RESUMO
Tumor cells must rewire nucleotide synthesis to satisfy the demands of unbridled proliferation. Meanwhile, they exhibit augmented reactive oxygen species (ROS) production which paradoxically damages DNA and free deoxy-ribonucleoside triphosphates (dNTPs). How these metabolic processes are integrated to fuel tumorigenesis remains to be investigated. MYC family oncoproteins coordinate nucleotide synthesis and ROS generation to drive the development of numerous cancers. We herein perform a Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-based functional screen targeting metabolic genes and identified nudix hydrolase 1 (NUDT1) as a MYC-driven dependency. Mechanistically, MYC orchestrates the balance of two metabolic pathways that act in parallel, the NADPH oxidase 4 (NOX4)-ROS pathway and the Polo like kinase 1 (PLK1)-NUDT1 nucleotide-sanitizing pathway. We describe LC-1-40 as a potent, on-target degrader that depletes NUDT1 in vivo. Administration of LC-1-40 elicits excessive nucleotide oxidation, cytotoxicity and therapeutic responses in patient-derived xenografts. Thus, pharmacological targeting of NUDT1 represents an actionable MYC-driven metabolic liability.
Assuntos
Nucleotídeos , Nudix Hidrolases , Humanos , Espécies Reativas de Oxigênio/metabolismo , Oxirredução , Nucleotídeos/metabolismoRESUMO
DHX15 has been implicated in RNA splicing and ribosome biogenesis, primarily functioning as an RNA helicase. To systematically assess the cellular role of DHX15, we conducted proteomic analysis to investigate the landscape of DHX15 interactome, and identified MYC as a binding partner. DHX15 co-localizes with MYC in cells and directly interacts with MYC in vitro. Importantly, DHX15 contributes to MYC protein stability at the post-translational level and independent of its RNA binding capacity. Mechanistic investigation reveals that DHX15 interferes the interaction between MYC and FBXW7, thereby preventing MYC polyubiquitylation and proteasomal degradation. Consequently, the abrogation of DHX15 drastically inhibits MYC-mediated transcriptional output. While DHX15 depletion blocks T cell development and leukemia cell survival as we recently reported, overexpression of MYC significantly rescues the phenotypic defects. These findings shed light on the essential role of DHX15 in mammalian cells and suggest that maintaining sufficient MYC expression is a significant contributor to DHX15-mediated cellular functions.
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Adaptation to low levels of oxygen (hypoxia) is a universal biological feature across metazoans. However, the unique mechanisms how different species sense oxygen deprivation remain unresolved. Here, we functionally characterize a novel long noncoding RNA (lncRNA), LOC105369301, which we termed hypoxia-induced lncRNA for polo-like kinase 1 (PLK1) stabilization (HILPS). HILPS exhibits appreciable basal expression exclusively in a wide variety of human normal and cancer cells and is robustly induced by hypoxia-inducible factor 1α (HIF1α). HILPS binds to PLK1 and sequesters it from proteasomal degradation. Stabilized PLK1 directly phosphorylates HIF1α and enhances its stability, constituting a positive feed-forward circuit that reinforces oxygen sensing by HIF1α. HILPS depletion triggers catastrophic adaptation defect during hypoxia in both normal and cancer cells. These findings introduce a mechanism that underlies the HIF1α identity deeply interconnected with PLK1 integrity and identify the HILPS-PLK1-HIF1α pathway as a unique oxygen-sensing axis in the regulation of human physiological and pathogenic processes.
Assuntos
RNA Longo não Codificante , Humanos , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Oxigênio , Transdução de Sinais , Hipóxia/genéticaRESUMO
RNA N6-methyladenosine (m6A) has been identified as the most common, abundant and conserved internal modification in RNA transcripts, especially within eukaryotic messenger RNAs (mRNAs). Accumulating evidence demonstrates that RNA m6A modification exploits a wide range of regulatory mechanisms to control gene expression in pathophysiological processes including cancer. Metabolic reprogramming has been widely recognized as a hallmark of cancer. Cancer cells obtain metabolic adaptation through a variety of endogenous and exogenous signaling pathways to promote cell growth and survival in the microenvironment with limited nutrient supply. Recent emerging evidence reveals reciprocal regulation between the m6A modification and disordered metabolic events in cancer cells, adding more complexity in the cellular network of metabolic rewiring. In this review, we summarize the most recent advances of how RNA methylation affects tumor metabolism and the feedback regulation of m6A modification by metabolic intermediates. We aim to highlight the important connection between RNA m6A modification and cancer metabolism, and expect that studise of RNA m6A and metabolic reprogramming will lead to greater understanding of cancer pathology.
RESUMO
RNA-binding proteins (RBP) have emerged as essential regulators that control gene expression and modulate multiple cancer traits. T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignancy derived from transformation of T-cell progenitors that normally undergo discrete steps of differentiation in the thymus. The implications of essential RBP during T-cell neoplastic transformation remain largely unclear. Systematic evaluation of RBP identifies RNA helicase DHX15, which facilitates the disassembly of the spliceosome and release of lariat introns, as a T-ALL dependency factor. Functional analysis using multiple murine T-ALL models demonstrates the essential importance of DHX15 in tumor cell survival and leukemogenesis. Moreover, single-cell transcriptomics reveals that DHX15 depletion in T-cell progenitors hinders burst proliferation during the transition from doublenegative to double-positive cells (CD4-CD8- to CD4+CD8+). Mechanistically, abrogation of DHX15 perturbs RNA splicing and leads to diminished levels of SLC7A6 and SLC38A5 transcripts due to intron retention, thereby suppressing glutamine import and mTORC1 activity. We further propose a DHX15 signature modulator drug ciclopirox and demonstrate that it has prominent anti-T-ALL efficacy. Collectively, our data highlight the functional contribution of DHX15 to leukemogenesis through regulation of established oncogenic pathways. These findings also suggest a promising therapeutic approach, i.e., splicing perturbation by targeting spliceosome disassembly, may achieve considerable anti-tumor efficacy.
Assuntos
Leucemia , RNA Helicases , Humanos , Animais , Camundongos , RNA Helicases/genética , RNA Helicases/metabolismo , Splicing de RNA , Spliceossomos/genética , Leucemia/metabolismo , Sistemas de Transporte de Aminoácidos Básicos/genética , Sistemas de Transporte de Aminoácidos Básicos/metabolismoRESUMO
Cyclin-dependent kinase 13 (CDK13) has been suggested to phosphorylate RNA polymerase II and is involved in transcriptional activation. However, whether CDK13 catalyzes other protein substrates and how CDK13 contributes to tumorigenesis remain largely unclear. We here identify key translation machinery components, 4E-BP1 and eIF4B, as novel CDK13 substrates. CDK13 directly phosphorylates 4E-BP1 at Thr46 and eIF4B at Ser422; genetically or pharmacologically inhibiting CDK13 disrupts mRNA translation. Polysome profiling analysis shows that MYC oncoprotein synthesis strictly depends on CDK13-regulated translation in colorectal cancer (CRC), and CDK13 is required for CRC cell proliferation. As mTORC1 is implicated in 4E-BP1 and eIF4B phosphorylation, inactivation of CDK13 in combination with the mTORC1 inhibitor rapamycin further dephosphorylates 4E-BP1 and eIF4B and blocks protein synthesis. As a result, dual inhibition of CDK13 and mTORC1 induces more profound tumor cell death. These findings clarify the pro-tumorigenic role of CDK13 by direct phosphorylation of translation initiation factors and enhancing protein synthesis. Therefore, therapeutic targeting of CDK13 alone or in combination with rapamycin may pave a new way for cancer treatment.
Assuntos
Proteínas de Ciclo Celular , Fosfoproteínas , Humanos , Fosfoproteínas/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Carcinogênese , Fosforilação , Sirolimo/farmacologia , Biossíntese de Proteínas , Proteína Quinase CDC2/metabolismoRESUMO
MYCN amplification in neuroblastoma leads to aberrant expression of MYCN oncoprotein, which binds active genes promoting transcriptional amplification. Yet, how MYCN coordinates transcription elongation to meet productive transcriptional amplification and which elongation machinery represents MYCN-driven vulnerability remain to be identified. We conducted a targeted screen of transcription elongation factors and identified the super elongation complex (SEC) as a unique vulnerability in MYCN-amplified neuroblastomas. MYCN directly binds EAF1 and recruits SEC to enhance processive transcription elongation. Depletion of EAF1 or AFF1/AFF4, another core subunit of SEC, leads to a global reduction in transcription elongation and elicits selective apoptosis of MYCN-amplified neuroblastoma cells. A combination screen reveals SEC inhibition synergistically potentiates the therapeutic efficacies of FDA-approved BCL-2 antagonist ABT-199, in part due to suppression of MCL1 expression, both in MYCN-amplified neuroblastoma cells and in patient-derived xenografts. These findings identify disruption of the MYCN-SEC regulatory axis as a promising therapeutic strategy in neuroblastoma.
Assuntos
Neuroblastoma , Proteínas Nucleares , Humanos , Proteína Proto-Oncogênica N-Myc/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Oncogênicas , Fatores de Elongação da Transcrição/genética , Fatores de Elongação da Transcrição/metabolismo , Neuroblastoma/genética , Neuroblastoma/metabolismo , Fatores de TranscriçãoRESUMO
Efforts to therapeutically target EZH2 have generally focused on inhibition of its methyltransferase activity, although it remains less clear whether this is the central mechanism whereby EZH2 promotes cancer. In the current study, we show that EZH2 directly interacts with both MYC family oncoproteins, MYC and MYCN, and promotes their stabilization in a methyltransferase-independent manner. By competing against the SCFFBW7 ubiquitin ligase to bind MYC and MYCN, EZH2 counteracts FBW7-mediated MYC(N) polyubiquitination and proteasomal degradation. Depletion, but not enzymatic inhibition, of EZH2 induces robust MYC(N) degradation and inhibits tumor cell growth in MYC(N) driven neuroblastoma and small cell lung carcinoma. Here, we demonstrate the MYC family proteins as global EZH2 oncogenic effectors and EZH2 pharmacologic degraders as potential MYC(N) targeted cancer therapeutics, pointing out that MYC(N) driven cancers may develop inherent resistance to the canonical EZH2 enzymatic inhibitors currently in clinical development.
Assuntos
Carcinoma de Células Pequenas , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Proteína Proto-Oncogênica N-Myc/metabolismo , Neuroblastoma , Carcinoma de Células Pequenas/tratamento farmacológico , Carcinoma de Células Pequenas/metabolismo , Linhagem Celular Tumoral , Sistemas de Liberação de Medicamentos , Humanos , Neuroblastoma/metabolismo , Neuroblastoma/terapia , Proteínas Oncogênicas/metabolismo , Carcinoma de Pequenas Células do Pulmão/tratamento farmacológico , Carcinoma de Pequenas Células do Pulmão/metabolismoRESUMO
Tumor cells must rewire cellular metabolism to satisfy the demands of unbridled growth and proliferation. How these metabolic processes are integrated to fuel cancer cell growth remains largely unknown. Deciphering the regulatory mechanisms is vital to develop targeted strategies for tumor-selective therapies. We herein performed an unbiased and functional siRNA screen against 96 deubiquitinases, which play indispensable roles in cancer and are emerging as therapeutic targets, and identified USP29 as a top candidate essential for metabolic reprogramming that support biosynthesis and survival in tumor cells. Integrated metabolic flux analysis and molecular investigation reveal that USP29 directly deubiquitinates and stabilizes MYC and HIF1α, two master regulators of metabolic reprogramming, enabling adaptive response of tumor cells in both normoxia and hypoxia. Systemic knockout of Usp29 depleted MYC and HIF1α in MYC-driven neuroblastoma and B cell lymphoma, inhibited critical metabolic targets and significantly prolonged survival of tumor-bearing mice. Strikingly, mice homozygous null for the Usp29 gene are viable, fertile, and display no gross phenotypic abnormalities. Altogether, these results demonstrate that USP29 selectively coordinates MYC and HIF1α to integrate metabolic processes critical for cancer cell growth, and therapeutic targeting of USP29, a potentially targetable enzyme, could create a unique vulnerability given deregulation of MYC and HIF1α frequently occurs in human cancers.
Assuntos
Subunidade alfa do Fator 1 Induzível por Hipóxia/química , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Linfoma de Células B/patologia , Neuroblastoma/patologia , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteases Específicas de Ubiquitina/metabolismo , Células A549 , Animais , Linhagem Celular Tumoral , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Técnicas de Inativação de Genes , Humanos , Linfoma de Células B/genética , Linfoma de Células B/metabolismo , Camundongos , Transplante de Neoplasias , Neuroblastoma/genética , Neuroblastoma/metabolismo , RNA Interferente Pequeno/farmacologia , Hipóxia Tumoral , Proteases Específicas de Ubiquitina/genética , UbiquitinaçãoRESUMO
Recombination activating genes 1 (Rag1) and Rag2 are expressed in immature lymphocytes and essential for generating the vast repertoire of antigen receptors. Yet, the mechanisms governing the transcription of Rag1 and Rag2 remain to be fully determined, particularly in thymocytes. Combining cDNA microarray and ChIP-seq analysis, we identify Rag1 and Rag2 as novel Notch1 transcriptional targets in acute T-cell lymphoblastic leukemia (T-ALL) cells. We further demonstrate that Notch1 transcriptional complexes directly bind the Rag1 and Rag2 locus in not only T-ALL but also primary double negative (DN) T-cell progenitors. Specifically, dimeric Notch1 transcriptional complexes activate Rag1 and Rag2 through a novel cis-element bearing a sequence-paired site (SPS). In T-ALL and DN cells, dimerization-defective Notch1 causes compromised Rag1 and Rag2 expression; conversely, dimerization-competent Notch1 achieves optimal upregulation of both. Collectively, these results reveal Notch1 dimerization-mediated transcription as one of the mechanisms for activating Rag1 and Rag2 expression in both primary and transformed thymocytes. Our data suggest a new role of Notch1 dimerization in compelling efficient TCRß rearrangements in DN progenitors during T-cell development.
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High-risk neuroblastoma remains therapeutically challenging to treat, and the mechanisms promoting disease aggression are poorly understood. Here, we show that elevated expression of dihydrolipoamide S-succinyltransferase (DLST) predicts poor treatment outcome and aggressive disease in patients with neuroblastoma. DLST is an E2 component of the α-ketoglutarate (αKG) dehydrogenase complex, which governs the entry of glutamine into the tricarboxylic acid cycle (TCA) for oxidative decarboxylation. During this irreversible step, αKG is converted into succinyl-CoA, producing NADH for oxidative phosphorylation (OXPHOS). Utilizing a zebrafish model of MYCN-driven neuroblastoma, we demonstrate that even modest increases in DLST expression promote tumor aggression, while monoallelic dlst loss impedes disease initiation and progression. DLST depletion in human MYCN-amplified neuroblastoma cells minimally affected glutamine anaplerosis and did not alter TCA cycle metabolites other than αKG. However, DLST loss significantly suppressed NADH production and impaired OXPHOS, leading to growth arrest and apoptosis of neuroblastoma cells. In addition, multiple inhibitors targeting the electron transport chain, including the potent IACS-010759 that is currently in clinical testing for other cancers, efficiently reduced neuroblastoma proliferation in vitro. IACS-010759 also suppressed tumor growth in zebrafish and mouse xenograft models of high-risk neuroblastoma. Together, these results demonstrate that DLST promotes neuroblastoma aggression and unveils OXPHOS as an essential contributor to high-risk neuroblastoma. SIGNIFICANCE: These findings demonstrate a novel role for DLST in neuroblastoma aggression and identify the OXPHOS inhibitor IACS-010759 as a potential therapeutic strategy for this deadly disease.
Assuntos
Aciltransferases/metabolismo , Neoplasias Encefálicas/metabolismo , Neuroblastoma/metabolismo , Fosforilação Oxidativa , Animais , Apoptose , Linhagem Celular Tumoral , Colágeno/química , Modelos Animais de Doenças , Combinação de Medicamentos , Feminino , Perfilação da Expressão Gênica , Células HEK293 , Humanos , Concentração Inibidora 50 , Complexo Cetoglutarato Desidrogenase/metabolismo , Laminina/química , Camundongos , Camundongos Endogâmicos BALB C , Invasividade Neoplásica , Transplante de Neoplasias , Oxigênio/metabolismo , Proteoglicanas/química , Interferência de RNA , Risco , Smegmamorpha , Resultado do Tratamento , Ácidos Tricarboxílicos/metabolismo , Peixe-ZebraRESUMO
T-cell acute lymphoblastic leukemias (T-ALLs) are aggressive and heterogeneous hematologic tumors resulting from the malignant transformation of T-cell progenitors. The major challenges in the treatments of T-ALL are dose-limiting toxicities of chemotherapeutics and drug resistance. Despite important progress in deciphering the genomic landscape of T-ALL, translation of these findings into effective targeted therapies remains largely unsuccessful. New targeted agents with significant antileukemic efficacy and less toxicity are in urgent need. We herein report that the expression of WEE1, a nuclear tyrosine kinase involved in cell cycle G2-M checkpoint signaling, is significantly elevated in T-ALL. Mechanistically, oncogenic MYC directly binds to the WEE1 promoter and activates its transcription. T-ALL cells particularly rely on the elevated WEE1 for cell viability. Pharmacological inhibition of WEE1 elicits global metabolic reprogramming which results in a marked suppression of aerobic glycolysis in T-ALL cells, leading to an increased dependency on glutaminolysis for cell survival. As such, dual targeting of WEE1 and glutaminase (GLS1) induces synergistic lethality in multiple T-ALL cell lines and shows great efficacy in T-ALL patient-derived xenografts. These findings provide mechanistic insights in the regulation of WEE1 kinase in T-ALL and suggest an additional vulnerability during WEE1 inhibitor treatments. In aggregate, we highlight a promising combination strategy of dual inhibition of cell cycle kinase and metabolic enzymes for T-ALL therapeutics.
Assuntos
Glutamina , Leucemia-Linfoma Linfoblástico de Células T Precursoras , Apoptose , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Humanos , Proteínas Nucleares/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Proteínas Tirosina Quinases/genéticaRESUMO
The MYC family oncoproteins are deregulated in more than 50 % of human cancers through a variety of mechanisms, such as gene amplification or translocation, super-enhancer activation, aberrant upstream signaling, and altered protein stability. As one of the major drivers in tumorigenesis, MYC regulates the expression of a large number of noncoding genes involved in multiple oncogenic processes. Noncoding RNAs, including miRNA, lncRNA, circRNA, rRNA and tRNA, are also deeply involved in the oncogenic MYC network by functioning as MYC regulators/effectors. In this review, we summarize representative studies depicting the crosstalk between oncogenic MYC and noncoding RNAs in carcinogenesis with the aim of providing potential implications for both basic science and clinical applications.
Assuntos
Biomarcadores Tumorais/metabolismo , Amplificação de Genes , Regulação Neoplásica da Expressão Gênica , Neoplasias/patologia , Proteínas Proto-Oncogênicas c-myc/genética , RNA Longo não Codificante/genética , Animais , Biomarcadores Tumorais/genética , Humanos , Neoplasias/genética , Neoplasias/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Transdução de SinaisRESUMO
Deregulation of v-myc avian myelocytomatosis viral oncogene homolog (MYC) occurs in a broad range of human cancers and often predicts poor prognosis and resistance to therapy. However, directly targeting oncogenic MYC remains unsuccessful, and indirectly inhibiting MYC emerges as a promising approach. Checkpoint kinase 1 (CHK1) is a protein kinase that coordinates the G2/M cell cycle checkpoint and protects cancer cells from excessive replicative stress. Using c-MYC-mediated T-cell acute lymphoblastic leukemia (T-acute lymphoblastic leukemia) and N-MYC-driven neuroblastoma as model systems, we reveal that both c-MYC and N-MYC directly bind to the CHK1 locus and activate its transcription. CHIR-124, a selective CHK1 inhibitor, impairs cell viability and induces remarkable synergistic lethality with mTOR inhibitor rapamycin in MYC-overexpressing cells. Mechanistically, rapamycin inactivates carbamoyl-phosphate synthetase 2, aspartate transcarbamoylase, and dihydroorotase (CAD), the essential enzyme for the first three steps of de novo pyrimidine synthesis, and deteriorates CHIR-124-induced replicative stress. We further demonstrate that dual treatments impede T-acute lymphoblastic leukemia and neuroblastoma progression in vivo. These results suggest simultaneous targeting of CHK1 and mTOR as a novel and powerful co-treatment modality for MYC-mediated tumors.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Quinase 1 do Ponto de Checagem/antagonistas & inibidores , Neuroblastoma/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Serina-Treonina Quinases TOR/antagonistas & inibidores , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linhagem Celular Tumoral , Quinase 1 do Ponto de Checagem/genética , Quinase 1 do Ponto de Checagem/metabolismo , Conjuntos de Dados como Assunto , Progressão da Doença , Sinergismo Farmacológico , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Camundongos , Proteína Proto-Oncogênica N-Myc/metabolismo , Neuroblastoma/genética , Neuroblastoma/mortalidade , Neuroblastoma/patologia , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Prognóstico , Proteínas Proto-Oncogênicas c-myc/metabolismo , Quinolinas/farmacologia , Quinolinas/uso terapêutico , Quinuclidinas/farmacologia , Quinuclidinas/uso terapêutico , Sirolimo/farmacologia , Sirolimo/uso terapêutico , Serina-Treonina Quinases TOR/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Cancer cells must rewire cellular metabolism to satisfy the demands of unbridled growth and proliferation. As such, most human cancers differ from normal counterpart tissues by a plethora of energetic and metabolic reprogramming. Transcription factors of the MYC family are deregulated in up to 70% of all human cancers through a variety of mechanisms. Oncogenic levels of MYC regulates almost every aspect of cellular metabolism, a recently revisited hallmark of cancer development. Meanwhile, unrestrained growth in response to oncogenic MYC expression creates dependency on MYC-driven metabolic pathways, which in principle provides novel targets for development of effective cancer therapeutics. In the current review, we summarize the significant progress made toward understanding how MYC deregulation fuels metabolic rewiring in malignant transformation.
Assuntos
Transformação Celular Neoplásica/metabolismo , Regulação Neoplásica da Expressão Gênica , Neoplasias/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Animais , Humanos , Neoplasias/terapiaRESUMO
Deregulation of MYC plays an essential role in T cell acute lymphoblastic leukemia (T-ALL), yet the mechanisms underlying its deregulation remain elusive. Herein, we identify a molecular mechanism responsible for reciprocal activation between Aurora B kinase (AURKB) and MYC. AURKB directly phosphorylates MYC at serine 67, counteracting GSK3ß-directed threonine 58 phosphorylation and subsequent FBXW7-mediated proteasomal degradation. Stabilized MYC, in concert with T cell acute lymphoblastic leukemia 1 (TAL1), directly activates AURKB transcription, constituting a positive feedforward loop that reinforces MYC-regulated oncogenic programs. Therefore, inhibitors of AURKB induce prominent MYC degradation concomitant with robust leukemia cell death. These findings reveal an AURKB-MYC regulatory circuit that underlies T cell leukemogenesis, and provide a rationale for therapeutic targeting of oncogenic MYC via AURKB inhibition.
Assuntos
Aurora Quinase B/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/imunologia , Linfócitos T/imunologia , Animais , Aurora Quinase A/genética , Aurora Quinase A/imunologia , Aurora Quinase B/imunologia , Linhagem Celular Tumoral , Proteína 7 com Repetições F-Box-WD/imunologia , Humanos , Camundongos , Fosforilação , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Linfócitos T/efeitos dos fármacos , Ativação Transcricional/efeitos dos fármacos , Ativação Transcricional/imunologia , Peixe-ZebraRESUMO
MYCN amplification in neuroblastoma predicts poor prognosis and resistance to therapy. Yet pharmacological strategies of direct MYC inhibition remain unsuccessful due to its "undruggable" protein structure. We herein developed a synthetic lethal screen against MYCN-amplified neuroblastomas using clinically approved therapeutic reagents. We performed a high-throughput screen, from a library of 938 FDA-approved drugs, for candidates that elicit synthetic lethal effects in MYC-driven neuroblastoma cells. The proteasome inhibitors, which are FDA approved for the first-line treatment of multiple myeloma, emerge as top hits to elicit MYC-mediated synthetic lethality. Proteasome inhibition activates the PERK-eIF2α-ATF4 axis in MYC-transformed cells and induces BAX-mediated apoptosis through ATF4-dependent NOXA and TRIB3 induction. A combination screen reveals the proteasome inhibitor bortezomib (BTZ) and the histone deacetylase (HDAC) inhibitor vorinostat (SAHA) concertedly induce dramatic cell death in part through synergistic activation of BAX. This combination causes marked tumor suppression in vivo, supporting dual proteasome/HDAC inhibition as a potential therapeutic approach for MYC-driven cancers. This FDA-approved drug screen with in vivo validation thus provides a rationale for clinical evaluation of bortezomib, alone or in combination with vorinostat, in MYC-driven neuroblastoma patients.
Assuntos
Antineoplásicos/farmacologia , Genes myc , Neuroblastoma/tratamento farmacológico , Complexo de Endopeptidases do Proteassoma/efeitos dos fármacos , Inibidores de Proteassoma/farmacologia , Fator 4 Ativador da Transcrição/metabolismo , Apoptose/efeitos dos fármacos , Bortezomib/farmacologia , Proteínas de Ciclo Celular/metabolismo , Fator de Iniciação 1 em Eucariotos/metabolismo , Ensaios de Triagem em Larga Escala , Humanos , Autoantígeno Ku/metabolismo , Neuroblastoma/enzimologia , Neuroblastoma/patologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Repressoras/metabolismo , Estados Unidos , United States Food and Drug Administration , Vorinostat/farmacologia , Proteína X Associada a bcl-2/metabolismo , eIF-2 Quinase/metabolismoRESUMO
T-acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignancy with complicated heterogeneity. Although expression profiling reveals common elevated genes in distinct T-ALL subtypes, little is known about their functional role(s) and regulatory mechanism(s). We here show that SHQ1, an H/ACA snoRNP assembly factor involved in snRNA pseudouridylation, is highly expressed in T-ALL. Mechanistically, oncogenic NOTCH1 directly binds to the SHQ1 promoter and activates its transcription. SHQ1 depletion induces T-ALL cell death in vitro and prolongs animal survival in murine T-ALL models. RNA-Seq reveals that SHQ1 depletion impairs widespread RNA splicing, and MYC is one of the most prominently downregulated genes due to inefficient splicing. MYC overexpression significantly rescues T-ALL cell death resulted from SHQ1 inactivation. We herein report a mechanism of NOTCH1-SHQ1-MYC axis in T-cell leukemogenesis. These findings not only shed light on the role of SHQ1 in RNA splicing and tumorigenesis, but also provide additional insight into MYC regulation.
Assuntos
Proteínas de Transporte/metabolismo , Regulação Leucêmica da Expressão Gênica , Leucemia de Células T/genética , Leucemia de Células T/patologia , Splicing de RNA/genética , Animais , Carcinogênese/metabolismo , Carcinogênese/patologia , Proteínas de Transporte/genética , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Técnicas de Inativação de Genes , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos Endogâmicos C57BL , Modelos Biológicos , Ligação Proteica , Precursores de RNA/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptor Notch1/metabolismoRESUMO
The MYC family oncogene is deregulated in >50% of human cancers, and this deregulation is frequently associated with poor prognosis and unfavorable patient survival. Myc has a central role in almost every aspect of the oncogenic process, orchestrating proliferation, apoptosis, differentiation, and metabolism. Although Myc inhibition would be a powerful approach for the treatment of many types of cancers, direct targeting of Myc has been a challenge for decades owing to its "undruggable" protein structure. Hence, alternatives to Myc blockade have been widely explored to achieve desirable anti-tumor effects, including Myc/Max complex disruption, MYC transcription and/or translation inhibition, and Myc destabilization as well as the synthetic lethality associated with Myc overexpression. In this review, we summarize the latest advances in targeting oncogenic Myc, particularly for cancer therapeutic purposes.
RESUMO
Aggressive NK-cell leukemia (ANKL) is a rare form of NK cell neoplasm that is more prevalent among people from Asia and Central and South America. Patients usually die within days to months, even after receiving prompt therapeutic management. Here we performed the first comprehensive study of ANKL by integrating whole genome, transcriptome and targeted sequencing, cytokine array as well as functional assays. Mutations in the JAK-STAT pathway were identified in 48% (14/29) of ANKL patients, while the extracellular STAT3 stimulator IL10 was elevated by an average of 56-fold (P < 0.0001) in the plasma of all patients examined. Additional frequently mutated genes included TP53 (34%), TET2 (28%), CREBBP (21%) and MLL2 (21%). Patient NK leukemia cells showed prominent activation of STAT3 phosphorylation, MYC expression and transcriptional activities in multiple metabolic pathways. Functionally, STAT3 activation and MYC expression were critical for the proliferation and survival of ANKL cells. STAT signaling regulated the MYC transcription program, and both STAT signaling and MYC transcription were required to maintain the activation of nucleotide synthesis and glycolysis. Collectively, the JAK-STAT pathway represents a major target for genomic alterations and IL10 stimulation in ANKL. This newly discovered JAK/STAT-MYC-biosynthesis axis may provide opportunities for the development of novel therapeutic strategies in treating this subtype of leukemia.