RESUMO
T- and NK-cell lymphomas (TCL) are a heterogenous group of lymphoid malignancies with poor prognosis. In contrast to B-cell and myeloid malignancies, there are few preclinical models of TCLs, which has hampered the development of effective therapeutics. Here we establish and characterize preclinical models of TCL. We identify multiple vulnerabilities that are targetable with currently available agents (e.g., inhibitors of JAK2 or IKZF1) and demonstrate proof-of-principle for biomarker-driven therapies using patient-derived xenografts (PDXs). We show that MDM2 and MDMX are targetable vulnerabilities within TP53-wild-type TCLs. ALRN-6924, a stapled peptide that blocks interactions between p53 and both MDM2 and MDMX has potent in vitro activity and superior in vivo activity across 8 different PDX models compared to the standard-of-care agent romidepsin. ALRN-6924 induced a complete remission in a patient with TP53-wild-type angioimmunoblastic T-cell lymphoma, demonstrating the potential for rapid translation of discoveries from subtype-specific preclinical models.
Assuntos
Antineoplásicos/farmacologia , Regulação Neoplásica da Expressão Gênica , Linfoma Extranodal de Células T-NK/tratamento farmacológico , Linfoma de Células T/tratamento farmacológico , Proteínas Nucleares/genética , Peptídeos/farmacologia , Proteínas Proto-Oncogênicas c-mdm2/genética , Proteínas Proto-Oncogênicas/genética , Proteína Supressora de Tumor p53/genética , Animais , Proteínas de Ciclo Celular , Depsipeptídeos/farmacologia , Avaliação Pré-Clínica de Medicamentos , Humanos , Fator de Transcrição Ikaros/antagonistas & inibidores , Fator de Transcrição Ikaros/genética , Fator de Transcrição Ikaros/metabolismo , Imidazolinas/farmacologia , Janus Quinase 2/antagonistas & inibidores , Janus Quinase 2/genética , Janus Quinase 2/metabolismo , Linfoma Extranodal de Células T-NK/genética , Linfoma Extranodal de Células T-NK/metabolismo , Linfoma Extranodal de Células T-NK/patologia , Linfoma de Células T/genética , Linfoma de Células T/metabolismo , Linfoma de Células T/patologia , Camundongos , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/metabolismo , Ligação Proteica/efeitos dos fármacos , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-mdm2/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Indução de Remissão , Transdução de Sinais , Proteína Supressora de Tumor p53/antagonistas & inibidores , Proteína Supressora de Tumor p53/metabolismo , Sequenciamento do Exoma , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The formation, distribution, and maintenance of functional mitochondria are achieved through dynamic processes that depend strictly on the transcription of nuclear genes encoding mitochondrial proteins. A large number of these mitochondrial genes contain binding sites for the transcription factor Yin Yang 1 (YY1) in their proximal promoters, but the physiological relevance is unknown. We report here that skeletal-muscle-specific YY1 knockout (YY1mKO) mice have severely defective mitochondrial morphology and oxidative function associated with exercise intolerance, signs of mitochondrial myopathy, and short stature. Gene set enrichment analysis (GSEA) revealed that the top pathways downregulated in YY1mKO mice were assigned to key metabolic and regulatory mitochondrial genes. This analysis was consistent with a profound decrease in the level of mitochondrial proteins and oxidative phosphorylation (OXPHOS) bioenergetic function in these mice. In contrast to the finding for wild-type mice, inactivation of the mammalian target of rapamycin (mTOR) did not suppress mitochondrial genes in YY1mKO mice. Mechanistically, mTOR-dependent phosphorylation of YY1 resulted in a strong interaction between YY1 and the transcriptional coactivator peroxisome proliferator-activated receptor gamma coactivator 1α (PGC1α), a major regulator of mitochondrial function. These results underscore the important role of YY1 in the maintenance of mitochondrial function and explain how its inactivation might contribute to exercise intolerance and mitochondrial myopathies.
Assuntos
Mitocôndrias/metabolismo , Fator de Transcrição YY1/genética , Alelos , Animais , Metabolismo Energético/fisiologia , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Knockout , Mitocôndrias Musculares/metabolismo , Fosforilação Oxidativa , Fenótipo , Serina-Treonina Quinases TOR/metabolismo , Fatores de Transcrição/metabolismo , Fator de Transcrição YY1/fisiologiaRESUMO
Transcriptional complexes that contain peroxisome-proliferator-activated receptor coactivator (PGC)-1alpha control mitochondrial oxidative function to maintain energy homeostasis in response to nutrient and hormonal signals. An important component in the energy and nutrient pathways is mammalian target of rapamycin (mTOR), a kinase that regulates cell growth, size and survival. However, it is unknown whether and how mTOR controls mitochondrial oxidative activities. Here we show that mTOR is necessary for the maintenance of mitochondrial oxidative function. In skeletal muscle tissues and cells, the mTOR inhibitor rapamycin decreased the gene expression of the mitochondrial transcriptional regulators PGC-1alpha, oestrogen-related receptor alpha and nuclear respiratory factors, resulting in a decrease in mitochondrial gene expression and oxygen consumption. Using computational genomics, we identified the transcription factor yin-yang 1 (YY1) as a common target of mTOR and PGC-1alpha. Knockdown of YY1 caused a significant decrease in mitochondrial gene expression and in respiration, and YY1 was required for rapamycin-dependent repression of those genes. Moreover, mTOR and raptor interacted with YY1, and inhibition of mTOR resulted in a failure of YY1 to interact with and be coactivated by PGC-1alpha. We have therefore identified a mechanism by which a nutrient sensor (mTOR) balances energy metabolism by means of the transcriptional control of mitochondrial oxidative function. These results have important implications for our understanding of how these pathways might be altered in metabolic diseases and cancer.