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)

Smoking is a risk factor for lung cancer, chronic obstructive pulmonary disease, chronic bronchitis and asthma. The chronic lung diseases are also a predisposing factor for the development of lung cancer. Glucocorticoids are used for the management of chronic lung diseases because of their anti-inflammatory activity. These drugs also have anti-tumourigenic effects in mouse models of lung cancer. Glucocorticoids are frequently used as co-treatment with cancer therapy. Using the human pulmonary adenocarcinoma (PAC) cell line NCI-H322 with features of bronchiolar Clara cells, and immortalised human small airway epithelial cells, our data show that the glucocorticoid dexamethasone increased cell proliferation in MTT assays in a PKA-dependent manner. Dexamethasone significantly increased intracellular cAMP in direct immunoassays. Immunoblot analysis revealed increased phosphorylation of ERK1/2 and of the transcription factor CREB in response to dexamethasone. These data suggest that glucocorticoids could have tumour promoting activity on a sub-set of human PAC.
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PMID:PKA-dependent growth stimulation of cells derived from human pulmonary adenocarcinoma and small airway epithelium by dexamethasone. 1623 8

Resistance to anticancer drugs is the major problem in the treatment of many advanced cancers, including androgen-independent prostate cancer. Recently, increased expression of Id-1, a basic helix-loop-helix protein, is reported in several types of advanced cancer. It is suggested that high expression of Id-1 may provide an advantage for cancer cell survival and inactivation of Id-1 may be able to increase cancer cells' susceptibility to apoptosis. To test this hypothesis, in this study, by using RNA interfering technology, we inactivated the Id-1 gene in 2 androgen-independent prostate cancer cell lines, DU145 and PC3, and investigated whether downregulation of Id-1 could lead to increased sensitivity to a commonly used anticancer drug, taxol. By using colony forming assay and MTT assay, we found that inactivation of Id-1 resulted in both decreased colony forming ability and cell viability in prostate cancer cells, after taxol treatment. In addition, the si-Id-1-induced sensitization to taxol was associated with activation of apoptosis pathway, which is demonstrated by increased apoptotic index, DNA laddering, sub-G1 phase of the cell cycle, as well as cleaved-PARP and Caspase 3. Furthermore, c-Jun N-terminal kinase (JNK), one of the common pathways responsible for taxol-induced apoptosis, was also activated in the si-Id-1 transfected cells. Inhibition of JNK activity by a specific inhibitor, SP600125, blocked the si-Id-1-induced sensitivity to taxol. These results indicate that increased Id-1 expression in prostate cancer cells may play a protective role against apoptosis, and downregulation of Id-1 may be a potential target to increase sensitivity of taxol-induced apoptosis in prostate cancer cells.
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PMID:Inactivation of Id-1 in prostate cancer cells: A potential therapeutic target in inducing chemosensitization to taxol through activation of JNK pathway. 1628 90

IGF-binding protein-3 (IGFBP-3) has been reported to exert a protective influence on the pathogenesis of colorectal cancer. This may reflect its modulation of IGF-I bioactivity as well as IGF-I-independent effects on cell proliferation and apoptosis. Although local expression of IGF-I in the colon is increasingly recognised as having important regulatory consequences, the role of locally expressed IGFBP-3 remains unknown. The aims of the present study were: (i) to quantify and localise the expression of IGFBP-3 in human normal and malignant colon; (ii) to relate this expression to that of other components of the IGF-I axis; and (iii) to investigate the effects of IGFBP-3 on colonic epithelial cell proliferation and apoptosis. RNA was extracted from 46 paired samples of normal and malignant colonic tissue. IGFBP-3, IGF-I, IGF-I receptor and GH receptor mRNA levels were quantified using real-time RT-PCR. Laser-capture microdissection of the same samples was used to isolate mRNA from epithelium and stromal components and localise mRNA expression. Expression was confirmed at a protein level by immunohistochemistry. Human colorectal cancer HT-29 and CaCo-2 cells were cultured with IGFBP-3 (200 ng/ml), +/- IGF-I (20 ng/ml), +/- sodium butyrate (5 mM). Cell number was assessed by an MTS assay (a modification of the MTT assay), and apoptosis assessed by cell morphology and FACS analysis using both annexin and propidium iodide staining. UO146, a MAP kinase inhibitor, and wortmannin, an inhibitor of the phosphatidylinositol 3-kinase (PI-3K) pathway, were used to determine the contribution of these signalling pathways on the effects of IGFBP-3. IGFBP-3 mRNA was detected in all samples (mean copy number/mug total RNA in normal colon, 2.6 x 10(6) compared with 1.3 x 10(7) in the cancers; P < 0.0001). Immunohistochemistry confirmed the expression and showed it to be equally distributed between epithelial and stromal components in normal tissue, but to be mainly restricted to the stromal component of malignant tissue. This differential expression was confirmed by RT-PCR of RNA from laser-capture microdissected samples. IGF-I mRNA was detected in 31 samples of normal colon; mean IGFBP-3 copy number was higher in the IGF-I-positive samples compared with IGF-I-negative samples. IGFBP-3 on its own induced apoptosis in HT-29 cells (P < 0.001). Co-incubation of 200 ng/ml IGFBP-3 with butyrate (5 mM) resulted in the potentiation of its apoptosis (P < 0.0001), which was not rescued by co-incubation with IGF-I (P < 0.0001). The addition of UO126 caused a decrease in cell number and increased the effects of IGFBP-3. IGFBP-3 is differentially expressed between stromal and epithelial components of normal and malignant colon, which may reflect its pro-apoptotic, IGF-I-independent effect on colonic epithelial cells. These effects are mediated in part by the PI-3K pathway in contrast to the MAP kinase pathway used by IGF-I.
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PMID:Differential expression of IGF-binding protein-3 in normal and malignant colon and its influence on apoptosis. 1632 29

Pramipexole, a novel non-ergot dopamine (DA) agonist, has been successfully applied to the treatment of Parkinson's disease (PD). Although the specific cause of PD remains unknown, recent studies have provided evidence that oxidative stress plays a role in the parthenogenesis of the disease. In the present study, we examined the effect of pramipexole on hydrogen peroxide (H2O2, 100 microM)-induced PC12 cell death, and the intracellular mechanism of this effect. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay revealed that pretreatment of PC12 cells with pramipexole (1-100 microM) resulted in significant protection against H2O2-induced cell death in a concentration-dependent manner. The protective effect of pramipexole was not affected by pretreatment with the DA receptor antagonists sulpiride, spiperone or domperidone, suggesting that the effect of pramipexole is not mediated by DA receptors. In PC12 cells, pramipexole inhibited H2O2-induced lactate dehydrogenase (LDH) leakage, as well as H2O2-induced cytochrome c release and caspase-3 activation with the resultant apoptosis. It was also observed in PC12 cells that H2O2 stimulated phosphorylation of mitogen-activated protein (MAP) kinases, i.e., extracellular signal-regulated kinase1/2 (ERK1/2), c-Jun NH2-terminal kinase (JNK) and p38 MAP kinase. Pramipexole inhibited H2O2-induced JNK and p38 MAP kinase, but not ERK1/2 phosphorylation. Furthermore, in these cells experiments with a fluorescent probe, 2-[6-(4'-amino)phenoxy-3H-xanthen-3-on-9-yl]benzoic acid, revealed that pramipexole, the JNK inhibitor SP600125 and the p38 MAP kinase inhibitor SB203580 inhibited the generation of H2O2-induced reactive oxygen species. Caspase inhibitors Z-DEVD-FMK and Z-IETD-FMK, as well as SP600125 and SB203580, inhibited H2O2-induced PC12 cell death to a similar extent as pramipexole. These results suggest that pramipexole exerts a protective effect against oxidative stress-induced PC12 cell death in part through an inhibition of JNK and p38 MAP kinase.
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PMID:Pramipexole protects against H2O2-induced PC12 cell death. 1636 28

Hepatocyte growth factor (HGF) is one of major growth factors in the bone marrow microenvironments with which the proliferation, differentiation and migration of bone marrow-derived mesenchymal stem cells were closely contacted. However, its roles in the regulation of proliferation, differentiation and migration of bone marrow-derived mesenchymal stem cells remain unclear. This study was aimed to investigate the effect of HGF on biological characteristics of bone marrow-derived mesenchymal stem cells. Expression of c-Met, the receptor for HGF was detected by immunohistochemistry assay, cell proliferation was determined by MTT, activity of ALP was quantitatively assayed, cell migration and anoikis-induced MSC apoptosis were analyzed. The results showed that HGF not influenced the proliferation and osteogenic differentiation of bone marrow-derived mesenchymal stem cells. Treatment of bone marrow-derived mesenchymal stem cells with recombinant human hepatocyte growth factor resulted in inhibition of anoikis-induced apoptosis. HGF significantly stimulated the migration of bone marrow-derived mesenchymal stem cells. Both PI-3 kinase and MAPK kinase were proved to be involved in HGF-induced migration. It is concluded that HGF/c-Met signal regulates the apoptosis and migration of bone marrow-derived mesenchymal stem cells.
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PMID:[Influence of hepatocyte growth factor on biological characteristics of bone marrow-derived mesenchymal stem cells]. 1640 77

Recent data showed that epidermal growth factor receptor (EGFR) inhibitors, such as ZD1839, alone or in combination with chemotherapeutic agents for androgen-independent prostate cancer (AIPC) did not produce promising results in clinical settings. More effective regimens involving novel stronger inhibitor of EGFR and better combinations are needed. The anti-tumor activity of PD168393, an irreversible EGFR inhibitor, with or without chemotherapeutic agents for the treatment of AIPC was investigated in vitro. In results, both the androgen-independent cell lines PC-3 and DU145 expressed higher levels of EGFR than the androgen-dependent MDA PCa 2b and androgen-responsive LNCaP cells by Western blotting. DU145 was much more sensitive to PD168393 and ZD1839 than MDA PCa 2b. PD168393, but not ZD1839, significantly potentiated paclitaxel cytotoxicity against DU145 by MTT assay and median-effect analysis. The combination of PD168393 or ZD1839 with other cytotoxic agents including docetaxel and 5-fluorouracil, however, was either additive or antagonistic. Compared to paclitaxel alone, PD168393 significantly enhanced paclitaxel-induced DNA fragmentation, sub-G1 fraction accumulation, mitochondrial membrane dysfunction, cytochrome C release, caspase-3 activation and eventually apoptosis. These molecular events were accompanied by Bad up-regulation, p53 and p21Waf1/Cip1 induction, ERK1/2 inactivation and inhibition of EGFR phosphorylation in the presence of PD168393. These effects did not involve significant alteration in the Akt1/2 and STAT3 signaling pathway. In conclusion, the combination of paclitaxel and PD168393 produced a profound synergistic growth inhibition of AIPC cells. Combining PD168393 with paclitaxel may have clinical benefits and warrants further investigation.
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PMID:Epidermal growth factor receptor inhibitor (PD168393) potentiates cytotoxic effects of paclitaxel against androgen-independent prostate cancer cells. 1641 5

Curcumin, the yellow pigment in the spice turmeric, has potent chemopreventive activities that involve diverse molecular pathways. It is widely believed that curcumin pro-apoptotic properties are mediated by downregulation of NF kappa B (NFkappaB). The p65/RelA subunit of NFkappaB may influence cell death, in part by activation of NFkappaB anti-apoptotic target genes including X-linked inhibitor of apoptosis (XIAP), A20, bcl-xL and inhibition of sustained activation of c-Jun N-terminal kinase (JNK). We have shown previously that curcumin inhibits NFkappaB, activates JNK and promotes apoptosis in HCT116 colorectal cancer cells. Here, we show that forced overexpression of p65 does not affect curcumin-induced JNK activation. Indeed, overexpression of p65 enhanced curcumin-mediated apoptosis as assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay and poly(ADP-ribose) polymerase (PARP) cleavage. This potentiating effect of p65 upon curcumin-mediated apoptosis was reversed by transfection of cells with an IkappaB super-repressor (DeltaNIkappaB). Curcumin treatment inhibited expression of NFkappaB anti-apoptotic target genes in mock-transfected and in p65-overexpressing HCT116 cells, although expression levels remained higher in the latter. Taken together, these results show that curcumin-mediated activation of JNK or induction of apoptosis does not require inhibition of p65. Furthermore, curcumin/p65 synergy in promotion of apoptosis cannot be attributed to active repression of NFkappaB anti-apoptotic genes.
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PMID:Overexpression of p65/RelA potentiates curcumin-induced apoptosis in HCT116 human colon cancer cells. 1649 2

Oxidative stress-induced retinal pigment epithelial (RPE) cell death is involved in the pathogenesis of age-related macular degeneration (AMD). Pigment epithelium-derived factor (PEDF) is an anti-angiogenic/neurotropic dual functional factor, and recently it was also shown to mediate anti-oxidative action. In the present study, the influence of PEDF in hydrogen peroxide (H(2)O(2))-induced RPE cell death was investigated using nontransformed human RPE cell line (ARPE-19). The recombinant PEDF was purified from E. coli. The MTT cell viability assay showed that PEDF rescued ARPE-19 from H(2)O(2)-induced cell death in a dose- and time-dependent manner. Western blot analysis revealed that PEDF stimulated the extracellular signal-regulated kinases (ERK1/2) phosphorylation. The PEDF cytoprotective effect was significantly attenuated by the ERK1/2 inhibitor PD98059. In this study, we demonstrate that PEDF induces ERK1/2 phosphorylation and we further suggest that the ERK signal cascade contributes to RPE cell's cytoprotection against oxidative stress.
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PMID:Pigment epithelium-derived factor inhibits oxidative stress-induced cell death by activation of extracellular signal-regulated kinases in cultured retinal pigment epithelial cells. 1650 12

Obesity is considered a risk factor for many cancers, including breast cancer. Our laboratory has previously shown that leptin is mitogenic in many cancer cell lines, including breast. Information regarding the effects of high leptin levels on leptin receptor expression and signaling is lacking. The purpose of this study was to characterize leptin receptor expression in response to leptin in breast cancer cells. In addition, SOCS-3 expression (a leptin inducible inhibitor of leptin signaling), plus MAPK and PI3K signaling, were examined to determine their role in leptin-induced cell proliferation. Breast cancer cell lines, ZR75-1 and HTB-26, were treated with 0, 4, 40 or 80 ng/ml of leptin. Multiplex RT-PCR was performed to determine relative mRNA expression levels of the human short (huOB-Ra) or long (huOB-Rb) leptin receptor isoforms, or SOCS-3. MAPK and PI3K signaling was analyzed by phosphorylation of ERK and Akt, respectively, via Western blotting. Cell proliferation and inhibitor studies were analyzed by MTT assay. HTB-26 and ZR75-1 both expressed huOB-Ra, huOB-Rb and SOCS-3 mRNA; however, mRNA expression levels generally remained unchanged over time with leptin treatment. MAPK and PI3K pathways were activated in the presence of leptin over time. MAPK and PI3K inhibitors significantly blocked leptin-induced proliferation. Higher levels of circulating leptin contribute to breast cancer proliferation by activation of the MAPK and PI3K signaling pathways involved in cell growth and survival. The mitogenic effects of leptin are not a consequence of altered leptin receptor or SOCS-3 mRNA expression.
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PMID:Leptin receptor expression and cell signaling in breast cancer. 1652 50

Angiotensin II (Ang II) induces vascular smooth muscle cells (VSMCs) proliferation, which plays an important role in the development and progression of atherosclerosis. Ang II-induced cellular events have been implicated, in part, in the activation of extracellular signal-regulated kinases 1/2 (ERK1/2). Crocetin is a natural carotenoid compound isolated from Gardenia jasminoids Ellis. In the present study, we investigated the effect of crocetin on the Ang II-induced VSMCs proliferation and ERK1/2 activation. 3-[4,5-dimethylthiazol-2-yl]-2,5-dephenyl tetrazolium bromide (MTT) and [3H]thymidine incorporation assay showed that the Ang II-induced VSMCs proliferation was inhibited significantly by crocetin. In-gel kinase assay indicated that Ang II elicited rapid and significant increase of ERK1/2 activity in VSMCs, which was suppressed by crocetin markedly. Western blotting analysis and cell-based enzyme-linked immunosorbent assay (ELISA) demonstrated that crocetin significantly inhibited the phosphorylation and activation of ERK1/2 induced by Ang II. Using the indirect immunofluorescent technique, we also found that crocetin inhibited nuclear translocation of activated ERK1/2 induced by Ang II. These findings suggest that the suppression by crocetin of the Ang II-induced VSMCs proliferation can be attributed, at least in part, to its inhibitory effect on ERK1/2 pathway.
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PMID:ERK1/2 pathway is involved in the inhibitory effect of crocetin on angiotensin II-induced vascular smooth muscle cell proliferation. 1658 Mar 46


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