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The quest for targeted therapies is critical in the battle against cancer. The RAS/MAP kinase pathway is frequently implicated in neoplasia, with ERK playing a crucial role as the most distal kinase in the RAS signaling cascade. Our previous research demonstrated that the interaction between ERK and MYD88, an adaptor protein in innate immunity, is crucial for RAS-dependent transformation and cancer cell survival. In this study, we examine the biological consequences of disrupting the ERK-MYD88 interaction through the ERK D-recruitment site (DRS), while preserving ERK's kinase activity. Our results indicate that EI-52, a small-molecule benzimidazole targeting ERK-MYD88 interaction induces an HRI-mediated integrated stress response (ISR), resulting in immunogenic apoptosis specific to cancer cells. Additionally, EI-52 exhibits anti-tumor efficacy in patient-derived tumors and induces an anti-tumor T cell response in mice in vivo. These findings suggest that inhibiting the ERK-MYD88 interaction may be a promising therapeutic approach in cancer treatment.
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Benzimidazóis , MAP Quinases Reguladas por Sinal Extracelular , Fator 88 de Diferenciação Mieloide , Fator 88 de Diferenciação Mieloide/metabolismo , Fator 88 de Diferenciação Mieloide/genética , Humanos , Animais , Camundongos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Linhagem Celular Tumoral , Benzimidazóis/farmacologia , Apoptose/efeitos dos fármacos , Morte Celular Imunogênica/efeitos dos fármacos , Neoplasias/imunologia , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Neoplasias/metabolismo , Feminino , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/imunologia , Ensaios Antitumorais Modelo de Xenoenxerto , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêuticoRESUMO
Although the involvement of protein kinase CK2 in cancer is well-documented, there is a need for selective CK2 inhibitors suitable for investigating CK2 specific roles in cancer-related biological pathways and further exploring its therapeutic potential. Here, we report the discovery of AB668, an outstanding selective inhibitor that binds CK2 through a bivalent mode, interacting both at the ATP site and an allosteric αD pocket unique to CK2. Using caspase activation assay, live-cell imaging, and transcriptomic analysis, we have compared the effects of this bivalent inhibitor to representative ATP-competitive inhibitors, CX-4945, and SGC-CK2-1. Our results show that in contrast to CX-4945 or SGC-CK2-1, AB668, by targeting the CK2 αD pocket, has a distinct mechanism of action regarding its anti-cancer activity, inducing apoptotic cell death in several cancer cell lines and stimulating distinct biological pathways in renal cell carcinoma.
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Modeling paraneoplastic neurological diseases to understand the immune mechanisms leading to neuronal death is a major challenge given the rarity and terminal access of patients' autopsies. Here, we present a pilot study aiming at modeling paraneoplastic cerebellar degeneration with Yo autoantibodies (Yo-PCD). Female mice were implanted with an ovarian carcinoma cell line expressing CDR2 and CDR2L, the known antigens recognized by anti-Yo antibodies. To boost the immune response, we also immunized the mice by injecting antigens with diverse adjuvants and immune checkpoint inhibitors. Ataxia and gait instability were assessed in treated mice as well as autoantibody levels, Purkinje cell density, and immune infiltration in the cerebellum. We observed the production of anti-Yo antibodies in the CSF and serum of all immunized mice. Brain immunoreaction varied depending on the site of implantation of the tumor, with subcutaneous administration leading to a massive infiltration of immune cells in the meningeal spaces, choroid plexus, and cerebellar parenchyma. However, we did not observe massive Purkinje cell death nor any motor impairments in any of the experimental groups. Self-sustained neuro-inflammation might require a longer time to build up in our model. Unusual tumor antigen presentation and/or intrinsic, species-specific factors required for pro-inflammatory engagement in the brain may also constitute strong limitations to achieve massive recruitment of antigen-specific T-cells and killing of antigen-expressing neurons in this mouse model.
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Ataxia Cerebelar , Degeneração Paraneoplásica Cerebelar , Humanos , Camundongos , Feminino , Animais , Projetos Piloto , Cerebelo/patologia , Células de Purkinje/metabolismo , Ataxia Cerebelar/patologia , AutoanticorposRESUMO
Title: Thérapies ciblées et immunothérapies dans le mélanome - Une approche temporelle pour une réponse optimale. Abstract: Dans le cadre d'un partenariat avec médecine/sciences, et pour la cinquième année consécutive, des étudiants du module d'enseignement « Immunologie, virologie et cancer ¼ du Master Cancer de Lyon présentent une analyse d'articles scientifiques récents faisant état d'observations innovantes et importantes. Ce travail a été encadré par des chercheurs confirmés du Centre de Recherche en Cancérologie de Lyon (CRCL). Le master Cancer (université Claude Bernard Lyon1- VetAgroSup) accueille chaque année 40 étudiants en M1 et environ 80 en M2. Ce master dit « d'excellence ¼ (master international labellisé université de Lyon) assure aux étudiants de M1 une formation en cancérologie reposant sur un socle de base commun (biologie cellulaire, moléculaire, immunologie, bio-statistique, épidémiologie, recherche translationnelle, etc.). Cette formation repose sur une forte implication des chercheurs et enseignants-chercheurs du CRCL, ainsi que sur un partenariat fort avec plusieurs instituts, dont le MIT (Massachusetts Institute of Technology, Cambridge, États-Unis), l'université d'Harvard (Boston, États-Unis), l'université de Californie à San Diego (UCSD) (États-Unis), la university of City of London (UCL), le Beatson Institute de Glasgow (Royaume-Uni), les universités de Shanghai Jiao Tong (République populaire de Chine, RPC), de Tokyo et Tohoku (Japon), de Melbourne (Australie) et d'Auckland (Nouvelle-Zélande).
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Melanoma , Neoplasias Cutâneas , Humanos , Melanoma/tratamento farmacológico , Imunoterapia , Terapia de Alvo Molecular , Neoplasias Cutâneas/tratamento farmacológicoRESUMO
Nutrient availability is a key determinant of tumor cell behavior. While nutrient-rich conditions favor proliferation and tumor growth, scarcity, and particularly glutamine starvation, promotes cell dedifferentiation and chemoresistance. Here, linking ribosome biogenesis plasticity with tumor cell fate, we uncover that the amino acid sensor general control non-derepressible 2 (GCN2; also known as eIF-2-alpha kinase 4) represses the expression of the precursor of ribosomal RNA (rRNA), 47S, under metabolic stress. We show that blockade of GCN2 triggers cell death by an irremediable nucleolar stress and subsequent TP53-mediated apoptosis in patient-derived models of colon adenocarcinoma (COAD). In nutrient-rich conditions, a cell-autonomous GCN2 activity supports cell proliferation by stimulating 47S rRNA transcription, independently of the canonical integrated stress response (ISR) axis. Impairment of GCN2 activity prevents nuclear translocation of methionyl-tRNA synthetase (MetRS), resulting in nucleolar stress, mTORC1 inhibition and, ultimately, autophagy induction. Inhibition of the GCN2-MetRS axis drastically improves the cytotoxicity of RNA polymerase I (RNA pol I) inhibitors, including the first-line chemotherapy oxaliplatin, on patient-derived COAD tumoroids. Our data thus reveal that GCN2 differentially controls ribosome biogenesis according to the nutritional context. Furthermore, pharmacological co-inhibition of the two GCN2 branches and RNA pol I activity may represent a valuable strategy for elimination of proliferative and metabolically stressed COAD cells.
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The incidence of the mobile tongue cancer in young patients has been rising. This oral cancer (OC) type has no identified risk factors (NIRF), no established molecular markers and is not yet recognized as a distinct clinical entity. To understand this emerging malignancy, we innovatively analyzed the public head and neck cancer multi-omics data. We identified mutational signatures that successfully stratified 307 OC and 109 laryngeal cancer cases according to their clinico-pathological characteristics. The NIRF OCs exhibited significantly increased activities of endogenous clock-like and APOBEC-associated mutagenesis, alongside specific cancer driver gene mutations, distinct methylome patterns and prominent antimicrobial transcriptomic responses. Furthermore, we show that mutational signature SBS16 in OCs reflects the combined effects of alcohol drinking and tobacco smoking. Our study characterizes the unique disease histories and molecular programs of the NIRF OCs revealing that this emerging cancer subtype is likely driven by increased endogenous mutagenesis correlated with responses to microbial insults.
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The kynurenine pathway has been highlighted as a gatekeeper of immune-privileged sites through its ability to generate from tryptophan a set of immunosuppressive metabolic intermediates. It additionally constitutes an important source of cellular NAD+ for the organism. Hijacking of its immunosuppressive functions, as recurrently observed in multiple cancers, facilitates immune evasion and promotes tumor development. Based on these observations, researchers have focused on characterizing indoleamine 2,3-dioxygenase (IDO1), the main enzyme catalyzing the first and limiting step of the pathway, and on developing therapies targeting it. Unfortunately, clinical trials studying IDO1 inhibitors have thus far not met expectations, highlighting the need to unravel this complex signaling pathway further. Recent advances demonstrate that these metabolites additionally promote tumor growth, metastatic dissemination and chemoresistance by a combination of paracrine and autocrine effects. Production of NAD+ also contributes to cancer progression by providing cancer cells with enhanced plasticity, invasive properties and chemoresistance. A comprehensive survey of this complexity is challenging but necessary to achieve medical success.
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INTRODUCTION: Most Toll-like receptors and IL-1/IL-18 receptors activate a signaling cascade via the adaptor molecule MyD88, resulting in NF-κB activation and inflammatory cytokine and chemokine production. Females are less susceptible than males to inflammatory conditions, presumably due to protection by estrogen. The exact mechanism underlying this protection is unknown. METHODS: MCF7 cells expressing wild-type or mutated LXXLL motif were used to determine MyD88/estrogen receptor (ER)-a interaction by immunoprecipitation and cell activation by ELISA and luciferase reporter assay. IL-1b and/or E2 were used to activate MCF7 cells expressing normal or knocked down levels of PRMT1. Finally, in situ proximity ligation assay with anti-MyD88 and anti-methylated ER-a (methER-a) antibodies was used to evaluate MyD88/methylated ER-a interaction in THP1 cells and histological sections. RESULTS: We show that MyD88 interacts with a methylated, cytoplasmic form of estrogen receptor-alpha (methER-α). This interaction is required for NF-κB transcriptional activity and pro-inflammatory cytokine production, and is dissociated by estrogen. Importantly, we show a strong gender segregation in gametogenic reproductive organs, with MyD88/methER-α interactions found in testicular tissues and in ovarian tissues from menopausal women, but not in ovaries from women age 49 and less - suggesting a role for estrogen in disrupting this complex in situ. DISCUSSION: Collectively, our results indicate that the formation of MyD88/methER-α complexes during inflammatory signaling and their disruption by estrogen may represent a mechanism that contributes to gender bias in inflammatory responses.
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This study explored the design of supersaturable self-microemulsifying drug delivery systems (S-SMEDDS) to address poor solubility and oral bioavailability of a novel benzimidazole derivative anticancer drug (BI). Firstly, self-microemulsifying drug delivery systems SMEDDS made of Miglyol® 812, Kolliphor® RH40, Transcutol® HP, and ethanol were prepared and loaded with the BI drug. Upon dispersion, the systems formed neutrally charged droplets of around 20 nm. However, drug precipitation was observed following incubation with simulated gastric fluid (pH 1.2). Aiming at reducing this precipitation and enhancing drug payload, supersaturable systems were then prepared by adding 1% hydroxypropyl cellulose as precipitation inhibitor. Supersaturable systems maintained a higher amount of drug in a supersaturated state in gastric medium compared with conventional formulations and were stable in simulated intestinal medium (pH 6.8). In vitro cell studies using Caco-2 cell line showed that these formulations reduced in a transient manner the transepithelial electrical resistance of the monolayers without toxicity. Accordingly, confocal images revealed that the systems accumulated at tight junctions after a 2 h exposure. In vivo pharmacokinetic studies carried out following oral administration of BI-loaded S-SMEDDS, SMEDDS, and free drug to healthy mice showed that supersaturable systems promoted drug absorption compared with the other formulations. Overall, these data highlight the potential of using the supersaturable approach as an alternative to conventional SMEDDS for improving oral systemic absorption of lipophilic drugs.
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Antineoplásicos , Sistemas de Liberação de Medicamentos , Administração Oral , Animais , Benzimidazóis , Disponibilidade Biológica , Células CACO-2 , Emulsões , Humanos , Camundongos , Ratos , Ratos Sprague-Dawley , SolubilidadeRESUMO
BACKGROUND & AIMS: Low levels of toll-like receptor 3 (TLR3) in patients with hepatocellular carcinoma (HCC) are associated with poor prognosis, primarily owing to the loss of inflammatory signaling and subsequent lack of immune cell recruitment to the liver. Herein, we explore the role of TLR3-triggered apoptosis in HCC cells. METHODS: Quantitative reverse transcription PCR, western blotting, immunohistochemistry and comparative genomic hybridization were used to analyze human and mouse HCC cell lines, as well as surgically resected primary human HCCs, and to study the impact of TLR3 expression on patient outcomes. Functional analyses were performed in HCC cells, following the restoration of TLR3 by lentiviral transduction. The role of TLR3-triggered apoptosis in HCC was analyzed in vivo in a transgenic mouse model of HCC. RESULTS: Lower expression of TLR3 in tumor compared to non-tumor matched tissue was observed at both mRNA and protein levels in primary HCC, and was predictive of shorter recurrence-free survival after surgical resection in both univariate (hazard ratio [HR] 1.79; 95% CI 1.04-3.06; pâ¯=â¯0.03) and multivariate analyses (HR 1.73; CI 1.01-2.97; pâ¯=â¯0.04). Immunohistochemistry confirmed frequent downregulation of TLR3 in human and mouse primary HCC cells. None of the 6 human HCC cell lines analyzed expressed TLR3, and ectopic expression of TLR3 following lentiviral transduction not only restored the inflammatory response but also sensitized cells to TLR3-triggered apoptosis. Lastly, in the transgenic mouse model of HCC, absence of TLR3 expression was accompanied by a lower rate of preneoplastic hepatocyte apoptosis and accelerated hepatocarcinogenesis without altering the tumor immune infiltrate. CONCLUSION: Downregulation of TLR3 protects transforming hepatocytes from direct TLR3-triggered apoptosis, thereby contributing to hepatocarcinogenesis and poor patient outcome. LAY SUMMARY: Hepatocellular carcinoma (HCC) is a heterogeneous disease associated with a poor prognosis. In patients with HCC, TLR3 downregulation is associated with reduced survival. Herein, we show that the absence of TLR3 is associated with a lower rate of apoptosis, and subsequently more rapid hepatocarcinogenesis, without any change to the immune infiltrate in the liver. Therefore, the poor prognosis associated with low TLR3 expression in HCC is likely linked to tumors ability to escape apoptosis. TLR3 may become a promising therapeutic target in TLR3-positive HCC.
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Carcinogênese/metabolismo , Carcinoma Hepatocelular , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas , Prognóstico , Receptor 3 Toll-Like/genética , Animais , Apoptose , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/terapia , Linhagem Celular Tumoral , Proliferação de Células , Regulação para Baixo , Feminino , Hepatectomia/métodos , Hepatectomia/mortalidade , Humanos , Estimativa de Kaplan-Meier , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/terapia , Masculino , Camundongos , Pessoa de Meia-Idade , Transdução de SinaisRESUMO
Telomere stability is a hallmark of immortalized cells, including cancer cells. While the telomere length is maintained in most cases by the telomerase, the activity of a protein complex called Shelterin is required to protect telomeres against unsuitable activation of the DNA damage response pathway. Within this complex, telomeric repeat binding factor 2 (TRF2) plays an essential role by blocking the ataxia telangiectasia-mutated protein (ATM) signaling pathway at telomeres and preventing chromosome end fusion. We showed that TRF2 was phosphorylated in vitro and in vivo on serine 323 by extracellular signal-regulated kinase (ERK1/2) in both normal and cancer cells. Moreover, TRF2 and activated ERK1/2 unexpectedly interacted in the cytoplasm of tumor cells and human tumor tissues. The expression of non-phosphorylatable forms of TRF2 in melanoma cells induced the DNA damage response, leading to growth arrest and tumor reversion. These findings revealed that the telomere stability is under direct control of one of the major pro-oncogenic signaling pathways (RAS/RAF/MEK/ERK) via TRF2 phosphorylation.
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MAP Quinases Reguladas por Sinal Extracelular/fisiologia , Sistema de Sinalização das MAP Quinases/fisiologia , Proteína 2 de Ligação a Repetições Teloméricas/fisiologia , Animais , Apoptose , Linhagem Celular , Feminino , Humanos , Camundongos , Fosforilação , Telômero/fisiologiaRESUMO
Cherubism is a rare autoinflammatory bone disorder that is associated with point mutations in the SH3-domain binding protein 2 (SH3BP2) gene, which encodes the adapter protein 3BP2. Individuals with cherubism present with symmetrical fibro-osseous lesions of the jaw, which are attributed to exacerbated osteoclast activation and defective osteoblast differentiation. Although it is a dominant trait in humans, cherubism appears to be recessively transmitted in mice, suggesting the existence of additional factors in the pathogenesis of cherubism. Here, we report that macrophages from 3BP2-deficient mice exhibited dramatically reduced inflammatory responses to microbial challenge and reduced phagocytosis. 3BP2 was necessary for LPS-induced activation of signaling pathways involved in macrophage function, including SRC, VAV1, p38MAPK, IKKα/ß, RAC, and actin polymerization pathways. Conversely, we demonstrated that the presence of a single Sh3bp2 cherubic allele and pathogen-associated molecular pattern (PAMP) stimulation had a strong cooperative effect on macrophage activation and inflammatory responses in mice. Together, the results from our study in murine genetic models support the notion that infection may represent a driver event in the etiology of cherubism in humans and suggest limiting inflammation in affected individuals may reduce manifestation of cherubic lesions.
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Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Querubismo/genética , Inflamação/fisiopatologia , Ativação de Macrófagos/fisiologia , Mutação de Sentido Incorreto , Mutação Puntual , Actinas/química , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Transferência Adotiva , Substituição de Aminoácidos , Animais , Citocinas/metabolismo , Modelos Animais de Doenças , Heterozigoto , Humanos , Inflamação/microbiologia , Lipopolissacarídeos , Macrófagos Peritoneais/transplante , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutagênese Sítio-Dirigida , Osteoclastos/metabolismo , Osteoclastos/patologia , Fagocitose/fisiologia , Receptor 4 Toll-Like/efeitos dos fármacos , Receptor 4 Toll-Like/fisiologiaRESUMO
PURPOSE OF REVIEW: Inflammation is emerging as a new hallmark of cancer, and the toll-like receptor and interleukin-1 receptor adaptor molecule MyD88 has been linked to tumorigenesis. The purpose of this review is to give a brief overview of the latest advances in understanding the complexity of MyD88 implication in tumorigenesis. RECENT FINDINGS: MyD88 is shown to play a protumorigenic role through two mechanisms. First, it activates the nuclear factor kappa-light-chain-enhancer of activated B cells signaling pathway in the hematopoietic compartment and in tumor cells, inducing an inflammatory environment favorable to carcinogenesis. Second, it plays a cell-autonomous role in Ras signaling and transformation, independently of its role in inflammatory signaling. MyD88 mediates the optimal activation of the Ras/extracellular signal-regulated kinase (ERK) pathway by binding to ERK and protecting it from dephosphorylation. This optimal activation of the Ras pathway is essential for the expression of important DNA repair enzymes, allowing cancer cells to efficiently repair damaged DNA. MyD88 is also shown in certain cases to play an antitumoral role through modulation of the immune response SUMMARY: These findings present a new dual function model for MyD88 implication in carcinogenesis making it a potential therapeutic target in cancer.
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Carcinogênese/genética , Transformação Celular Neoplásica/genética , Fator 88 de Diferenciação Mieloide/fisiologia , Carcinogênese/metabolismo , Carcinogênese/patologia , Transformação Celular Neoplásica/metabolismo , Humanos , Inflamação/genética , Sistema de Sinalização das MAP Quinases/fisiologia , Fator 88 de Diferenciação Mieloide/genética , Neoplasias/genética , Neoplasias/terapia , Proteínas Proto-Oncogênicas/fisiologia , Transdução de Sinais/fisiologiaRESUMO
BACKGROUND: MyD88 is an adaptor molecule in Toll-like receptor and interleukin 1 receptor signaling implicated in tumorigenesis through proinflammatory mechanisms. We have recently reported that MyD88 also directly promotes optimal activation of the Ras/Erk pathway. Here we investigate MyD88 implication in the maintenance of the transformation of Ras-dependent tumors. METHODS: RNA interference was used to inhibit MyD88 expression in the colon cancer cell lines HCT116 and LS513. Apoptosis, DNA damage, p53 function, ERCC1 levels, and Ras and inflammatory signaling pathways were analyzed. Using in vitro assays and xenotransplantation in nude mice (five per group), HCT116 tumor growth was assessed following MyD88 knockdown in presence or absence of chemotherapy. RESULTS: MyD88 exerts antiapoptotic functions in colon cancer cells via the Ras/Erk, but not the NF-κB, pathway. MyD88 inhibition leads to defective ERCC1-dependent DNA repair and to accumulation of DNA damage, resulting in cancer cell death via p53. Furthermore, we show that knocking down MyD88 sensitizes cancer cells to genotoxic agents such as platinum salts in vitro and in vivo. Indeed, HCT116 tumor growth following treatment with a combination of suboptimal MyD88 inhibition and suboptimal doses of cisplatin (fold tumor increase = 5.4 ± 1.6) was statistically significantly reduced in comparison to treatment with doxycycline alone (12.4 ± 3.1) or with cisplatin alone (12.5 ± 2.6) (P = .005 for both, one-sided Student t test). CONCLUSIONS: Collectively, these results indicate a novel and original link between inflammation, DNA repair, and cancer, and provide further rationale for MyD88 as a potential therapeutic target in Ras-dependent cancers, in the context of concomitant genotoxic chemotherapy.
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Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias do Colo/tratamento farmacológico , Neoplasias do Colo/genética , Reparo do DNA/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos , Glicoproteínas de Membrana/antagonistas & inibidores , Glicoproteínas de Membrana/metabolismo , Receptores de Interleucina-1/antagonistas & inibidores , Receptores de Interleucina-1/metabolismo , Animais , Sequência de Bases , Western Blotting , Linhagem Celular Tumoral , Transformação Celular Neoplásica/efeitos dos fármacos , Transformação Celular Neoplásica/genética , Cisplatino/farmacologia , Neoplasias do Colo/metabolismo , Dano ao DNA/efeitos dos fármacos , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Doxiciclina/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Endonucleases/genética , Endonucleases/metabolismo , Feminino , Citometria de Fluxo , Humanos , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Dados de Sequência Molecular , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , RNA Interferente Pequeno/análise , Receptores de Interleucina-1/genética , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Accumulating evidence points to inflammation as a promoter of carcinogenesis. MyD88 is an adaptor molecule in TLR and IL-1R signaling that was recently implicated in tumorigenesis through proinflammatory mechanisms. Here we have shown that MyD88 is also required in a cell-autonomous fashion for RAS-mediated carcinogenesis in mice in vivo and for MAPK activation and transformation in vitro. Mechanistically, MyD88 bound to the key MAPK, Erk, and prevented its inactivation by its phosphatase, MKP3, thereby amplifying the activation of the canonical RAS pathway. The relevance of this mechanism to human neoplasia was suggested by the finding that MyD88 was overexpressed and interacted with activated Erk in primary human cancer tissues. Collectively, these results show that in addition to its role in inflammation, MyD88 plays what we believe to be a crucial direct role in RAS signaling, cell-cycle control, and cell transformation.
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Transformação Celular Neoplásica , Inflamação/complicações , Fator 88 de Diferenciação Mieloide/fisiologia , Transdução de Sinais , Proteínas ras/fisiologia , 9,10-Dimetil-1,2-benzantraceno , Animais , Ciclo Celular , MAP Quinases Reguladas por Sinal Extracelular/fisiologia , Humanos , Sistema de Sinalização das MAP Quinases , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação , Acetato de TetradecanoilforbolRESUMO
BACKGROUND & AIMS: Inappropriate activation of beta-catenin in adult tissues is associated with a wide variety of cancers, especially in the digestive tract. Classic transgenic and knockout murine models in which beta-catenin is activated in large fields of cells have provided experimental support in favor of a role for this molecule in tumorigenesis. However, these models do not reproduce the sporadic nature of the majority of human cancers, beginning with the activation of an oncogene at random in a single cell. METHODS: We used the "hit and run" strategy to generate a mouse model in which the expression of an activated form of beta-catenin occurs sporadically in vivo. RESULTS: Sporadic, multifocal lesions were observed in the stomach of 3% of mice aged 8 months and older. These lesions were associated with loss of Sonic hedgehog (Shh), and a causal relationship between beta-catenin activation and Shh inhibition was established in gastric cells in vitro. No lesion was detected in the intestine or in the liver. In addition, one third of female mutant mice developed benign perimammary papillomas. Mutant mice were also hypersensitive to chemically induced premalignant skin lesions. CONCLUSIONS: These results challenge the view that activation of beta-catenin induces malignant cancerogenesis, because they show in mice that sporadically activated beta-catenin is sufficient for tumor initiation, yet without further malignant progression, and that it sensitizes cells to environmental hits. This model represents a powerful tool to investigate the interplay between genetic and environmental factors in tumor progression.
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Regulação Neoplásica da Expressão Gênica , Lesões Pré-Cancerosas/patologia , RNA Neoplásico/genética , Neoplasias Cutâneas/patologia , Neoplasias Gástricas/patologia , beta Catenina/genética , Animais , Linhagem Celular Tumoral , Progressão da Doença , Feminino , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neoplasias Experimentais , Fenótipo , Reação em Cadeia da Polimerase , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/metabolismo , Gravidez , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/metabolismo , Neoplasias Gástricas/embriologia , Neoplasias Gástricas/metabolismo , beta Catenina/metabolismoRESUMO
Multiple endocrine neoplasia type 1 (MEN1) is a hereditary syndrome caused by the inactivation of the responsible gene, MEN1. To date, the lack of MEN1-deficient cell lines derived directly from MEN1 tumours has hampered the detailed study of the MEN1 gene. We have established several stable Men1-deficient Leydig cell tumour (LCT) lines derived from a Leydig cell tumour developed in a male heterozygous Men1 mutant mouse. Our data show that these cell lines maintain the basic characteristics of Leydig cells in terms of both androgen synthesis and gene expression. Interestingly, reconstituted menin expression in one of Men1-deficient LCT cell lines resulted in cell growth inhibition, suggesting that the function of cell growth suppression of the menin pathway, apart from menin itself, is essentially preserved in these cells. Furthermore, we show that menin re-expression in these Men1-deficient cells leads to a block in the transition from G0/G1 to S phase of the cell cycle and an increase in apoptosis, accompanied by a marked increase of p18INK4C and p27Kip1 expression. The current study therefore highlights the importance of menin expression in cell cycle and cell survival control in endocrine cells, and may provide insights into the mechanisms of tumour suppression by menin in related endocrine tumours.
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Apoptose/genética , Ciclo Celular/genética , Tumor de Células de Leydig/genética , Neoplasia Endócrina Múltipla Tipo 1/genética , Mutação/genética , Proteínas Proto-Oncogênicas/genética , Animais , Linhagem Celular Tumoral , Imuno-Histoquímica , Tumor de Células de Leydig/metabolismo , Perda de Heterozigosidade/genética , Masculino , Camundongos , Neoplasia Endócrina Múltipla Tipo 1/metabolismo , Progesterona/metabolismo , Proteínas Proto-Oncogênicas/deficiência , Proteínas Proto-Oncogênicas/metabolismoRESUMO
TLRs function as molecular sensors to detect pathogen-derived products and trigger protective responses ranging from secretion of cytokines that increase the resistance of infected cells and chemokines that recruit immune cells to cell death that limits microbe spreading. Viral dsRNA participate in virus-infected cell apoptosis, but the signaling pathway involved remains unclear. In this study we show that synthetic dsRNA induces apoptosis of human breast cancer cells in a TLR3-dependent manner, which involves the molecular adaptor Toll/IL-1R domain-containing adapter inducing IFN-beta and type I IFN autocrine signaling, but occurs independently of the dsRNA-activated kinase. Moreover, detailed molecular analysis of dsRNA-induced cell death established the proapoptotic role of IL-1R-associated kinase-4 and NF-kappaB downstream of TLR3 as well as the activation of the extrinsic caspases. The direct proapoptotic activity of endogenous human TLR3 expressed by cancerous cells reveals a novel aspect of the multiple-faced TLR biology, which may open new clinical prospects for using TLR3 agonists as cytotoxic agents in selected cancers.
Assuntos
Apoptose/imunologia , Neoplasias da Mama/imunologia , Neoplasias da Mama/patologia , Receptor 3 Toll-Like/metabolismo , Sequência de Bases , Neoplasias da Mama/genética , Caspases/metabolismo , Linhagem Celular Tumoral , DNA de Neoplasias/genética , Feminino , Humanos , Interferon Tipo I/metabolismo , Quinases Associadas a Receptores de Interleucina-1 , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , NF-kappa B/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , RNA Interferente Pequeno/genética , Transdução de Sinais , Fator 6 Associado a Receptor de TNF/metabolismo , Receptor 3 Toll-Like/agonistas , Receptor 3 Toll-Like/genética , eIF-2 Quinase/metabolismoRESUMO
Langerin is a C-type lectin expressed by a subset of dendritic leukocytes, the Langerhans cells (LC). Langerin is a cell surface receptor that induces the formation of an LC-specific organelle, the Birbeck granule (BG). We generated a langerin(-/-) mouse on a C57BL/6 background which did not display any macroscopic aberrant development. In the absence of langerin, LC were detected in normal numbers in the epidermis but the cells lacked BG. LC of langerin(-/-) mice did not present other phenotypic alterations compared to wild-type littermates. Functionally, the langerin(-/-) LC were able to capture antigen, to migrate towards skin draining lymph nodes, and to undergo phenotypic maturation. In addition, langerin(-/-) mice were not impaired in their capacity to process native OVA protein for I-A(b)-restricted presentation to CD4(+) T lymphocytes or for H-2K(b)-restricted cross-presentation to CD8(+) T lymphocytes. langerin(-/-) mice inoculated with mannosylated or skin-tropic microorganisms did not display an altered pathogen susceptibility. Finally, chemical mutagenesis resulted in a similar rate of skin tumor development in langerin(-/-) and wild-type mice. Overall, our data indicate that langerin and BG are dispensable for a number of LC functions. The langerin(-/-) C57BL/6 mouse should be a valuable model for further functional exploration of langerin and the role of BG.
Assuntos
Antígenos de Superfície/genética , Antígenos de Superfície/fisiologia , Ilhotas Pancreáticas/citologia , Células de Langerhans/citologia , Lectinas Tipo C/genética , Lectinas Tipo C/fisiologia , Lectinas de Ligação a Manose/genética , Lectinas de Ligação a Manose/fisiologia , 9,10-Dimetil-1,2-benzantraceno , Animais , Antígenos/metabolismo , Blastocisto/metabolismo , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Carcinógenos , Movimento Celular , Fenômenos Fisiológicos Celulares , Grânulos Citoplasmáticos/metabolismo , Células Dendríticas , Relação Dose-Resposta a Droga , Eletroporação , Embrião de Mamíferos/citologia , Citometria de Fluxo , Vetores Genéticos , Imuno-Histoquímica , Ilhotas Pancreáticas/fisiologia , Cinética , Lectinas/metabolismo , Linfonodos/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microscopia Eletrônica , Modelos Genéticos , Mutagênese , Mutação , Neoplasias/induzido quimicamente , Ovalbumina/metabolismo , Fenótipo , Células-Tronco/citologiaRESUMO
We have previously identified a mAb that binds to a molecule expressed preferentially on the surface of cycling thymocytes. In this study the molecule recognized by this mAb has been identified in the mouse as CD147 (basigin) by expression cloning. We show that CD147 expression correlates with cycling of immature thymocytes even in the absence of TCRbeta selection and that ligation of this molecule on immature fetal thymocytes inhibits their further development into mature T cells.