Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Easily accessible normal tissues expressing the same molecular site(s) of drug action as malignant tissue offer an enhanced potential for early proof of anticancer drug mechanism and estimation of the biologically effective dose. Studies were undertaken in healthy male volunteers to assess the tolerability of single and multiple (four in 24 h) 3 mm punch biopsies of the buccal mucosa, and to determine the feasibility of detecting and quantifying a range of proliferation, cell-cycle arrest and apoptosis markers by immunohistochemistry (IHC) for use as potential pharmacodynamic (PD) end points. The biopsy procedure was well tolerated with 100% of volunteers stating that they would undergo single (n = 10) and multiple (n = 12) biopsies again. Total retinoblastoma protein (pRb), phosphorylated pRb (phospho-pRb), total p27, phosphorylated p27 (phospho-p27), phosphorylated-histone H3 (phospho-HH3), p21, p53, Cyclin A, Cyclin E, Ki67 all produced good signal detection, but M30, cleaved caspase 3 and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling did not. Total pRb, phospho-pRb, total p27 and phospho-p27 were quantified further in a multiple biopsy study to allow components of variability to be addressed to inform future sizing decisions on intervention studies. Neither site of biopsy within the oral cavity, nor the nominal time of biopsy had any significant impact on any of the four markers expression levels. Inter- and intrasubject coefficients of variation (CVs) that could be used to size future intervention studies for pRb, phospho-pRb, total p27 and phospho-p27 were 14, 19, 18 and 16%; and 18, 29, 25 and 19%, respectively. In conclusion, quantitation of such markers in 3 mm buccal punch biopsies would be suitable to explore as PD end points within intervention studies of drugs acting on these pathways.
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PMID:Assessing proliferation, cell-cycle arrest and apoptotic end points in human buccal punch biopsies for use as pharmacodynamic biomarkers in drug development. 1599 99

Pituitary tumors are common and cause considerable morbidity due to local invasion and altered hormone secretion. Doxazosin (dox), a selective alpha(1)-adrenergic receptor antagonist, used to treat hypertension, also inhibits prostate cancer cell proliferation. We examined the effects of dox on murine and human pituitary tumor cell proliferation in vitro and in vivo. dox treatment inhibited proliferation of murine pituitary tumor cells, induced G(0)-G(1) cell cycle arrest, and reduced phosphorylated retinoblastoma levels. In addition, increased annexin-fluorescein isothiocyanate immunoreactivity and cleaved caspase-3 levels, in keeping with dox-mediated apoptosis, were observed in the human and murine pituitary tumor cells, and dox administration to mice, harboring corticotroph tumors, decreased tumor growth and reduced plasma ACTH levels. dox-mediated antiproliferative and proapoptotic actions were not confined to alpha-adrenergic receptor-expressing pituitary tumor cells and were unaffected by cotreatment with the alpha-adrenergic receptor blocker, phenoxybenzamine. dox treatment led to reduced phosphorylated inhibitory kappaB (IkappaB)-alpha expression, and nuclear factor-kappaB transcription and decreased basal and TNFalpha-induced proopiomelanocortin transcriptional activation. These results demonstrate that the selective alpha(1)-adrenergic receptor antagonist dox inhibits pituitary tumor cell growth in vitro and in vivo by mechanisms that are in part independent of its alpha-adrenergic receptor-blocking actions and involve down-regulation of nuclear factor-kappaB signaling. dox is proposed as a possible novel medical therapy for pituitary tumors.
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PMID:Alpha1-adrenergic receptor antagonists: novel therapy for pituitary adenomas. 1602 Apr 84

The phosphatidylinositol 3'-kinase (PI3K)/Akt pathway is often constitutively activated in malignant glioma cells, in many cases as a result of mutation of phosphatase and tensin homologue deleted on chromosome ten (PTEN), an endogenous inhibitor of Akt, which renders tumor cells resistant to cytotoxic insults, including those related to anticancer drugs. Pharmacological inhibition of this pathway may potentially restore or augment the effectiveness of conventional chemotherapy or other signaling-targeted agents. Because the heat shock protein (HSP) is involved in the conformational maturation of a number of signaling proteins critical to the proliferation of malignant glioma cells, we hypothesized that the combination of the PI3K inhibitor LY294002 and the HSP90 inhibitor 17-allyl-aminogeldanamycin (17-AAG) would promote glioma cytotoxicity by decreasing both the activation status and levels of Akt, as well as downregulating the levels of other relevant signaling effectors. We, therefore, examined the effects of LY294002 and 17-AAG, alone and in combination, on signal transduction and apoptosis in a series of malignant glioma cell lines. Simultaneous exposure to these inhibitors significantly induced cell death, and irreversibly inhibited proliferative activity and colony forming ability of the glioma cell lines. Quantitative analysis revealed that enhancement by LY294002 of 17-AAG-induced cytotoxicity was synergistic, leading to a pronounced increase in active caspase-3 and poly (adenosine diphosphate-ribose) polymerase (PARP) cleavage together with the release of cytochrome c and apoptosis inducing factor (AIF). No significant growth inhibition or caspase activation was seen in control cells. The enhanced cytotoxicity of this combination was associated with diminished Akt activation and a significant downregulation of epidermal growth factor receptor (EGFR), Raf-1, and mitogen activated protein kinase. Combination of 17-AAG and LY294002 did not modify phospho-JNK/SPK and phospho-p38. Cells exposed to 17-AAG and LY294002 displayed a significant reduction in cell-cycle regulatory proteins, such as retinoblastoma (Rb), cyclin dependent kinase (CDK)4, CDK6, cyclin D1, and cyclin D3. Taken together, these findings suggest that the PI3K/Akt pathway plays a critical role in regulating the apoptotic response to 17-AAG and that targeting this pathway could provide a potent strategy to treat patients with malignant gliomas.
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PMID:Synergistic interaction between 17-AAG and phosphatidylinositol 3-kinase inhibition in human malignant glioma cells. 1626 32

Clade B serine proteinase inhibitors (serpins) are intracellular proteins, whereas most of their identified targets are extracellular. A proposed intracellular role for these inhibitors is protection from apoptosis. We investigated the contribution of serpinB2 (plasminogen activator inhibitor-2, PAI-2) activity in TNF-alpha-induced apoptosis. PAI-2 is expressed in many normal and transformed cell types, particularly after stimulation with inflammatory cytokines. PAI-2 has been linked to protection from TNF-alpha-induced apoptosis, and a stabilizing interaction with the retinoblastoma protein (Rb1) has been proposed. We examined the activity of PAI-2 in TNF-alpha-induced apoptosis using HeLa, Isreco-1 and HT1080 cell lines. Stimulation with TNF-alpha protected each cell type from apoptosis induced by TNF-alpha and cycloheximide. Protection correlated with an increase in PAI-2 expression in IS-1 and HT1080 cells but not in HeLa cells where PAI-2 mRNA and protein were undetectable. PAI-2 was overexpressed in each cell type but gave no protection from TNF-alpha-induced apoptosis measured by cell viability, annexinV binding and caspase-3/7 activity. We detected wild-type Rb1, unchanged TNF receptor levels and induction of other apoptosis-protective factors in all cell types. In conclusion, elevated PAI-2 levels do not protect cells from TNF-alpha-induced apoptosis, and the protective effect of prior stimulation with TNF-alpha does not require PAI-2.
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PMID:Evidence for serpinB2-independent protection from TNF-alpha-induced apoptosis. 1633 24

Either the absence or dysfunction of a number of critical pathways, such as those that involve the nuclear retinoblastoma protein (Rb) and the transcription factor E2F1, may account for the aberrant induction of the cell cycle in post-mitotic neurons that can be responsible for oxidative stress-induced apoptotic cellular destruction. Yet, it is unclear whether early programs of apoptotic injury that involve membrane phosphatidylserine (PS) exposure and calreticulin expression as well as later phases of apoptotic injury with nuclear DNA injury require the critical modulation of Rb and E2F1. We demonstrate that both the post-translational of phosphorylation of Rb to prevent E2F1 transcription as well as the protein integrity of Rb are closely aligned with the modulation of cell cycle induction in post mitotic neurons during oxidative stress. More importantly, we illustrate that both the initial onset of apoptosis with either membrane PS exposure or calreticulin analysis as well as the more terminal phases of apoptosis that involve nuclear DNA degradation proceed concurrently in the same neuronal cells with cell cycle induction. Progression of attempted cell cycle induction is closely associated with the phosphorylation of Rb, its inability to bind to E2F1, and the degradation of the Rb protein. Inhibition of Rb phosphorylation using cyclin dependent kinase inhibitors maintains the integrity of the E2F1/Rb complex and is neuroprotective during free radical exposure. Furthermore, maintenance of the integrity of the Rb protein is specifically dependent upon caspase 3-like activity, since caspase 3 can cleave Rb during free radical activity and this degradation of Rb can be blocked during the inhibition of caspase 3 activity. Our studies not only highlight the critical role of attempted cell cycle induction during oxidative stress-induced neuronal apoptotic injury, but also bring to light the significant impact of the Rb and E2F1 pathways upon early apoptotic programs that can directly influence both intrinsic cell survival as well as extrinsic inflammatory cell activation.
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PMID:Attempted cell cycle induction in post-mitotic neurons occurs in early and late apoptotic programs through Rb, E2F1, and caspase 3. 1647 23

We studied the expression of pro-apoptotic neurotrophin receptor p75 (p75(NTR)) in human and murine retinoblastoma, compared to normal retina, and examined changes in p75(NTR) expression with the onset of apoptosis in the course of murine retinoblastoma progression, using immunohistochemistry and quantitative real-time RT-PCR. The murine retinoblastoma is induced by retinal specific expression of SV40 T-antigen (TAg), which blocks the function of the retinoblastoma protein (pRB) and related proteins, and is a well-studied model that closely simulates human retinoblastoma. The majority of human retinoblastoma either lacked or expressed decreased levels of p75(NTR) mRNA, compared to human retina. Moreover, p75(NTR) protein was not detected in any tumor studied, unlike normal retina. Like human retinoblastoma, advanced murine retinoblastoma did not express p75(NTR). However, before tumors emerged, small clusters of TAg-positive cells coexpressed p75(NTR) and activated caspase-3, a marker of apoptosis. Furthermore, in three rare human eyes containing retinoblastoma adjacent to regions resembling the benign retinal tumor retinoma, both normal retina and retinoma-like tissue expressed p75(NTR) protein, while the retinoblastoma did not. We suggest that p75(NTR) loss accompanies progression from retinoma to retinoblastoma.
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PMID:Loss of p75 neurotrophin receptor expression accompanies malignant progression to human and murine retinoblastoma. 1655 52

2-Methoxyestradiol (2-ME), an endogenous metabolite of estradiol with no affinity for estrogen receptors, is a potent anticarcinogenic agent (in phase II clinical trials) and mediates the inhibitory effects of estradiol on smooth muscle cell (SMC) growth. Here we studied the intracellular mechanisms by which 2-ME inhibits SMC growth and whether 2-ME prevents injury-induced neointima formation. 2-ME concentrations that inhibit proliferation of cycling human aortic SMCs by >or=50% blocked cell-cycle progression in G(0)/G(1) and in G(2)/M phase, as determined by flow cytometry. Consistent with the cell-cycle effects, at a molecular level (Western blots), 2-ME inhibited cyclin D(1) and cyclin B(1) expression; cyclin-dependent kinase (cdk)-1 and cdk-2 activity; and retinoblastoma protein (pRb), extracellular signal-regulated kinase (ERK) 1/2, and Akt phosphorylation. 2-ME also upregulated the Cdk inhibitor p27 and interfered with tubulin polymerization. Moreover, 2-ME augmented COX-2 expression, suggesting that it may also inhibit SMC growth via prostaglandin formation. In rats, treatment with 2-ME abrogated injury-induced neointima formation; decreased proliferating SMCs; downregulated expression of proliferating-cell nuclear antigen (PCNA), c-myc, cyclin D(1), cyclin B(1), phosphorylated Akt, phosphorylated ERK1/2, p21, and pRb; inhibited cdk-1 and cdk-4 activity; and upregulated expression of cyclooxygenase (COX)-2 and p27. Caspase-3 cleavage assay and fluorescence-activated cell-sorting (FACS) analysis showed no evidence of apoptosis in 2-ME-treated SMCs, and TUNEL staining in carotid segments showed no evidence of 2-ME-induced apoptosis in vivo. The antimitotic effects of 2-ME on SMCs are mediated by the inhibition of key cell-cycle regulatory proteins and effects on tubulin polymerization and COX-2 upregulation. These effects of 2-ME most likely contribute to the antivasoocclusive actions of this endogenous compound.
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PMID:2-Methoxyestradiol, an estradiol metabolite, inhibits neointima formation and smooth muscle cell growth via double blockade of the cell cycle. 1688 48

The Rho GTPases are the molecular regulators of the cell motility processes and are involved in cell cycle progression and gene transcription. We studied the expression of Rho-like GTPases molecules, particularly Rac, Tiam1 and cdc42, in retinoblastoma and correlated these with clinicopathological parameters of the tumors. Sixty-seven tumors were included which were divided in to two groups; group A: tumors with optic nerve/choroidal/orbital invasion (n=35) and group B: tumors with no invasion (n=32). Immunohistochemistry was done on paraffin sections for all the proteins and were confirmed by Western blot on fresh tumor samples. In group A tumors, Rac was positive in 10/35 (28%), cdc42 was positive in 12/35 (34%) and Tiam1 was positive in 30/35 (85%) tumors. In group 2 tumors, Rac was positive in 5/32 (15%), cdc42 was positive in 4/32 (12%) and Tiam1 was positive in 30/32 (93%) tumors. Two groups (both invasive and non-invasive tumors) showed decreased expression of Rac1 and cdc42 whereas Tiam1 was significantly expressed in invasive tumors compared to non-invasive tumors (P<0.0001). We observed a 70K cleavage product of Tiam1 along with an 110K product by blotting in RB samples. Caspase-3 was also demonstrated in RB samples, which showed Tiam1 cleavage products. This is the first study that showed the expression patterns of Rac, cdc42 and Tiam1 in retinoblastoma tumors. Thus, further studies are required to prove the involvement of caspase-3 in the cleavage of Tiam1 in vitro in RB cells and to trace out alternative pathways involved in tumor progression.
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PMID:Expressions of Rac1, Tiam1 and Cdc42 in retinoblastoma. 1702 2

We previously reported that N-(4-hydroxyphenyl)retinamide (4HPR) inhibits retinoblastoma tumor growth in a murine model in vivo and kills Y79 retinoblastoma cells in vitro. In this work, we assayed different cell death-related parameters, including mitochondrial damage and caspase activation, in Y79 cells exposed to 4HPR. 4HPR induced cytochrome c release from mitochondria, caspase-3 activation, and oligonucleosomal DNA fragmentation. However, pharmacologic inactivation of caspases by the pan-caspase inhibitor BOC-D-fmk, or specific caspase-3 inhibition by Z-DEVD-fmk, was not sufficient to prevent cell death, as assessed by loss of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction, lactate dehydrogenase release, disruption of mitochondrial transmembrane potential (Deltapsi(m)), and ATP depletion. We found that 4HPR causes lysosomal membrane permeabilization and cytosolic relocation of cathepsin D. Pepstatin A partially rescued cell viability and reduced DNA fragmentation and cytosolic cytochrome c. The antioxidant N-acetylcysteine attenuated cathepsin D relocation into the cytosol, suggesting that lysosomal destabilization is dependent on elevation of reactive oxygen species and precedes mitochondrial dysfunction. Activation of AKT, which regulates energy level in the cell, by the retinal survival facto]r insulin-like growth factor I was impaired and insulin-like growth factor I was ineffective against ATP and Deltapsi(m) loss in the presence of 4HPR. Lysosomal destabilization, associated with mitochondrial dysfunction, was induced by 4HPR also in other cancer cell lines, including PC3 prostate adenocarcinoma and the vascular tumor Kaposi sarcoma KS-Imm cells. The novel finding of a lysosome-mediated cell death pathway activated by 4HPR could have implications at clinical level for the development of combination chemoprevention and therapy of cancer.
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PMID:Novel cell death pathways induced by N-(4-hydroxyphenyl)retinamide: therapeutic implications. 1723 88

Cyclin-dependent kinases (Cdk) and their associated pathways represent some of the most attractive targets for the development of anticancer therapeutics. Based on antitumor activity in animal models, a variety of Cdk inhibitors are undergoing clinical evaluation either as a single agent or in combination with other approved drugs. In our anticancer drug discovery program, a novel series of flavones have been synthesized for evaluation against the activity of Cdk4-D1. This enzyme catalyzes the phosphorylation of retinoblastoma protein, thus inhibiting its function. We have identified a series of potent Cdk4-D1 inhibitors with IC(50) below 250 nmol/L. In this report, we have described the properties of one of the best compound, P276-00 of the flavone's series. P276-00 shows 40-fold selectivity toward Cdk4-D1, compared with Cdk2-E. The specificity toward 14 other related and unrelated kinases was also determined. P276-00 was found to be more selective with IC(50)s <100 nmol/L for Cdk4-D1, Cdk1-B, and Cdk9-T1, as compared with other Cdks, and less selective for non-Cdk kinases. It showed potent antiproliferative effects against various human cancer cell lines, with an IC(50) ranging from 300 to 800 nmol/L and was further compared for its antiproliferative activity against cancer and normal fibroblast cell lines. P276-00 was found to be highly selective for cancer cells as compared with normal fibroblast cells. To delineate its mechanism of action, the effect of P276-00 on cell cycle proteins was studied in human breast cancer cell line (MCF-7) and human non-small cell lung carcinoma (H-460). A significant down-regulation of cyclin D1 and Cdk4 and a decrease in Cdk4-specific pRb Ser(780) phosphorylation was observed. P276-00 produced potent inhibition of Cdk4-D1 activity that was found to be competitive with ATP and not with retinoblastoma protein. The compound also induced apoptosis in human promyelocytic leukemia (HL-60) cells, as evidenced by the induction of caspase-3 and DNA ladder studies. These data suggest that P276-00 has the potential to be developed as an anti-Cdk chemotherapeutic agent.
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PMID:In vitro antitumor properties of a novel cyclin-dependent kinase inhibitor, P276-00. 1736 86


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