Ephexin1 cooperates with K-Ras to promote oncogenic Ras-driven tumorigenesis
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ABSTRACT:
PROVIDER: PRJNA619876 | ENA |
REPOSITORIES: ENA
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Project description:Ephexin1 was initially identified as a neuronal guanine nucleotide exchange factor involved in the control of neuronal development and synaptic homeostasis. Here, we demonstrate that the induction of Ephexin1 expression by an oncogenic K-Ras mutation amplifies the MAPK signaling via direct interaction with oncogenic Ras and contributes to colon and lung tumorigenesis. Ephexin1 cooperates with mutant Ras to accelerate skin tumorigenesis in vivo. In addition, we have demonstrated that the functionally relevant interaction between oncogenic K-Ras and Ephexin1. Together, these findings suggest that Ephexin1 serves as a positive regulator of Ras-driven oncogenesis and potentially represents a novel target for therapeutic intervention.
2021-10-27 | GSE147809 | GEO
Project description:Several aspects of a Western lifestyle such as increased obesity and decreased physical activity are associated with increased risk for gastrointestinal cancers1. Although high-fat diet (HFD) induced low-grade inflammation has been closely linked to tumorigenesis2, however, the microbial shift that occurs due to diet and consequent alterations in host immunity have merely been considered to play a critical role during carcinogenesis. Here we show that HFD promotes tumor progression in the small intestine of genetically susceptible mice, however, independently of obesity and diet-induced chronic inflammation. HFD consumption cooperates with mutant K-Ras to mediate a shift in the composition of microbiota, which is associated with a decrease in Paneth cell antimicrobial host defense that compromises dendritic cell (DC) recruitment and MHCII presentation in the gut-associated lymphoid tissues (GALTs). DC recruitment in GALTs can be normalized and tumor progression attenuated completely when K-Ras mutant mice are supplemented with the short chain fatty acid butyrate, a bacterial fermentation end product, or partially when provided with probiotics. Importantly, Myd88-deficiency completely blocks tumor progression in K-ras mutants, however, rather by substantial changes in the microbiota than host-mediated signaling mechanisms. Strikingly, transfer of fecal samples from diseased donors into healthy adult K-ras mutants is sufficient to enhance tumor progression in the absence of HFD suggesting a pivotal role for distinct microbiota shifts in aggravating disease in the small intestine. Collectively, these data underscore the reciprocal interaction between host and environmental factors for the composition of intestinal microbiota that favors carcinogenesis and suggest tumor progression could potentially be “transmitted” in genetically predisposed individuals. 13 samples; S103_396_GroupA_Arkan and S104_429_GroupA_Arkan represent the controls of the first group, S105_394_GroupB_Arkan and S106_429_GroupB_Arkan represent ViRas (mutated) mice of the first group. S982_groupA_ 1 and S983_groupA_2 represent the cotrols of the second group, S984_groupB_3, S985_groupB_4 and S986_groupB_5 represent ViRas (mutant) mice of the second group, S563_CO1979 represent the control of the third group, S564_KO1_1231, S565_KO2_1984 and S566_KO3_2013 represent the ViRas (mutant) mice of the third group. The first group are mice kept on HFD, second group kept on ND and third group kept on HFD plus treated with butyrate
2013-07-01 | E-GEOD-42840 | biostudies-arrayexpress
Project description:Oncolytic viruses exploit common molecular changes in cancer cells, which are not present in normal cells, to target and kill cancer cells. Ras transformation and defects in type I interferon (IFN)-mediated antiviral responses are known to be the major mechanisms underlying viral oncolysis. Previously, we demonstrated that oncogenic RAS/Mitogen-activated protein kinase kinase (Ras/MEK) activation suppresses the transcription of many IFN-inducible genes in human cancer cells, suggesting that Ras transformation underlies type I IFN defects in cancer cells. Here, we investigated how Ras/MEK downregulates IFN-induced transcription. By conducting promoter deletion analysis of IFN-inducible genes, namely guanylate-binding protein 2 and IFN gamma inducible protein 47 (Ifi47), we identified the IFN regulatory factor 1 (IRF1) binding site as the promoter region responsible for the regulation of transcription by MEK. MEK inhibition promoted transcription of the IFN-inducible genes in wild type mouse embryonic fibroblasts (MEFs), but not in IRF1?/? MEFs, showing that IRF1 is involved in MEK-mediated downregulation of IFN-inducible genes. Furthermore, IRF1 protein expression was lower in RasV12 cells compared with vector control NIH3T3 cells, but was restored to equivalent levels by inhibition of MEK. Similarly, the restoration of IRF1 expression by MEK inhibition was observed in human cancer cells. IRF1 re-expression in human cancer cells caused cells to become resistant to infection by the oncolytic vesicular stomatitis virus strain. Together, this work demonstrates that Ras/MEK activation in cancer cells downregulates transcription of IFN-inducible genes by targeting IRF1 expression, resulting in increased susceptibility to viral oncolysis. RNA was isolated from RasV12 transformed NIH/3T3 cells (RasV12 cells) treated with 20?M U0126 or 500U/ml IFN-?, or left untreated, for 6 hours, triplicate biological samples (9 samples).
2014-11-13 | E-GEOD-49469 | biostudies-arrayexpress
Project description:Several aspects of a Western lifestyle such as increased obesity and decreased physical activity are associated with increased risk for gastrointestinal cancers1. Although high-fat diet (HFD) induced low-grade inflammation has been closely linked to tumorigenesis2, however, the microbial shift that occurs due to diet and consequent alterations in host immunity have merely been considered to play a critical role during carcinogenesis. Here we show that HFD promotes tumor progression in the small intestine of genetically susceptible mice, however, independently of obesity and diet-induced chronic inflammation. HFD consumption cooperates with mutant K-Ras to mediate a shift in the composition of microbiota, which is associated with a decrease in Paneth cell antimicrobial host defense that compromises dendritic cell (DC) recruitment and MHCII presentation in the gut-associated lymphoid tissues (GALTs). DC recruitment in GALTs can be normalized and tumor progression attenuated completely when K-Ras mutant mice are supplemented with the short chain fatty acid butyrate, a bacterial fermentation end product, or partially when provided with probiotics. Importantly, Myd88-deficiency completely blocks tumor progression in K-ras mutants, however, rather by substantial changes in the microbiota than host-mediated signaling mechanisms. Strikingly, transfer of fecal samples from diseased donors into healthy adult K-ras mutants is sufficient to enhance tumor progression in the absence of HFD suggesting a pivotal role for distinct microbiota shifts in aggravating disease in the small intestine. Collectively, these data underscore the reciprocal interaction between host and environmental factors for the composition of intestinal microbiota that favors carcinogenesis and suggest tumor progression could potentially be “transmitted” in genetically predisposed individuals.
2013-07-01 | GSE42840 | GEO
Project description:Oncolytic viruses exploit common molecular changes in cancer cells, which are not present in normal cells, to target and kill cancer cells. Ras transformation and defects in type I interferon (IFN)-mediated antiviral responses are known to be the major mechanisms underlying viral oncolysis. Previously, we demonstrated that oncogenic RAS/Mitogen-activated protein kinase kinase (Ras/MEK) activation suppresses the transcription of many IFN-inducible genes in human cancer cells, suggesting that Ras transformation underlies type I IFN defects in cancer cells. Here, we investigated how Ras/MEK downregulates IFN-induced transcription. By conducting promoter deletion analysis of IFN-inducible genes, namely guanylate-binding protein 2 and IFN gamma inducible protein 47 (Ifi47), we identified the IFN regulatory factor 1 (IRF1) binding site as the promoter region responsible for the regulation of transcription by MEK. MEK inhibition promoted transcription of the IFN-inducible genes in wild type mouse embryonic fibroblasts (MEFs), but not in IRF1−/− MEFs, showing that IRF1 is involved in MEK-mediated downregulation of IFN-inducible genes. Furthermore, IRF1 protein expression was lower in RasV12 cells compared with vector control NIH3T3 cells, but was restored to equivalent levels by inhibition of MEK. Similarly, the restoration of IRF1 expression by MEK inhibition was observed in human cancer cells. IRF1 re-expression in human cancer cells caused cells to become resistant to infection by the oncolytic vesicular stomatitis virus strain. Together, this work demonstrates that Ras/MEK activation in cancer cells downregulates transcription of IFN-inducible genes by targeting IRF1 expression, resulting in increased susceptibility to viral oncolysis.
2014-11-13 | GSE49469 | GEO
Project description: Not available
| S-EPMC2719950 | biostudies-literature
Project description:MAPK scaffolds, such as IQGAP1, assemble pathway kinases together to effect signal transmission and disrupting scaffold function therefore offers a potentially orthogonal approach to MAPK cascade inhibition. Consistent with this possibility, we observed an IQGAP1 requirement in Ras-driven tumorigenesis in mouse and human tissue. Delivery of the IQGAP1 WW peptide sequence that mediates Erk1/4 binding, moreover, disrupted IQGAP1-Erk1/2 interactions, abolished Ras/Raf-driven tumorigenesis, bypassed acquired resistance to the B-Raf inhibitor vemurafinib (PLX- 4032), and acts as a systemically deliverable therapeutic to significantly increase lifespan of tumor bearing mice. Scaffold-kinase interaction blockade (SKIB) acts by a mechanism distinct from direct kinase inhibition and represents a strategy to target over-active oncogenic kinase cascades in cancer. Gene expression profiling: Fragmented cRNA was hybridized to the Mouse Gene 1.0 ST Array (Affymetrix). Iqgap1 wild-type and Iqgap1 knockout mouse treated with topical 4OHT for 0 days and 6 days days are compared.
2013-04-01 | E-GEOD-44967 | biostudies-arrayexpress
Project description:Oncogenic K-Ras suppresses global miRNA function
| PRJNA784250 | ENA
Project description:K-Ras is frequently hyperactivated in human cancers through gain-of-function mutations that drive tumorigenesis. K-RasG12D, the most common oncogenic K-Ras allele, triggers massive transcriptomic and proteomic changes in the murine colon. Here, we report a comprehensive profile of physiological miRNA targets in murine colonic epithelium and tumor expressing K-RasG12D. Combining it with transcriptional, transcriptomic, and proteomic landscapes, we uncover a K-RasG12D-induced global suppression of miRNA activity that up-regulates hundreds of genes post-transcriptionally. K-RasG12D suppresses Csnk1a1 and Csnk2a1, which can decrease Ago2 phosphorylation at Ser825/829/831/835. Hypo-phosphorylated Ago2 increases binding with mRNA, reducing its regulatory activity by locking Ago2 in a small set of target transcripts. While expanding the repertoire of miRNA targets identified, it functionally decreases active Ago2, resulting in global de-repression of miRNA targets. Our findings establish a regulatory relationship among K-Ras, Csnk1a1/Csnk2a1, and Ago2 that provides a mechanistic link between oncogenic K-Ras and the up-regulation of hundreds of miRNA targets.
2022-05-13 | GSE189704 | GEO
Project description:K-Ras is frequently hyperactivated in human cancers through gain-of-function mutations that drive tumorigenesis. K-RasG12D, the most common oncogenic K-Ras allele, triggers massive transcriptomic and proteomic changes in the murine colon. Here, we report a comprehensive profile of physiological miRNA targets in murine colonic epithelium and tumor expressing K-RasG12D. Combining it with transcriptional, transcriptomic, and proteomic landscapes, we uncover a K-RasG12D-induced global suppression of miRNA activity that up-regulates hundreds of genes post-transcriptionally. K-RasG12D suppresses Csnk1a1 and Csnk2a1, which can decrease Ago2 phosphorylation at Ser825/829/831/835. Hypo-phosphorylated Ago2 increases binding with mRNA, reducing its regulatory activity by locking Ago2 in a small set of target transcripts. While expanding the repertoire of miRNA targets identified, it functionally decreases active Ago2, resulting in global de-repression of miRNA targets. Our findings establish a regulatory relationship among K-Ras, Csnk1a1/Csnk2a1, and Ago2 that provides a mechanistic link between oncogenic K-Ras and the up-regulation of hundreds of miRNA targets.
2022-05-13 | GSE189702 | GEO