Identification of Resistance Genes to BRAF Inhibitor in Melanoma by piggyBac Transposon Activation Mutagenesis Screen
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE73470 | GEO | 2016/07/01
SECONDARY ACCESSION(S): PRJNA297064
REPOSITORIES: GEO
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Project description:Genotype directed anti-cancer therapies such BRAF inhibitor in BRAF mutant melanoma can show remarkable clinical efficacy but resistance limits their benefit. We show that a transposon activation screen efficiently identifies resistance genes to BRAF and captures a number of previously uncharacterized resistance mechanisms, including an E3 ubiquitin ligase NEDD4L and the Hippo pathway effector WWTR1 (TAZ). Resistance can be reversed by combining BRAF inhibition with tyrosine kinase inhibitors as observed previously for other resistance genes. Moreover, an integrative analysis of several gain- and loss-of-function genetic screens performed in the same context reveals smaller functional diversity of resistance mechanisms to MAPK inhibition than suggested by the broad range of resistance genes identified, implying common therapeutic strategies. A375 cells with lentiviral vector controls or WWTR1 cDNA plasmid.
2016-07-01 | E-GEOD-73470 | biostudies-arrayexpress
Project description:Tumor cells carrying KRAS mutations activate the NF-?B pathway by different mechanisms, which contribute to the acquisition of essential cancer properties. The BRAF kinase, a downstream mediator of KRAS, is also mutated in a subset of colorectal cancers (CRC), which predicts bad prognosis and therapy resistance. However, nothing is known on whether NF-?B participates of BRAF-mediated tumorigenesis. We here found that in CRC cells, mutant BRAF does not trigger canonical or alternative NF-?B signaling but induces p45-IKK? activation. Moreover, IKK? activity is required for BRAF-induced transformation and to support BRAF-dependent transcription in CRC cells. Activation of p45-IKK? downstream of BRAF requires the TAK1 kinase, and is associated to the endosomal compartment. Inhibition of endosomal V-ATPase abolished p45-IKK? phosphorylation, and induced apoptosis of BRAF mutated CRC cells. Pharmacologic inhibition of endosome acidification reduced the in vivo growth of tumors carrying mutant BRAF, and abrogated the metastatic capacity of a primary human CRC tumor with acquired resistance to standard chemotherapy in an orthotopic xenograft model. 18 samples were analyzed: HT29 controls (n=3); HT28 BRAF inhibited (n=3), WiDr controls (n=3); WiDr BRAF inhibited (n=3); WiDr transduced with control shRNA (n=3) and WiDr transduced with shRNA against IKKalpha (n=3)
2015-05-08 | E-GEOD-57979 | biostudies-arrayexpress
Project description:Tumor cells carrying KRAS mutations activate the NF-κB pathway by different mechanisms, which contribute to the acquisition of essential cancer properties. The BRAF kinase, a downstream mediator of KRAS, is also mutated in a subset of colorectal cancers (CRC), which predicts bad prognosis and therapy resistance. However, nothing is known on whether NF-κB participates of BRAF-mediated tumorigenesis. We here found that in CRC cells, mutant BRAF does not trigger canonical or alternative NF-κB signaling but induces p45-IKKα activation. Moreover, IKKα activity is required for BRAF-induced transformation and to support BRAF-dependent transcription in CRC cells. Activation of p45-IKKα downstream of BRAF requires the TAK1 kinase, and is associated to the endosomal compartment. Inhibition of endosomal V-ATPase abolished p45-IKKα phosphorylation, and induced apoptosis of BRAF mutated CRC cells. Pharmacologic inhibition of endosome acidification reduced the in vivo growth of tumors carrying mutant BRAF, and abrogated the metastatic capacity of a primary human CRC tumor with acquired resistance to standard chemotherapy in an orthotopic xenograft model.
2015-05-08 | GSE57979 | GEO
Project description:Melanoma cell lines were assessed for differences in gene expression patterns between the lines sensitive and resistant to BRAF and MEK inhibitor drugs. 22 BRAF-mutant melanoma cell lines were assessed for response to BRAF and MEK inhibitors in a 3 day drug treatment dose response assay. Based on the IC50, 18 lines were found to be responsive to BRAF or MEK inhibition and 4 were resistant. Normalised gene expression data generated from experimental replicate affymetrix arrays was assessed to identify differential patterns of inherent gene expression between the cell lines grouped as drug-responsive or drug-resistant. This were used to idenify specific candidate genes and pathways associated with inherent BRAF/MEK inhibitor drug resistance in melanoma cells.
2015-08-26 | E-GEOD-45558 | biostudies-arrayexpress
Project description:Fifty percent of cutaneous melanomas are driven by activated BRAFV600E, but tumors treated with RAF inhibitors, even when they respond dramatically, rapidly adapt and develop resistance. Thus, there is a pressing need to identify the major mechanisms of intrinsic and adaptive resistance and develop drug combinations that target these resistance mechanisms. In a combinatorial drug screen on a panel of 12 treatment-naïve BRAFV600E mutant melanoma cell lines of varying levels of resistance to MAPK pathway inhibition we identified the combination PLX4720, a targeted inhibitor of mutated BRaf, and lapatinib, an inhibitor of the ERBB family of receptor tyrosine kinases, as synergistically cytotoxic in the subset of cell lines that displayed the most resistance to PLX4720. To identify potential mechanisms of resistance to PLX4720 treatment and synergy with lapatinib treatment we performed a multi-platform functional genomics analysis to profile the genome as well as the transcriptional and proteomic responses of these cell lines to treatment with PLX4720. We found modest levels of resistance correlated with the zygosity of the BRAF V600E allele and RTK mutational status. Layered over base-line resistance was substantial upregulation of many ERBB pathway genes in response to BRaf inhibition, thus generating the vulnerability to combination with lapatinib. The transcriptional responses of ERBB pathway genes are associated with a number of transcription factors, including ETS2 and its associated cofactors that represent a convergent regulatory mechanism conferring synergistic drug susceptibility in the context of diverse mutational landscapes. 12 BRAF mutant melanomas and 4 melanomas with WT BRAF were exposed plx4720 treatment to evaluate their responses after 8 hours of treatment. 5 of the 12 BRAF mutant melanomas responses were also evaluated in response to the treatment of lapatinib alone, masitinib alone, the combination of lapatinib with plx4720, or the combination of masitinib with plx4720. All samples were run in at least triplicate.
2015-09-16 | E-GEOD-68453 | biostudies-arrayexpress
Project description:The activation of transcriptional coactivators YAP and its paralog TAZ has been shown to promote resistance to anti-cancer therapies. YAP/TAZ activity is tightly coupled to actin cytoskeleton architecture. However, the influence of actin remodeling on cancer drug resistance remains largely unexplored. Here, we report a pivotal role of actin remodeling in YAP/TAZ-dependent BRAF inhibitor resistance in BRAF V600E mutant melanoma cells. Melanoma cells resistant to BRAF inhibitor PLX4032 exhibit an increase in actin stress fiber formation, which appears to promote the nuclear accumulation of YAP/TAZ. Knockdown of YAP/TAZ overcomes PLX4032 resistance, whereas overexpression of constitutively active YAP induces resistance. Moreover, inhibition of actin polymerization and cytoskeletal tension in melanoma cells suppresses both YAP/TAZ activation and PLX4032 resistance. Our siRNA library screening identifies actin dynamics regulator TESK1 as a novel vulnerable point of the YAP/TAZ-dependent resistance pathway. These results suggest that inhibition of actin remodeling is a promising synthetic lethal strategy to suppress resistance in BRAF inhibitor therapies.
2015-11-18 | GSE68599 | GEO
Project description:BRAF V600 mutation influences cellular signaling pathways for melanoma development. Here, we show that mutated BRAF plays an essential role in the adaptive stress response following activation of general control non-derepressible 2 (GCN2) kinase. In parallel with GCN2, BRAF ensures ATF4 induction by utilizing mTOR and eIF4B as downstream regulators during nutrient stress and BRAF-targeted, therapeutic stress. Upon pharmacological BRAF inhibition, this signaling pathway exhibits temporal resistance, compared with the MEK-ERK pathway, thereby enabling transient induction of ATF4 under GCN2 activation. Notably, the prevention of GCN2 activation, using a chemical inhibitor that we identified, produces synergistic cell killing with BRAF inhibition. Thus, oncogenic BRAF can collaborate with the GCN2–ATF4 pathway, promoting stress adaptation for cell survival.
2020-04-06 | GSE136614 | GEO
Project description:BRAF V600 mutation influences cellular signaling pathways for melanoma development. Here, we show that mutated BRAF plays an essential role in the adaptive stress response following activation of general control non-derepressible 2 (GCN2) kinase. In parallel with GCN2, BRAF ensures ATF4 induction by utilizing mTOR and eIF4B as downstream regulators during nutrient stress and BRAF-targeted, therapeutic stress. Upon pharmacological BRAF inhibition, this signaling pathway exhibits temporal resistance, compared with the MEK-ERK pathway, thereby enabling transient induction of ATF4 under GCN2 activation. Notably, the prevention of GCN2 activation, using a chemical inhibitor that we identified, produces synergistic cell killing with BRAF inhibition. Thus, oncogenic BRAF can collaborate with the GCN2–ATF4 pathway, promoting stress adaptation for cell survival.
2020-04-06 | GSE136613 | GEO
Project description:Preclinical and clinical data implicate the transcriptional co-activator YAP1 in resistance to multiple targeted therapies, including BRAF and MEK inhibitors. However, tumor subtypes driven by YAP1 activity and associated vulnerabilities are poorly defined. Here, we show particularly high YAP1 activity in the MITFlow/AXLhigh subset of melanoma cell lines and patient tumors characterized by resistance to MAPK pathway inhibition and broad receptor tyrosine kinase activity. To uncover genetic dependencies of melanoma cells with high YAP1 activity, we used a genome-wide CRISPR/Cas9 functional screen and identified SLC35B2, the 3′-phosphoadenosine-5′-phosphosulfate transporter of the Golgi apparatus, as an essential gene for YAP1-mediated drug resistance. SLC35B2 expression correlates with tumor progression, and its loss decreases heparan sulfate expression, reduces receptor tyrosine kinase activity, and sensitizes resistant melanoma cells to BRAF inhibition in vitro and in vivo. Thus, SLC35B2 is a target in YAP1-driven BRAF mutant melanoma for overcoming drug resistance to MAPK pathway inhibitors.
2022-08-15 | GSE193775 | GEO
Project description:Fusion genes can be oncogenic drivers in a variety of cancer types and represent potential targets for targeted therapy. The BRAF gene is frequently involved in oncogenic fusions, with fusion frequencies of 0.2-3% throughout different cancers. However, BRAF fusions rarely occur in the same gene configuration, potentially challenging personalized therapy design. In particular, the influence that is imposed by the wide variety of fusion partners on the oncogenic role of BRAF during tumor growth and drug response is unknown. Here, we used patient-derived colorectal cancer organoids to functionally characterize and cross-compare previously identified BRAF fusions containing various partner genes (AGAP3, DLG1 and TRIM24) with respect to cellular behaviour, downstream signaling activation and response to targeted therapies. We demonstrate that 5’ partner choice of BRAF fusions affects their subcellular localization and intracellular signaling capacity. In particular the DLG1-BRAF fusion protein showed distinct localization to the plasma membrane and exhibited increased activation of downstream MAPK signaling under unperturbed conditions. Moreover, phosphoproteomics and RNA sequencing identified distinct subsets of affected signaling pathways and altered gene expression of BRAF fusions. The different BRAF fusions exhibited varying sensitivities to simultaneous targeted inhibition of MEK and the EGF receptor family. However, all BRAF fusions conveyed resistance to targeted monotherapy against the EGF receptor family, suggesting that BRAF fusions should be screened alongside other MAPK pathway alterations to identify mCRC patients to exclude from cetuximab treatment
2020-01-16 | PXD013461 | Pride