RESUMEN
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.
Asunto(s)
Proteína Fosfatasa 2/metabolismo , Secuencia de Aminoácidos , Animales , Línea Celular Tumoral , Activadores de Enzimas/metabolismo , Células HEK293 , Xenoinjertos , Humanos , Masculino , Ratones , Ratones Desnudos , Modelos Moleculares , Complejos Multiproteicos/metabolismo , Proteína Fosfatasa 2/química , Subunidades de ProteínaRESUMEN
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.
Asunto(s)
Biomarcadores de Tumor/metabolismo , Proteínas Portadoras/metabolismo , Proteínas de Unión al ADN/metabolismo , Glucólisis , Proteínas de la Membrana/metabolismo , Neoplasias/enzimología , Fosfoglicerato Quinasa/metabolismo , Fosfoglicerato Mutasa/metabolismo , Fosfopiruvato Hidratasa/metabolismo , ARN Largo no Codificante/metabolismo , Hormonas Tiroideas/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Biomarcadores de Tumor/genética , Proteínas Portadoras/genética , Proliferación Celular , Proteínas de Unión al ADN/genética , Femenino , Regulación Enzimológica de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Células HEK293 , Células HeLa , Células Hep G2 , Humanos , L-Lactato Deshidrogenasa/genética , L-Lactato Deshidrogenasa/metabolismo , Proteínas de la Membrana/genética , Ratones Desnudos , Complejos Multienzimáticos , Neoplasias/genética , Neoplasias/patología , Fosfoglicerato Quinasa/genética , Fosfoglicerato Mutasa/genética , Fosfopiruvato Hidratasa/genética , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , ARN Largo no Codificante/genética , Serina/deficiencia , Hormonas Tiroideas/genética , Carga Tumoral , Proteínas Supresoras de Tumor/genética , Proteínas de Unión a Hormona TiroideRESUMEN
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.
Asunto(s)
Glioblastoma , Telomerasa , Animales , Ratones , Argininosuccinatoliasa/genética , Argininosuccinatoliasa/metabolismo , Línea Celular Tumoral , Receptores ErbB/genética , Fumaratos , Regulación Neoplásica de la Expresión Génica , Glioblastoma/genética , Histonas/genética , Histonas/metabolismo , Mutación , Telomerasa/genética , Telomerasa/metabolismo , Telómero/metabolismo , Acortamiento del Telómero , Factores de Transcripción/metabolismo , Regiones Promotoras GenéticasRESUMEN
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.
Asunto(s)
Linfocitos T CD8-positivos , Factor 4F Eucariótico de Iniciación , Diferenciación Celular , Activación de Linfocitos , Diana Mecanicista del Complejo 1 de la Rapamicina/genéticaRESUMEN
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.
Asunto(s)
Inflamación/genética , Conformación Proteica , Ubiquitina Tiolesterasa/genética , Secuencia de Aminoácidos/genética , Dominio Catalítico/genética , Enzimas Desubicuitinizantes/química , Enzimas Desubicuitinizantes/genética , Humanos , Inflamación/patología , Mutación/genética , Unión Proteica/genética , Dominios Proteicos/genética , Multimerización de Proteína/genética , Proteínas Proto-Oncogénicas c-myb/química , Proteínas Proto-Oncogénicas c-myb/genética , Transducción de Señal/genética , Especificidad por Sustrato , Péptidos y Proteínas Asociados a Receptores de Factores de Necrosis Tumoral/genética , Ubiquitina/genética , Ubiquitina Tiolesterasa/químicaRESUMEN
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.
Asunto(s)
Progresión de la Enfermedad , Regulación Neoplásica de la Expresión Génica , Neoplasias de la Próstata , Proteínas Proto-Oncogénicas c-myc , Receptores Androgénicos , Tioléster Hidrolasas , Humanos , Masculino , Línea Celular Tumoral , Proliferación Celular/genética , Histonas/metabolismo , Regiones Promotoras Genéticas/genética , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata Resistentes a la Castración/genética , Neoplasias de la Próstata Resistentes a la Castración/metabolismo , Neoplasias de la Próstata Resistentes a la Castración/patología , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , Receptores Androgénicos/metabolismo , Receptores Androgénicos/genética , Tioléster Hidrolasas/metabolismo , Tioléster Hidrolasas/genética , Ubiquitinación , Regulación hacia ArribaRESUMEN
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.
Asunto(s)
Carcinoma Hepatocelular , Antígeno 2 Relacionado con Fos , Neoplasias Hepáticas , Proteínas Proto-Oncogénicas c-fos , Proteínas Proto-Oncogénicas c-jun , Proteínas Proto-Oncogénicas c-myc , Factor de Transcripción AP-1 , Animales , Factor de Transcripción AP-1/metabolismo , Factor de Transcripción AP-1/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , Ratones , Proteínas Proto-Oncogénicas c-fos/metabolismo , Proteínas Proto-Oncogénicas c-fos/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patología , Proteínas Proto-Oncogénicas c-jun/metabolismo , Antígeno 2 Relacionado con Fos/metabolismo , Antígeno 2 Relacionado con Fos/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patología , Humanos , Hepatocitos/metabolismo , Multimerización de Proteína , Regulación Neoplásica de la Expresión Génica , Ratones TransgénicosRESUMEN
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.
Asunto(s)
Células Endoteliales , Neoplasias , Ratones , Animales , Células Endoteliales/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Receptores de Péptidos/genética , Receptores de Péptidos/metabolismo , Transducción de Señal , Antígenos Bacterianos/metabolismo , Neoplasias/genética , Microambiente TumoralRESUMEN
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.
Asunto(s)
Encefalomielitis Autoinmune Experimental , Linfocitos T , Animales , Ratones , Linfocitos T CD4-Positivos , Citocinas/metabolismo , Ratones Endogámicos C57BL , Ratones Noqueados , Coactivador 2 del Receptor Nuclear/metabolismo , Regulación hacia ArribaRESUMEN
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.
Asunto(s)
Neoplasias Pulmonares , Proteínas Proto-Oncogénicas c-myc , Proteínas de Unión al ARN , Proteínas Ribosómicas , Humanos , Carcinogénesis , Proliferación Celular/genética , Transformación Celular Neoplásica , Neoplasias Pulmonares/genética , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteínas Ribosómicas/genética , Proteínas Ribosómicas/metabolismo , Motivos de Unión al ARN , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismoRESUMEN
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.
Asunto(s)
Enfermedades Renales Poliquísticas , Riñón Poliquístico Autosómico Dominante , Proteínas Adaptadoras Transductoras de Señales , Animales , Proteínas de Ciclo Celular , Ratones , Mutación , Fosfoproteínas , Transducción de Señal , Canales Catiónicos TRPP/genética , Proteínas Señalizadoras YAP , Proteína de Unión al GTP rhoARESUMEN
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.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Riñón/fisiopatología , Fosfoproteínas/metabolismo , Enfermedades Renales Poliquísticas/genética , Enfermedades Renales Poliquísticas/fisiopatología , Proteínas Proto-Oncogénicas c-myc/metabolismo , Transducción de Señal , Proteínas de Unión al GTP rho/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Proteínas de Ciclo Celular , Línea Celular , Células Cultivadas , Modelos Animales de Enfermedad , Células HEK293 , Humanos , Riñón/citología , Riñón/patología , Ratones , Fosfoproteínas/genética , Enfermedades Renales Poliquísticas/patología , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Señalizadoras YAP , Proteínas de Unión al GTP rho/genética , Proteína de Unión al GTP rhoARESUMEN
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.
Asunto(s)
Janus Quinasa 2/genética , Janus Quinasa 2/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/fisiopatología , Animales , Antineoplásicos/farmacología , Azepinas/farmacología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Técnicas de Silenciamiento del Gen , Humanos , Masculino , Ratones , Mutación , Nitrilos , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Pirazoles/farmacología , Pirazoles/uso terapéutico , Pirimidinas , Interferencia de ARN , Receptores de Citocinas/genética , Transcriptoma , Triazoles/farmacologíaRESUMEN
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.
RESUMEN
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.
Asunto(s)
Proteínas Bacterianas/metabolismo , Nucléolo Celular/metabolismo , Proliferación Celular/fisiología , Proteínas Proto-Oncogénicas c-myc/metabolismo , Sistemas de Secreción Tipo III/metabolismo , Vibrio parahaemolyticus/metabolismo , Virulencia/fisiología , Animales , Células CACO-2 , Proteínas Portadoras/metabolismo , Línea Celular Tumoral , Células Epiteliales/metabolismo , Infecciones por Virus de Epstein-Barr/metabolismo , Antígenos Nucleares del Virus de Epstein-Barr/metabolismo , Regulación Bacteriana de la Expresión Génica/fisiología , Herpesvirus Humano 4/patogenicidad , Humanos , ARN Ribosómico/metabolismo , Proteínas de Unión al ARN/metabolismo , Conejos , Vibriosis/metabolismoRESUMEN
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.
Asunto(s)
Proliferación Celular , Proteínas Cromosómicas no Histona , Proteínas Proto-Oncogénicas c-akt , Transducción de Señal , Serina-Treonina Quinasas TOR , Neoplasias de la Vejiga Urinaria , Neoplasias de la Vejiga Urinaria/patología , Neoplasias de la Vejiga Urinaria/genética , Neoplasias de la Vejiga Urinaria/metabolismo , Humanos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteínas Proto-Oncogénicas c-akt/genética , Serina-Treonina Quinasas TOR/metabolismo , Serina-Treonina Quinasas TOR/genética , Proteínas Cromosómicas no Histona/metabolismo , Proteínas Cromosómicas no Histona/genética , Proliferación Celular/genética , Animales , Línea Celular Tumoral , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , Regulación Neoplásica de la Expresión Génica , Ratones , Progresión de la Enfermedad , Ratones Desnudos , Masculino , Femenino , Pronóstico , Ratones Endogámicos BALB C , Proteínas de Unión al ADNRESUMEN
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.
Asunto(s)
Carcinoma Hepatocelular/metabolismo , Quinasa 4 Dependiente de la Ciclina/metabolismo , Mutación , Peptidilprolil Isomerasa de Interacción con NIMA/metabolismo , Proteínas Proto-Oncogénicas c-myc/metabolismo , Serina/metabolismo , Proteína p53 Supresora de Tumor/genética , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patología , Proliferación Celular , Quinasa 4 Dependiente de la Ciclina/genética , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Peptidilprolil Isomerasa de Interacción con NIMA/genética , Fosforilación , Unión Proteica , Proteínas Proto-Oncogénicas c-myc/genética , Serina/genética , Células Tumorales CultivadasRESUMEN
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.
Asunto(s)
Modelos Animales de Enfermedad , Síndrome de Down , Neurogénesis , Animales , Síndrome de Down/tratamiento farmacológico , Síndrome de Down/patología , Síndrome de Down/metabolismo , Síndrome de Down/complicaciones , Síndrome de Down/genética , Neurogénesis/efectos de los fármacos , Ratones , Femenino , Embarazo , Hipocampo/metabolismo , Hipocampo/patología , Hipocampo/efectos de los fármacos , Microglía/metabolismo , Microglía/efectos de los fármacos , Microglía/patología , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Proteínas Tirosina Quinasas/metabolismo , Proteínas Tirosina Quinasas/genética , Quinasas DyrK , Disfunción Cognitiva/tratamiento farmacológico , Disfunción Cognitiva/metabolismo , Disfunción Cognitiva/patología , Masculino , Trastornos del Conocimiento/tratamiento farmacológico , Trastornos del Conocimiento/patologíaRESUMEN
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.
Asunto(s)
Histonas , Neoplasias Pancreáticas , Humanos , Histonas/genética , Histonas/metabolismo , Resistencia a Antineoplásicos/genética , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteínas Proto-Oncogénicas c-myc/uso terapéutico , Línea Celular Tumoral , Transducción de Señal , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/genética , Proliferación Celular , Regulación Neoplásica de la Expresión GénicaRESUMEN
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.