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 inhibitors of protein prenylation have been proposed for chemotherapy of tumors. Lovastatin, a 3-hydroxy-3-methylglutaryl-Coenzyme A (HMG-CoA) reductase inhibitor, displays proapoptotic activity in tumor cells blocking the synthesis of isoprenoids compounds. To test whether HMG-CoA reductase inhibition can induce apoptosis in proliferating thyroid cells, we studied the effects of lovastatin in normal and neoplastic thyroid cells and in primary cultures from normal human thyroids. In an immortalized human thyroid cell line (TAD-2) and in neoplastic cells, lovastatin induced cell rounding within 24 h of treatment. After 48 h the cells were detached from the plate and underwent apoptosis, as evidenced by DNA fragmentation. Morphological changes and apoptosis did not occur in serum-starved quiescent TAD-2 cells or in primary cultures of normal thyrocytes. Mevalonate, the product of the HMG-CoA reductase enzymatic activity, and the protein synthesis inhibitor cycloheximide completely blocked the effects of lovastatin in a dose-dependent fashion. The geranylgeranyl transferase GGTI-298 inhibitor mimicked the effects of lovastatin on cell morphology and induced cell death, whereas the farnesyl transferase inhibitor FTI-277 was less effective to induce both cell rounding and apoptosis. Resistance to lovastatin-induced apoptosis by expression of the viral serpine CrmA and by the peptide inhibitor of caspases, Z-DEVD-fmk, demonstrated the involvement of CrmA-sensitive, caspase-3-like proteases. Inhibition of endogenous p53 activity did not affect the sensitivity of thyroid cells to lovastatin, demonstrating that this type of apoptosis is p53 independent. We conclude that lovastatin is a potent inducer of apoptosis in proliferating thyroid cells through inhibition of protein prenylation. This type of apoptosis requires protein synthesis, is CrmA sensitive and caspase-3-like protease dependent, and is independent from p53.
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PMID:Prenyltransferase inhibitors induce apoptosis in proliferating thyroid cells through a p53-independent CrmA-sensitive, and caspase-3-like protease-dependent mechanism. 992 96

Bisphosphonates inhibit osteoclast-mediated bone resorption by mechanisms that have only recently become clear. Whereas nitrogen-containing bisphosphonates affect osteoclast function by preventing protein prenylation (especially geranylgeranylation), non-nitrogen-containing bisphosphonates have a different molecular mechanism of action. In this study, we demonstrate that nitrogen-containing bisphosphonates (risedronate, alendronate, pamidronate, and zoledronic acid) and non-nitrogen-containing bisphosphonates (clodronate and etidronate) cause apoptosis of rabbit osteoclasts, human osteoclastoma-derived osteoclasts, and human osteoclast-like cells generated in cultures of bone marrow in vitro. Osteoclast apoptosis was shown to involve characteristic morphological changes, loss of mitochondrial membrane potential, and the activation of caspase-3-like proteases capable of cleaving peptide substrates with the sequence DEVD. Caspase-3-like activity could be visualized in unfixed, dying osteoclasts and osteoclast-like cells using a cell-permeable, fluorogenic substrate. Bisphosphonate-induced osteoclast apoptosis was dependent on caspase activation, because apoptosis resulting from alendronate, clodronate, or zoledronic acid treatment was suppressed by zVAD-fmk, a broad-range caspase inhibitor, or by SB-281277, a specific isatin sulfonamide inhibitor of caspase-3/-7. Furthermore, caspase-3 (but not caspase-6 or caspase-7) activity could be detected and quantitated in lysates from purified rabbit osteoclasts, whereas the p17 fragment of active caspase-3 could be detected in human osteoclast-like cells by immunofluorescence staining. Caspase-3, therefore, appears to be the major effector caspase activated in osteoclasts by bisphosphonate treatment. Caspase activation and apoptosis induced by nitrogen-containing bisphosphonates are likely to be the consequence of the loss of geranylgeranylated rather than farnesylated proteins, because the ability to cause apoptosis and caspase activation was mimicked by GGTI-298, a specific inhibitor of protein geranylgeranylation, whereas FTI-277, a specific inhibitor of protein farnesylation, had no effect on apoptosis or caspase activity.
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PMID:Visualization of bisphosphonate-induced caspase-3 activity in apoptotic osteoclasts in vitro. 1134 45

Geranylgeranylation of RhoA small G-protein is essential for its localization to cell membranes and for its biological functions. Many RhoA effects are mediated by its downstream effector RhoA kinase. The role of protein geranylgeranylation and the RhoA pathway in the regulation of endothelial cell survival has not been elucidated. The hydroxy-3-methylglutaryl (HMG)-CoA reductase inhibitor lovastatin depletes cellular pools of geranylgeranyl pyrophosphate and farnesol pyrophosphate and thereby inhibits both geranylgeranylation and farnesylation. Human umbilical vein endothelial cells (HUVECs) were exposed to lovastatin (3 microm-30 microm) for 48 h, and cell death was quantitatively determined by cytoplasmic histone-associated DNA fragments as well as caspase-3 activity. The assays showed that lovastatin caused a dose-dependent endothelial cell death. The addition of geranylgeraniol, which restores geranylgeranylation, rescued HUVEC from apoptosis. The geranylgeranyltransferase inhibitor GGTI-298, but not the farnesyltransferase inhibitor FTI-277, induced apoptosis in HUVEC. Cell death was also induced by a blockade of RhoA function by exoenzyme C3. In addition, treatment of HUVEC with the RhoA kinase inhibitors Y-27632 and HA-1077 caused dose-dependent cell death. Y-27632 did not inhibit other well known survival pathways, such as NF-kappa B, ERK, and phosphatidylinositol 3-kinase/Akt. However, there was an increase in p53 protein level concomitant with Y-27632-induced cell death. Unlike the apoptosis induced by TNF-alpha, which occurs only with inhibition of new protein synthesis, apoptosis induced by inhibitors of HMG-CoA reductase, geranylgeranyltransferase, or RhoA kinase was blocked by cycloheximide. Our data indicate that inhibition of protein geranylgeranylation and RhoA pathways induce apoptosis in HUVEC and that induction of p53 or other proapoptotic proteins is required for this process.
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PMID:Inhibition of protein geranylgeranylation and RhoA/RhoA kinase pathway induces apoptosis in human endothelial cells. 1183 65

Statins are widely used to treat lipid disorders. These drugs are safe and well tolerated; however, in <1% of patients, myopathy and/or rhabdomyolysis can develop. To better understand the mechanism of statin-induced myopathy, we examined the ability of structurally distinct statins to induce apoptosis in an optimized rat myotube model. Compound A (a lactone) and Cerivastatin (an open acid) induced apoptosis, as measured by TUNEL and active caspase 3 staining, in a concentration- and time-dependent manner. In contrast, an epimer of Compound A (Compound B) exhibited a much weaker apoptotic response. Statin-induced apoptosis was completely prevented by mevalonate or geranylgeraniol, but not by farnesol. Zaragozic acid A, a squalene synthase inhibitor, caused no apoptosis on its own and had no effect on Compound-A-induced myotoxicity, suggesting the apoptosis was not a result of cholesterol synthesis inhibition. The geranylgeranyl transferase inhibitors GGTI-2133 and GGTI-2147 caused apoptosis in myotubes; the farnesyl transferase inhibitor FTI-277 exhibited a much weaker effect. In addition, the prenylation of rap1a, a geranylgeranylated protein, was inhibited by Compound A in myotubes at concentrations that induced apoptosis. A similar statin-induced apoptosis profile was seen in human myotube cultures but primary rat hepatocytes were about 200-fold more resistant to statin-induced apoptosis. Although the statin-induced hepatotoxicity could be attenuated with mevalonate, no effect was found with either geranylgeraniol or farnesol. In studies assessing ubiquinone levels after statin treatment in rat and human myotubes, there was no correlation between ubiquinone levels and apoptosis. Taken together, these observations suggest that statins cause apoptosis in myotube cultures in part by inhibiting the geranylgeranylation of proteins, but not by suppressing ubiquinone concentration. Furthermore, the data from primary hepatocytes suggests a cell-type differential sensitivity to statin-induced toxicity.
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PMID:Statins induce apoptosis in rat and human myotube cultures by inhibiting protein geranylgeranylation but not ubiquinone. 1550 60

Progesterone receptor (PR) stimulation promotes survival in human and rat periovulatory granulosa cells. PR antagonists, Org 31710 and RU 486, both increase apoptosis and decrease cholesterol synthesis in these cells. The decrease in cholesterol synthesis also causes decreased synthesis of other products branching from the cholesterol synthesis pathway, including substrates for protein prenylation. In this study we focus on the link between apoptosis and prenylation in human periovulatory granulosa cells. A decreased cholesterol synthesis and increased apoptosis was verified in experiments with human periovulatory granulosa cells treated with the PR antagonists Org 31710 or RU 486 by measuring caspase-3/7 activity and incorporation of 14C-acetate into cholesterol and progesterone. Correspondingly, specific inhibition of cholesterol synthesis in periovulatory human granulosa cells using HMG-CoA reductase inhibitors (lovastatin or simvastatin) increased apoptosis, measured as caspase-3/7 activity. The increase in apoptosis caused by simvastatin or Org 31710 was partially reversed by addition of the protein prenylation precursors farnesol or geranylgeraniol. In addition, the prenylation inhibitors FTI R115777 and GGTI 2147 increased apoptosis in these cells. In conclusion our data suggest that PR antagonists increase apoptosis and reduce cholesterol synthesis in periovulatory granulosa cells and that the resulting depletion of substrates for protein prenylation may contribute to the increased apoptosis sensitivity.
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PMID:Depletion of substrates for protein prenylation increases apoptosis in human periovulatory granulosa cells. 1686 26

Statins are widely used cholesterol-lowering drugs that selectively inhibit the enzyme 3-hydroxy-3-methylglutaryl CoA reductase, leading to decreased cholesterol biosynthesis. Emerging data indicate that statins stimulate apoptotic cell death in several types of proliferating tumor cells, including breast cancer cells, which is independent of its cholesterol-lowering property. The objective here was to elucidate the molecular mechanism(s) by which statins induce breast cancer cell death. Fluvastatin and simvastatin (5-10 mumol/L) treatment enhanced the caspase-3-like activity and DNA fragmentation in MCF-7 cells, and significantly inhibited the proliferation of MCF-7 cells but not MCF-10 cells (noncancerous epithelial cells). Statin-induced cytotoxic effects were reversed by mevalonate, an immediate metabolic product of the acetyl CoA/3-hydroxy-3-methylglutaryl CoA reductase reaction. Both simvastatin and fluvastatin enhanced nitric oxide ((.)NO) levels which were inhibited by mevalonate. Statin-induced (.)NO and tumor cell cytotoxicity were inhibited by 1400W, a more specific inhibitor of inducible nitric oxide synthase (iNOS or NOS II). Both fluvastatin and simvastatin increased iNOS mRNA and protein expression. Stimulation of iNOS by statins via inhibition of geranylgeranylation by GGTI-298, but not via inhibition of farnesylation by FTI-277, enhanced the proapoptotic effects of statins in MCF-7 cells. Statin-mediated antiproliferative and proapoptotic effects were exacerbated by sepiapterin, a precursor of tetrahydrobiopterin, an essential cofactor of (.)NO biosynthesis by NOS. We conclude that iNOS-mediated (.)NO is responsible in part for the proapoptotic, tumoricidal, and antiproliferative effects of statins in MCF-7 cells.
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PMID:Statin-induced breast cancer cell death: role of inducible nitric oxide and arginase-dependent pathways. 1767 Dec 9

Bisphosphonates are widely used agents for the treatment of malignant bone disease. They inhibit osteoclast-mediated bone resorption and can have direct effects on cancer cells. In this study, we investigated whether the anticancer activity of the third-generation bisphosphonate zoledronic acid (ZOL) could be enhanced by combination with the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA). We found that ZOL and SAHA cooperated to induce cell death in the prostate cancer cell lines LNCaP and PC-3. The effect was synergistic, as evidenced by combination index isobologram analysis. ZOL and SAHA synergized to induce dissipation of the mitochondrial transmembrane potential, to activate caspase-3, and to trigger DNA fragmentation, showing that the combination of ZOL and SAHA resulted in the initiation of apoptosis. Because ZOL acts by inhibiting the mevalonate pathway, thereby preventing protein prenylation, we explored whether the mevalonate pathway was also the target of the cooperative action of ZOL and SAHA. We found that geranylgeraniol, but not farnesol, significantly reduced ZOL/SAHA-induced cell death, indicating that the synergistic action of the agents was due to the inhibition of geranylgeranylation. Consistently, a direct inhibitor of geranylgeranylation, GGTI-298, synergized with SAHA to induce cell death, whereas an inhibitor of farnesylation, FTI-277, had no effect. In addition, SAHA synergized with mevastatin, an inhibitor of the proximal enzyme in the mevalonate pathway. These in vitro findings provide a rationale for an in vivo exploration into the potential of combining SAHA and ZOL, or other inhibitors of the mevalonate pathway, as an effective strategy for anticancer therapy.
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PMID:Synergistic activity of the histone deacetylase inhibitor suberoylanilide hydroxamic acid and the bisphosphonate zoledronic acid against prostate cancer cells in vitro. 1802 82

Prolongation of cell survival through prevention of apoptosis is considered to be a significant factor leading to anabolic responses in bone. The current studies were carried out to determine the role of the small GTPase, RhoA, in osteoblast apoptosis, since RhoA has been found to be critical for cell survival in other tissues. We investigated the effects of inhibitors and activators of RhoA signaling on osteoblast apoptosis. In addition, we assessed the relationship of this pathway to parathyroid hormone (PTH) effects on apoptotic signaling and cell survival. RhoA is activated by geranylgeranylation, which promotes its membrane anchoring. In serum-starved MC3T3-E1 osteoblastic cells, inhibition of geranylgeranylation with geranylgeranyl transferase I inhibitors increased activity of caspase-3, a component step in the apoptosis cascade, and increased cell death. Dominant negative RhoA and Y27632, an inhibitor of the RhoA effector Rho kinase, also increased caspase-3 activity. A geranylgeranyl group donor, geranylgeraniol, antagonized the effect of the geranylgeranyl transferase I inhibitor GGTI-2166, but could not overcome the effect of the Rho kinase inhibitor. PTH 1-34, a potent anti-apoptotic agent, completely antagonized the stimulatory effects of GGTI-2166, dominant negative RhoA, and Y27632, on caspase-3 activity. The results suggest that RhoA signaling is essential for osteoblastic cell survival but that the survival effects of PTH 1-34 are independent of this pathway.
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PMID:The small GTPase RhoA is crucial for MC3T3-E1 osteoblastic cell survival. 1918 80

We have previously reported that addition of prefibrillar aggregates (PFAs) derived from W7FW14F apomyoglobin mutant to NIH-3T3 cells affects their viability. In this article, we have found that cytotoxicity induced by PFAs in NIH 3T3 and SH-SY5Y human neuroblastoma cells was due to early activation of apoptotic cell death dependent from a caspase-3- and -9-mediated mitochondrial pathway. A time-dependent increase of intracellular ROS and an about twofold decrease of mitochondrial localization of scavenger protein MnSOD was found. The use of the anti-oxidant agent N-acetyl-cysteine (NAC) antagonized both the increase of intracellular ROS and apoptosis induced by PFAs. PFAs caused an about 60% increase of the activity of both Ras and Erk-1/2 at 30 and 45 min while they were restored to basal levels at later time points. This effect was paralleled by a time-dependent decrease of the activity of the survival enzyme Akt. Effects similar to those on Ras activity were also recorded on the activity of the stress involved small GTP binding protein Rac that was about 75% increased after 30 min but resumed to basal levels at later time points. This effect was paralleled by a time-dependent activation of p38 kinase activity and HSP-70 expression. The use of both the ras farnesyltransferase inhibitor tipifarnib and the Rac geranyl-geranyltransferase GGTI-298, but not of the MEK-1 inhibitor U0126 partially antagonized the effects of PFAs on apoptosis occurrence. On the other hand, the PI3K/Akt inhibitor LY 294002 potentiated apoptosis induced by PFAs. Our results indicate a role for Ras and Rac in the induction of both intracellular ROS increased levels and apoptosis mediated by PFAs and disclose a new scenario of intervention in neurodegenerative diseases.
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PMID:W7FW14F apomyoglobin amyloid aggregates-mediated apoptosis is due to oxidative stress and AKT inactivation caused by Ras and Rac. 1958 24

Giant cell tumor (GCT) is the most common nonmalignant primary bone tumor reported in Hong Kong. It usually affects young adults between the ages of 20 and 40. This tumor is well known for its potential to recur following treatment. To date no effective adjuvant therapy exists for GCT. Our project aimed to study the effects of pamidronate (PAM), farnesyl transferase inhibitor (FTI-277), geranylgeranyl transferase inhibitor (GGTI-298), and their combinations on GCT stromal cells (SC). Individual treatment with PAM, FTI-277, and GGTI-298, inhibited the cell viability and proliferation of GCT SC in a dose-dependent way. Combination of FTI-277 with GGTI-298 caused synergistic effects in reducing cell viability, and its combination index was 0.49, indicating a strong synergism. Moreover, the combination of FTI-277 with GGTI-298 synergistically enhanced cell apoptosis and activated caspase-3/7, -8, and -9 activities. PAM induced cell-cycle arrest at the S-phase. The combination of PAM with GGTI-298 significantly increased OPG/RANKL mRNA ratio and activated caspase-3/7 activity. Our findings support that the combination of bisphosphonates with GGTIs or FTIs with GGTIs may be used as potential adjuvants in the treatment of GCT of bone.
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PMID:Pamidronate, farnesyl transferase, and geranylgeranyl transferase-I inhibitors affects cell proliferation, apoptosis, and OPG/RANKL mRNA expression in stromal cells of giant cell tumor of bone. 2088 53


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