Therapeutic effect of ?-secretase inhibition in KrasG12V-driven non-small cell lung carcinoma through derepression of DUSP1 phosphatase and inhibition of ERK
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Maraver A
PROVIDER: S-ECPF-GEOD-38054 | biostudies-other | 2012 Aug
REPOSITORIES: biostudies-other
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Project description:Here, we have investigated the role of the Notch pathway in the generation and maintenance of Kras(G12V)-driven non-small cell lung carcinomas (NSCLCs). We demonstrate by genetic means that ?-secretase and RBPJ are essential for the formation of NSCLCs. Of importance, pharmacologic treatment of mice carrying autochthonous NSCLCs with a ?-secretase inhibitor (GSI) blocks cancer growth. Treated carcinomas present reduced HES1 levels and reduced phosphorylated ERK without changes in phosphorylated MEK. Mechanistically, we show that HES1 directly binds to and represses the promoter of DUSP1, encoding a dual phosphatase that is active against phospho-ERK. Accordingly, GSI treatment upregulates DUSP1 and decreases phospho-ERK. These data provide proof of the in vivo therapeutic potential of GSIs in primary NSCLCs.
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Project description:We have investigated the role of the Notch pathway in the generation and maintenance of KrasG12V-driven non-small cell lung carcinomas (NSCLCs). We demonstrate by genetic means that γ-secretase and Rbpj activities are both essential in the formation of NSCLCs. Interestingly, pharmacologic treatment of mice carrying endogenous NSCLCs with a γ-secretase inhibitor (GSI) blocks cancer growth and induces partial regression. Treated cancers show a reduction in Hes1 levels, reduced phosphorylated Erk, decreased proliferation and higher apoptosis. We demonstrate that HES1 directly binds and represses the promoter of DUSP1, a dual phosphatase with activity against phospho-ERK, and this repression is relieved by GSI treatment both in mouse and human NSCLCs. Our data provide proof for the in vivo therapeutic potential of γ-secretase inhibitors in primary NSCLCs and provide a mechanistic explanation for its therapeutical effect. We have included 6 samples. 3 with vehicle and 3 with the gamma-secretase inhibitor DAPT and we compare both groups.
2012-12-01 | E-GEOD-38054 | biostudies-arrayexpress
Project description:We have investigated the role of the Notch pathway in the generation and maintenance of KrasG12V-driven non-small cell lung carcinomas (NSCLCs). We demonstrate by genetic means that γ-secretase and Rbpj activities are both essential in the formation of NSCLCs. Interestingly, pharmacologic treatment of mice carrying endogenous NSCLCs with a γ-secretase inhibitor (GSI) blocks cancer growth and induces partial regression. Treated cancers show a reduction in Hes1 levels, reduced phosphorylated Erk, decreased proliferation and higher apoptosis. We demonstrate that HES1 directly binds and represses the promoter of DUSP1, a dual phosphatase with activity against phospho-ERK, and this repression is relieved by GSI treatment both in mouse and human NSCLCs. Our data provide proof for the in vivo therapeutic potential of γ-secretase inhibitors in primary NSCLCs and provide a mechanistic explanation for its therapeutical effect.
2012-12-01 | GSE38054 | GEO
Project description:DUSP1 is a dual-specificity phosphatase that regulates mitogen-activated protein (MAP) kinase activity. Studies have associated loss of DUSP1 expression with certain cancers, but there has been no report of a mechanism by which this supports tumor progression. In this study, we found DUSP1 mRNA and protein decreased in human head and neck squamous cell carcinoma tissues compared with adjacent nontumor controls. To evaluate the impact of this difference, we compared the susceptibility of Dusp1-deficient mice with oral squamous carcinogenesis induced by 4-nitroquinoline 1-oxide. Dusp1-deficient mice displayed enhanced disease progression, characterized by advanced onset, histologic stage, and tumor burden. In a syngeneic model of tumor progression, subcutaneous injection of EO771 cells formed faster-growing tumors in Dusp1-deficient mice, an effect abrogated by inhibition of p38 MAP kinase with SB203580. Histologic and quantitative assessments demonstrated increased inflammation and deregulated chemokine and cytokine expression in Dusp1-deficient tumor tissues. Specifically, proinflammatory cytokine IL1β was elevated. IL1β production was recapitulated ex vivo in primary bone marrow-derived macrophages from Dusp1-deficient mice. Together, our results clearly establish the role of Dusp1 as a tumor suppressor gene that regulates cancer-associated inflammation.
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Project description:Poxviruses encode a large variety of proteins that mimic, block or enhance host cell signaling pathways on their own benefit. It has been reported that mitogen-activated protein kinases (MAPKs) are specifically upregulated during vaccinia virus (VACV) infection. Here, we have evaluated the role of the MAPK negative regulator dual specificity phosphatase 1 (DUSP1) in the infection of VACV. We demonstrated that DUSP1 expression is enhanced upon infection with the replicative WR virus and with the attenuated VACV viruses MVA and NYVAC. This upregulation is dependent on early viral gene expression. In the absence of DUSP1 in cultured cells, there is an increased activation of its molecular targets JNK and ERK and an enhanced WR replication. Moreover, DUSP1 knock-out (KO) mice are more susceptible to WR infection as a result of enhanced virus replication in the lungs. Significantly, MVA, which is known to produce non-permissive infections in most mammalian cell lines, is able to grow in DUSP1 KO immortalized murine embryo fibroblasts (MEFs). By confocal and electron microscopy assays, we showed that in the absence of DUSP1 MVA morphogenesis is similar as in permissive cell lines and demonstrated that DUSP1 is involved at the stage of transition between IVN and MV in VACV morphogenesis. In addition, we have observed that the secretion of pro-inflammatory cytokines at early times post-infection in KO mice infected with MVA and NYVAC is increased and that the adaptive immune response is enhanced in comparison with WT-infected mice. Altogether, these findings reveal that DUSP1 is involved in the replication and host range of VACV and in the regulation of host immune responses through the modulation of MAPKs. Thus, in this study we demonstrate that DUSP1 is actively involved in the antiviral host defense mechanism against a poxvirus infection.
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Project description:We previously demonstrated that sodium butyrate is neuroprotective in Huntington's disease (HD) mice and that this therapeutic effect is associated with increased expression of mitogen-activated protein kinase/dual-specificity phosphatase 1 (MKP-1/DUSP1). Here we show that enhancing MKP-1 expression is sufficient to achieve neuroprotection in lentiviral models of HD. Wild-type MKP-1 overexpression inhibited apoptosis in primary striatal neurons exposed to an N-terminal fragment of polyglutamine-expanded huntingtin (Htt171-82Q), blocking caspase-3 activation and significantly reducing neuronal cell death. This neuroprotective effect of MKP-1 was demonstrated to be dependent on its enzymatic activity, being ablated by mutation of its phosphatase domain and being attributed to inhibition of specific MAP kinases (MAPKs). Overexpression of MKP-1 prevented the polyglutamine-expanded huntingtin-induced activation of c-Jun N-terminal kinases (JNKs) and p38 MAPKs, whereas extracellular signal-regulated kinase (ERK) 1/2 activation was not altered by either polyglutamine-expanded Htt or MKP-1. Moreover, mutants of MKP-1 that selectively prevented p38 or JNK binding confirmed the important dual contributions of p38 and JNK regulation to MKP-1-mediated neuroprotection. These results demonstrate additive effects of p38 and JNK MAPK inhibition by MKP-1 without consequence to ERK activation in this striatal neuron-based paradigm. MKP-1 also provided neuroprotection in vivo in a lentiviral model of HD neuropathology in rat striatum. Together, these data extend previous evidence that JNK- and p38-mediated pathways contribute to HD pathogenesis and, importantly, show that therapies simultaneously inhibiting both JNK and p38 signaling pathways may lead to improved neuroprotective outcomes.
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Project description:About 50% of human malignancies exhibit unregulated signalling through the Ras-ERK1/2 (ERK) pathway, as a consequence of activating mutations in members of Ras and Raf families. However, the quest for alternative Ras-ERK pathway-directed therapies is desirable. Upon phosphorylation ERK dimerize. We had previously demonstrated that dimerization is essential for ERK extranuclear but not nuclear signaling. Furthermore, by molecular biology approaches, we showed that specifically inhibiting ERK extranuclear component, by impeding ERK dimerization, is sufficient for curtailing tumor progression. Here, we have identified a small molecule inhibitor for ERK dimerization in vitro and in vivo that, without affecting ERK phosphorylation, prevents tumorigenesis driven by Ras-ERK pathway oncogenes, both in cellular and animal models. Importantly, this compound is unaffected by resistance-acquisition processes that hamper “classical” Ras-ERK pathway inhibitors. Thus, ERK dimerization inhibitors provide the proof of principle for two novel concepts in cancer therapy: 1) The blockade of sublocalization-specific sub-signals, rather than total signals, as a means of effectively counteracting oncogenic Ras-ERK signaling. 2) Targeting regulatory protein-protein interactions such as dimerization, rather than catalytic activities, within a signaling route, as an approach for producing effective anti-tumoral agents. Strategies aimed at preventing aberrant flux through this route remain an attractive option for therapeutic intervention in cancer. In this respect, drugs inhibiting the kinase activities of BRaf and MEK have yielded promising results. A375p cells treated with10 μM of either DEL22379, SCH772984 or DMSO as a control for two hours. mRNA from A375p cells was extrated using RNeasy mini kit (Qiagen, Germany) according to the manufacturer's instructions. Cells were previously treated with10 μM of either DEL22379, SCH772984 or DMSO as a control for two hours.
2015-04-24 | E-GEOD-68230 | biostudies-arrayexpress
Project description:There is abundant epidemiological evidence that heavy alcohol intake contributes to hepatocellular carcinoma (HCC) development. Previous reports indicated that connexin 32 (Cx32), which is a major hepatocyte gap junction protein, is down-regulated in chronic liver disease and has a protective role in hepatocarcinogenesis. However, functions of Cx32 in alcohol-related hepatocarcinogenesis have not been clarified. To evaluate them, 9-week-old Cx32 dominant negative transgenic (Tg) rats and their wild-type (Wt) littermates were given 1 % or 5 % ethanol (EtOH) or water ad libitum, for 16 weeks after an intraperitoneal injection of diethylnitrosamine (200 mg/kg). EtOH significantly increased the incidence and multiplicity of HCC and total tumors in a dose-dependent manner in Tg rats, but not in Wt rats. Although the number and area of glutathione S-transferase placental form (GST-P) positive foci were not significantly different between the groups, EtOH increased the Ki-67 labeling indices in GST-P positive foci only in Tg rats. EtOH up-regulated phosphorylated Erk1/2 with decrease of the Erk1/2 inhibitor, dual specificity protein phosphatase 1 (Dusp1) in whole livers of Tg and Wt rats. Immunofluorescence staining and quantitative RT-PCR revealed that EtOH significantly increased nucleolar localization of phosphorylated Erk1/2 and contrastingly reduced Dusp1 protein and mRNA expression in GST-P positive foci and HCC of Tg rats as compared to those of Wt rats. These findings suggest that Cx32 dysfunction like in chronic liver disease promoted EtOH-associated hepatocarcinogenesis through dysregulation of Erk-Dusp1 signaling.
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Project description:Unlike solid tumors, the primary strategy for leukemia treatment is chemotherapy. However, leukemia chemotherapy is associated with adverse drug effects and drug resistance. Therefore, it is imperative to identify novel agents that effectively treat leukemia while minimizing adverse effects. The Raf/MEK/extracellular regulated kinase (ERK) and signal transducer and activator of transcription 3 (STAT3) pathways have been implicated in leukemia carcinogenesis, and provide novel molecular targets for therapeutic intervention in cancer. Mogrol, a biometabolite of mogrosides found in Siraitia grosvenorii, has exhibited anti-cancer activities; however, the underlying mechanism of this effect remains unclear. To clarify its anti-cancer activity and mechanism of action, we treated K562 leukemia cells with mogrol. Mogrol suppressed leukemia cell growth via inhibition of the ERK1/2 and STAT3 pathways, in particular, through the suppression of p-ERK1/2 and p-STAT3. Inhibition of these pathways suppressed Bcl-2 expression, thereby inducing K562 cell apoptosis. Furthermore, mogrol enhanced p21 expression, resulting in G0/G1 cell cycle arrest. The findings provide new perspectives regarding the role of mogrol in leukemia treatment.
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Project description:BackgroundGlucocorticoids are potent anti-inflammatory agents commonly used to treat inflammatory diseases. They convey signals through the intracellular glucocorticoid receptor (GR), which upon binding to ligands, associates with genomic glucocorticoid response elements (GREs) to regulate transcription of associated genes. One mechanism by which glucocorticoids inhibit inflammation is through induction of the dual specificity phosphatase-1 (DUSP1, a.k.a. mitogen-activated protein kinase phosphatase-1, MKP-1) gene.Methodology/principal findingsWe found that glucocorticoids rapidly increased transcription of DUSP1 within 10 minutes in A549 human lung adenocarcinoma cells. Using chromatin immunoprecipitation (ChIP) scanning, we located a GR binding region between -1421 and -1118 upstream of the DUSP1 transcription start site. This region is active in a reporter system, and mutagenesis analyses identified a functional GRE located between -1337 and -1323. We found that glucocorticoids increased DNase I hypersensitivity, reduced nucleosome density, and increased histone H3 and H4 acetylation within genomic regions surrounding the GRE. ChIP experiments showed that p300 was recruited to the DUSP1 GRE, and RNA interference experiments demonstrated that reduction of p300 decreased glucocorticoid-stimulated DUSP1 gene expression and histone H3 hyperacetylation. Furthermore, overexpression of p300 potentiated glucocorticoid-stimulated activity of a reporter gene containing the DUSP1 GRE, and this coactivation effect was compromised when the histone acetyltransferase domain was mutated. ChIP-reChIP experiments using GR followed by p300 antibodies showed significant enrichment of the DUSP1 GRE upon glucocorticoid treatment, suggesting that GR and p300 are in the same protein complex recruited to the DUSP1 GRE.Conclusions/significanceOur studies identified a functional GRE for the DUSP1 gene. Moreover, the transcriptional activation of DUSP1 by glucocorticoids requires p300 and a rapid modification of the chromatin structure surrounding the GRE. Overall, understanding the mechanism of glucocorticoid-induced DUSP1 gene transcription could provide insights into therapeutic approaches against inflammatory diseases.
| S-EPMC2966426 | biostudies-literature