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1.
Mol Cell ; 82(6): 1140-1155.e11, 2022 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-35245435

RESUMO

MLL rearrangements produce fusion oncoproteins that drive leukemia development, but the direct effects of MLL-fusion inactivation remain poorly defined. We designed models with degradable MLL::AF9 where treatment with small molecules induces rapid degradation. We leveraged the kinetics of this system to identify a core subset of MLL::AF9 target genes where MLL::AF9 degradation induces changes in transcriptional elongation within 15 minutes. MLL::AF9 degradation subsequently causes loss of a transcriptionally active chromatin landscape. We used this insight to assess the effectiveness of small molecules that target members of the MLL::AF9 multiprotein complex, specifically DOT1L and MENIN. Combined DOT1L/MENIN inhibition resembles MLL::AF9 degradation, whereas single-agent treatment has more modest effects on MLL::AF9 occupancy and gene expression. Our data show that MLL::AF9 degradation leads to decreases in transcriptional elongation prior to changes in chromatin landscape at select loci and that combined inhibition of chromatin complexes releases the MLL::AF9 oncoprotein from chromatin globally.


Assuntos
Leucemia , Proteína de Leucina Linfoide-Mieloide , Cromatina/genética , Humanos , Leucemia/genética , Proteína de Leucina Linfoide-Mieloide/genética , Proteína de Leucina Linfoide-Mieloide/metabolismo , Proteínas de Fusão Oncogênica/genética , Fatores de Transcrição/genética
2.
Mol Cell ; 78(6): 996-998, 2020 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-32559428

RESUMO

In this month's issue of Cancer Cell, Su et al. (2020) describe two small-molecule inhibitors of the RNA demethylase FTO that demonstrate significant anti-tumor effects in various models of acute myeloid leukemia.


Assuntos
Evasão da Resposta Imune , Leucemia Mieloide Aguda , Dioxigenase FTO Dependente de alfa-Cetoglutarato , Humanos , Metilação , Células-Tronco Neoplásicas , RNA
3.
Proc Natl Acad Sci U S A ; 121(26): e2405905121, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38889153

RESUMO

Aberrant regulation of chromatin modifiers is a common occurrence across many cancer types, and a key priority is to determine how specific alterations of these proteins, often enzymes, can be targeted therapeutically. MOZ, a histone acyltransferase, is recurrently fused to coactivators CBP, p300, and TIF2 in cases of acute myeloid leukemia (AML). Using either pharmacological inhibition or targeted protein degradation in a mouse model for MOZ-TIF2-driven leukemia, we show that KAT6 (MOZ/MORF) enzymatic activity and the MOZ-TIF2 protein are necessary for indefinite proliferation in cell culture. MOZ-TIF2 directly regulates a small subset of genes encoding developmental transcription factors, augmenting their high expression. Furthermore, transcription levels in MOZ-TIF2 cells positively correlate with enrichment of histone H3 propionylation at lysine 23 (H3K23pr), a recently appreciated histone acylation associated with gene activation. Unexpectedly, we also show that MOZ-TIF2 and MLL-AF9 regulate transcription of unique gene sets, and their cellular models exhibit distinct sensitivities to multiple small-molecule inhibitors directed against AML pathways. This is despite the shared genetic pathways of wild-type MOZ and MLL. Overall, our data provide insight into how aberrant regulation of MOZ contributes to leukemogenesis. We anticipate that these experiments will inform future work identifying targeted therapies in the treatment of AML and other diseases involving MOZ-induced transcriptional dysregulation.


Assuntos
Histona Acetiltransferases , Histonas , Animais , Camundongos , Histonas/metabolismo , Histona Acetiltransferases/metabolismo , Histona Acetiltransferases/genética , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Humanos , Modelos Animais de Doenças , Coativador 2 de Receptor Nuclear/metabolismo , Coativador 2 de Receptor Nuclear/genética , Regulação Leucêmica da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Fusão Oncogênica/metabolismo , Proteínas de Fusão Oncogênica/genética
4.
Blood ; 143(15): 1513-1527, 2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38096371

RESUMO

ABSTRACT: Small molecules that target the menin-KMT2A protein-protein interaction (menin inhibitors) have recently entered clinical trials in lysine methyltransferase 2A (KMT2A or MLL1)-rearranged (KMT2A-r) and nucleophosmin-mutant (NPM1c) acute myeloid leukemia (AML) and are demonstrating encouraging results. However, rationally chosen combination therapy is needed to improve responses and prevent resistance. We have previously identified IKZF1/IKAROS as a target in KMT2A-r AML and shown in preclinical models that IKAROS protein degradation with lenalidomide or iberdomide has modest single-agent activity yet can synergize with menin inhibitors. Recently, the novel IKAROS degrader mezigdomide was developed with greatly enhanced IKAROS protein degradation. In this study, we show that mezigdomide has increased preclinical activity in vitro as a single-agent in KMT2A-r and NPM1c AML cell lines, including sensitivity in cell lines resistant to lenalidomide and iberdomide. Further, we demonstrate that mezigdomide has the greatest capacity to synergize with and induce apoptosis in combination with menin inhibitors, including in MEN1 mutant models. We show that the superior activity of mezigdomide compared with lenalidomide or iberdomide is due to its increased depth, rate, and duration of IKAROS protein degradation. Single-agent mezigdomide was efficacious in 5 patient-derived xenograft models of KMT2A-r and 1 NPM1c AML. The combination of mezigdomide with the menin inhibitor VTP-50469 increased survival and prevented and overcame MEN1 mutations that mediate resistance in patients receiving menin inhibitor monotherapy. These results support prioritization of mezigdomide for early phase clinical trials in KMT2A-r and NPM1c AML, either as a single agent or in combination with menin inhibitors.


Assuntos
Leucemia Mieloide Aguda , Morfolinas , Proteína de Leucina Linfoide-Mieloide , Ftalimidas , Piperidonas , Humanos , Lenalidomida/uso terapêutico , Proteína de Leucina Linfoide-Mieloide/genética , Proteína de Leucina Linfoide-Mieloide/metabolismo , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Fatores de Transcrição/genética , Mutação
5.
Biochemistry ; 56(12): 1706-1715, 2017 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-28272875

RESUMO

Terpenes make up the largest and most diverse class of natural compounds and have important commercial and medical applications. Limonene is a cyclic monoterpene (C10) present in nature as two enantiomers, (+) and (-), which are produced by different enzymes. The mechanism of production of the (-)-enantiomer has been studied in great detail, but to understand how enantiomeric selectivity is achieved in this class of enzymes, it is important to develop a thorough biochemical description of enzymes that generate (+)-limonene, as well. Here we report the first cloning and biochemical characterization of a (+)-limonene synthase from navel orange (Citrus sinensis). The enzyme obeys classical Michaelis-Menten kinetics and produces exclusively the (+)-enantiomer. We have determined the crystal structure of the apoprotein in an "open" conformation at 2.3 Å resolution. Comparison with the structure of (-)-limonene synthase (Mentha spicata), which is representative of a fully closed conformation (Protein Data Bank entry 2ONG ), reveals that the short H-α1 helix moves nearly 5 Å inward upon substrate binding, and a conserved Tyr flips to point its hydroxyl group into the active site.


Assuntos
Apoproteínas/química , Citrus sinensis/química , Cicloexenos/química , Liases Intramoleculares/química , Proteínas de Plantas/química , Proteínas Recombinantes de Fusão/química , Terpenos/química , Apoproteínas/genética , Apoproteínas/metabolismo , Domínio Catalítico , Citrus sinensis/enzimologia , Clonagem Molecular , Cristalografia por Raios X , Cicloexenos/metabolismo , Difosfatos/química , Difosfatos/metabolismo , Diterpenos/química , Diterpenos/metabolismo , Ensaios Enzimáticos , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Liases Intramoleculares/genética , Liases Intramoleculares/metabolismo , Cinética , Limoneno , Mentha spicata/química , Mentha spicata/enzimologia , Modelos Moleculares , Mutagênese Sítio-Dirigida , Mutação , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Domínios Proteicos , Estrutura Secundária de Proteína , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Estereoisomerismo , Terpenos/metabolismo
6.
Nat Cell Biol ; 25(9): 1346-1358, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37591951

RESUMO

Small cell lung cancer (SCLC) exists broadly in four molecular subtypes: ASCL1, NEUROD1, POU2F3 and Inflammatory. Initially, SCLC subtypes were thought to be mutually exclusive, but recent evidence shows intra-tumoural subtype heterogeneity and plasticity between subtypes. Here, using a CRISPR-based autochthonous SCLC genetically engineered mouse model to study the consequences of KDM6A/UTX inactivation, we show that KDM6A inactivation induced plasticity from ASCL1 to NEUROD1 resulting in SCLC tumours that express both ASCL1 and NEUROD1. Mechanistically, KDM6A normally maintains an active chromatin state that favours the ASCL1 subtype with its loss decreasing H3K4me1 and increasing H3K27me3 at enhancers of neuroendocrine genes leading to a cell state that is primed for ASCL1-to-NEUROD1 subtype switching. This work identifies KDM6A as an epigenetic regulator that controls ASCL1 to NEUROD1 subtype plasticity and provides an autochthonous SCLC genetically engineered mouse model to model ASCL1 and NEUROD1 subtype heterogeneity and plasticity, which is found in 35-40% of human SCLCs.


Assuntos
Neoplasias Pulmonares , Carcinoma de Pequenas Células do Pulmão , Humanos , Animais , Camundongos , Carcinoma de Pequenas Células do Pulmão/genética , Histona Desmetilases/genética , Cromatina , Epigenômica , Neoplasias Pulmonares/genética
7.
Nat Cancer ; 3(5): 595-613, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35534777

RESUMO

Acute myeloid leukemia (AML) remains difficult to treat and requires new therapeutic approaches. Potent inhibitors of the chromatin-associated protein MENIN have recently entered human clinical trials, opening new therapeutic opportunities for some genetic subtypes of this disease. Using genome-scale functional genetic screens, we identified IKAROS (encoded by IKZF1) as an essential transcription factor in KMT2A (MLL1)-rearranged (MLL-r) AML that maintains leukemogenic gene expression while also repressing pathways for tumor suppression, immune regulation and cellular differentiation. Furthermore, IKAROS displays an unexpected functional cooperativity and extensive chromatin co-occupancy with mixed lineage leukemia (MLL)1-MENIN and the regulator MEIS1 and an extensive hematopoietic transcriptional complex involving homeobox (HOX)A10, MEIS1 and IKAROS. This dependency could be therapeutically exploited by inducing IKAROS protein degradation with immunomodulatory imide drugs (IMiDs). Finally, we demonstrate that combined IKAROS degradation and MENIN inhibition effectively disrupts leukemogenic transcriptional networks, resulting in synergistic killing of leukemia cells and providing a paradigm for improved drug targeting of transcription and an opportunity for rapid clinical translation.


Assuntos
Leucemia Mieloide Aguda , Cromatina , Expressão Gênica , Humanos , Fator de Transcrição Ikaros/metabolismo , Leucemia Mieloide Aguda/tratamento farmacológico , Proteína Meis1/genética , Fatores de Transcrição/genética
8.
Cancer Discov ; 7(2): 202-217, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27974415

RESUMO

Luminal breast cancers are typically estrogen receptor-positive and generally have the best prognosis. However, a subset of luminal tumors, namely luminal B cancers, frequently metastasize and recur. Unfortunately, the causal events that drive their progression are unknown, and therefore it is difficult to identify individuals who are likely to relapse and should receive escalated treatment. Here, we identify a bifunctional RasGAP tumor suppressor whose expression is lost in almost 50% of luminal B tumors. Moreover, we show that two RasGAP genes are concomitantly suppressed in the most aggressive luminal malignancies. Importantly, these genes cooperatively regulate two major oncogenic pathways, RAS and NF-κB, through distinct domains, and when inactivated drive the metastasis of luminal tumors in vivo Finally, although the cooperative effects on RAS drive invasion, NF-κB activation triggers epithelial-to-mesenchymal transition and is required for metastasis. Collectively, these studies reveal important mechanistic insight into the pathogenesis of luminal B tumors and provide functionally relevant prognostic biomarkers that may guide treatment decisions. SIGNIFICANCE: The lack of insight into mechanisms that underlie the aggressive behavior of luminal B breast cancers impairs treatment decisions and therapeutic advances. Here, we show that two RasGAP tumor suppressors are concomitantly suppressed in aggressive luminal B tumors and demonstrate that they drive metastasis by activating RAS and NF-κB. Cancer Discov; 7(2); 202-17. ©2016 AACR.See related commentary by Sears and Gray, p. 131This article is highlighted in the In This Issue feature, p. 115.


Assuntos
Neoplasias da Mama/patologia , Proteínas de Transporte/genética , NF-kappa B/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Proteínas Ativadoras de ras GTPase/genética , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Proteínas de Transporte/metabolismo , Linhagem Celular Tumoral , Progressão da Doença , Transição Epitelial-Mesenquimal , Feminino , Proteínas Ativadoras de GTPase , Humanos , Células MCF-7 , Camundongos , Mutação , Metástase Neoplásica , Transplante de Neoplasias , Transdução de Sinais , Proteínas Ativadoras de ras GTPase/metabolismo
9.
Cancer Cell ; 24(3): 365-78, 2013 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-24029233

RESUMO

RAS genes are commonly mutated in cancer; however, RAS mutations are rare in breast cancer, despite frequent hyperactivation of Ras and ERK. Here, we report that the RasGAP gene, RASAL2, functions as a tumor and metastasis suppressor. RASAL2 is mutated or suppressed in human breast cancer, and RASAL2 ablation promotes tumor growth, progression, and metastasis in mouse models. In human breast cancer, RASAL2 loss is associated with metastatic disease; low RASAL2 levels correlate with recurrence of luminal B tumors; and RASAL2 ablation promotes metastasis of luminal mouse tumors. Additional data reveal a broader role for RASAL2 inactivation in other tumor types. These studies highlight the expanding role of RasGAPs and reveal an alternative mechanism of activating Ras in cancer.


Assuntos
Proteínas de Transporte/genética , Neoplasias/genética , Neoplasias/patologia , Proteínas Supressoras de Tumor/genética , Proteínas Ativadoras de ras GTPase/genética , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Proteínas de Transporte/metabolismo , Linhagem Celular Tumoral , Movimento Celular/genética , Transformação Celular Neoplásica/genética , Modelos Animais de Doenças , Progressão da Doença , Feminino , Proteínas Ativadoras de GTPase , Genes p53 , Humanos , Camundongos , Camundongos Knockout , Mutação , Invasividade Neoplásica , Metástase Neoplásica , Neoplasias/metabolismo , Neoplasias/mortalidade , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Transplante Heterólogo , Proteínas Supressoras de Tumor/metabolismo , Proteínas Ativadoras de ras GTPase/metabolismo
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