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1.
Cell ; 181(3): 702-715.e20, 2020 04 30.
Article in English | MEDLINE | ID: mdl-32315619

ABSTRACT

Protein phosphatase 2A (PP2A) enzymes can suppress tumors, but they are often inactivated in human cancers overexpressing inhibitory proteins. Here, we identify a class of small-molecule iHAPs (improved heterocyclic activators of PP2A) that kill leukemia cells by allosterically assembling a specific heterotrimeric PP2A holoenzyme consisting of PPP2R1A (scaffold), PPP2R5E (B56ε, regulatory), and PPP2CA (catalytic) subunits. One compound, iHAP1, activates this complex but does not inhibit dopamine receptor D2, a mediator of neurologic toxicity induced by perphenazine and related neuroleptics. The PP2A complex activated by iHAP1 dephosphorylates the MYBL2 transcription factor on Ser241, causing irreversible arrest of leukemia and other cancer cells in prometaphase. In contrast, SMAPs, a separate class of compounds, activate PP2A holoenzymes containing a different regulatory subunit, do not dephosphorylate MYBL2, and arrest tumor cells in G1 phase. Our findings demonstrate that small molecules can serve as allosteric switches to activate distinct PP2A complexes with unique substrates.


Subject(s)
Protein Phosphatase 2/metabolism , Apoptosis , Cell Cycle Proteins/drug effects , Cell Cycle Proteins/metabolism , Cell Line, Tumor , Enzyme Activators/metabolism , G1 Phase , Humans , Multiprotein Complexes/metabolism , Multiprotein Complexes/physiology , Phenothiazines/pharmacology , Phosphorylation , Protein Phosphatase 2/physiology , Protein Subunits/metabolism , Trans-Activators/drug effects , Trans-Activators/metabolism , Transcription Factors/metabolism
3.
Br J Haematol ; 201(3): 489-501, 2023 05.
Article in English | MEDLINE | ID: mdl-36746437

ABSTRACT

TET2 inactivating mutations serve as initiating genetic lesions in the transformation of haematopoietic stem and progenitor cells (HSPCs). In this study, we analysed known drugs in zebrafish embryos for their ability to selectively kill tet2-mutant HSPCs in vivo. We found that the exportin 1 (XPO1) inhibitors, selinexor and eltanexor, selectively kill tet2-mutant HSPCs. In serial replating colony assays, these small molecules were selectively active in killing murine Tet2-deficient Lineage-, Sca1+, Kit+ (LSK) cells, and also TET2-inactivated human acute myeloid leukaemia (AML) cells. Selective killing of TET2-mutant HSPCs and human AML cells by these inhibitors was due to increased levels of apoptosis, without evidence of DNA damage based on increased γH2AX expression. The finding that TET2 loss renders HSPCs and AML cells selectively susceptible to cell death induced by XPO1 inhibitors provides preclinical evidence of the selective activity of these drugs, justifying further clinical studies of these small molecules for the treatment of TET2-mutant haematopoietic malignancies, and to suppress clonal expansion in age-related TET2-mutant clonal haematopoiesis.


Subject(s)
Dioxygenases , Leukemia, Myeloid, Acute , Animals , Humans , Mice , Zebrafish , Hematopoietic Stem Cells/metabolism , Leukemia, Myeloid, Acute/drug therapy , Leukemia, Myeloid, Acute/genetics , Leukemia, Myeloid, Acute/pathology , DNA-Binding Proteins/genetics , Dioxygenases/metabolism , Exportin 1 Protein
4.
Nat Chem Biol ; 17(9): 954-963, 2021 09.
Article in English | MEDLINE | ID: mdl-33972797

ABSTRACT

The peptidyl-prolyl isomerase, Pin1, is exploited in cancer to activate oncogenes and inactivate tumor suppressors. However, despite considerable efforts, Pin1 has remained an elusive drug target. Here, we screened an electrophilic fragment library to identify covalent inhibitors targeting Pin1's active site Cys113, leading to the development of Sulfopin, a nanomolar Pin1 inhibitor. Sulfopin is highly selective, as validated by two independent chemoproteomics methods, achieves potent cellular and in vivo target engagement and phenocopies Pin1 genetic knockout. Pin1 inhibition had only a modest effect on cancer cell line viability. Nevertheless, Sulfopin induced downregulation of c-Myc target genes, reduced tumor progression and conferred survival benefit in murine and zebrafish models of MYCN-driven neuroblastoma, and in a murine model of pancreatic cancer. Our results demonstrate that Sulfopin is a chemical probe suitable for assessment of Pin1-dependent pharmacology in cells and in vivo, and that Pin1 warrants further investigation as a potential cancer drug target.


Subject(s)
Antineoplastic Agents/pharmacology , Enzyme Inhibitors/pharmacology , NIMA-Interacting Peptidylprolyl Isomerase/antagonists & inhibitors , Proto-Oncogene Proteins c-myc/antagonists & inhibitors , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Apoptosis/drug effects , Cell Proliferation/drug effects , Cell Survival/drug effects , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Humans , Mice , Mice, Inbred C57BL , Molecular Structure , NIMA-Interacting Peptidylprolyl Isomerase/metabolism , Neoplasms, Experimental/drug therapy , Neoplasms, Experimental/metabolism , Neoplasms, Experimental/pathology , Proto-Oncogene Proteins c-myc/metabolism , Structure-Activity Relationship , Tumor Cells, Cultured
5.
Nat Chem Biol ; 16(6): 635-643, 2020 06.
Article in English | MEDLINE | ID: mdl-32251410

ABSTRACT

Doublecortin like kinase 1 (DCLK1) is an understudied kinase that is upregulated in a wide range of cancers, including pancreatic ductal adenocarcinoma (PDAC). However, little is known about its potential as a therapeutic target. We used chemoproteomic profiling and structure-based design to develop a selective, in vivo-compatible chemical probe of the DCLK1 kinase domain, DCLK1-IN-1. We demonstrate activity of DCLK1-IN-1 against clinically relevant patient-derived PDAC organoid models and use a combination of RNA-sequencing, proteomics and phosphoproteomics analysis to reveal that DCLK1 inhibition modulates proteins and pathways associated with cell motility in this context. DCLK1-IN-1 will serve as a versatile tool to investigate DCLK1 biology and establish its role in cancer.


Subject(s)
Carcinoma, Pancreatic Ductal/drug therapy , Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Pancreatic Neoplasms/drug therapy , Protein Kinase Inhibitors/chemistry , Protein Serine-Threonine Kinases/antagonists & inhibitors , Animals , Cell Line, Tumor , Cell Movement , Doublecortin Protein , Doublecortin-Like Kinases , Drug Screening Assays, Antitumor , Gene Expression Regulation , Humans , Intracellular Signaling Peptides and Proteins/metabolism , Male , Mice , Molecular Docking Simulation , Molecular Structure , Protein Kinase Inhibitors/pharmacokinetics , Proteomics , Rats , Structure-Activity Relationship , Zebrafish , Pancreatic Neoplasms
6.
PLoS Genet ; 15(4): e1008039, 2019 04.
Article in English | MEDLINE | ID: mdl-30970016

ABSTRACT

The SWI/SNF-family chromatin remodeling protein ATRX is a tumor suppressor in sarcomas, gliomas and other malignancies. Its loss of function facilitates the alternative lengthening of telomeres (ALT) pathway in tumor cells, while it also affects Polycomb repressive complex 2 (PRC2) silencing of its target genes. To further define the role of inactivating ATRX mutations in carcinogenesis, we knocked out atrx in our previously reported p53/nf1-deficient zebrafish line that develops malignant peripheral nerve sheath tumors and gliomas. Complete inactivation of atrx using CRISPR/Cas9 was lethal in developing fish and resulted in an alpha-thalassemia-like phenotype including reduced alpha-globin expression. In p53/nf1-deficient zebrafish neither peripheral nerve sheath tumors nor gliomas showed accelerated onset in atrx+/- fish, but these fish developed various tumors that were not observed in their atrx+/+ siblings, including epithelioid sarcoma, angiosarcoma, undifferentiated pleomorphic sarcoma and rare types of carcinoma. These cancer types are included in the AACR Genie database of human tumors associated with mutant ATRX, indicating that our zebrafish model reliably mimics a role for ATRX-loss in the early pathogenesis of these human cancer types. RNA-seq of p53/nf1- and p53/nf1/atrx-deficient tumors revealed that down-regulation of telomerase accompanied ALT-mediated lengthening of the telomeres in atrx-mutant samples. Moreover, inactivating mutations in atrx disturbed PRC2-target gene silencing, indicating a connection between ATRX loss and PRC2 dysfunction in cancer development.


Subject(s)
Sarcoma, Experimental/etiology , Tumor Suppressor Protein p53/deficiency , Tumor Suppressor Protein p53/genetics , X-linked Nuclear Protein/deficiency , X-linked Nuclear Protein/genetics , Zebrafish Proteins/deficiency , Zebrafish Proteins/genetics , Animals , Animals, Genetically Modified , CRISPR-Cas Systems , Carcinogenesis/genetics , Carcinogenesis/metabolism , Disease Models, Animal , Erythropoiesis , Female , Gene Knockout Techniques , Globins/genetics , Humans , Loss of Function Mutation , Male , Neurofibromin 1/deficiency , Neurofibromin 1/genetics , Sarcoma, Experimental/genetics , Sarcoma, Experimental/metabolism , Telomere Homeostasis/genetics , Zebrafish/embryology , Zebrafish/genetics , Zebrafish/metabolism
7.
Adv Exp Med Biol ; 916: 495-530, 2016.
Article in English | MEDLINE | ID: mdl-27165368

ABSTRACT

Malignant peripheral nerve sheath tumors (MPNST) are tumors derived from Schwann cells or Schwann cell precursors. Although rare overall, the incidence of MPNST has increased with improved clinical management of patients with the neurofibromatosis type 1 (NF1) tumor predisposition syndrome. Unfortunately, current treatment modalities for MPNST are limited, with no targeted therapies available and poor efficacy of conventional radiation and chemotherapeutic regimens. Many murine and zebrafish models of MPNST have been developed, which have helped to elucidate the genes and pathways that are dysregulated in MPNST tumorigenesis, including the p53, and the RB1, PI3K-Akt-mTOR, RAS-ERK and Wnt signaling pathways. Preclinical results have suggested that new therapies, including mTOR and ERK inhibitors, may synergize with conventional chemotherapy in human tumors. The discovery of new genome editing technologies, like CRISPR-cas9, and their successful application to the zebrafish model will enable rapid progress in the faithful modeling of MPNST molecular pathogenesis. The zebrafish model is especially suited for high throughput screening of new targeted therapeutics as well as drugs approved for other purposes, which may help to bring enhanced treatment modalities into human clinical trials for this devastating disease.


Subject(s)
Disease Models, Animal , Nerve Sheath Neoplasms/pathology , Animals , Mice , Nerve Sheath Neoplasms/genetics , Nerve Sheath Neoplasms/metabolism , Nerve Sheath Neoplasms/therapy , Rodentia , Zebrafish
8.
Cell Rep Med ; 5(3): 101472, 2024 Mar 19.
Article in English | MEDLINE | ID: mdl-38508140

ABSTRACT

Anaplastic large cell lymphoma (ALCL) is an aggressive, CD30+ T cell lymphoma of children and adults. ALK fusion transcripts or mutations in the JAK-STAT pathway are observed in most ALCL tumors, but the mechanisms underlying tumorigenesis are not fully understood. Here, we show that dysregulated STAT3 in ALCL cooccupies enhancers with master transcription factors BATF3, IRF4, and IKZF1 to form a core regulatory circuit that establishes and maintains the malignant cell state in ALCL. Critical downstream targets of this network in ALCL cells include the protooncogene MYC, which requires active STAT3 to facilitate high levels of MYC transcription. The core autoregulatory transcriptional circuitry activity is reinforced by MYC binding to the enhancer regions associated with STAT3 and each of the core regulatory transcription factors. Thus, activation of STAT3 provides the crucial link between aberrant tyrosine kinase signaling and the core transcriptional machinery that drives tumorigenesis and creates therapeutic vulnerabilities in ALCL.


Subject(s)
Lymphoma, Large-Cell, Anaplastic , Signal Transduction , Adult , Child , Humans , Signal Transduction/genetics , Anaplastic Lymphoma Kinase/genetics , Anaplastic Lymphoma Kinase/metabolism , Lymphoma, Large-Cell, Anaplastic/genetics , Lymphoma, Large-Cell, Anaplastic/metabolism , Lymphoma, Large-Cell, Anaplastic/pathology , Janus Kinases/metabolism , STAT Transcription Factors/metabolism , Cell Transformation, Neoplastic , Carcinogenesis/genetics , STAT3 Transcription Factor/genetics
9.
Breast Cancer Res ; 15(6): R106, 2013 Nov 07.
Article in English | MEDLINE | ID: mdl-24196484

ABSTRACT

INTRODUCTION: The transforming growth factor beta (TGF-ß) signalling pathway is known to control human breast cancer invasion and metastasis. We demonstrate that the zebrafish xenograft assay is a robust and dependable animal model for examining the role of pharmacological modulators and genetic perturbation of TGF-ß signalling in human breast tumour cells. METHODS: We injected cancer cells into the embryonic circulation (duct of cuvier) and examined their invasion and metastasis into the avascular collagenous tail. Various aspects of the TGF-ß signalling pathway were blocked by chemical inhibition, small interfering RNA (siRNA), or small hairpin RNA (shRNA). Analysis was conducted using fluorescent microscopy. RESULTS: Breast cancer cells with different levels of malignancy, according to in vitro and in vivo mouse studies, demonstrated invasive and metastatic properties within the embryonic zebrafish model that nicely correlated with their differential tumourigenicity in mouse models. Interestingly, MCF10A M2 and M4 cells invaded into the caudal hematopoietic tissue and were visible as a cluster of cells, whereas MDA MB 231 cells invaded into the tail fin and were visible as individual cells. Pharmacological inhibition with TGF-ß receptor kinase inhibitors or tumour specific Smad4 knockdown disturbed invasion and metastasis in the zebrafish xenograft model and closely mimicked the results we obtained with these cells in a mouse metastasis model. Inhibition of matrix metallo proteinases, which are induced by TGF-ß in breast cancer cells, blocked invasion and metastasis of breast cancer cells. CONCLUSIONS: The zebrafish-embryonic breast cancer xenograft model is applicable for the mechanistic understanding, screening and development of anti-TGF-ß drugs for the treatment of metastatic breast cancer in a timely and cost-effective manner.


Subject(s)
Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Transforming Growth Factor beta/metabolism , Xenograft Model Antitumor Assays , Zebrafish/metabolism , Animals , Benzamides/pharmacology , Breast Neoplasms/drug therapy , Chromones/pharmacology , Dioxoles/pharmacology , Dipeptides/pharmacology , Disease Models, Animal , Drug Screening Assays, Antitumor/methods , Embryo, Nonmammalian , Enzyme Inhibitors/pharmacology , Female , Humans , Matrix Metalloproteinase Inhibitors/pharmacology , Morpholines/pharmacology , Protein Serine-Threonine Kinases/antagonists & inhibitors , RNA, Small Interfering/pharmacology , Receptor, Transforming Growth Factor-beta Type I , Receptors, Transforming Growth Factor beta/antagonists & inhibitors , Signal Transduction/drug effects , Smad2 Protein/metabolism , Smad4 Protein/genetics , Smad4 Protein/metabolism , Small Molecule Libraries/pharmacology , Transforming Growth Factor beta/antagonists & inhibitors , Zebrafish/embryology , Zebrafish Proteins/genetics , Zebrafish Proteins/metabolism
10.
J Pathol ; 227(4): 431-45, 2012 Aug.
Article in English | MEDLINE | ID: mdl-22374800

ABSTRACT

Inhibition of VEGF signalling effectively suppresses localized tumour growth but accelerates tumour invasiveness and micrometastasis by unknown mechanisms. To study the dynamic and reciprocal interactions between tumour cells and their microenvironment during these processes, we established a xenograft model by injecting tumour cells into the blood circulation of transparent zebrafish embryos. This reproducibly results in rapid simultaneous formation of a localized tumour and experimental micrometastasis, allowing time-resolved imaging of both processes at single-cell resolution within 1 week. The tumour vasculature was initiated de novo by remodelling of primitive endothelial cells into a functional network. Roles of myeloid cells in critical tumourigenesis steps such as vascularization and invasion were revealed by genetic and pharmaceutical approaches. We discovered that the physiological migration of neutrophils controlled tumour invasion by conditioning the collagen matrix and forming the metastatic niche, as detected by two-photon confocal microscopy and second harmonic generation. Administration of VEGFR inhibitors blocked tumour vascularization and a localized tumour growth but enhanced migration of neutrophils, which in turn promoted tumour invasion and formation of micrometastasis. This demonstrates the in vivo cooperation between VEGF signalling and myeloid cells in metastasis and provides a new mechanism underlying the recent findings that VEGFR targeting can promote tumour invasiveness.


Subject(s)
Disease Models, Animal , Neoplasm Metastasis/physiopathology , Neutrophils/physiology , Receptors, Vascular Endothelial Growth Factor/antagonists & inhibitors , Xenograft Model Antitumor Assays , Zebrafish/embryology , Animals , Beclomethasone/pharmacology , Breast Neoplasms/pathology , Cell Movement/physiology , Cell Transformation, Neoplastic , Endothelial Cells/pathology , Humans , Indoles/pharmacology , Mice , Myeloid Cells/pathology , Myeloid Cells/physiology , Neutrophils/pathology , Pyrroles/pharmacology , Receptors, Vascular Endothelial Growth Factor/drug effects , Signal Transduction/physiology , Sunitinib
11.
J Endod ; 49(7): 836-845, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37182792

ABSTRACT

INTRODUCTION: Concentrated growth factor (CGF) is the third-generation platelet concentrate product. This study aimed to evaluate whether the use of CGF during endodontic microsurgery had a positive influence on surgical outcomes. METHODS: Fifty-four patients who underwent endodontic microsurgery from January 2017 to November 2021 were enrolled. They were assigned to the CGF and the control groups according to whether CGF was used during the surgery and followed up at 6, 12, and 18 months after surgery. Preoperative classification of the cases and follow-up radiographic outcomes were based on Kim's classification and Molven's criteria, respectively, and evaluated by 2 calibrated endodontists. The Student t test and χ2 test were used to assess the baseline of 2 groups. Rank sum test was used to determine whether CGF had an impact on the surgical outcome. RESULTS: Thirty-one patients (41 periapical lesion sites) were included in the CGF group, and 23 patients (26 periapical lesion sites) were included in the control group. The overall success rate of endodontic microsurgery was greater than 90%. The baseline of the 2 groups had no difference (P < .05). In the CGF group, the success rate was always 100% in 3 follow-ups, whereas the success rate was 84.2%, 92.8%, and 90%, respectively, in the control group. The success rate between the CGF group and the control group was statistically significant in all 3 follow-up points (P < .05). CONCLUSIONS: The application of CGF during endodontic microsurgery might have a positive influence on surgical outcomes, thus, its prognosis. However, higher-grade evidence is needed to demonstrate its role.


Subject(s)
Intercellular Signaling Peptides and Proteins , Microsurgery , Humans , Treatment Outcome , Cross-Sectional Studies , Prognosis , Intercellular Signaling Peptides and Proteins/therapeutic use
12.
Article in English | MEDLINE | ID: mdl-37937078

ABSTRACT

Introduction: Myelodysplastic syndrome (MDS) is a heterogeneous group of clonal hematopoietic disorders characterized by ineffective hematopoiesis, cytopenias, and dysplasia. The gene encoding ten-eleven translocation 2 (tet2), a dioxygenase enzyme that catalyzes the conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine, is a recurrently mutated tumor suppressor gene in MDS and other myeloid malignancies. Previously, we reported a stable zebrafish line with a loss-of-function mutation in the tet2 gene. The tet2m/m-mutant zebrafish developed a pre-MDS state with kidney marrow dysplasia, but normal circulating blood counts by 11 months of age and accompanying anemia, signifying the onset of MDS, by 24 months of age. Methods: In the current study, we collected progenitor cells from the kidney marrows of the adult tet2m/m and tet2wt/wt fish at 4 and 15 months of age and conducted enhanced reduced representation of bisulfite sequencing (ERRBS) and bulk RNA-seq to measure changes in DNA methylation and gene expression of hematopoietic stem and progenitor cells (HSPCs). Results and discussion: A global increase in DNA methylation of gene promoter regions and CpG islands was observed in tet2m/m HSPCs at 4 months of age when compared with the wild type. Furthermore, hypermethylated genes were significantly enriched for targets of SUZ12 and the metal-response-element-binding transcription factor 2 (MTF2)-involved in the polycomb repressive complex 2 (PRC2). However, between 4 and 15 months of age, we observed a paradoxical global decrease in DNA methylation in tet2m/m HSPCs. Gene expression analyses identified upregulation of genes associated with mTORC1 signaling and interferon gamma and alpha responses in tet2m/m HSPCs at 4 months of age when compared with the wild type. Downregulated genes in HSPCs of tet2-mutant fish at 4 months of age were enriched for cell cycle regulation, heme metabolism, and interleukin 2 (IL2)/signal transducer and activator of transcription 5 (STAT5) signaling, possibly related to increased self-renewal and clonal advantage in HSPCs with tet2 loss of function. Finally, there was an overall inverse correlation between overall increased promoter methylation and gene expression.

13.
J Pathol ; 225(1): 19-28, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21744342

ABSTRACT

Although the underlying molecular mechanism of hepatocellular carcinoma remains unclear, signalling pathways essential in cell survival and growth are altered, including the Raf-MEK-MAPK pathway. This pathway can be activated by hepatitis B or C virus infections and the ectopic expression of the Raf-1 oncogene is frequently seen in hepatocellular carcinomas. In addition, the Raf-MEK-MAPK pathway was also shown to be deregulated in zebrafish liver tumours. Based on the genetic conservation between zebrafish and human liver tumours, the zebrafish was used as an animal model to better understand the molecular basis of hepatocellular carcinoma. Here we establish an inducible oncogenic zebrafish cell model, in which oncogenic human Raf-1(ΔRaf1) can be post-transcriptionally activated in zebrafish liver cells by administration of 4-hydroxytamoxifen (4HT). The ΔRaf1 activation resulted in the hyperactivation of the zebrafish MEK-ERK cascade, promoted cell growth and proliferation, and inhibited apoptosis. The mitogenic transformation of the ZFL-ΔRaf1-ER cells was confirmed by in vivo allo-transplantation and in silico microarray analyses. Gene expression profiling of cells treated with 4HT and a MEK-inhibitor identified a Raf-MEK-dependent signature set. This transcriptome response was compared to zebrafish and human liver cancer transcriptomes. We identified, and validated by quantitative PCR, a set of genes transcriptionally regulated by hyperactive MAPK signalling in ZFL-ΔRaf1-ER cells, zebrafish liver tumours and human liver tumours, suggesting that the in vitro zebrafish liver cell model can be used for further study of the molecular basis of human hepatocellular carcinoma. The molecular targeting of the commonly regulated hepatocellular carcinoma genes using the ZFL-ΔRaf1-ER cell model can be applied for high-throughput preclinical target discovery.


Subject(s)
Carcinoma, Hepatocellular/genetics , Liver Neoplasms, Experimental/genetics , 9,10-Dimethyl-1,2-benzanthracene , Animals , Carcinogens , Carcinoma, Hepatocellular/chemically induced , Carcinoma, Hepatocellular/metabolism , Carcinoma, Hepatocellular/pathology , Cell Proliferation/drug effects , Cell Survival/drug effects , Cell Transformation, Neoplastic/genetics , Gene Expression Profiling/methods , Gene Expression Regulation, Neoplastic/physiology , Humans , Liver Neoplasms, Experimental/chemically induced , Liver Neoplasms, Experimental/metabolism , Liver Neoplasms, Experimental/pathology , MAP Kinase Signaling System/drug effects , MAP Kinase Signaling System/genetics , MAP Kinase Signaling System/physiology , Neoplasm Transplantation , Proto-Oncogene Proteins c-raf/genetics , Proto-Oncogene Proteins c-raf/metabolism , Tamoxifen/analogs & derivatives , Tamoxifen/pharmacology , Transplantation, Heterologous , Tumor Cells, Cultured , Zebrafish
14.
Sci Adv ; 7(43): eabe0834, 2021 Oct 22.
Article in English | MEDLINE | ID: mdl-34669465

ABSTRACT

Neuroblastoma cell identity depends on a core regulatory circuit (CRC) of transcription factors that collaborate with MYCN to drive the oncogenic gene expression program. For neuroblastomas dependent on the adrenergic CRC, treatment with retinoids can inhibit cell growth and induce differentiation. Here, we show that when MYCN-amplified neuroblastoma cells are treated with retinoic acid, histone H3K27 acetylation and methylation become redistributed to decommission super-enhancers driving the expression of PHOX2B and GATA3, together with the activation of new super-enhancers that drive high levels of MEIS1 and SOX4 expression. These findings indicate that treatment with retinoids can reprogram the enhancer landscape, resulting in down-regulation of MYCN expression, while establishing a new retino-sympathetic CRC that causes proliferative arrest and sympathetic differentiation. Thus, we provide mechanisms that account for the beneficial effects of retinoids in high-risk neuroblastoma and explain the rapid down-regulation of expression of MYCN despite massive levels of amplification of this gene.

15.
Oncogene ; 40(38): 5718-5729, 2021 09.
Article in English | MEDLINE | ID: mdl-34331013

ABSTRACT

Melanomas driven by loss of the NF1 tumor suppressor have a high risk of treatment failure and effective therapies have not been developed. Here we show that loss-of-function mutations of nf1 and pten result in aggressive melanomas in zebrafish, representing the first animal model of NF1-mutant melanomas harboring PTEN loss. MEK or PI3K inhibitors show little activity when given alone due to cross-talk between the pathways, and high toxicity when given together. The mTOR inhibitors, sirolimus, everolimus, and temsirolimus, were the most active single agents tested, potently induced tumor-suppressive autophagy, but not apoptosis. Because addition of the BCL2 inhibitor venetoclax resulted in compensatory upregulation of MCL1, we established a three-drug combination composed of sirolimus, venetoclax, and the MCL1 inhibitor S63845. This well-tolerated drug combination potently and synergistically induces apoptosis in both zebrafish and human NF1/PTEN-deficient melanoma cells, providing preclinical evidence justifying an early-stage clinical trial in patients with NF1/PTEN-deficient melanoma.


Subject(s)
Bridged Bicyclo Compounds, Heterocyclic/administration & dosage , MTOR Inhibitors/administration & dosage , Melanoma/drug therapy , Neurofibromin 1/genetics , PTEN Phosphohydrolase/genetics , Pyrimidines/administration & dosage , Sulfonamides/administration & dosage , Thiophenes/administration & dosage , Animals , Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Drug Synergism , Everolimus/administration & dosage , Everolimus/pharmacology , Humans , Loss of Function Mutation , MTOR Inhibitors/pharmacology , Melanoma/genetics , Melanoma/pathology , Myeloid Cell Leukemia Sequence 1 Protein/antagonists & inhibitors , Proto-Oncogene Proteins c-bcl-2/antagonists & inhibitors , Pyrimidines/pharmacology , Sirolimus/administration & dosage , Sirolimus/analogs & derivatives , Sirolimus/pharmacology , Sulfonamides/pharmacology , Thiophenes/pharmacology , Xenograft Model Antitumor Assays , Zebrafish
16.
Cancer Res ; 81(11): 2995-3007, 2021 06 01.
Article in English | MEDLINE | ID: mdl-33602789

ABSTRACT

One of the greatest barriers to curative treatment of neuroblastoma is its frequent metastatic outgrowth prior to diagnosis, especially in cases driven by amplification of the MYCN oncogene. However, only a limited number of regulatory proteins that contribute to this complex MYCN-mediated process have been elucidated. Here we show that the growth arrest-specific 7 (GAS7) gene, located at chromosome band 17p13.1, is preferentially deleted in high-risk MYCN-driven neuroblastoma. GAS7 expression was also suppressed in MYCN-amplified neuroblastoma lacking 17p deletion. GAS7 deficiency led to accelerated metastasis in both zebrafish and mammalian models of neuroblastoma with overexpression or amplification of MYCN. Analysis of expression profiles and the ultrastructure of zebrafish neuroblastoma tumors with MYCN overexpression identified that GAS7 deficiency led to (i) downregulation of genes involved in cell-cell interaction, (ii) loss of contact among tumor cells as critical determinants of accelerated metastasis, and (iii) increased levels of MYCN protein. These results provide the first genetic evidence that GAS7 depletion is a critical early step in the cascade of events culminating in neuroblastoma metastasis in the context of MYCN overexpression. SIGNIFICANCE: Heterozygous deletion or MYCN-mediated repression of GAS7 in neuroblastoma releases an important brake on tumor cell dispersion and migration to distant sites, providing a novel mechanism underlying tumor metastasis in MYCN-driven neuroblastoma.See related commentary by Menard, p. 2815.


Subject(s)
Biomarkers, Tumor/metabolism , Bone Marrow Neoplasms/secondary , Chromosome Deletion , Gene Expression Regulation, Neoplastic , N-Myc Proto-Oncogene Protein/metabolism , Nerve Tissue Proteins/deficiency , Neuroblastoma/pathology , Animals , Apoptosis , Biomarkers, Tumor/genetics , Bone Marrow Neoplasms/genetics , Bone Marrow Neoplasms/metabolism , Cell Proliferation , Humans , Mice , Mice, SCID , N-Myc Proto-Oncogene Protein/genetics , Nerve Tissue Proteins/genetics , Neuroblastoma/genetics , Neuroblastoma/metabolism , Prognosis , Survival Rate , Tumor Cells, Cultured , Xenograft Model Antitumor Assays , Zebrafish
17.
Leukemia ; 34(11): 2992-3006, 2020 11.
Article in English | MEDLINE | ID: mdl-32572188

ABSTRACT

Inactivating mutations in TET2 serve as an initiating genetic lesion in the transformation of hematopoietic stem and progenitor cells (HSPCs). Thus, effective therapy for this subset of patients would ideally include drugs that are selectively lethal in TET2-mutant HSPCs, at dosages that spare normal HSPCs. In this study, we tested 129 FDA-approved anticancer drugs in a tet2-deficient zebrafish model and showed that topoisomerase 1 (TOP1)-targeted drugs and PARP1 inhibitors selectively kill tet2-mutant HSPCs. We found that Tet2-deficient murine bone marrow progenitors and CRISPR-Cas9-induced TET2-mutant human AML cells were more sensitive to both classes of drugs compared with matched control cells. The mechanism underlying the selective killing of TET2-mutant blood cells by these drugs was due to aberrantly low levels of tyrosyl-DNA phosphodiesterase 1 (TDP1), an enzyme that is important for removing TOP1 cleavage complexes (TOP1cc). Low TDP1 levels yield sensitivity to TOP1-targeted drugs or PARP1 inhibitors and an inability to remove TOP1 cleavage complexes, leading to DNA double-strand breaks and cell death. The finding that TET2 mutations render HSPCs uniquely vulnerable to disruption of TOP1 and PARP1 activity may therefore represent a unique opportunity to use relatively low dosages of these drugs for the "precision therapy" of TET2-mutant myeloid malignancies.


Subject(s)
DNA Topoisomerases, Type I/metabolism , DNA-Binding Proteins/genetics , Hematopoietic Stem Cells/drug effects , Hematopoietic Stem Cells/metabolism , Poly (ADP-Ribose) Polymerase-1/antagonists & inhibitors , Proto-Oncogene Proteins/genetics , Synthetic Lethal Mutations , Topoisomerase I Inhibitors/pharmacology , Animals , Animals, Genetically Modified , Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Apoptosis/genetics , Cell Survival/drug effects , Cell Survival/genetics , DNA Breaks, Double-Stranded/drug effects , Dioxygenases , Genotype , Humans , Mice , Mice, Knockout , Phenotype , Topotecan/pharmacology , Zebrafish
18.
Dis Model Mech ; 13(8)2020 08 27.
Article in English | MEDLINE | ID: mdl-32651197

ABSTRACT

Polycomb repressive complex 2 (PRC2) is an epigenetic regulator of gene expression that possesses histone methyltransferase activity. PRC2 trimethylates lysine 27 of histone H3 proteins (H3K27me3) as a chromatin modification associated with repressed transcription of genes frequently involved in cell proliferation or self-renewal. Loss-of-function mutations in the PRC2 core subunit SUZ12 have been identified in a variety of tumors, including malignant peripheral nerve sheath tumors (MPNSTs). To determine the consequences of SUZ12 loss in the pathogenesis of MPNST and other cancers, we used CRISPR-Cas9 to disrupt the open reading frame of each of two orthologous suz12 genes in zebrafish: suz12a and suz12b We generated these knockout alleles in the germline of our previously described p53 (also known as tp53)- and nf1-deficient zebrafish model of MPNSTs. Loss of suz12 significantly accelerated the onset and increased the penetrance of MPNSTs compared to that in control zebrafish. Moreover, in suz12-deficient zebrafish, we detected additional types of tumors besides MPNSTs, including leukemia with histological characteristics of lymphoid malignancies, soft tissue sarcoma and pancreatic adenocarcinoma, which were not detected in p53/nf1-deficient control fish, and are also contained in the human spectrum of SUZ12-deficient malignancies identified in the AACR Genie database. The suz12-knockout tumors displayed reduced or abolished H3K27me3 epigenetic marks and upregulation of gene sets reported to be targeted by PRC2. Thus, these zebrafish lines with inactivation of suz12 in combination with loss of p53/nf1 provide a model of human MPNSTs and multiple other tumor types, which will be useful for mechanistic studies of molecular pathogenesis and targeted therapy with small molecule inhibitors.


Subject(s)
Cell Transformation, Neoplastic/genetics , Gene Silencing , Neurofibromin 1/genetics , Neurofibrosarcoma/genetics , Tumor Suppressor Protein p53/genetics , Zebrafish Proteins/genetics , Zebrafish/genetics , Adenocarcinoma/genetics , Adenocarcinoma/metabolism , Adenocarcinoma/pathology , Animals , Animals, Genetically Modified , Antineoplastic Agents/pharmacology , Cell Transformation, Neoplastic/metabolism , Cell Transformation, Neoplastic/pathology , DNA Methylation , Disease Models, Animal , Epigenesis, Genetic , Gene Expression Regulation, Neoplastic , Leukemia/genetics , Leukemia/metabolism , Leukemia/pathology , MAP Kinase Kinase Kinases/antagonists & inhibitors , MAP Kinase Kinase Kinases/metabolism , Neurofibromin 1/deficiency , Neurofibrosarcoma/drug therapy , Neurofibrosarcoma/metabolism , Neurofibrosarcoma/pathology , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/metabolism , Pancreatic Neoplasms/pathology , Protein Kinase Inhibitors/pharmacology , Sarcoma/genetics , Sarcoma/metabolism , Sarcoma/pathology , Signal Transduction , Soft Tissue Neoplasms/genetics , Soft Tissue Neoplasms/metabolism , Soft Tissue Neoplasms/pathology , Tumor Suppressor Protein p53/deficiency , Zebrafish/metabolism , Zebrafish Proteins/deficiency
19.
Dev Biol ; 319(2): 370-83, 2008 Jul 15.
Article in English | MEDLINE | ID: mdl-18514184

ABSTRACT

The MAPKs are key regulatory signaling molecules in many cellular processes. Here we define differential functions for ERK1 and ERK2 MAPKs in zebrafish embryogenesis. Morpholino knockdown of ERK1 and ERK2 resulted in cell migration defects during gastrulation, which could be rescued by co-injection of the corresponding mRNA. Strikingly, Erk2 mRNA cross-rescued ERK1 knockdown, but erk1 mRNA was unable to compensate for ERK2 knockdown. Cell-tracing experiments revealed a convergence defect for ERK1 morphants without a severe posterior-extension defect, whereas ERK2 morphants showed a more severe reduction in anterior-posterior extension. These defects were primary changes in gastrulation cell movements and not caused by altered cell fate specification. Saturating knockdown conditions showed that the absence of FGF-mediated dual-phosphorylated ERK2 from the blastula margin blocked initiation of epiboly, actin and tubulin cytoskeleton reorganization processes and further arrested embryogenesis, whereas ERK1 knockdown had only a mild effect on epiboly progression. Together, our data define distinct roles for ERK1 and ERK2 in developmental cell migration processes during zebrafish embryogenesis.


Subject(s)
Cell Movement/physiology , Gastrula/enzymology , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/metabolism , Zebrafish/embryology , Animals , Embryo, Nonmammalian/cytology , Embryo, Nonmammalian/enzymology , Embryo, Nonmammalian/physiology , Fibroblast Growth Factors/physiology , Gastrula/cytology , Immunohistochemistry , Morphogenesis/physiology , Signal Transduction , Zebrafish Proteins/metabolism
20.
Zebrafish ; 16(4): 421-426, 2019 08.
Article in English | MEDLINE | ID: mdl-31063042

ABSTRACT

In July 2018, the 11th Zebrafish Disease Models Conference (ZDM11) was held at Leiden University, The Netherlands, providing an excellent international opportunity for scientific presentations and collaborative discussion regarding the modeling of disease using zebrafish. Much like the original ZDM1, which was also hosted in Leiden in 2007, immunology and cancer had a strong presence at ZDM11, with zebrafish still proving an invaluable tool to interrogate their disease genetics and progression in vivo. In addition, ZDM11 built upon the inclusion and development of other key areas making use of zebrafish disease models, with sessions on neuroscience, behavior, muscle, skeletal and cardiac disease, and more. ZDM11 also highlighted the rapid progression and application of new and exciting technologies to assist in the generation and analysis of zebrafish disease models, including Crispr/Cas9 gene targeting tools, electroporation techniques, computational analysis, drug screening pipelines, and advances in vivo imaging such as high-resolution correlative electron microscopy and lightsheet microscopy. Here, we provide a summary of the ZDM11 conference proceedings, giving an overview of the stimulating science presented across 4 days and 13 conference sessions.


Subject(s)
Fish Diseases , Zebrafish , Animals , Congresses as Topic , Disease Models, Animal , Fish Diseases/etiology , Fish Diseases/immunology , Neoplasms/etiology , Netherlands
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