Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 7 de 7
Filter
Add more filters










Database
Language
Publication year range
1.
Nat Cell Biol ; 25(2): 285-297, 2023 02.
Article in English | MEDLINE | ID: mdl-36658220

ABSTRACT

Transcription factors (TFs) are frequently mutated in cancer. Paediatric cancers exhibit few mutations genome-wide but frequently harbour sentinel mutations that affect TFs, which provides a context to precisely study the transcriptional circuits that support mutant TF-driven oncogenesis. A broadly relevant mechanism that has garnered intense focus involves the ability of mutant TFs to hijack wild-type lineage-specific TFs in self-reinforcing transcriptional circuits. However, it is not known whether this specific type of circuitry is equally crucial in all mutant TF-driven cancers. Here we describe an alternative yet central transcriptional mechanism that promotes Ewing sarcoma, wherein constraint, rather than reinforcement, of the activity of the fusion TF EWS-FLI supports cancer growth. We discover that ETV6 is a crucial TF dependency that is specific to this disease because it, counter-intuitively, represses the transcriptional output of EWS-FLI. This work discovers a previously undescribed transcriptional mechanism that promotes cancer.


Subject(s)
Sarcoma, Ewing , Child , Humans , Cell Line, Tumor , Cell Transformation, Neoplastic/genetics , Gene Expression Regulation, Neoplastic , Oncogene Proteins, Fusion/genetics , Oncogene Proteins, Fusion/metabolism , Proto-Oncogene Protein c-fli-1/genetics , Proto-Oncogene Protein c-fli-1/metabolism , Proto-Oncogene Proteins c-ets/genetics , RNA-Binding Protein EWS/genetics , RNA-Binding Protein EWS/metabolism , Sarcoma, Ewing/genetics
2.
Cancer Discov ; 12(2): 432-449, 2022 02.
Article in English | MEDLINE | ID: mdl-34531254

ABSTRACT

CRISPR-Cas9-based genetic screens have successfully identified cell type-dependent liabilities in cancer, including acute myeloid leukemia (AML), a devastating hematologic malignancy with poor overall survival. Because most of these screens have been performed in vitro using established cell lines, evaluating the physiologic relevance of these targets is critical. We have established a CRISPR screening approach using orthotopic xenograft models to validate and prioritize AML-enriched dependencies in vivo, including in CRISPR-competent AML patient-derived xenograft (PDX) models tractable for genome editing. Our integrated pipeline has revealed several targets with translational value, including SLC5A3 as a metabolic vulnerability for AML addicted to exogenous myo-inositol and MARCH5 as a critical guardian to prevent apoptosis in AML. MARCH5 repression enhanced the efficacy of BCL2 inhibitors such as venetoclax, further highlighting the clinical potential of targeting MARCH5 in AML. Our study provides a valuable strategy for discovery and prioritization of new candidate AML therapeutic targets. SIGNIFICANCE: There is an unmet need to improve the clinical outcome of AML. We developed an integrated in vivo screening approach to prioritize and validate AML dependencies with high translational potential. We identified SLC5A3 as a metabolic vulnerability and MARCH5 as a critical apoptosis regulator in AML, both of which represent novel therapeutic opportunities.This article is highlighted in the In This Issue feature, p. 275.


Subject(s)
Antineoplastic Agents/therapeutic use , CRISPR-Cas Systems , Leukemia, Myeloid, Acute/drug therapy , Precision Medicine , Xenograft Model Antitumor Assays , Animals , Humans , Leukemia, Myeloid, Acute/genetics
3.
Cancer Cell ; 39(9): 1262-1278.e7, 2021 09 13.
Article in English | MEDLINE | ID: mdl-34329586

ABSTRACT

Fusion-transcription factors (fusion-TFs) represent a class of driver oncoproteins that are difficult to therapeutically target. Recently, protein degradation has emerged as a strategy to target these challenging oncoproteins. The mechanisms that regulate fusion-TF stability, however, are generally unknown. Using CRISPR-Cas9 screening, we discovered tripartite motif-containing 8 (TRIM8) as an E3 ubiquitin ligase that ubiquitinates and degrades EWS/FLI, a driver fusion-TF in Ewing sarcoma. Moreover, we identified TRIM8 as a selective dependency in Ewing sarcoma compared with >700 other cancer cell lines. Mechanistically, TRIM8 knockout led to an increase in EWS/FLI protein levels that was not tolerated. EWS/FLI acts as a neomorphic substrate for TRIM8, defining the selective nature of the dependency. Our results demonstrate that fusion-TF protein stability is tightly regulated and highlight fusion oncoprotein-specific regulators as selective therapeutic targets. This study provides a tractable strategy to therapeutically exploit oncogene overdose in Ewing sarcoma and potentially other fusion-TF-driven cancers.


Subject(s)
Bone Neoplasms/mortality , Carrier Proteins/metabolism , Nerve Tissue Proteins/metabolism , Oncogene Proteins, Fusion/chemistry , Proto-Oncogene Protein c-fli-1/chemistry , Proto-Oncogene Protein c-fli-1/metabolism , RNA-Binding Protein EWS/chemistry , RNA-Binding Protein EWS/metabolism , Sarcoma, Ewing/mortality , Bone Neoplasms/metabolism , Carrier Proteins/genetics , Cell Line, Tumor , Cell Proliferation , Cell Survival , Gene Knockout Techniques , HEK293 Cells , Humans , Microfilament Proteins/metabolism , Nerve Tissue Proteins/genetics , Oncogene Proteins, Fusion/metabolism , Protein Stability , Proteolysis , Sarcoma, Ewing/metabolism , Trans-Activators/metabolism
4.
Cancer Res ; 81(15): 3971-3984, 2021 08 01.
Article in English | MEDLINE | ID: mdl-34099491

ABSTRACT

Gene fusions frequently result from rearrangements in cancer genomes. In many instances, gene fusions play an important role in oncogenesis; in other instances, they are thought to be passenger events. Although regulatory element rearrangements and copy number alterations resulting from these structural variants are known to lead to transcriptional dysregulation across cancers, the extent to which these events result in functional dependencies with an impact on cancer cell survival is variable. Here we used CRISPR-Cas9 dependency screens to evaluate the fitness impact of 3,277 fusions across 645 cell lines from the Cancer Dependency Map. We found that 35% of cell lines harbored either a fusion partner dependency or a collateral dependency on a gene within the same topologically associating domain as a fusion partner. Fusion-associated dependencies revealed numerous novel oncogenic drivers and clinically translatable alterations. Broadly, fusions can result in partner and collateral dependencies that have biological and clinical relevance across cancer types. SIGNIFICANCE: This study provides insights into how fusions contribute to fitness in different cancer contexts beyond partner-gene activation events, identifying partner and collateral dependencies that may have direct implications for clinical care.


Subject(s)
Cell Survival/genetics , Gene Fusion/genetics , Neoplasms/genetics , Humans
5.
Cancer Cell ; 39(6): 827-844.e10, 2021 06 14.
Article in English | MEDLINE | ID: mdl-34129824

ABSTRACT

The core cohesin subunit STAG2 is recurrently mutated in Ewing sarcoma but its biological role is less clear. Here, we demonstrate that cohesin complexes containing STAG2 occupy enhancer and polycomb repressive complex (PRC2)-marked regulatory regions. Genetic suppression of STAG2 leads to a compensatory increase in cohesin-STAG1 complexes, but not in enhancer-rich regions, and results in reprogramming of cis-chromatin interactions. Strikingly, in STAG2 knockout cells the oncogenic genetic program driven by the fusion transcription factor EWS/FLI1 was highly perturbed, in part due to altered enhancer-promoter contacts. Moreover, loss of STAG2 also disrupted PRC2-mediated regulation of gene expression. Combined, these transcriptional changes converged to modulate EWS/FLI1, migratory, and neurodevelopmental programs. Finally, consistent with clinical observations, functional studies revealed that loss of STAG2 enhances the metastatic potential of Ewing sarcoma xenografts. Our findings demonstrate that STAG2 mutations can alter chromatin architecture and transcriptional programs to promote an aggressive cancer phenotype.


Subject(s)
Bone Neoplasms/genetics , Bone Neoplasms/pathology , Cell Cycle Proteins/genetics , Sarcoma, Ewing/genetics , Sarcoma, Ewing/pathology , Animals , Cell Cycle Proteins/metabolism , Cell Line, Tumor , Cell Movement/genetics , Chromosomal Proteins, Non-Histone/metabolism , Enhancer Elements, Genetic , Female , Gene Expression Regulation, Neoplastic , Homeodomain Proteins/genetics , Homeodomain Proteins/metabolism , Humans , Mice, Inbred NOD , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Oncogene Proteins, Fusion/genetics , POU Domain Factors/genetics , POU Domain Factors/metabolism , Polycomb Repressive Complex 2/genetics , Polycomb Repressive Complex 2/metabolism , Promoter Regions, Genetic , Proto-Oncogene Protein c-fli-1/genetics , RNA-Binding Protein EWS/genetics , Xenograft Model Antitumor Assays , Zebrafish/genetics , Cohesins
6.
Nat Commun ; 11(1): 4687, 2020 09 18.
Article in English | MEDLINE | ID: mdl-32948771

ABSTRACT

Chemical biology strategies for directly perturbing protein homeostasis including the degradation tag (dTAG) system provide temporal advantages over genetic approaches and improved selectivity over small molecule inhibitors. We describe dTAGV-1, an exclusively selective VHL-recruiting dTAG molecule, to rapidly degrade FKBP12F36V-tagged proteins. dTAGV-1 overcomes a limitation of previously reported CRBN-recruiting dTAG molecules to degrade recalcitrant oncogenes, supports combination degrader studies and facilitates investigations of protein function in cells and mice.


Subject(s)
Peptide Hydrolases/metabolism , Proteins/metabolism , Von Hippel-Lindau Tumor Suppressor Protein/metabolism , Animals , Female , Gene Knockout Techniques , HEK293 Cells , Humans , Male , Mice , Mice, Inbred C57BL , Mice, Inbred NOD , Mice, Knockout , Models, Animal , Proteomics , Proto-Oncogene Proteins p21(ras)/genetics , Tacrolimus Binding Protein 1A/genetics , Tacrolimus Binding Protein 1A/metabolism , Tacrolimus Binding Proteins , Von Hippel-Lindau Tumor Suppressor Protein/genetics
7.
Cancer Res ; 77(3): 696-706, 2017 02 01.
Article in English | MEDLINE | ID: mdl-27899382

ABSTRACT

Metastatic relapse is the major cause of death in pediatric neuroblastoma, where there remains a lack of therapies to target this stage of disease. To understand the molecular mechanisms mediating neuroblastoma metastasis, we developed a mouse model using intracardiac injection and in vivo selection to isolate malignant cell subpopulations with a higher propensity for metastasis to bone and the central nervous system. Gene expression profiling revealed primary and metastatic cells as two distinct cell populations defined by differential expression of 412 genes and of multiple pathways, including CADM1, SPHK1, and YAP/TAZ, whose expression independently predicted survival. In the metastatic subpopulations, a gene signature was defined (MET-75) that predicted survival of neuroblastoma patients with metastatic disease. Mechanistic investigations demonstrated causal roles for CADM1, SPHK1, and YAP/TAZ in mediating metastatic phenotypes in vitro and in vivo Notably, pharmacologic targeting of SPHK1 or YAP/TAZ was sufficient to inhibit neuroblastoma metastasis in vivo Overall, we identify gene expression signatures and candidate therapeutics that could improve the treatment of metastatic neuroblastoma. Cancer Res; 77(3); 696-706. ©2017 AACR.


Subject(s)
Neoplasm Invasiveness/genetics , Neoplasm Invasiveness/pathology , Neuroblastoma/genetics , Neuroblastoma/pathology , Transcriptome , Animals , Cell Line, Tumor , Disease Models, Animal , Gene Expression Profiling , Heterografts , Immunoblotting , Magnetic Resonance Imaging , Male , Mice , Mice, Inbred NOD , Mice, SCID , Oligonucleotide Array Sequence Analysis , X-Ray Microtomography
SELECTION OF CITATIONS
SEARCH DETAIL
...