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)

The effects of manumycin, a competitive farnesyltransferase (FTase) inhibitor, on pancreatic cancer cell lines with or without K-ras mutation were studied. Manumycin inhibited the growth of human pancreatic cancer cells (SUIT-2, MIA PaCa-2, AsPC-1, BxPC-3) in a dose-dependent manner. The 50% inhibitory concentration (IC50) in cell lines with a mutant K-ras gene (SUIT-2, MIA PaCa-2, AsPC-1) was lower than that in BxPC-3 with a wild-type ras. Both mitogen-activated protein kinase activity after growth stimuli and the ability for chemotactic invasion were markedly more inhibited by manumycin in SUIT-2 than in BxPC-3. These results suggest that mutated Ras is more sensitive to manumycin than the wild type. Furthermore, tumor growth and liver metastasis in nude mice inoculated with manumycin-treated SUIT-2 cells were inhibited dose dependently. Inhibition of Ras activity might be a new anticancer strategy in pancreatic cancer in which Ras plays a role.
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PMID:Inhibition of growth and invasive activity of human pancreatic cancer cells by a farnesyltransferase inhibitor, manumycin. 936 Oct 92

Restenosis after angioplasty is thought to be caused by proliferation and migration of vascular smooth muscle cells (VSMCs), and it is a most serious problem in medical treatment. A low dose (50 ng/ml) of manumycin A, an inhibitor of p21(ras) (ras) farnesylation, significantly inhibited proliferation of rat VSMCs stimulated by the platelet-derived growth factor (PDGF). The mitoinhibitory effect of manumycin A was dose- and time-dependent but was independent of cell density. Western blot analysis showed that manumycin A reduced the amount of functional ras localized at the cytoplasmic membrane and inhibited the phosphorylation of p42/44 mitogen-activated protein kinase (MAPK). Manumycin A also inhibited VSMC migration and disorganized alpha actin fibers, as shown by immnofluorecence staining. These results indicate that the interruption of the ras/MAPK signal transduction pathway and the disorganization of alpha actin fibers are the main cause of manumycin A inhibition of VSMC proliferation and migration induced by PDGF.
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PMID:Manumycin A, inhibitor of ras farnesyltransferase, inhibits proliferation and migration of rat vascular smooth muscle cells. 1054 30

The aim of the present study was to assess the cytotoxicity of manumycin, a specific inhibitor of farnesyl:protein transferase, as well as its effects on protein isoprenylation and kinase-dependent signal transduction in COLO320-DM human colon adenocarcinoma which harbours a wild-type K-ras gene. Immunoblot analysis of isolated cell membranes and total cellular lysates of COLO320-DM cells demonstrated that manumycin dose-dependently reduced p21 ras farnesylation with a 50% inhibitory concentration (IC50) of 2.51 +/- 0.11 microM and 2.68 +/- 0.20 microM, respectively, while the geranylgeranylation of p21 rhoA and p21rap1 was not affected. Manumycin dose-dependently inhibited (IC50 = 2.40 +/- 0.67 microM) the phosphorylation of the mitogen-activated protein kinase/extracellular-regulated kinase 2 (p42MAPK/ERK2), the main cytoplasmic effector of p21ras, as well as COLO320-DM cell growth (IC50 = 3.58 +/- 0.27 microM) without affecting the biosynthesis of cholesterol. Mevalonic acid (MVA, 100 microM), a substrate of the isoprenoid synthesis, was unable to protect COLO320-DM cells from manumycin cytotoxicity. Finally, manumycin 1-25 microM for 24-72 h induced oligonucleosomal fragmentation in a dose- and time-dependent manner and MVA did not protect COLO320-DM cells from undergoing DNA cleavage. The present findings indicate that the inhibition of p21ras processing and signal transduction by manumycin is associated with marked inhibition of cell proliferation and apoptosis in colon cancer cells and the effect on cell growth does not require the presence of a mutated ras gene for maximal expression of chemotherapeutic activity.
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PMID:Manumycin inhibits ras signal transduction pathway and induces apoptosis in COLO320-DM human colon tumour cells. 1073 65

In this study it was shown that growth factor receptors (GFR) play a crucial role in early embryogenesis of the echinoderms Hemicentrotus pulcherrimus and Clypeaster japonicus by transmitting signals to the mitogen-activated protein kinase (MAPK) pathway. The phosphorylation ratio of extracellular signal-regulated kinase 1 (ERK1) changed dynamically during early embryogenesis and showed a peak at the swimming blastula (sBl) stage. Suramin, an inhibitor of GFR, when applied during the sBl stage perturbed morphogenesis, including primary mesenchyme cell (PMC) migration, cell proliferation, archenteron elongation, spiculogenesis, pigment cell differentiation and phosphorylation of myosin light chains (MLC). Genistein, a receptor-type protein tyrosine kinase inhibitor, severely inhibited PMC migration, gastrulation and the phosphorylation of MLC. Manumycin A, a Ras inhibitor, inhibited spiculogenesis and invagination. PD98059, a MAPK/ERK kinase inhibitor, perturbed early PMC migration and pigment cell differentiation, but not spiculogenesis and gastrulation (although these two events were significantly delayed). PMC ingression was not perturbed by genistein, suramin, manumycin A or PD98059. All of the inhibitors perturbed the phosphorylation of ERK1, which was completely restored by exogenous platelet-derived growth factor (PDGF)-AB. PDGF-AB also partially restored elongation of the archenteron by restoring cell proliferation that had been perturbed by suramin.
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PMID:Essential role of growth factor receptor-mediated signal transduction through the mitogen-activated protein kinase pathway in early embryogenesis of the echinoderm. 1239 77

We reported that corticosterone (CORT) can induce differentiation of growth hormone (GH) cells in vitro and in vivo during chick embryonic development. In the present study, a quantitative in situ hybridization plate assay (ISHPA) for GH mRNA was developed and used to assess the mechanism of glucocorticoid-induced GH gene expression directly in cell culture plates. Embryonic pituitary cells were treated with GH-releasing hormone (GHRH) alone, CORT alone and GHRH and CORT in combination. CORT increased levels of GH mRNA 22-fold, while GHRH acted synergistically with CORT to further augment GH mRNA levels (130-fold relative to control). GHRH alone induced only a 2.5-fold increase in GH mRNA. GH mRNA levels were increased after 8 h but not after 4 h of CORT treatment. In addition, synergistic effects of GHRH on CORT-induced GH mRNA were also observed after 8 h of treatment, however, GHRH alone for up to 24 h failed to increase GH mRNA levels, suggesting that embryonic pituitary cells do not respond substantially to GHRH in the absence of CORT. Cycloheximide (CHX) blocked CORT induction of GH mRNA, indicating that synthesis of some protein(s) is required for CORT induction of GH gene expression. Bypassing the GHRH receptor through treatment with forskolin and 3-isobutyl-1-methylxanthine (IBMX) and phorbol 12-myristate-13-acetate failed to increase GH mRNA levels, suggesting that a lack of GHRH receptors alone cannot account for the lack of GHRH responses in the absence of CORT. Treatment with inhibitors of protein kinase A (PKA; H-89), protein kinase C (PKC; calphostin C) and mitogen activated protein kinase (MAPK; PD098059) did not block induction of GH mRNA by CORT. In contrast, Manumycin, an inhibitor of Ras-GTPase, significantly suppressed the effect of CORT on GH mRNA. These results indicate that glucocorticoid induction of GH gene expression in embryonic pituitary cells requires active protein synthesis. The protein(s) involved in this induction is probably not a component of the PKA, PKC or MAPK signaling cascades but may involve Ras or a Ras-like compound. Current efforts in our laboratory are directed at identifying this intermediary protein(s).
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PMID:Evaluation of glucocorticoid-induced growth hormone gene expression in chicken embryonic pituitary cells using a novel in situ mRNA quantitation method. 1270 89

Manumycin was reported to have inhibitory effect on farnesyltransferase by competing with the farnesyl pyrophosphate substrate. It exhibited different antiproliferative activity in human hepatocellular carcinoma HepG2 cells, primary cultured human cardiac muscle cells and human liver cells (CLC). HepG2 cells overexpressing ras gene were more sensitive to manumycin than the other cells. The difference might be related to Ras protein levels in these cell lines. Manumycin reduced the amount of functional ras localized at the cytoplasmic membrane, resulting in blocked C-raf-1 assocation with Ras. Manumycin inhibited ERK1/2 phosphorylation in HepG2 cells without reduced expression of ERK1/2 protein. The levels of protein MKP-1 were significantly up-regulated. Our study also demonstrated that manumycin inhibited p85/PI3K and Akt phosphorylation without reduced expression of p85/PI3K and Akt, and interfered with the association of p85/PI3K and Ras. These findings indicated that manumycin interfered with Ras membrane localization, shut down the downstream pathways of Ras and inhibited cell proliferation in HepG2 cells.
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PMID:Manumycin inhibits cell proliferation and the Ras signal transduction pathway in human hepatocellular carcinoma cells. 1273 20

Our previous studies demonstrated that manumycin A, a farnesyltransferase inhibitor, induced apoptosis of anaplastic thyroid cancer cells via the intrinsic apoptosis pathway and induced reactive oxygen species (ROS), which mediated DNA damage. In this study, we investigated the hypothesis that the mechanism of apoptosis induced by manumycin in anaplastic thyroid cancer cells fits the general pattern of the "xenobiotic apoptosis pathway," the hallmarks of which are induction of oxidative stress, mitogen-activated protein kinase (MAPK) signaling, and cytochrome c release, which activates the intrinsic apoptosis pathway. We found that manumycin reduced intracellular glutathione and generated ROS: nitric oxide and superoxide anions. Manumycin-induced apoptosis correlated with increase in ROS. Quenching of ROS with N-acetyl-L-cysteine prevented cytochrome c release by manumycin. Manumycin induced phosphorylation of p38 MAPK, which was blocked by N-acetyl-L-cysteine. p38 MAPK may be an important signaling mediator in the activation of the intrinsic apoptotic pathway by manumycin because the p38 MAPK inhibitor SB203580 inhibited cytochrome c release and activation of caspase-3 by manumycin. In conclusion, manumycin activated the intrinsic apoptosis pathway via activation of p38 MAPK by oxidative stress. The mechanism of apoptosis induced by manumycin fits the emerging general pattern for apoptosis induced by xenobiotics.
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PMID:Redox control of manumycin A-induced apoptosis in anaplastic thyroid cancer cells: involvement of the xenobiotic apoptotic pathway. 1641 Jul 25

Furanodiene (C15H20O), a pure compound isolated from Traditional Chinese medicine, Curcuma wenyujin, named Ezhu in Chinese, which structure was determined on the basis of NMR, MS and UV spectrum. In this study, we attempted to characterize in detail the signaling cascades resulted from furanodiene-induced apoptosis in human hepatoma HepG2 cells. Furanodiene inhibited HepG2 cell growth by causing cell cycle arrest at G2/M and inducing apoptosis as evidenced by DNA fragmentation assay. We found that furanodiene induced mitochondrial transmembrane depolarization, release of mitochondrial cytochrome c, activation of caspases-3 and the cleavage of PARP. The furanodiene mediated mitochondria-caspase apoptotic pathway also involved activation of p38 and inhibition of ERK mitogen-activated protein kinase (MAPK) signaling. These results for the first time have identified the biological activity of furanodiene against HepG2 cells and provide rationales for further development of essential oil of Ezhu and its ingredients such as furanodiene on treatment of liver diseases.
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PMID:Furanodiene induces G2/M cell cycle arrest and apoptosis through MAPK signaling and mitochondria-caspase pathway in human hepatocellular carcinoma cells. 1761 10

Emerging evidence links exosomes to cancer progression by the trafficking of oncogenic factors and neoplastic reprogramming of stem cells. This necessitates identification and integration of functionally validated exosome-targeting therapeutics into current cancer management regimens. We employed quantitative high throughput screen on two libraries to identify exosome-targeting drugs; a commercially available collection of 1280 pharmacologically active compounds and a collection of 3300 clinically approved compounds. Manumycin-A (MA), a natural microbial metabolite, was identified as an inhibitor of exosome biogenesis and secretion by castration-resistant prostate cancer (CRPC) C4-2B, but not the normal RWPE-1, cells. While no effect was observed on cell growth, MA attenuated ESCRT-0 proteins Hrs, ALIX and Rab27a and exosome biogenesis and secretion by CRPC cells. The MA inhibitory effect is primarily mediated via targeted inhibition of the Ras/Raf/ERK1/2 signaling. The Ras-dependent MA suppression of exosome biogenesis and secretion is partly mediated by ERK-dependent inhibition of the oncogenic splicing factor hnRNP H1. Our findings suggest that MA is a potential drug candidate to suppress exosome biogenesis and secretion by CRPC cells.
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PMID:Manumycin A suppresses exosome biogenesis and secretion via targeted inhibition of Ras/Raf/ERK1/2 signaling and hnRNP H1 in castration-resistant prostate cancer cells. 2884 15