Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.24 (mitogen-activated protein kinase)
 95,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gold(III) porphyrin 1a is a novel gold(III) complex with selective anticancer effect in a number of human carcinoma cell lines. We have previously shown that gold(III) porphyrin 1a mediated mitochondrial transmembrane potential (DeltaPsi(m)) depletion, leading to cytochrome c release, nucleus translocation of apoptosis-inducing factor (AIF), and generation of reactive oxygen species (ROS). The current study addressed gold(III) porphyrin 1a-induced phosphoproteome alterations and modulation of cell death by the mitogen-activated protein kinase (MAPK) family proteins. ERK and p38(MAPK) were transiently activated upon gold(III) porphyrin 1a treatment. Inhibition of p38(MAPK) phosphorylation rescued gold(III) porphyrin 1a-induced cell death upstream of caspase activation. Attenuation of DeltaPsi(m) was the primary effect of gold(III) porphyrin 1a leading to p38(MAPK) phosphorylation. Further functional proteomic study suggested that differential regulation of phosphotyrosine proteins were related to p38(MAPK) activation in gold(III) porphyrin 1a-induced signal transduction cascade. In summary, p38(MAPK) modulated gold(III) porphyrin 1a-induced cell death downstream of mitochondria, and phosphorylation of multiple proteins also involved in this process. These results suggested that gold(III) porphyrin 1a is a promising anticancer agent directed toward the mitochondria.
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PMID:Modulation of gold(III) porphyrin 1a-induced apoptosis by mitogen-activated protein kinase signaling pathways. 1824 39

This study investigated the biological significance of the inhibition of fatty acid synthase (FAS) in multiple myeloma (MM) using the small molecule inhibitor Cerulenin. Cerulenin triggered growth inhibition in both MM cell lines and MM patient cells, and overcame the survival and growth advantages conferred by interleukin-6, insulin-like growth factor-1, and bone marrow stromal cells. It induced apoptosis in MM cell lines with only modest activation of caspase -8, -9, -3 and PARP; moreover, the pan-caspase inhibitor Z-VAD-FMK did not inhibit Cerulenin-induced apoptosis and cell death. In addition, treatment of MM cells with Cerulenin primarily up-regulated apoptosis-inducing factor/endonuclease G, mediators of caspase-independent apoptosis. Importantly, Cerulenin induced endoplasmic reticulum stress response via up-regulation of the Grp78/IRE1alpha/JNK pathway. Although the C-Jun-NH(2)-terminal kinase (JNK) inhibitor SP600215 blocked Cerulenin-induced cytotoxicity, it did not inhibit apoptosis and caspase cleavage. Furthermore, Cerulenin showed synergistic cytotoxic effects with various agents including Bortezomib, Melphalan and Doxorubicin. Our results therefore indicate that inhibition of FAS by Cerulenin primarily triggered caspase-independent apoptosis and JNK-dependent cytotoxicity in MM cells. This report demonstrated that inhibition of FAS has anti-tumour activity against MM cells, suggesting that it represents a novel therapeutic target in MM.
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PMID:Fatty acid synthase is a novel therapeutic target in multiple myeloma. 2071 68

Using a nonhuman primate model of surgical menopause, our laboratory has shown that ovarian hormone treatment (HT) improves 5-HT neural function in the dorsal raphe nucleus (DRN). We further hypothesize that HT may increase 5-HT neuronal resilience. Recent data from microarray analysis indicated that HT regulates gene expression in pathways that lead to apoptosis. In this study, we questioned whether HT alters protein expression in caspase-dependent and independent pathways. Ovariectomized monkeys received Silastic implants containing placebo (empty), estrogen (E) or E+ progesterone (P). A small block of the midbrain containing the DRN was dissected and subjected to subcellular fractionation, yielding cytosolic, nuclear and mitochondrial fractions (n=4/group). The pro-apoptotic protein, c-jun n-terminal kinase (JNK1) and its phosphorylation were decreased by E+P treatment in the cytosolic fraction. Downstream of JNK are proteins in the caspase-dependent and -independent pathways. First, in the caspase-dependent pathway, cytoplasmic and mitochondrial fractions were immunoblotted for Bcl-2 family members, cytochrome c, Apaf1 and XIAP. However, the expression of these proteins did not differ among treatments. Pro-caspase 3 was decreased by E+P, but there was no evidence of active caspase in any group. Then, we examined the involvement of a protein in the caspase-independent pathway, called apoptosis-inducing factor (AIF). AIF mRNA (n=3/group) and AIF mitochondrial protein tended to decrease with hormone treatment. However, AIF protein in the nuclear fraction in E+P treated monkeys was significantly reduced. This indicates that HT is reducing the translocation of AIF from mitochondria to nucleus, thus inhibiting AIF-mediated apoptosis. AIF was immunocytochemically localized to large 5-HT-like neurons of the dorsal raphe. These data suggest that in the absence of global trauma or ischemia, HT may act through the caspase-independent pathway to promote neuroprotection in the 5-HT system.
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PMID:Neuroprotective actions of ovarian hormones without insult in the raphe region of rhesus macaques. 1848 49

Recent studies have revealed that procaspase-8 has an important function in cell adhesion and motility. Src phosphorylation controls this function by preventing the conversion of procaspase-8, which is an adhesion/migration factor, to mature caspase-8, which is an apoptosis-inducing factor. This provides a mechanism to switch these opposing functions. In its migratory role, procaspase-8 interacts with the phosphatidylinositol-3-OH kinase regulatory subunit p85alpha and c-src to modulate signaling by Rac and extracellular signal-regulated kinase, and promote calpain activation. Here, I survey the findings of these studies and discuss potential mechanisms and ramifications for cancer prognosis and therapy.
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PMID:Caspase-8: fly or die. 1855 90

Histone deacetylase inhibitors have emerged as promising anticancer drugs. Using an unbiased ultrahigh throughput screening system, a novel mercaptoketone-based histone deacetylase inhibitor series was identified that was optimized to the lead compound, KD5170. KD5170 inhibited the proliferation of myeloma cell lines and the viability of CD138(+) primary myeloma cells by induction of apoptosis, accompanied by an increase of acetylation of histones and activation of caspase-3, caspase-8, and caspase-9. Treatment with KD5170 caused a loss of mitochondrial membrane potential resulting in release of apoptogenic factors such as cytochrome c, Smac, and apoptosis-inducing factor. Furthermore, KD5170 induced oxidative stress and oxidative DNA damage in myeloma cells as evidenced by the up-regulation of heme oxygenase-1 and H2A.X phosphorylation. Combination of KD5170 with proteasome inhibitor bortezomib or tumor necrosis factor-related apoptosis-inducing ligand synergistically enhanced the antimyeloma activity. We further found that resistance of myeloma cells to KD5170 was associated with activation of the extracellular signal-regulated kinase/mitogen-activated protein kinase pathway under treatment with KD5170. Pretreatment with the mitogen-activated protein kinase inhibitor U0126 restored sensitivity to KD5170, suggesting that the combination of KD5170 with U0126 could overcome drug resistance. Growth of myeloma tumor xenografts in KD5170-treated nude mice was significantly inhibited and survival was prolonged. Histone acetylation was increased in spleen and tumor tissues of animals treated with KD5170. Our data indicate that KD5170 has potent antimyeloma activity in vitro and in vivo, which is mediated by DNA damage and mitochondrial signaling and subsequent induction of apoptosis.
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PMID:KD5170, a novel mercaptoketone-based histone deacetylase inhibitor, exerts antimyeloma effects by DNA damage and mitochondrial signaling. 1856 20

Here, we identify a panel of melanoma lines with non-V600E mutations in BRAF. These G469E- and D594G-mutated melanomas were found to exhibit constitutive levels of phospho-extracellular signal-regulated kinase (pERK) and low levels of phospho-mitogen-activated protein kinase/ERK kinase (pMEK) and were resistant to MEK inhibition. Upon treatment with the CRAF inhibitor sorafenib, these lines underwent apoptosis and associated with mitochondrial depolarization and relocalization of apoptosis-inducing factor, whereas the BRAF-V600E-mutated melanomas did not. Studies have shown low-activity mutants of BRAF (G469E/D594G) instead signal through CRAF. Unlike BRAF, CRAF directly regulates apoptosis through mitochondrial localization where it binds to Bcl-2 and phosphorylates BAD. The CRAF inhibitor sorafenib was found to induce a time-dependent reduction in both BAD phosphorylation and Bcl-2 expression in the D594G/G469E lines only. Knockdown of CRAF using a lentiviral shRNA suppressed both Bcl-2 expression and induced apoptosis in the D594G melanoma line but not in a V600E-mutated line. Finally, we showed in a series of xenograft studies that sorafenib was more potent at reducing the growth of tumors with the D594G mutation than those with the V600E mutation. In summary, we have identified a group of melanomas with low-activity BRAF mutations that are reliant upon CRAF-mediated survival activity.
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PMID:CRAF inhibition induces apoptosis in melanoma cells with non-V600E BRAF mutations. 1879 3

Glutamate is an endogenous excitatory neurotransmitter. At high concentrations, it is neurotoxic and contributes to the development of certain neurodegenerative diseases. There is considerable controversy in the literature with regard to whether glutamate-induced cell death in cultured HT22 cells (an immortalized mouse hippocampal cell line) is apoptosis, necrosis, or a new form of cell death. The present study focused on investigating the mechanism of glutamate-induced cell death. We found that glutamate induced, in a time-dependent manner, both necrosis and apoptosis in HT22 cells. At relatively early time points (8-12 h), glutamate induced mostly necrosis, whereas at late time points (16-24 h), it induced mainly apoptosis. Glutamate-induced mitochondrial oxidative stress and dysfunction were crucial early events required for the induction of apoptosis through the release of the mitochondrial apoptosis-inducing factor (AIF), which catalyzed DNA fragmentation (an ATP-independent process). Glutamate-induced cell death proceeded independently of the Bcl-2 family proteins and caspase activation. The lack of caspase activation likely resulted from the lack of intracellular ATP when the mitochondrial functions were rapidly disrupted by the mitochondrial oxidative stress. In addition, it was observed that activation of JNK, p38, and ERK signaling molecules was also involved in the induction of apoptosis by glutamate. In conclusion, glutamate-induced apoptosis is AIF-dependent but caspase-independent, and is accompanied by DNA ladder formation but not chromatin condensation.
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PMID:Mechanism of glutamate-induced neurotoxicity in HT22 mouse hippocampal cells. 1958 Aug 6

1. Erlotinib, a small-molecule epidermal growth factor receptor-tyrosine kinase (EGFR-TK) inhibitor, has been approved for the management of advanced non-small cell lung cancer. The aim of the present study was to investigate whether erlotinib exerts potent antitumour activities through the reactive oxygen species (ROS)-c-Jun N-terminal kinase (JNK) pathway in the human non-small cell lung cancer cell line A549. 2. The 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and Hoechst 33342 staining showed that erlotinib produced a decline in cell viability of A549 cells and induced cell apoptosis, coupled with quick accumulation of ROS. In addition, erlotinib increased the respiratory control ratio, NADPH oxidase catalytic subunit gp91(phox) expression and superoxide anion (O2(-)) generation, suggesting that erlotinib induced ROS production in A549 cells from both mitochondrial and NADPH oxidase sources. 3. Fluorescence microscopy with the JC-1 probe and western blot analysis indicated that erlotinib induced loss of mitochondrial membrane potential, the release of cytochrome c and apoptosis-inducing factor (AIF) and activation of JNK. 4. The results of the present study suggest that erlotinib has potent antitumour activity in A549 cells by activating ROS-dependent, JNK-driven cell apoptosis. These findings provide a novel insight into the mechanism of action of erlotinib in the treatment of human non-small cell lung cancer in addition to its effects in inhibiting EGFR-TK.
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PMID:Erlotinib activates mitochondrial death pathways related to the production of reactive oxygen species in the human non-small cell lung cancer cell line A549. 1967 30

Galectin-13 transcripts have been identified in several normal and malignant tissues, but the physiological function of galectin-13 is still poorly understood. Here, we present evidence for its possible role in promoting cell death in the U-937 human macrophage cell line. Transfection of U-937 human macrophages by a galectin-13 cDNA-containing mammalian expression vector increased the galectin-13 level and sensitized the cells to stress stimuli. Galectin-13 overexpression facilitated paclitaxel-induced cell death and nuclear translocation of apoptosis-inducing factor (AIF) and endonuclease-G without inducing mitochondrial cytochrome-c release or caspase-3 activation. Immunoblot and immunofluorescence data showed that overexpression of galectin-13 induced long-term activation of c-Jun N-terminal kinase (JNK) and p38-mitogen-activated protein kinase (MAPK) pathways, as well as activation of apoptosis signal-regulating kinase-1 (Ask-1) kinase while it suppressed paclitaxel-induced long-term activation of the phosphatidilylositol-3-kinase (PI-3K)-Akt and extracellular signal-regulated kinase (ERK1/2) cytoprotective pathways. In addition, pharmacological inhibition of JNK and p38-MAPK pathways protected the cells from paclitaxel-induced cell death. All this data indicate that galectin-13 overexpression promoted apoptosis presumably by activating the Ask-1 kinase-JNK and p38-MAPK pro-apoptotic pathways and by suppressing the PI-3K-Akt and ERK1/2 cytoprotective pathways.
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PMID:Potentiation of paclitaxel-induced apoptosis by galectin-13 overexpression via activation of Ask-1-p38-MAP kinase and JNK/SAPK pathways and suppression of Akt and ERK1/2 activation in U-937 human macrophage cells. 1971 9

The role of Fas/Fas ligand in ultraviolet B (UVB)-induced apoptosis of murine peritoneal macrophages, the terminally differentiated, non-dividing cells was investigated. UVB (100 mJ/cm(2)) irradiation induced apoptosis in macrophages concurrent with expression of Fas, Fas ligand, Fas-associated death domain (FADD), activation of caspase-8, -3 and cleavage of poly (ADP-ribose) polymerase (PARP). Pretreatment of macrophages with a p38 mitogen activated protein kinase (MAPK) inhibitor SB202190, and c-Jun N-terminal kinase (JNK) inhibitor SP600125, inhibited UVB irradiation induced Fas expression and apoptosis. Alternatively, pretreatment with MAP kinase kinase (MEK) inhibitor PD98059, and phosphatidylinositol 3-kinase (PI3-K) inhibitor wortmannin, enhanced UVB induced expression of Fas and apoptosis. Apoptosis-inducing factor (AIF) release from mitochondria and Bcl-2 downregulation is also observed during apoptosis in UVB-irradiated macrophages. The data suggests that UVB-induced apoptosis is at least in part mediated by Fas/FasL system, and that MAPKs and PI3-K play an important role in the apoptotic process of macrophages exposed to UVB irradiation.
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PMID:Involvement of fas/fas ligand in ultraviolet B-induced apoptosis of murine peritoneal macrophages. 2002 Nov 33


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