RESUMO
Impairment of protein phosphatases, including the family of serine/threonine phosphatases designated PP2A, is essential for the pathogenesis of many diseases, including cancer. The ability of PP2A to dephosphorylate hundreds of proteins is regulated by over 40 specificity-determining regulatory "B" subunits that compete for assembly and activation of heterogeneous PP2A heterotrimers. Here, we reveal how a small molecule, DT-061, specifically stabilizes the B56α-PP2A holoenzyme in a fully assembled, active state to dephosphorylate selective substrates, such as its well-known oncogenic target, c-Myc. Our 3.6 Å structure identifies molecular interactions between DT-061 and all three PP2A subunits that prevent dissociation of the active enzyme and highlight inherent mechanisms of PP2A complex assembly. Thus, our findings provide fundamental insights into PP2A complex assembly and regulation, identify a unique interfacial stabilizing mode of action for therapeutic targeting, and aid in the development of phosphatase-based therapeutics tailored against disease specific phospho-protein targets.
Assuntos
Proteína Fosfatase 2/metabolismo , Sequência de Aminoácidos , Animais , Linhagem Celular Tumoral , Ativadores de Enzimas/metabolismo , Células HEK293 , Xenoenxertos , Humanos , Masculino , Camundongos , Camundongos Nus , Modelos Moleculares , Complexos Multiproteicos/metabolismo , Proteína Fosfatase 2/química , Subunidades ProteicasRESUMO
Non-covalent complexes of glycolytic enzymes, called metabolons, were postulated in the 1970s, but the concept has been controversial. Here we show that a c-Myc-responsive long noncoding RNA (lncRNA) that we call glycoLINC (gLINC) acts as a backbone for metabolon formation between all four glycolytic payoff phase enzymes (PGK1, PGAM1, ENO1, and PKM2) along with lactate dehydrogenase A (LDHA). The gLINC metabolon enhances glycolytic flux, increases ATP production, and enables cell survival under serine deprivation. Furthermore, gLINC overexpression in cancer cells promotes xenograft growth in mice fed a diet deprived of serine, suggesting that cancer cells employ gLINC during metabolic reprogramming. We propose that gLINC makes a functional contribution to cancer cell adaptation and provide the first example of a lncRNA-facilitated metabolon.
Assuntos
Biomarcadores Tumorais/metabolismo , Proteínas de Transporte/metabolismo , Proteínas de Ligação a DNA/metabolismo , Glicólise , Proteínas de Membrana/metabolismo , Neoplasias/enzimologia , Fosfoglicerato Quinase/metabolismo , Fosfoglicerato Mutase/metabolismo , Fosfopiruvato Hidratase/metabolismo , RNA Longo não Codificante/metabolismo , Hormônios Tireóideos/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Biomarcadores Tumorais/genética , Proteínas de Transporte/genética , Proliferação de Células , Proteínas de Ligação a DNA/genética , Feminino , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Células HeLa , Células Hep G2 , Humanos , L-Lactato Desidrogenase/genética , L-Lactato Desidrogenase/metabolismo , Proteínas de Membrana/genética , Camundongos Nus , Complexos Multienzimáticos , Neoplasias/genética , Neoplasias/patologia , Fosfoglicerato Quinase/genética , Fosfoglicerato Mutase/genética , Fosfopiruvato Hidratase/genética , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , RNA Longo não Codificante/genética , Serina/deficiência , Hormônios Tireóideos/genética , Carga Tumoral , Proteínas Supressoras de Tumor/genética , Proteínas de Ligação a Hormônio da TireoideRESUMO
Cancer-specific TERT promoter mutations have been linked to the reactivation of epigenetically silenced TERT gene by creating de novo binding motifs for E-Twenty-Six transcription factors, especially GABPA. How these mutations switch on TERT from epigenetically repressed states to expressed states have not been defined. Here, we revealed that EGFR activation induces ERK1/2-dependent phosphorylation of argininosuccinate lyase (ASL) at Ser417 (S417), leading to interactions between ASL and GABPA at the mutant regions of TERT promoters. The ASL-generated fumarate inhibits KDM5C, leading to enhanced trimethylation of histone H3 Lys4 (H3K4me3), which in turn promotes the recruitment of c-Myc to TERT promoters for TERT expression. Expression of ASL S417A, which abrogates its binding with GABPA, results in reduced TERT expression, inhibited telomerase activity, shortened telomere length, and impaired brain tumor growth in mice. This study reveals an unrecognized mechanistic insight into epigenetically activation of mutant TERT promoters where GABPA-interacted ASL plays an instrumental role.
Assuntos
Glioblastoma , Telomerase , Animais , Camundongos , Argininossuccinato Liase/genética , Argininossuccinato Liase/metabolismo , Linhagem Celular Tumoral , Receptores ErbB/genética , Fumaratos , Regulação Neoplásica da Expressão Gênica , Glioblastoma/genética , Histonas/genética , Histonas/metabolismo , Mutação , Telomerase/genética , Telomerase/metabolismo , Telômero/metabolismo , Encurtamento do Telômero , Fatores de Transcrição/metabolismo , Regiões Promotoras GenéticasRESUMO
Activated CD8+ T lymphocytes differentiate into heterogeneous subsets. Using super-resolution imaging, we found that prior to the first division, dynein-dependent vesicular transport polarized active TORC1 toward the microtubule-organizing center (MTOC) at the proximal pole. This active TORC1 was physically associated with active eIF4F, required for the translation of c-myc mRNA. As a consequence, c-myc-translating polysomes polarized toward the cellular pole proximal to the immune synapse, resulting in localized c-myc translation. Upon division, the TORC1-eIF4A complex preferentially sorted to the proximal daughter cell, facilitating asymmetric c-Myc synthesis. Transient disruption of eIF4A activity at first division skewed long-term cell fate trajectories to memory-like function. Using a genetic barcoding approach, we found that first-division sister cells often displayed differences in transcriptional profiles that largely correlated with c-Myc and TORC1 target genes. Our findings provide mechanistic insights as to how distinct T cell fate trajectories can be established during the first division.
Assuntos
Linfócitos T CD8-Positivos , Fator de Iniciação 4F em Eucariotos , Diferenciação Celular , Ativação Linfocitária , Alvo Mecanístico do Complexo 1 de Rapamicina/genéticaRESUMO
The evolutionarily related deubiquitinating enzymes (DUBs) USP25 and USP28 comprise an identical overall domain architecture but are functionally non-redundant: USP28 stabilizes c-MYC and other nuclear proteins, and USP25 regulates inflammatory TRAF signaling. We here compare molecular features of USP25 and USP28. Active enzymes form distinctively shaped dimers, with a dimerizing insertion spatially separating independently active catalytic domains. In USP25, but not USP28, two dimers can form an autoinhibited tetramer, where a USP25-specific, conserved insertion sequence blocks ubiquitin binding. In full-length enzymes, a C-terminal domain with a previously unknown fold has no impact on oligomerization, but N-terminal regions affect the dimer-tetramer equilibrium in vitro. We confirm oligomeric states of USP25 and USP28 in cells and show that modulating oligomerization affects substrate stabilization in accordance with in vitro activity data. Our work highlights how regions outside of the catalytic domain enable a conceptually intriguing interplay of DUB oligomerization and activity.
Assuntos
Inflamação/genética , Conformação Proteica , Ubiquitina Tiolesterase/genética , Sequência de Aminoácidos/genética , Domínio Catalítico/genética , Enzimas Desubiquitinantes/química , Enzimas Desubiquitinantes/genética , Humanos , Inflamação/patologia , Mutação/genética , Ligação Proteica/genética , Domínios Proteicos/genética , Multimerização Proteica/genética , Proteínas Proto-Oncogênicas c-myb/química , Proteínas Proto-Oncogênicas c-myb/genética , Transdução de Sinais/genética , Especificidade por Substrato , Peptídeos e Proteínas Associados a Receptores de Fatores de Necrose Tumoral/genética , Ubiquitina/genética , Ubiquitina Tiolesterase/químicaRESUMO
Androgen receptor (AR) is a main driver for castration-resistant prostate cancer (CRPC). c-Myc is an oncogene underlying prostate tumorigenesis. Here, we find that the deubiquitinase USP11 targets both AR and c-Myc in prostate cancer (PCa). USP11 expression was up-regulated in metastatic PCa and CRPC. USP11 knockdown (KD) significantly inhibited PCa cell growth. Our RNA-seq studies revealed AR and c-Myc as the top transcription factors altered after USP11 KD. ChIP-seq analysis showed that either USP11 KD or replacement of endogenous USP11 with a catalytic-inactive USP11 mutant significantly decreased chromatin binding by AR and c-Myc. We find that USP11 employs two mechanisms to up-regulate AR and c-Myc levels: namely, deubiquitination of AR and c-Myc proteins to increase their stability and deubiquitination of H2A-K119Ub, a repressive histone mark, on promoters of AR and c-Myc genes to increase their transcription. AR and c-Myc reexpression in USP11-KD PCa cells partly rescued cell growth defects. Thus, our studies reveal a tumor-promoting role for USP11 in aggressive PCa through upregulation of AR and c-Myc activities and support USP11 as a potential target against PCa.
Assuntos
Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Neoplasias da Próstata , Proteínas Proto-Oncogênicas c-myc , Receptores Androgênicos , Tioléster Hidrolases , Humanos , Masculino , Linhagem Celular Tumoral , Proliferação de Células/genética , Histonas/metabolismo , Regiões Promotoras Genéticas/genética , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Neoplasias da Próstata/metabolismo , Neoplasias de Próstata Resistentes à Castração/genética , Neoplasias de Próstata Resistentes à Castração/metabolismo , Neoplasias de Próstata Resistentes à Castração/patologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Receptores Androgênicos/metabolismo , Receptores Androgênicos/genética , Tioléster Hidrolases/metabolismo , Tioléster Hidrolases/genética , Ubiquitinação , Regulação para CimaRESUMO
Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death. HCC incidence is on the rise, while treatment options remain limited. Thus, a better understanding of the molecular pathways involved in HCC development has become a priority to guide future therapies. While previous studies implicated the Activator Protein-1 (AP-1) (Fos/Jun) transcription factor family members c-Fos and c-Jun in HCC formation, the contribution of Fos-related antigens (Fra-) 1 and 2 is unknown. Here, we show that hepatocyte-restricted expression of a single chain c-Jun~Fra-2 protein, which functionally mimics the c-Jun/Fra-2 AP-1 dimer, results in spontaneous HCC formation in c-Jun~Fra-2hep mice. Several hallmarks of human HCC, such as cell cycle dysregulation and the expression of HCC markers are observed in liver tumors arising in c-Jun~Fra-2hep mice. Tumorigenesis occurs in the context of mild inflammation, low-grade fibrosis, and Pparγ-driven dyslipidemia. Subsequent analyses revealed increased expression of c-Myc, evidently under direct regulation by AP-1 through a conserved distal 3' enhancer. Importantly, c-Jun~Fra-2-induced tumors revert upon switching off transgene expression, suggesting oncogene addiction to the c-Jun~Fra-2 transgene. Tumors escaping reversion maintained c-Myc and c-Myc target gene expression, likely due to increased c-Fos. Interfering with c-Myc in established tumors using the Bromodomain and Extra-Terminal motif inhibitor JQ-1 diminished liver tumor growth in c-Jun~Fra-2 mutant mice. Thus, our data establish c-Jun~Fra-2hep mice as a model to study liver tumorigenesis and identify the c-Jun/Fra-2-Myc interaction as a potential target to improve HCC patient stratification and/or therapy.
Assuntos
Carcinoma Hepatocelular , Antígeno 2 Relacionado a Fos , Neoplasias Hepáticas , Proteínas Proto-Oncogênicas c-fos , Proteínas Proto-Oncogênicas c-jun , Proteínas Proto-Oncogênicas c-myc , Fator de Transcrição AP-1 , Animais , Fator de Transcrição AP-1/metabolismo , Fator de Transcrição AP-1/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Camundongos , Proteínas Proto-Oncogênicas c-fos/metabolismo , Proteínas Proto-Oncogênicas c-fos/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Proteínas Proto-Oncogênicas c-jun/metabolismo , Antígeno 2 Relacionado a Fos/metabolismo , Antígeno 2 Relacionado a Fos/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Humanos , Hepatócitos/metabolismo , Multimerização Proteica , Regulação Neoplásica da Expressão Gênica , Camundongos TransgênicosRESUMO
The limited efficacy of the current antitumor microenvironment strategies is due in part to the poor understanding of the roles and relative contributions of the various tumor stromal cells to tumor development. Here, we describe a versatile in vivo anthrax toxin protein delivery system allowing for the unambiguous genetic evaluation of individual tumor stromal elements in cancer. Our reengineered tumor-selective anthrax toxin exhibits potent antiproliferative activity by disrupting ERK signaling in sensitive cells. Since this activity requires the surface expression of the capillary morphogenesis protein-2 (CMG2) toxin receptor, genetic manipulation of CMG2 expression using our cell-type-specific CMG2 transgenic mice allows us to specifically define the role of individual tumor stromal cell types in tumor development. Here, we established mice with CMG2 only expressed in tumor endothelial cells (ECs) and determined the specific contribution of tumor stromal ECs to the toxin's antitumor activity. Our results demonstrate that disruption of ERK signaling only within tumor ECs is sufficient to halt tumor growth. We discovered that c-Myc is a downstream effector of ERK signaling and that the MEK-ERK-c-Myc central metabolic axis in tumor ECs is essential for tumor progression. As such, disruption of ERK-c-Myc signaling in host-derived tumor ECs by our tumor-selective anthrax toxins explains their high efficacy in solid tumor therapy.
Assuntos
Células Endoteliais , Neoplasias , Camundongos , Animais , Células Endoteliais/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Receptores de Peptídeos/genética , Receptores de Peptídeos/metabolismo , Transdução de Sinais , Antígenos de Bactérias/metabolismo , Neoplasias/genética , Microambiente TumoralRESUMO
T cell activation stimulates substantially increased protein synthesis activity to accumulate sufficient biomass for cell proliferation. The protein synthesis is fueled by the amino acids transported from the environment. Steroid nuclear receptor coactivator 2 (SRC2) is a member of a family of transcription coactivators. Here, we show that SRC2 recruited by c-Myc enhances CD4+ T cell activation to stimulate immune responses via upregulation of amino acid transporter Slc7a5. Mice deficient of SRC2 in T cells (SRC2fl/fl/CD4Cre) are resistant to the induction of experimental autoimmune encephalomyelitis (EAE) and susceptible to Citrobacter rodentium (C. rodentium) infection. Adoptive transfer of naive CD4+ T cells from SRC2fl/fl/CD4Cre mice fails to elicit EAE and colitis in Rag1/ recipients. Further, CD4+ T cells from SRC2fl/fl/CD4Cre mice display defective T cell proliferation, cytokine production, and differentiation both in vitro and in vivo. Mechanically, SRC2 functions as a coactivator to work together with c-Myc to stimulate the expression of amino acid transporter Slc7a5 required for T cell activation. Slc7a5 fails to be up-regulated in CD4+ T cells from SRC2fl/fl/CD4Cre mice, and forced expression of Slc7a5 rescues proliferation, cytokine production, and the ability of SRC2fl/fl/CD4Cre CD4+ T cells to induce EAE. Therefore, SRC2 is essential for CD4+ T cell activation and, thus, a potential drug target for controlling CD4+ T cell-mediated autoimmunity.
Assuntos
Encefalomielite Autoimune Experimental , Linfócitos T , Animais , Camundongos , Linfócitos T CD4-Positivos , Citocinas/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Coativador 2 de Receptor Nuclear/metabolismo , Regulação para CimaRESUMO
RNA-binding motif protein 10 (RBM10) is a frequently mutated tumor suppressor in lung adenocarcinoma (LUAD). Yet, it remains unknown whether cancer-derived mutant RBM10 compromises its tumor suppression function and, if so, the molecular insight of the underlying mechanisms. Here, we show that wild-type RBM10 suppresses lung cancer cell growth and proliferation by inactivating c-Myc that is essential for cancer cell survival. RBM10 directly binds to c-Myc and promotes c-Myc's ubiquitin-dependent degradation, while RBM10 knockdown leads to the induction of c-Myc level and activity. This negative action on c-Myc is further boosted by ribosomal proteins (RPs) uL18 (RPL5) and uL5 (RPL11) via their direct binding to RBM10. Cancer-derived mutant RBM10-I316F fails to bind to uL18 and uL5 and to inactivate c-Myc, thus incapable of suppressing tumorigenesis. Our findings uncover RBM10 as a pivotal c-Myc repressor by cooperating with uL18 and uL5 in lung cancer cells, as its failure to do so upon mutation favors tumorigenesis.
Assuntos
Neoplasias Pulmonares , Proteínas Proto-Oncogênicas c-myc , Proteínas de Ligação a RNA , Proteínas Ribossômicas , Humanos , Carcinogênese , Proliferação de Células/genética , Transformação Celular Neoplásica , Neoplasias Pulmonares/genética , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/metabolismo , Motivos de Ligação ao RNA , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismoRESUMO
Mutations in PKD1 and PKD2 are the leading cause of autosomal dominant polycystic kidney disease (ADPKD). In this issue of Genes & Development, a report by Cai and colleagues (pp. 781-793) reveals new insight into the molecular basis by which PKD1 deficiency leads to cystic kidney pathogenesis. By using extensive mouse genetic analyses coupled with in vitro cystic assays, the investigators delineate a RhoA-YAP-c-Myc signaling axis as a key downstream from PKD1 deficiency in ADPKD pathogenesis. Their findings provide evidence that the Hippo pathway could be a potential target for treating ADPKD.
Assuntos
Doenças Renais Policísticas , Rim Policístico Autossômico Dominante , Proteínas Adaptadoras de Transdução de Sinal , Animais , Proteínas de Ciclo Celular , Camundongos , Mutação , Fosfoproteínas , Transdução de Sinais , Canais de Cátion TRPP/genética , Proteínas de Sinalização YAP , Proteína rhoA de Ligação ao GTPRESUMO
Autosomal dominant polycystic kidney disease (ADPKD) is an inherited disorder caused by mutations in PKD1 or PKD2 and affects one in 500-1000 humans. Limited treatment is currently available for ADPKD. Here we identify the Hippo signaling effector YAP and its transcriptional target, c-Myc, as promoters of cystic kidney pathogenesis. While transgenic overexpression of YAP promotes proliferation and tubule dilation in mouse kidneys, loss of YAP/TAZ or c-Myc suppresses cystogenesis in a mouse ADPKD model resulting from Pkd1 deficiency. Through a comprehensive kinase inhibitor screen based on a novel three-dimensional (3D) culture of Pkd1 mutant mouse kidney cells, we identified a signaling pathway involving the RhoGEF (guanine nucleotide exchange factor) LARG, the small GTPase RhoA, and the RhoA effector Rho-associated kinase (ROCK) as a critical signaling module between PKD1 and YAP. Further corroborating its physiological importance, inhibition of RhoA signaling suppresses cystogenesis in 3D culture of Pkd1 mutant kidney cells as well as Pkd1 mutant mouse kidneys in vivo. Taken together, our findings implicate the RhoA-YAP-c-Myc signaling axis as a critical mediator and potential drug target in ADPKD.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Rim/fisiopatologia , Fosfoproteínas/metabolismo , Doenças Renais Policísticas/genética , Doenças Renais Policísticas/fisiopatologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , Transdução de Sinais , Proteínas rho de Ligação ao GTP/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Proteínas de Ciclo Celular , Linhagem Celular , Células Cultivadas , Modelos Animais de Doenças , Células HEK293 , Humanos , Rim/citologia , Rim/patologia , Camundongos , Fosfoproteínas/genética , Doenças Renais Policísticas/patologia , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas de Sinalização YAP , Proteínas rho de Ligação ao GTP/genética , Proteína rhoA de Ligação ao GTPRESUMO
Activating JAK2 point mutations are implicated in the pathogenesis of myeloid and lymphoid malignancies, including high-risk B-cell acute lymphoblastic leukemia (B-ALL). In preclinical studies, treatment of JAK2 mutant leukemias with type I JAK2 inhibitors (e.g., Food and Drug Administration [FDA]-approved ruxolitinib) provided limited single-agent responses, possibly due to paradoxical JAK2Y1007/1008 hyperphosphorylation induced by these agents. To determine the importance of mutant JAK2 in B-ALL initiation and maintenance, we developed unique genetically engineered mouse models of B-ALL driven by overexpressed Crlf2 and mutant Jak2, recapitulating the genetic aberrations found in human B-ALL. While expression of mutant Jak2 was necessary for leukemia induction, neither its continued expression nor enzymatic activity was required to maintain leukemia survival and rapid proliferation. CRLF2/JAK2 mutant B-ALLs with sustained depletion or pharmacological inhibition of JAK2 exhibited enhanced expression of c-Myc and prominent up-regulation of c-Myc target genes. Combined indirect targeting of c-Myc using the BET bromodomain inhibitor JQ1 and direct targeting of JAK2 with ruxolitinib potently killed JAK2 mutant B-ALLs.
Assuntos
Janus Quinase 2/genética , Janus Quinase 2/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/fisiopatologia , Animais , Antineoplásicos/farmacologia , Azepinas/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Humanos , Masculino , Camundongos , Mutação , Nitrilas , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Pirazóis/farmacologia , Pirazóis/uso terapêutico , Pirimidinas , Interferência de RNA , Receptores de Citocinas/genética , Transcriptoma , Triazóis/farmacologiaRESUMO
Our previous studies determined that elevating SOX2 in a wide range of tumor cells leads to a reversible state of tumor growth arrest. Efforts to understand how tumor cell growth is inhibited led to the discovery of a SOX2:MYC axis that is responsible for downregulating c-MYC (MYC) when SOX2 is elevated. Although we had determined that elevating SOX2 downregulates MYC transcription, the mechanism responsible was not determined. Given the challenges of targeting MYC clinically, we set out to identify how elevating SOX2 downregulates MYC transcription. In this study, we focused on the MYC promoter region and an upstream region of the MYC locus that contains a MYC super-enhancer encompassing five MYC enhancers and which is associated with several cancers. Here we report that BRD4 and p300 associate with each of the MYC enhancers in the upstream MYC super-enhancer as well as the MYC promoter region and that elevating SOX2 decreases the recruitment of BRD4 and p300 to these sites. Additionally, we determined that elevating SOX2 leads to increases in the association of SOX2 and H3K27me3 within the MYC super-enhancer and the promoter region of MYC. Importantly, we conclude that the increases in SOX2 within the MYC super-enhancer precipitate a cascade of events that culminates in the repression of MYC transcription. Together, our studies identify a novel molecular mechanism able to regulate MYC transcription in two distinctly different tumor types and provide new mechanistic insights into the molecular interrelationships between two master regulators, SOX2 and MYC, widely involved in multiple cancers.
RESUMO
Pathogen type 3 secretion systems (T3SS) manipulate host cell pathways by directly delivering effector proteins into host cells. In Vibrio parahaemolyticus, the leading cause of bacterial seafood-borne diarrheal disease, we showed that a T3SS effector, VgpA, localizes to the host cell nucleolus where it binds Epstein-Barr virus nuclear antigen 1-binding protein 2 (EBP2). An amino acid substitution in VgpA (VgpAL10A ) did not alter its translocation to the nucleus but abolished the effector's capacity to interact with EBP2. VgpA-EBP2 interaction led to the re-localization of c-Myc to the nucleolus and increased cellular rRNA expression and proliferation of cultured cells. The VgpA-EBP2 interaction elevated EBP2's affinity for c-Myc and prolonged the oncoprotein's half-life. Studies in infant rabbits demonstrated that VgpA is translocated into intestinal epithelial cells, where it interacts with EBP2 and leads to nucleolar re-localization of c-Myc. Moreover, the in vivo VgpA-EBP2 interaction during infection led to proliferation of intestinal cells and heightened V. parahaemolyticus' colonization and virulence. These observations suggest that direct effector stimulation of a c-Myc controlled host cell growth program can contribute to pathogenesis.
Assuntos
Proteínas de Bactérias/metabolismo , Nucléolo Celular/metabolismo , Proliferação de Células/fisiologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , Sistemas de Secreção Tipo III/metabolismo , Vibrio parahaemolyticus/metabolismo , Virulência/fisiologia , Animais , Células CACO-2 , Proteínas de Transporte/metabolismo , Linhagem Celular Tumoral , Células Epiteliais/metabolismo , Infecções por Vírus Epstein-Barr/metabolismo , Antígenos Nucleares do Vírus Epstein-Barr/metabolismo , Regulação Bacteriana da Expressão Gênica/fisiologia , Herpesvirus Humano 4/patogenicidade , Humanos , RNA Ribossômico/metabolismo , Proteínas de Ligação a RNA/metabolismo , Coelhos , Vibrioses/metabolismoRESUMO
Bladder cancer(BC) is one of the most prevalent cancers in the urinary tract, with high recurrence and fatality rates. Research indicates that go-ichi-ni-san complex subunit 1 (GINS1) crucially influences cancer progression by regulating DNA replication through cell cycle modulation. Thus, suppressing the active proliferation of cells in tumor tissues may require silencing GINS1. However, the consequences of GINS1 in bladder cancer aren't to be determined. In this paper, we examine the role and mechanism of GINS1 in the development of bladder cancer. GINS1 expression levels and prognostic relevance in bladder cancer were validated using Western blotting, immunohistochemistry, and Kaplan-Meier survival analysis. The influence of GINS1 on bladder cancer was investigated using a variety of approaches, including cell transfection, cell counts, transwell migrations, colony formation, and flow cytometry. Immunohistochemistry studies demonstrate that GINS1 expression is increased in bladder cancer tissues. GINS1 silencing resulted in an arrest of the cell cycle at the phase of G0/G1, which inhibited BC cell growth both in vitro and in vivo. GINS1 knockdown also hindered the AKT/mTOR pathway. Furthermore, increased GINS1 expression affects the cell cycle and stimulates the AKT/mTOR pathway, allowing BC to develop more quickly. Consequently, GINS1 occurs as a latent therapeutic target, particularly for individuals with BC.
Assuntos
Proliferação de Células , Proteínas Cromossômicas não Histona , Proteínas Proto-Oncogênicas c-akt , Transdução de Sinais , Serina-Treonina Quinases TOR , Neoplasias da Bexiga Urinária , Neoplasias da Bexiga Urinária/patologia , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/metabolismo , Humanos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Serina-Treonina Quinases TOR/metabolismo , Serina-Treonina Quinases TOR/genética , Proteínas Cromossômicas não Histona/metabolismo , Proteínas Cromossômicas não Histona/genética , Proliferação de Células/genética , Animais , Linhagem Celular Tumoral , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Regulação Neoplásica da Expressão Gênica , Camundongos , Progressão da Doença , Camundongos Nus , Masculino , Feminino , Prognóstico , Camundongos Endogâmicos BALB C , Proteínas de Ligação a DNARESUMO
TP53 missense mutations significantly influence the development and progression of various human cancers via their gain of new functions (GOF) through different mechanisms. Here we report a unique mechanism underlying the GOF of p53-R249S (p53-RS), a p53 mutant frequently detected in human hepatocellular carcinoma (HCC) that is highly related to hepatitis B infection and aflatoxin B1. A CDK inhibitor blocks p53-RS's nuclear translocation in HCC, whereas CDK4 interacts with p53-RS in the G1/S phase of the cells, phosphorylates it, and enhances its nuclear localization. This is coupled with binding of a peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (PIN1) to p53-RS, but not the p53 form with mutations of four serines/threonines previously shown to be crucial for PIN1 binding. As a result, p53-RS interacts with c-Myc and enhances c-Myc-dependent rDNA transcription key for ribosomal biogenesis. These results unveil a CDK4-PIN1-p53-RS-c-Myc pathway as a novel mechanism for the GOF of p53-RS in HCC.
Assuntos
Carcinoma Hepatocelular/metabolismo , Quinase 4 Dependente de Ciclina/metabolismo , Mutação , Peptidilprolil Isomerase de Interação com NIMA/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Serina/metabolismo , Proteína Supressora de Tumor p53/genética , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Proliferação de Células , Quinase 4 Dependente de Ciclina/genética , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Peptidilprolil Isomerase de Interação com NIMA/genética , Fosforilação , Ligação Proteica , Proteínas Proto-Oncogênicas c-myc/genética , Serina/genética , Células Tumorais CultivadasRESUMO
Down syndrome (DS) is a genetic disease characterized by a supernumerary chromosome 21. Intellectual deficiency (ID) is one of the most prominent features of DS. Central nervous system defects lead to learning disabilities, motor and language delays, and memory impairments. At present, a prenatal treatment for the ID in DS is lacking. Subcutaneous administration of synthetic preimplantation factor (sPIF, a peptide with a range of biological functions) in a model of severe brain damage has shown neuroprotective and anti-inflammatory properties by directly targeting neurons and microglia. Here, we evaluated the effect of PIF administration during gestation and until weaning on Dp(16)1Yey mice (a mouse model of DS). Possible effects at the juvenile stage were assessed using behavioral tests and molecular and histological analyses of the brain. To test the influence of perinatal sPIF treatment at the adult stage, hippocampus-dependent memory was evaluated on postnatal day 90. Dp(16)1Yey pups showed significant behavioral impairment, with impaired neurogenesis, microglial cell activation and a low microglial cell count, and the deregulated expression of genes linked to neuroinflammation and cell cycle regulation. Treatment with sPIF restored early postnatal hippocampal neurogenesis, with beneficial effects on astrocytes, microglia, inflammation, and cell cycle markers. Moreover, treatment with sPIF restored the level of DYRK1A, a protein that is involved in cognitive impairments in DS. In line with the beneficial effects on neurogenesis, perinatal treatment with sPIF was associated with an improvement in working memory in adult Dp(16)1Yey mice. Perinatal treatment with sPIF might be an option for mitigating cognitive impairments in people with DS.
Assuntos
Modelos Animais de Doenças , Síndrome de Down , Neurogênese , Animais , Síndrome de Down/tratamento farmacológico , Síndrome de Down/patologia , Síndrome de Down/metabolismo , Síndrome de Down/complicações , Síndrome de Down/genética , Neurogênese/efeitos dos fármacos , Camundongos , Feminino , Gravidez , Hipocampo/metabolismo , Hipocampo/patologia , Hipocampo/efeitos dos fármacos , Microglia/metabolismo , Microglia/efeitos dos fármacos , Microglia/patologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Proteínas Tirosina Quinases/genética , Quinases Dyrk , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/patologia , Masculino , Transtornos Cognitivos/tratamento farmacológico , Transtornos Cognitivos/patologiaRESUMO
AIMS: Pancreatic cancer (PC) is a highly metastatic malignant tumor of the digestive system. Drug resistance frequently occurs during cancer treatment process. This study aimed to explore the link between chemoresistance and tumor metastasis in PC and its possible molecular and cellular mechanisms. METHODS: A Metastasis and Chemoresistance Signature (MCS) scoring system was built and validated based on metastasis- and chemoresistance-related genes using gene expression data of PC, and the model was applied to single-cell RNA sequencing data. The influence of linker histone H1.2 (H1-2) on PC was explored through in vitro and in vivo experiments including proliferation, invasion, migration, drug sensitivity, rescue experiments and immunohistochemistry, emphasizing its regulation with c-MYC signaling pathway. RESULTS: A novel MCS scoring system accurately predicted PC patient survival and was linked to chemoresistance and epithelial-mesenchymal transition (EMT) in PC single-cell RNA sequencing data. H1-2 emerged as a significant prognostic factor, with its high expression indicating increased chemoresistance and EMT. This upregulation was mediated by c-MYC, which was also found to be highly expressed in PC tissues. CONCLUSION: The MCS scoring system offers insights into PC chemoresistance and metastasis potential. Targeting H1-2 could enhance therapeutic strategies and improve PC patient outcomes.
Assuntos
Histonas , Neoplasias Pancreáticas , Humanos , Histonas/genética , Histonas/metabolismo , Resistencia a Medicamentos Antineoplásicos/genética , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Proto-Oncogênicas c-myc/uso terapêutico , Linhagem Celular Tumoral , Transdução de Sinais , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/genética , Proliferação de Células , Regulação Neoplásica da Expressão GênicaRESUMO
The pathophysiological foundations of various diseases are often subject to alteration through the utilization of small compounds, rendering them invaluable tools for the exploration and advancement of novel therapeutic strategies. Within the scope of this study, we meticulously curated a diverse library of novel small compounds meticulously designed to specifically target the c-Myc/Max complex. We conducted in vitro examinations of novel c-Myc inhibitors across a spectrum of cancer cell lines, including PANC1 (pancreatic adenocarcinoma), MCF7 (breast carcinoma), DU-145 (prostate carcinoma), and A549 (lung cancer). The initial analysis involved a 25 µM dose, which enabled the identification of potent anticancer compounds effective against a variety of tumour types. We identified c-Myc inhibitors with remarkable potency, featuring IC50 values as low as 1.6 µM and up to 40 times more effective than the reference molecule in diminishing cancer cell viability. Notably, c-Myc-i7 exhibited exceptional selectivity, displaying 37-fold and 59-fold preference for targeting prostate and breast cancers, respectively, over healthy cells. Additionally, we constructed drug-likeness models. This study underscores the potential for in vitro investigations of various tumour types using novel c-Myc inhibitors to yield ground-breaking and efficacious anticancer compounds.