BCL6 is regulated by the RAS/MAPK/ELK axis and promotes KRAS-driven lung cancers
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA783366 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR17038557_1.fastq.gz | Fastqsanger.gz | |||
| SRR17038557_2.fastq.gz | Fastqsanger.gz | |||
| SRR17038558_1.fastq.gz | Fastqsanger.gz | |||
| SRR17038558_2.fastq.gz | Fastqsanger.gz | |||
| SRR17038559_1.fastq.gz | Fastqsanger.gz |
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Project description:Mutational activation of KRAS represents a common oncogenic event in lung cancers and still lacks effective treatments so far. Here, we identify the proto-oncogene B-cell lymphoma 6 (BCL6) as a lynchpin for KRAS dependence. BCL6 transcription was markedly promoted upon inducible activation of KRAS in either LSL-KrasG12D mice lung tumor tissue or engineered KRAS isogenic cell lines. Constitutive expression of BCL6 was also observed in patients with KRAS-mutant lung adenocarcinoma and associated with poor survival. Employing chemical and genetic screens, we characterized that the MAPK/ELK1 axis downstream of KRAS directly regulated BCL6 expression. Genetic depletion or pharmacological inhibitor targeting BCL6 preferentially impedes the proliferation of KRAS-mutant lung cancer cells by suppressing pre-RC protein expression in cycling cells, ultimately leading to stalled replication and DNA damage in vitro. Accordingly, targeted inhibition of BCL6 significantly reduced tumor burden and mortality in LSL-KrasG12D/+ and patient-derived lung cancer xenograft mouse models in vivo. Taken together, these findings reveal an oncogenic role of BCL6 in promoting KRAS-addicted lung cancers and define that BCL6 inhibition confers a targetable vulnerability for this kind of disease.
2022-10-19 | GSE189545 | GEO
Project description:Ras plays roles across the spectrum of proliferation, invasion and metastasis. The activity of Ras genes, usually K-Ras, is altered by mutations in around 20% of human cancers, and activation of the Ras-ERK pathway is a critical event in melanomas, colorectal and renal cancers but the degree to which Ras- or Raf-driven transformation is dependent on the activity of the SRF network remains largely obscure. Oncogenic active Ras is known to mediate the cellular response to multiple growth factors leading to the activation of immediate-early genes (IE). A key player in IE gene response is the SRF transcriptional network that we identified being crucial to mediate allegedly the entire transcriptional response downstream of Ras/ERK. The Serum response factor (SRF) is a transcription factor with low intrinsic transcriptional activity and requires the recruitment of one of two families of co-activators: the MRTFs (myocardin-related transcription factors) and the TCFs (ternary complex factors, Elk-1, SAP-1, Net). In particular the TCF, member of the wide family of ETS transcription factors, are specifically activated by MAPK signalling downstream of Ras. We characterised the transcriptional program downstream of Ras/ERK signalling using short TPA stimulations (12-O-tetradecanoyl phorbol-13-acetate, compunt known to induced Ras/ERK activation) by RNA-seq. The investigation of the transcriptional response was performed using Mouse Embryonic Fibroblasts (MEFs) derived from different animals: (i) wild type, (ii) TKO (MEFs derived from mice lacking all three TCFs), (iiI) TKO recon pMY Empty (TKO reconstituted with empty vectors by retrovirus infection), (iv) TKO recon Elk-1 wt (TKO reconstituted with retrovirus vectors expressing Elk-1 wild type by retrovirus infection), (v) TKO recon Elk-1 FW (TKO reconstituted with retrovirus vectors expressing Elk-1 mutant lacking the FW residues in its activation domain), (vi) TKO recon Elk-1 nonA (TKO reconstituted with retrovirus vectors expressing Elk-1 mutant where all phosphor-acceptor residues in its activation domain have been mutagenized to alanines). In order to map SRF and Elk-1 binding sites we performed ChIP-seq of SRF in wild type MEFs and TKO and ChIP-seq of Elk-1 in TKO reconstituted cell lines.
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Project description:Mitochondrial dysfunction causes biophysical, metabolic and signalling changes that alter homeostasis and reprogram cells. We used a Drosophila model in which TFAM is overexpressed in the nervous system with or without Ras/MAPK pathway inhibition, by knock-down of the ETS transcription factor pointed, to investigate the how mitochondrial dysfunction and Ras/MAPK signalling affect the transcriptome. We used microarray analysis to investigate gene expression in cases of mitochondrial dysfunction in the CNS with or without Ras/MAPK pathway inhibition by knock-down of pointed (Pnt) and anterior open (Aop).
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Project description:RAS-MAPK activating mutations in NRAS, KRAS and PTPN11 were present in 24/55 (44%) cases in our series of diangosis and relapsed ALL. To evaluate the specific role of RAS-MAPK activating mutations in chemotherapy resistance in ALL we used primary isogenic leukemia cells expressing either Kras wild type or a mutant oncogenic form of Kras (Kras G12D) Mechanistically, functional dissection of Kras wild type and mutant Kras (Kras G12D) isogenic ALL cells demonstrated induction of methotrexate resistance, but also improved response to vincristine, in mutant Kras-expressing ALL cells. These results pave the road for the development of tailored personalized therapies for the treatment of relapsed ALL
2018-11-01 | GSE75090 | GEO
Project description:We performed tanscriptional profiling of ARPE19 and four isogenic transformed cells lines in which Ras or two downstream pathways, MAPK or PI3K/mTOR, were up-regulated. The purpose of this study is to understand how Ras signaling impacts kinetochore function.
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Project description:We report that BCL6 interacts with BRD3 and that BRD3 inhibition upregulates BCL6. By obtaining sequence from chromatin immunoprecipitated DNA of A549 cells, we generated genome-wide binding gene spectrums of BCL6 and BRD3. By locating -3000 to +200 bps around TSS, we find that BRD3 binds to the promoters of 2470 genes and that BCL6 binds to the promoters of 694 genes, with 82 genes shared by BRD3 and BCL6. Interestingly, BCL6 itself is one of these 82 shared genes, implying that BCL6 mediated self-repression may require the participation of BRD3. Other shared genes includes SGK2, IDH2, HOXB6, SIRT1, SOCS3 and ZFNs, demonstrating the widely involvement of BRD3 in the regulatory role of BCL6. To examine the dependency of BCL6 on BRD3, we also compared BCL6-binding spectrums with or without a BET inhibitor, OTX015. The ChIP-seq data with BCL6 antibody exhibited a diverse BCL-binding spectrum composed of 731 genes in OTX015 treatment, with only 117 genes overlapped with that of DMSO treatment. These data demonstrates that BET inhibition is sufficient to change BCL6-binding spectrum. This study provides a new insight of BCL6 regulatory roles in KRAS-mutant NSCLCs, where BRD3 is recruited by BCL6 and affect BCL6 binding preference as a cofactor.
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Project description:Basal cell carcinomas (BCCs) rely on Hedgehog (HH) pathway growth signal amplification by the microtubule-based organelle, the primary cilium. Despite naïve tumors responsiveness to Smoothened inhibitors (Smoi), resistance in advanced tumors remains frequent. While the resistant BCCs usually maintain HH pathway activation, squamous cell carcinomas with Ras/MAPK pathway activation also arise, with the molecular basis of tumor type and pathway selection still obscure. Here we identify the primary cilium as a critical determinant controlling tumor pathway switching. Strikingly, Smoi-resistant BCCs possess an increased mutational load in ciliome genes, resulting in reduced primary cilia and HH pathway activation compared to naive or Gorlin patient BCCs. Gene set enrichment analysis of resistant BCCs with a low HH pathway signature reveals increased Ras/MAPK pathway activation. Tissue analysis confirms an inverse relationship between primary cilia presence and Ras/MAPK activation, and primary cilia removal in BCCs potentiates Ras/MAPK pathway activation. Moreover, activating Ras in HH-responsive cell lines confers resistance to both canonical (vismodegib) and non-canonical (aPKC and MRTF inhibitors) HH pathway inhibitors, while conferring sensitivity to MAPK inhibitors. Our results provide new insights into BCC treatment and identify the primary cilium as an important lineage gatekeeper, preventing HH to Ras/MAPK pathway switching.
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Project description:Approximately 50% of prostate cancers have chromosomal translocations resulting in the over-expression one of four ETS family transcription factors. However, it is not known why these four four family members are selected for oncogenic roles, while other ETS proteins are not. We found that the four oncogenic ETS family members have a specific role in prostate cell migration. Using chromatin immunoprecipitation coupled with next-generation sequencing, this specific biological function was matched to a specific set of genomic targets highlighted by the presence of an AP-1 binding site. ETS/AP-1 binding sites are prototypical Ras-responsive elements, but oncogenic ETS proteins could activate a Ras/MAPK transcriptional program in the absence of MAPK activation. These findings indicate that the specific function of ETS proteins over-expressed in prostate cancer is the activation of a Ras/MAPK gene expression program in the absence of signaling pathway mutations. 16 samples were analyzed, comprised of four replicates each of four different biological conditions. RNA from U0126 treated RWPE-1 empty vector cell RNA serves as a control for each experiment. Cell lines have retroviral expression constructs expressing either empty vector, Flag-ERG, or Flag-ETV1.
2011-10-18 | E-GEOD-29438 | biostudies-arrayexpress