc, as well as the induction of senescence and multiple modes of cell death. EB 1089 failed to increase the extent of radiation-induced DNA damage or to attenuate the rate of DNA repair. The reactive oxygen scavengers N-acetyl-l-cysteine and reduced glutathione failed to protect the cells from the promotion of cell death by EB 1089 and radiation. Whereas MCF-7 cells expressing caspase-3 showed significant apoptosis with radiation alone as well as with EB 1089 followed by radiation, EB 1089 maintained its ability to confer susceptibility to radiation-induced cell killing, in large part by interference with proliferative recovery. In contrast, in breast tumor cells lacking p53, where radiation promoted extensive apoptosis and the cells failed to recover after radiation treatment, EB 1089 failed to influence the effect of radiation. EB 1089 treatment interfered with radiation-induced suppression of c-myc; however, induction of c-myc did not prevent senescence by radiation alone or radiation-induced cell death promoted by EB 1089. EB 1089 did not increase the extent of micronucleation, indicative of mitotic catastrophe, induced by radiation alone. However, EB 1089 did promote extensive autophagic cell death in the irradiated cells. Taken together, these studies suggest that the effect of EB 1089 treatment on the radiation response is related in part to enhanced promotion of autophagic cell death and in part to interference with the proliferative recovery that occurs with radiation alone in p53 wild-type breast tumor cells.
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PMID:Potentiation of radiation sensitivity in breast tumor cells by the vitamin D3 analogue, EB 1089, through promotion of autophagy and interference with proliferative recovery. 1712 25

Calcitriol (1,25-dihydroxycholecalciferol) has antiproliferative and/or proapoptotic effects on many cell types and the glucocorticoid dexamethasone enhances these effects. We have shown that calcitriol modulates several key signaling proteins involved in differentiation, proliferation and apoptosis in tumor-derived murine endothelial cells (TDEC) and that these effects were not seen with endothelial cells isolated similarly from normal tissues. In the present study, TDEC and mouse embryonic yolk sac endothelial cells (MYSEC) were treated with calcitriol and followed over time for an effect. MYSEC were utilized as 'normal' control endothelial cells because they were more primitive, being isolated from a highly neovascular tissue, and had a similar morphology without the stimulus of the tumor microenvironment. The vitamin D receptor (VDR) is present in TDEC and MYSEC, and was upregulated in calcitriol-treated TDEC and MYSEC; dexamethasone further increased VDR expression following 48 h of treatment. The modulatory effects on signaling proteins were maximal by treatment for 48 h; phospho-Erk, phospho-Akt, p21 and bcl-2 were decreased in treated TDEC with the induction of p27 but there were no effects on MYSEC. After 48 h increased apoptosis was seen in treated TDEC by annexin V labeling with caspase-3 cleavage and decreased levels of poly(ADP-ribose) polymerase, but no effects were seen in MYSEC. Cell cycle analysis showed increased G(0)/G(1) arrest and an increase in the apoptotic sub-G(1) peak in treated TDEC but similar effects were not seen in MYSEC following 48-hour treatment. Proliferation assays were utilized and TDEC demonstrated decreased proliferation compared to normal endothelial cells at 48 h. To determine whether or not the VDR signaling was impaired in MYSEC, we performed the 24-hydroxylase (CYP24) promoter-luciferase reporter assay. CYP24 is a key enzyme involved in the breakdown of vitamin D. VDR signaling was intact in both cell types and calcitriol induced CYP24 mRNA expression in MYSEC but not in TDEC. Taken together, despite similar levels of VDR expression and intact signaling in both cell types, calcitriol selectively inhibits proliferation and induces apoptosis in TDEC with no effect on MYSEC. Thus calcitriol exerts differential effects on TDEC compared to normal cells.
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PMID:Calcitriol (1,25-dihydroxycholecalciferol) selectively inhibits proliferation of freshly isolated tumor-derived endothelial cells and induces apoptosis. 1723 20

The active metabolite of vitamin D(3) (1alpha,25-dihydroxyvitamin D(3), calcitriol) has potent antitumor activities in vitro and in vivo in multiple cancers. Concerns about induction of hypercalcemia by calcitriol and the desire for more potent agents have prompted development of less-calcemic vitamin D analogs. These studies demonstrate that two vitamin D analogs, 19-nor-1alpha,25-dihydroxyvitamin D(2) (paricalcitol) and 1alpha-hydroxymethyl-16-ene-24,24-difluoro-25-hydroxy-26,27-bis-homovitamin D(3) (QW-1624F(2)-2, QW), have anticancer effects in the calcitriol-responsive squamous cell carcinoma (SCC) cell line. Paricalcitol (GI50 = 0.7 nM) and QW (GI50 = 0.001 nM) inhibited SCC cell growth; however, QW was more potent. Paricalcitol (10 nM) and QW (10 nM) induced G0/G1 cell cycle arrest and inhibited DNA synthesis by approximately 95%. The vitamin D analogs modulated cell cycle regulators, including decreasing mRNA and protein levels of p21(Waf1/Cip1) (p21) and cyclin-dependent kinase 2 (cdk2), and increasing p27(Kip1) (p27) protein expression. Vitamin D analogs induced apoptosis, caspase-3 cleavage and increased expression of pro-apoptotic MEKK-1. Phosphorylation of Akt, MEK and ERK1/2 that promote cell growth and survival were inhibited by vitamin D analogs. The anticancer effects of paricalcitol and QW are comparable to the effect of calcitriol. These less-calcemic vitamin D analogs are as effective as calcitriol in vitro and are promising for prevention and treatment of cancer and other diseases.
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PMID:Antitumor effects of two less-calcemic vitamin D analogs (Paricalcitol and QW-1624F2-2) in squamous cell carcinoma cells. 1723 23

Calcitriol, the active form of vitamin D, exerts important immunoregulatory effects. After rat liver allografting, calcitriol suppresses acute rejection. The aim of this study was to investigate whether calcitriol regulates hepatocyte apoptosis, in parallel with its inhibition of acute rejection in rat liver allografts. Liver allografts were transplanted in a high responder strain combination (SD to Wistar rats) and calcitriol was administered to the recipients, while control recipients received no immunosuppressant. Graft specimens were harvested on postoperative days 1, 3, 5 and 7 for histological analysis and protein assay. Hepatocyte apoptosis was assessed by the TUNEL method. Levels of intragraft Bcl-2, Bcl-xL, Bax, TNF-alpha and IFN-gamma proteins were measured by Western blot analysis. Expression of Fas, Fas ligand and caspase-3 was determined by immunohistochemical analysis. Calcitriol markedly inhibited hepatocyte apoptosis. In the calcitriol-treated allografts, Bcl-2 and Bcl-xL levels increased while Bax and caspase-3 levels significantly decreased. The expression of Fas ligand was clearly reduced while Fas remained unchanged. TNF-alpha and IFN-gamma proteins were also significantly decreased in the presence of calcitriol. These results show that calcitriol acts as a promoter of the anti-apoptosis genes Bcl-2 and Bcl-xL and an inhibitor of the pro-apoptosis genes Bax and caspase-3. These effects may be related to its suppression of the Fas/Fas ligand pathway and its inhibition of cytotoxic T lymphocyte products.
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PMID:Calcitriol inhibits hepatocyte apoptosis in rat allograft by regulating apoptosis-associated genes. 1757 Mar 29

The fate and phenotype of lesion macrophages is regulated by cellular oxidative stress. Thioredoxin-1 (Trx-1) plays a major role in the regulation of cellular redox balance, with resultant effects on gene expression and cellular responses including cell growth and death. Trx-1 activity is inhibited by interaction with vitamin D-upregulated protein-1 (VDUP-1). Peroxisome proliferator-activated receptor gamma (PPARgamma) is expressed by human monocyte-derived macrophages (HMDM) and PPARgamma agonism has been reported to decrease expression of inflammatory genes and to promote apoptosis of these cells. To determine whether VDUP-1 may be involved in regulating the effects of PPARgamma agonists in macrophages, we investigated the effect of a synthetic PPARgamma agonist (GW929) on the expression of VDUP-1 in HMDM. GW929 concentration-dependently increased HMDM expression of VDUP-1 (mRNA and protein). Transfection of different fragments of the VDUP-1 promoter as well as gel shift analysis revealed the presence of functional PPARgamma response elements (PPRE) in the promoter. Under conditions in which PPAR agonism altered levels of VDUP-1, caspase-3 activity, and macrophage apoptosis were also elevated. The results suggest that PPARgamma activation stimulates apoptosis in human macrophages by altering the cellular redox balance via regulation of VDUP-1.
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PMID:Enhanced VDUP-1 gene expression by PPARgamma agonist induces apoptosis in human macrophage. 1757 52

Calcitriol actions are mediated by the vitamin D receptor (VDR), a nuclear transcription factor of the steroid-retinoid-thyroid nuclear receptor gene superfamily. Calcitriol inhibits the growth of many cells including cancer cells by inducing cell cycle arrest. In some cancer cell lines, calcitriol also induces apoptosis. In the LNCaP prostate cancer cell line, induction of apoptosis and caspase-3/7 activities by staurosporine (STS) abolished [(3)H]1,25-dihydroxy vitamin D(3) binding and VDR protein, suggesting that the VDR may be targeted for inactivation by caspases during apoptosis. A potential caspase-3 site (D(195)MMD(198)S) was identified in the human VDR ligand-binding domain. Mutations D195A, D198A, and S199A were generated in the putative capase-3 cleavage site. In transfected COS-7 cells, STS treatment resulted in the cleavage of the wild-type (WT) VDR and S199A mutant VDR but not the D195A or D198A mutants. In in vitro assays, the WT VDR and S199A mutant VDR were cleaved by caspase-3, although the D195A and D198A mutants were resistant to caspase-3. In vitro, the WT VDR was also cleaved by caspase-6 and caspase-7 and in extracts of STS-treated LNCaP cells. In STS-treated LNCaP cells and human skin fibroblasts, the proteasome inhibitor MG-132 protected the VDR caspase cleavage fragment from further degradation by the 26S proteasome. The rat VDR that does not contain the caspase-3 cleavage site was not cleaved in STS-treated COS-7 cells. In conclusion, our results demonstrate that the human VDR is a target of caspase-3 and suggest that activation of caspase-3 may limit VDR activity.
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PMID:Inactivation of the human vitamin D receptor by caspase-3. 1883 97

Macrophage-derived reactive oxygen species contribute to the initiation and development of atherosclerosis. The cellular balance between oxidative and reductive states depends on the endogenous antioxidant capacity, with the thioredoxin-1 (Trx-1) system playing a major role. Peroxisome proliferator-activated receptor-alpha (PPARalpha) is expressed by human macrophages and exhibits anti-inflammatory properties. Here we show that the selective PPARalpha activator GW647 significantly increased the Trx-1 mRNA and protein expression in human macrophages as determined by quantitative polymerase chain reaction and Western immunoblotting. Consistently, the Trx-1 activity was significantly increased by PPARalpha activation. By contrast, PPARalpha activation led to the down-regulation of vitamin D(3) up-regulated protein 1 (VDUP-1), the physiological inhibitor of Trx-1. Analysis of the Trx-1 and VDUP-1 promoters with gene reporter assays, mutational analysis, gel shift assays and chromatin immunoprecipitation analyses revealed the presence of a functional response element specific for PPARalpha in the Trx-1 promoter and the presence of a functional activator protein 1 (AP-1) site in the VDUP-1 promoter. The interference of PPARalpha/retinoid X receptor alpha with the AP-1 transcription factor elements c-Jun/c-Fos resulted in the inhibition of AP-1 binding and down-regulation of the VDUP-1 gene expression. Finally, PPARalpha activation reduced the lidocaine-induced caspase-3 activity and apoptosis, which might be due to the VDUP-1-mediated regulation of the Bax/Bcl-2 ratio. Together these data indicate that stimulation of PPARalpha in human macrophages might reduce arterial inflammation through differential regulation of the Trx-1 and VDUP-1 gene expression.
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PMID:Thioredoxin-1 and its natural inhibitor, vitamin D3 up-regulated protein 1, are differentially regulated by PPARalpha in human macrophages. 1884 38

Growth plate cartilage is responsible for long bone growth in children and adolescents and is regulated by vitamin D metabolites in a cell zone-specific manner. Resting zone chondrocytes (RC cells) are regulated by 24,25-dihydroxyvitamin D3 via a phospholipase D-dependent pathway, suggesting downstream phospholipid metabolites are involved. In this study, we showed that 24R,25(OH)2D3 stimulates rat costochondral RC chondrocytes to release lysophosphatidic acid (LPA) and, therefore sought to determine the role of LPA signaling in these cells. RC cells expressed the G-protein coupled receptors LPA1-5 and peroxisome proliferator-activated receptor gamma (PPAR-gamma). LPA and the LPA1/3 selective agonist OMPT increased proliferation and two maturation markers, alkaline phosphatase activity and [35S]-sulfate incorporation. LPA and 24R,25(OH)2D3's effects were inhibited by the LPA1/3 selective antagonist VPC32183(S). Furthermore, apoptosis induced by either inorganic phosphate or chelerythrine was attenuated by LPA, based on DNA fragmentation, TUNEL staining, caspase-3 activity, and Bcl-2:Bax protein ratio. LPA prevented apoptotic signaling by decreasing the abundance, nuclear localization, and transcriptional activity of the tumor-suppressor p53. LPA treatment also regulated the expression of the p53-target genes Bcl-2 and Bax to enhance cell survival. Collectively, these data suggest that LPA promotes differentiation and survival in RC chondrocytes, demonstrating a novel physiological function of LPA-signaling.
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PMID:Lysophosphatidic acid signaling promotes proliferation, differentiation, and cell survival in rat growth plate chondrocytes. 1923 32

Chondrogenic ATDC5 cells were used as a model of in vitro endochondral maturation to study the role of inorganic phosphate (Pi) in the regulation of growth plate chondrocytes by vitamin D3 metabolites. ATDC5 cells that were cultured for 10 days post-confluence in differentiation media and then treated for 24 h with Pi produced a type II collagen matrix based on immunohistochemistry and expressed mRNAs for several chondrocytic markers, including aggrecan, collagen types II and X, cartilage oligomeric matrix protein, and SOX9. Pi also caused a decrease in [(35)S]-sulfate incorporation and stimulated apoptosis, as evidenced by increased DNA fragmentation and caspase-3 activity. In addition, treatment with Pi induced sensitivity to 24,25-dihydroxyvitamin D3 and this effect was both dose-dependent and was blocked by phosphonoformic acid (PFA), a specific inhibitor of sodium dependent type III Pi transporters. Treatment with 24R,25(OH)(2)D(3) reduced cell number and increased alkaline phosphatase specific activity in a dose-dependent manner. Moreover, 24R,25(OH)(2)D(3) reversed the Pi-induced decrease in incorporation of [(3)H]-thymidine and [(35)S]-sulfate incorporation, as well as the Pi-induced increase in apoptosis. These results suggest that Pi acts as an early chondrogenic differentiation factor, inducing response to 24R,25(OH)(2)D(3); treatment of committed chondrocytes with Pi induces apoptosis, but 24R,25(OH)(2)D(3) mitigates these effects, indicating a possible inhibitory feedback loop.
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PMID:Inorganic phosphate modulates responsiveness to 24,25(OH)2D3 in chondrogenic ATDC5 cells. 1928 98


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