MEK inhibition rewires enhancer landscapes in RAS-driven Rhabdomyosarcoma to unlock a myogenic differentation block
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE85170 | GEO | 2018/04/01
REPOSITORIES: GEO
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Project description:Trametinib-treated rhabdomyosarcoma cells undergo transcriptional reprogramming akin to myogenic differentiation. This reprogramming is induced by loss of ERK-mediated inhibition of MYOG expression. Restoration of MYOG allows establishment of super-enhancers at genes expressed by terminally differentiated myotubes. Our findings demonstrate that aberrant MAP kinase activity blocks differentiation in rhabdomyosarcoma and highlight trametinib as a potential therapeutic for RAS-mutated rhabdomyosarcoma.
2018-04-01 | GSE85169 | GEO
Project description:The first clinical trial testing the combination of targeted therapy with a BRAF inhibitor vemurafenib and immunotherapy with a CTLA-4 antibody ipilimumab was terminated early due to significant liver toxicities, possibly due to paradoxical activation of the MAPK pathway by BRAF inhibitors in tumors with wild type BRAF. MEK inhibitors can potentiate the MAPK inhibition in tumor, while potentially alleviating the unwanted paradoxical MAPK activation. With a mouse model of syngeneic BRAFV600E driven melanoma (SM1), we tested whether the addition of the MEK inhibitor trametinib would enhance the immunosensitization effects of the BRAF inhibitor dabrafenib. Combination of dabrafenib and trametinib with pmel-1 adoptive cell transfer (ACT) showed complete tumor regression. Bioluminescent imaging and tumor infiltrating lymphocyte (TIL) phenotyping showed increased effector infiltration to tumors with dabrafenib, trametinib or dabrafenib plus trametinib with pmel-1 ACT combination. Intracellular IFN gamma staining of the TILs and in vivo cytotoxicity studies showed trametinib was not detrimental to the effector functions in vivo. Dabrafenib increased tumor associated macrophages and T regulatory cells (Tregs) in the tumors, which can be overcome by addition of trametinib. Microarray analysis revealed increased melanoma antigen, MHC expression, and global immune-related gene upregulation with the triple combination therapy. Given the up-regulation of PD-L1 seen with dabrafenib and/or trametinib combined with antigen specific ACT, we tested the triple combination of dabrafenib, trametinib with anti-PD1 therapy, and observed superior anti-tumor effect to SM1 tumors. Our findings support the testing of these combinations in patients with BRAFV600E mutant metastatic melanoma. SM1 tumors were implanted into C57BL/6 mice. Mice were treated by ACT of pmel-1 splenocytes or C57BL/6 splenocytes as control. Pmel-1 treated mice were additionally treated with either vehicle, dabrafenib, trametinib, or combination of both drugs and control mice were treated with vehicle or combination of both drugs.
2014-12-12 | E-GEOD-64102 | biostudies-arrayexpress
Project description:Skeletal muscle differentiation (myogenesis) is a complex and highly coordinated biological process regulated by a series of myogenic marker genes. Chromatin interactions between gene’s promoters and their enhancers have an important role in transcriptional control. However, the high-resolution chromatin interactions of myogenic genes and their functional enhancers during myogenesis remain largely unclear. Here, we used circularized chromosome conformation capture coupled with next-generation sequencing (4C-seq) to investigate eight myogenic marker genes in C2C12 myoblasts (C2C12-MBs) and C2C12 myotubes (C2C12-MTs). We revealed dynamic chromatin interactions of these marker genes during differentiation, and identified 163 and 314 significant interaction sites (SISs) in C2C12-MBs and C2C12-MTs, respectively. The interacting genes of SISs in C2C12-MTs were mainly involved in muscle development, and histone modifications of the SISs changed during differentiation. Through functional genomic screening, we also identified 25 and 41 putative active enhancers in C2C12-MBs and C2C12-MTs, respectively. Using luciferase reporter assays for putative enhancers of Myog and Myh3, we identified eight activating enhancers. Furthermore, dCas9-KRAB epigenome editing and RNA-seq revealed a role for Myog enhancers in the regulation of Myog expression and myogenic differentiation in the native genomic context. Taken together, this study lays the groundwork for understanding 3D chromatin interaction changes of myogenic genes during myogenesis and provides insights that contribute to our understanding of the role of enhancers in regulating myogenesis.
2022-06-10 | GSE201138 | GEO
Project description:Epigenetic Reprogramming of mutant RAS-driven Rhabdomyosarcoma via MEK Inhibition
| PRJNA336377 | ENA
Project description:The RAF/MEK/ERK pathway is central to the control of cell physiology, and its dysregulation is associated with many cancers. Accordingly, the proteins constituting this pathway, including MEK1/2 (MEK), have been subject to intense drug discovery and development efforts. Allosteric MEK inhibitors (MEKi) exert complex effects on RAF/MEK/ERK pathway signaling and are employed clinically in combination with BRAF inhibitors in malignant melanoma. Although mechanisms and structures of MEKi bound to MEK have been described for many of these compounds, recent studies suggest that RAF/MEK complexes, rather than free MEK, should be evaluated as the target of MEKi. Here, we describe structural and biochemical studies of eight structurally diverse, clinical-stage MEKi to better understand their mechanism of action on BRAF/MEK complexes. We find that all of these agents bind in the MEK allosteric site in BRAF/MEK complexes, in which they stabilize the MEK activation loop in a conformation that is resistant to BRAF-mediated dual phosphorylation required for full activation of MEK. We also show that allosteric MEK inhibitors act most potently on BRAF/MEK complexes rather than on free active MEK, further supporting the notion that a BRAF/MEK complex is the physiologically relevant pharmacologic target for this class of compounds. Our findings provide a conceptual and structural framework for rational development of RAF-selective MEK inhibitors as an avenue to more effective and better-tolerated agents targeting this pathway.
| S-EPMC8433572 | biostudies-literature
Project description:The first clinical trial testing the combination of targeted therapy with a BRAF inhibitor vemurafenib and immunotherapy with a CTLA-4 antibody ipilimumab was terminated early due to significant liver toxicities, possibly due to paradoxical activation of the MAPK pathway by BRAF inhibitors in tumors with wild type BRAF. MEK inhibitors can potentiate the MAPK inhibition in tumor, while potentially alleviating the unwanted paradoxical MAPK activation. With a mouse model of syngeneic BRAFV600E driven melanoma (SM1), we tested whether the addition of the MEK inhibitor trametinib would enhance the immunosensitization effects of the BRAF inhibitor dabrafenib. Combination of dabrafenib and trametinib with pmel-1 adoptive cell transfer (ACT) showed complete tumor regression. Bioluminescent imaging and tumor infiltrating lymphocyte (TIL) phenotyping showed increased effector infiltration to tumors with dabrafenib, trametinib or dabrafenib plus trametinib with pmel-1 ACT combination. Intracellular IFN gamma staining of the TILs and in vivo cytotoxicity studies showed trametinib was not detrimental to the effector functions in vivo. Dabrafenib increased tumor associated macrophages and T regulatory cells (Tregs) in the tumors, which can be overcome by addition of trametinib. Microarray analysis revealed increased melanoma antigen, MHC expression, and global immune-related gene upregulation with the triple combination therapy. Given the up-regulation of PD-L1 seen with dabrafenib and/or trametinib combined with antigen specific ACT, we tested the triple combination of dabrafenib, trametinib with anti-PD1 therapy, and observed superior anti-tumor effect to SM1 tumors. Our findings support the testing of these combinations in patients with BRAFV600E mutant metastatic melanoma.
2014-12-12 | GSE64102 | GEO
Project description:Here, we report the generation of human induced Pluripotent Stem (iPS) cell reporter line in which a venus fluorescent protein have been introduced into the MYOGENIN (MYOG) locus. We use microarrays to compare the transcriptome of MYOG-venus+ cells after 3 weeks of myogenic differentiation to that of undifferentiated iPS Satellite cells (SC) are muscle stem cells which can regenerate adult muscles upon injury. Most SC originate from PAX7-positive myogenic precursors set aside during development. While myogenesis has been studied in mouse and chicken embryos, little is known about human muscle development. Here, we use microarrays to compare the transcriptome of myogenic cells differentiated in vitro from human and mouse ES and iPS cells reporter cell lines. We generated fluorescent reporter lines in which a fluorescent protein was introduced into the loci coding for Pax7 (mouse ES and human iPS) or MYOG (human iPS). Mouse ES and human iPS cells were differentiated to the myogenic lineage in vitro for three weeks according to the protocols described in Chal et al, Nature Biotech 2015 and to Chal, Al Tanoury et al, Nature Protocols, 2016. Fluorescent Pax7 or MYOG-positive cells were FACS-sorted after 3-weeks of differentiation in vitro and we used Affymetrix microarrays to analyze the transcriptome of the purified mouse and human cell populations and compare it to the transcriptome of undifferentiated mouse ES or human iPS cells.
2020-04-21 | GSE148994 | GEO
Project description:PAX3-FOXO1 expression in endothelial progenitors dictates myogenic reprogramming and rhabdomyosarcoma identity
| PRJNA902903 | ENA
Project description:Defective germline reprogramming in Miwi2- and Dnmt3l-deficient mice results in the failure to reestablish transposon silencing, meiotic arrest and progressive loss of spermatogonia. Here we sought to understand the molecular basis for this spermatogonial dysfunction. Through a combination of imaging, conditional genetics and transcriptome analysis, we demonstrate that germ cell elimination in the respective mutants arises due to defective germline reprogramming rather than a function for the respective factors within spermatogonia. In both Miwi2-/- and Dnmt3l-/- spermatogonia the intracisternal-A particle (IAP) family of endogenous retroviruses is de-repressed, but in contrast to meiotic cells DNA damage is not observed. Instead we find that unmethylated IAP promoters rewire the spermatogonial transcriptome by driving expression of neighboring host genes. In summary, defective reprogramming deregulates the spermatogonial transcriptome that may underlie spermatogonial dysfunction.
2018-03-09 | E-MTAB-6202 | biostudies-arrayexpress
Project description:Oncogenic KRAS mutations frequently detected in non-small cell lung cancer (NSCLC) have been considered undruggable until recent development of inhibitors, e.g., sortorasib, adagrasib or divarasib, specifically targeting KRASG12C. However, it still remains as a big challenge to target all the KRAS mutants besides KRASG12C. We here found that MEK inhibitor trametinib treatment results in the feedback activation of multiple receptor tyrosine kinases (RTKs) in NSCLC, and combined treatments with trametinib and anlotinib, a pan-RTK inhibitor, effectively inhibited KRAS-mutant lung cancer progression.
2024-12-08 | GSE283634 | GEO