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: 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

The intracellular events involved in normal pancreatic growth have been extensively investigated in response to cholecystokinin. Recent data indicate that tyrosine kinase, phospholipase D, phosphatidylinositol 3-kinase, and p42/p44 MAPK are stimulated in rat pancreatic acinar cells. Although we begin to understand the intracellular signaling pathways activated in normal pancreas, such information is not yet available in pancreatic cancer cells. This study was undertaken to identify the growth factors and hormones involved in cell proliferation of two human pancreatic cancer cell lines of ductal origin, the MIA PaCa-2, and PANC-1 cells, and to establish the intracellular events involved in the control of their growth. We demonstrated that FGF-2, IGF-1, cerulein, and gastrin but not FGF-1, HGF, secretin, and PACAP, stimulated proliferation of MIA PaCa-2 and PANC-1 cells. Autocrine factors such as gastrin and IGF-1 were also responsible for their proliferation. In response to EGF, FGF-2, IGF-1, cerulein, gastrin and bombesin, tyrosine kinase, and tyrosine phosphatase activities were stimulated in both cell lines. The close relationship established between cell growth and tyrosine kinase activation results from the observation that maximal growth stimulation paralleled with maximal enzyme activation and that genistein, the tyrosine kinase inhibitor, blocked cell growth and enzyme activation. The implication of PLD in growth-stimulated processes is doubtful since all growth factors and hormones tested failed to stimulate an already very active PLD activity. We finally observed a constitutive activity of p44 MAPK in both cell lines and of p42 in MIA PaCa-2 cells. However, p38 and p42 were stimulated in MIA PaCa-2 and PANC-1 cells, respectively, by all growth factors and hormones.
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PMID:Growth effects of regulatory peptides and intracellular signaling routes in human pancreatic cancer cell lines. 986 51

Somatostatin (SS-14) and its structural analogue SMS 201-995 (SMS) are recognized as physiological inhibitors of multiple organs and tissue functions through specific membrane receptors (sst1-sst5). The effects of SS-14 and SMS in the growth control of the pancreatic cancer cell lines MIA PaCa-2 and PANC-1 were investigated to identify and clarify the intracellular events involved. In PANC-1 cells, SS-14 and SMS caused inhibition of their basal growth, and that stimulated by epidermal growth factor, with a maximal effect at 0.1-1 microM. To understand the inhibitory mechanisms, we investigated the effects of SS-14 and SMS on phosphotyrosine phosphatase (PTPase) activity and, more specifically, that of tyrosine phosphatase SHP-1 (PTP1C). SS-14 and SMS caused significant increases in total cellular PTPase activity, and particularly SHP-1, with maximal activation within 1 min. Inhibition of membrane tyrosine kinase and p42 MAP kinase activities was also observed, in response to SS-14 and SMS. In MIA PaCa-2 cells, SS-14 and SMS were associated with a positive growth response at 1-10 nM, after 4 days of culture in serum-free medium. Total cellular PTPase activity was slightly increased, but SHP-1 activity could not be detected; its absence in this cell line was confirmed by Western blot. Membrane tyrosine kinase activities were significantly increased by SS-14 and SMS at concentrations needed for maximal growth. p44/p42, which are constitutively active in this cell line, and p38 activities were not affected by somatostatin. In conclusion, somatostatin can exert different effects on human pancreatic cancer cell growth, depending upon the presence or absence of SHP-1. This enzyme can play a key role in the control of cell proliferation, and its cellular presence may determine the therapeutic potential of somatostatin in the control of cancer cell growth.
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PMID:Inhibitory and stimulatory effects of somatostatin on two human pancreatic cancer cell lines: a primary role for tyrosine phosphatase SHP-1. 992 4

The implication of MAP kinases in the proliferation control of pancreatic cancer cells is still unknown. This study was undertaken to examine the contribution of the p44/p42 and p38 MAP kinases in the mitogenic response to epidermal growth factor (EGF) and bombesin in human pancreatic cancer cells, MIA PaCa-2 and PANC-1. Data indicate that EGF and bombesin stimulated growth of both cell lines. In MIA PaCa-2 cells, EGF and bombesin stimulated the in gel activation of p38 while p44/p42 kinases exhibited high basal activity and no response to stimuli. Growth and p38 activation were inhibited by genistein, wortmannin, PD98059 and SB203580, specific inhibitors of tyrosine kinase, phosphatidylinositol 3-kinase, MEK-1 and p38 kinases, respectively. In PANC-1 cells, EGF and bombesin stimulated p42 in gel activation; p44 remained highly activated and unresponsive to stimuli and p38 did not respond. Stimulated growth and p42 activation were inhibited by genistein, wortmannin and PD98059. Estimation of MAPK activities with a specific anti-active MAP kinase antibody indicated, however, that EGF increased the intensity of the bands corresponding to p42 and p44 MAP kinases in both cell lines, indicating that the mitogenic factor can regulate MAP kinase activity. Data also pointed out that ATP is sufficient to increase MAP kinase activity within the in gel assay technique and may thus explain the discrepancies existing between the in gel assay data and those obtained with the anti-active MAP kinase antibody.
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PMID:Activation of MAP kinases in growth responsive pancreatic cancer cells. 1043 20

Neurotensin (NT), a gastrointestinal (GI) hormone, binds its receptor (NTR) to stimulate proliferation of normal and neoplastic GI tissues; the molecular mechanisms remain largely undefined. Mitogen-activated protein kinases (MAPKs) are a family of intracellular kinases that transmit mitogenic signals by translocating to the nucleus and activating transcription factors. The purposes of this study were: (1) to identify whether the MAPKs (ERK1/2 and JNK) are activated by NT and (2) to determine the effect of NT on downstream transcription factors using the human pancreatic adenocarcinoma cell line, MIA PaCa-2, which possesses high-affinity NTR. Both ERK and JNK activity were stimulated within 3-6 min by treatment with NT (10 nM); steady-state levels of ERK and JNK protein were unchanged. Moreover, NT treatment resulted in increased AP-1 binding activity as determined by gel shift analysis. Delineating the signal transduction mechanisms regulating the cellular effects of NT will provide important insights into the molecular pathways responsible for NT-mediated effects on both normal and neoplastic cells.
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PMID:Neurotensin-mediated activation of MAPK pathways and AP-1 binding in the human pancreatic cancer cell line, MIA PaCa-2. 1072 Apr 80

We investigated whether microtubule-interfering agents (MIAs: taxol, colchicine, nocodazole, vinblastine, vincristine, 17-beta-estradiol, 2-methoxyestradiol) altered cyclooxygenase-2 (COX-2) expression in human mammary epithelial cells. MIAs enhanced prostaglandin E(2) synthesis and increased levels of COX-2 protein and mRNA. Nuclear run-off assays revealed increased rates of COX-2 transcription after treatment with MIAs. Calphostin C, an inhibitor of protein kinase C, blocked the induction of COX-2 by MIAs. The stimulation of COX-2 promoter activity by MIAs was inhibited by overexpressing dominant negative forms of Rho and Raf-1. MIAs stimulated ERK, JNK, and p38 mitogen-activated protein kinases (MAPK); pharmacological inhibitors of MAPK kinase and p38 MAPK blocked the induction of COX-2 by MIAs. Overexpressing dominant negative forms of ERK1 or p38 MAPK inhibited MIA-mediated activation of the COX-2 promoter. MIAs stimulated the binding of the activator protein-1 transcription factor complex to the cyclic AMP response element in the COX-2 promoter. A dominant negative form of c-Jun inhibited the activation of the COX-2 promoter by MIAs. Additionally, cytochalasin D, an agent that inhibits actin polymerization, stimulated COX-2 transcription by the same signaling pathway as MIAs. Thus, microtubule- or actin-interfering agents stimulated MAPK signaling and activator protein-1 activity. This led, in turn, to induction of COX-2 gene expression via the cyclic AMP response element site in the COX-2 promoter.
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PMID:Microtubule-interfering agents stimulate the transcription of cyclooxygenase-2. Evidence for involvement of ERK1/2 AND p38 mitogen-activated protein kinase pathways. 1080 26

Nerve growth factor (NGF) exerts both stimulatory and inhibitory effects on neuronal and certain nonneuronal tumors with the effect based on the type of tumor. We investigated NGF and its receptors (TrkA and p75) in pancreatic cancer cells (PANC-1, MIA-PaCa-2, CAPAN-1, ASPC-1, and T3M4) by reverse transcription-PCR, Western blot analysis, NGF ELISA, and growth assays. NGF mRNA was present at comparable levels in all five pancreatic cancer cell lines. TrkA expression was relatively high in PANC-1 and MIA-PaCa-2 cells and low in CAPAN-1, ASPC-1, and T3M4 cells. p75 expression was high in PANC-1, MIA-PaCa-2, and T3M4 cells, moderate in CAPAN-1, and low in ASPC-1 cells. By ELISA assay, the intracellular NGF content in all cell lines was approximately 40 pg/10(6) cells. NGF content increased significantly in PANC-1 and MIA-PaCa-2 cells when these cells were cultured with serum-free media, whereas there was no change in the other cancer cell lines. PANC-1 and MIA-PaCa-2 cells but not the other cell lines released NGF in the culture media. Exogenous NGF stimulated the growth of PANC-1 and MIA-PaCa-2 cells, inhibited the growth of T3M4 and CAPAN-1 cells in a dose- and time-dependent manner, and did not affect the growth of ASPC-1 cells. NGF led to the phosphorylation of TrkA, mitogen-activated protein kinase (MAPK), and p38 MAPK but not stress-activated protein kinase/c-Jun NH2-terminal kinase in PANC-1 and MIA-PaCa-2 cells. In contrast, in the other pancreatic cancer cell lines none of these kinases were phosphorylated by NGF. In conclusion, the effects of NGF on pancreatic cancer cell growth are dependent on the expression levels and the balance of its TrkA and p75 receptors. NGF-induced pancreatic cancer cell growth seems to be mediated through the phosphorylation of TrkA and subsequently via MAPK. These results point to a previously unknown autocrine/paracrine pathway in pancreatic cancer, suggesting that NGF-TrkA interactions are important factors influencing cell growth and spread in this malignancy.
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PMID:Nerve growth factor exerts differential effects on the growth of human pancreatic cancer cells. 1120 97

In the present study we investigated the mechanisms responsible for and the biological consequences of the constitutive activation of the insulin-like growth factor-1 receptor (IGF-1R) in the MIA PaCa-2 cells. An aberrant increase in the expression and activation of the IGF-1R was observed during the transition of growth states from exponential to quiescent. The increase in IGF-1R expression is preceded by an increase in IGF-1R mRNA transcript and is associated with an increase in the IGF-1R promoter activity. Inhibition of de novo transcription by actinomycin D increased the stability of IGF-1R mRNA in exponentially growing cells, thereby increasing the expression of IGF-1R to a level similar to that seen in quiescent cells. Increased IGF-1R signaling mediated the growth factor independence of quiescent MIA PaCa-2 cells through the constitutive activation of mitogen-activated protein kinase (MAPK). Exogenous IGF-1 increased cell proliferation and activated MAPK and AKT signaling pathways. The resistance of cells to apoptosis by IGF-1R signaling was mediated through MAPK and phosphatidylinositol 3-kinase (PI3K) pathways and a yet unidentified pathway(s). Thus, aberrant regulation of IGF-1R signaling is required for resistance to apoptosis and growth factor independence of MIA PaCa-2 cells. This likely protects cells from unfavorable conditions and allows cells to rapidly re-enter the cell cycle when conditions are favorable.
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PMID:Aberrant expression and activation of insulin-like growth factor-1 receptor (IGF-1R) are mediated by an induction of IGF-1R promoter activity and stabilization of IGF-1R mRNA and contributes to growth factor independence and increased survival of the pancreatic cancer cell line MIA PaCa-2. 1178 36

Metabolic responses induced by thrombin in human umbilical vein endothelial cells (HUVECs) were investigated by using the cytosensor technique. Thrombin increased the extracellular acidification rate of endothelial cells, measured as an index of metabolic activity with a cytosensor microphysiometer, in a concentration-dependent fashion with an EC(50) of 1.27+/-0.59 IU/ml, which was abolished by the MAP kinase inhibitor PD98059. When intracellular Ca(2+) was chelated or PKC was inactivated, PD98059 failed to abolish the thrombin-induced acidification rate response in HUVECs. In addition, the tyrosine kinase inhibitor genistein, PKC inhibitor calphostin C, and Na(+)/H(+)exchanger antagonist MIA also partly inhibited thrombin-induced acidification rate responses. It is suggested that thrombin stimulated rapid metabolic responses via MAP kinase in HUVECs, which are calcium- and PKC-dependent.
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PMID:Metabolic responses induced by thrombin in human umbilical vein endothelial cells. 1205 56

We found that 12-O-tetradecanoylphorbol-13-acetate (TPA) promoted anchorage-independent growth but did not affect anchorage-dependent growth of MIA PaCa-2 human pancreatic carcinoma cells. TPA markedly activated mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase in an anchorage-independent manner. Two protein kinase C (PKC) isoforms, conventional PKC (cPKC) and novel PKC (nPKC), but not apical PKC, translocated from the cytosolic to the particulate fraction upon TPA treatment. To identify the PKC isoforms involved in the regulation of anchorage-independent growth, four PKC isoforms (alpha, delta, epsilon, and zeta) were forced to be expressed in MIA PaCa-2 cells with an adenovirus vector. Overexpression of nPKCdelta or nPKC epsilon activated MAPK and promoted anchorage-independent growth. Overexpression of cPKCalpha alone did not influence anchorage-independent growth but lowered the concentration of TPA that was required to enhance such growth. Expression of constitutively active MAPK kinase-1 (MEK1) also promoted anchorage-independent growth. Furthermore, PKC inhibitors or an MEK inhibitor completely suppressed both TPA-induced activation of MAPK and promotion of anchorage-independent growth, but a cPKC-selective inhibitor partially suppressed TPA-induced promotion of the growth. Based on these results, we suggest that MAPK activation, mediated by certain isoforms of PKC, plays a part in oncogenic growth of MIA PaCa-2 cells. In summary, our data indicated that specific inhibitors of the cPKC and nPKC signaling pathway might be selective anti-oncogenic growth agents for some types of human pancreatic cancer.
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PMID:Enhancement of anchorage-independent growth of human pancreatic carcinoma MIA PaCa-2 cells by signaling from protein kinase C to mitogen-activated protein kinase. 1220 69


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