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PURPOSE: More than half of the familial cutaneous melanomas have unknown genetic predisposition. This study aims at characterizing a novel melanoma susceptibility gene. METHODS: We performed exome and targeted sequencing in melanoma-prone families without any known melanoma susceptibility genes. We analyzed the expression of candidate gene DENND5A in melanoma samples in relation to pigmentation and UV signature. Functional studies were carried out using microscopic approaches and zebrafish model. RESULTS: We identified a novel DENND5A truncating variant that segregated with melanoma in a Swedish family and 2 additional rare DENND5A variants, 1 of which segregated with the disease in an American family. We found that DENND5A is significantly enriched in pigmented melanoma tissue. Our functional studies show that loss of DENND5A function leads to decrease in melanin content in vitro and pigmentation defects in vivo. Mechanistically, harboring the truncating variant or being suppressed leads to DENND5A losing its interaction with SNX1 and its ability to transport the SNX1-associated vesicles from melanosomes. Consequently, untethered SNX1-premelanosome protein and redundant tyrosinase are redirected to lysosomal degradation by default, causing decrease in melanin content. CONCLUSION: Our findings provide evidence of a physiological role of DENND5A in the skin context and link its variants to melanoma susceptibility.
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Factores de Intercambio de Guanina Nucleótido/genética , Melanoma , Neoplasias Cutáneas , Animales , Predisposición Genética a la Enfermedad , Humanos , Melanoma/genética , Melanosomas , Monofenol Monooxigenasa/metabolismo , Neoplasias Cutáneas/genética , Nexinas de Clasificación , Secuenciación del Exoma , Pez Cebra/genéticaRESUMEN
Viruses can inhibit host autophagy through multiple mechanisms, and evasion of autophagy plays an important role in immune suppression and viral oncogenesis. Merkel cell polyomavirus (MCPyV) T-antigens are expressed and involved in the pathogenesis of a large proportion of Merkel cell carcinoma (MCC). Yet, how MCPyV induces tumorigenesis is not fully understood. Herein, we show that MCPyV T-antigens induce miR-375, miR-30a-3p and miR-30a-5p expressions, which target multiple key genes involved in autophagy, including ATG7, SQSTM1 (p62) and BECN1. In MCC tumors, low expression of ATG7 and p62 are associated with MCPyV-positive tumors. Ectopic expression of MCPyV small T-antigen and truncated large T-antigen (LT), but not the wild-type LT, resulted in autophagy suppression, suggesting the importance of autophagy evasion in MCPyV-mediated tumorigenesis. Torin-1 treatment induced cell death, which was attenuated by autophagy inhibitor, but not pan-caspase inhibitor, suggesting a potential role of autophagy in promoting cell death in MCC. Conceptually, our study shows that MCPyV oncoproteins suppress autophagy to protect cancer cells from cell death, which contribute to a better understanding of MCPyV-mediated tumorigenesis and potential MCC treatment.
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Carcinoma de Células de Merkel/virología , Poliomavirus de Células de Merkel/metabolismo , MicroARNs/biosíntesis , Neoplasias Cutáneas/virología , Antígenos Virales de Tumores/metabolismo , Autofagia/efectos de los fármacos , Autofagia/genética , Proteína 7 Relacionada con la Autofagia/biosíntesis , Proteína 7 Relacionada con la Autofagia/genética , Beclina-1/biosíntesis , Beclina-1/genética , Carcinoma de Células de Merkel/tratamiento farmacológico , Carcinoma de Células de Merkel/genética , Carcinoma de Células de Merkel/patología , Línea Celular Tumoral , Humanos , Macrólidos/farmacología , MicroARNs/genética , MicroARNs/metabolismo , Naftiridinas/farmacología , Infecciones por Polyomavirus/genética , Infecciones por Polyomavirus/metabolismo , Infecciones por Polyomavirus/patología , Infecciones por Polyomavirus/virología , Procesamiento Postranscripcional del ARN , Proteína Sequestosoma-1/biosíntesis , Proteína Sequestosoma-1/genética , Neoplasias Cutáneas/tratamiento farmacológico , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patología , Infecciones Tumorales por Virus/genética , Infecciones Tumorales por Virus/metabolismo , Infecciones Tumorales por Virus/patología , Infecciones Tumorales por Virus/virologíaRESUMEN
Nuclear receptor coactivator 5 (NCOA5) specifically enhances estrogen receptor α-modulated transcriptional activity. As a novel tumor suppressor, depletion of NCOA5 is associated with the development of a variety of tumors, but its function in cervical cancer is currently unclear. In this study, we addressed how expression of NCOA5 changed in the development of human cervical cancer and its association with clinicopathological features, prognosis, and biology characteristics of cervical cancer. Analysis of the microarrays in the Oncomine database indicated that NCOA5 expression was lower in human cervical squamous cell carcinoma tissues than that in normal cervical tissues. That was corroborated by our experiments using fresh tissues: the expression levels of NCOA5 messenger RNA and protein were both significantly decreased in cervical cancer tissues compared with paired adjacent nontumor tissues (P < 0.01). Low expression of NCOA5 is associated with the International Federation of Gynecology and Obstetrics stage ( P = 0.043) and histological grade ( P = 0.018) of human cervical cancer. In addition, patients possessing low NCOA5 expression had poorer prognosis. Univariate and multivariate Cox regression analyses indicated that low NCOA5 expression may be an independent prognostic factor for poorer overall survival in cervical cancer. Further, downregulation of NCOA5 expression results in a significant increase in proliferation, migration, and invasion of HeLa cells. Data of xenograft tumor on BALB/c nude mice manifested that HeLa cells with low NCOA5 expression tend to form larger tumors than negative control ones. In contrast, overexpression of NCOA5 expression leads to the opposite results. Finally, we found that NCOA5 might affect the biological function of human cervical cancer cells by mediating the notch3 signaling pathway. These findings suggest that NCOA5 acts as a tumor suppressor to inhibit tumorigenicity, migration, and invasion, and thus represents a potential novel prognostic marker for overall survival in cervical cancer.
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Regulación hacia Abajo , Coactivadores de Receptor Nuclear/genética , Coactivadores de Receptor Nuclear/metabolismo , Transducción de Señal , Neoplasias del Cuello Uterino/patología , Adulto , Animales , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Femenino , Regulación Neoplásica de la Expresión Génica , Células HeLa , Humanos , Ratones , Persona de Mediana Edad , Clasificación del Tumor , Invasividad Neoplásica , Trasplante de Neoplasias , Pronóstico , Receptor Notch3/metabolismo , Análisis de Supervivencia , Neoplasias del Cuello Uterino/genética , Neoplasias del Cuello Uterino/metabolismoRESUMEN
CONTEXT: BRAFV600E and TERT promoter mutations in papillary thyroid carcinoma (PTC) have a synergistic effect on prognosis. This effect is believed to arise from MAPK activation triggered by BRAFV600E, leading to the upregulation of ETS transcription factors that bind to the mutant TERT promoter. OBJECTIVE: To explore the role of ETS factors in relation to clinical features, BRAFV600E and TERT promoter mutations in PTC. DESIGN: Transcriptomic data for 28 ETS factors were analyzed in the PTC cohort of The Cancer Genome Atlas (TCGA, n=399) and subsequently validated in a local cohort (n=93). In vitro experiments were performed to investigate the regulatory role in relation to BRAFV600E and TERT expression. RESULTS: TCGA identified ETS1, ERG, FLI1, GABPA, EHF, ETV6 and SPDEF as differentially expressed genes between stages I+II and III+IV. In both cohorts, EHF was consistently associated with adverse clinical features, BRAFV600E and TERT promoter mutation/expression. Notably, in BRAFV600E mutated PTC, high EHF expression was associated with shorter disease-free survival. Cases harboring concurrent BRAFV600E, TERT promoter mutations and high EHF expression exhibited the shortest disease-free survival. In cells harboring concurrent BRAFV600E and TERT promoter mutation, over-expression of EHF significantly increased TERT expression while knockdown or pharmacological inhibition of BRAF significantly decreased both EHF and TERT expression. In addition, ChIP-qPCR analysis suggested a potential binding of EHF in TERT promoter mutant cells but not in TERT promoter wild-type cells. CONCLUSION: The ETS transcription factor EHF is associated with poor prognosis in PTC. This is potentially mediated by BRAF-induced upregulation of EHF which in turn increases TERT expression in TERT promoter mutated cells.
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Cancer is a heterogeneous disease. Although both tumor metabolism and tumor immune microenvironment are recognized as driving factors in tumorigenesis, the relationship between them is still not well-known, and potential combined targeting approaches remain to be identified. Here, we demonstrated a negative correlation between the expression of NAMPT, an NAD+ metabolism enzyme, and PD-L1 expression in various cancer cell lines. A clinical study showed that a NAMPTHigh PD-L1Low expression pattern predicts poor prognosis in patients with various cancers. In addition, pharmacological inhibition of NAMPT results in the transcription upregulation of PD-L1 by SIRT-mediated acetylation change of NF-κB p65, and blocking PD-L1 would induce NAMPT expression through a HIF-1-dependent glycolysis pathway. Based on these findings, we designed and synthesized a dual NAMPT/PD-L1 targeting compound, LZFPN-90, which inhibits cell growth in a NAMPT-dependent manner and blocks the cell cycle, subsequently inducing apoptosis. Under co-culture conditions, LZFPN-90 treatment contributes to the proliferation and activation of T cells and blocks the growth of cancer cells. Using mice bearing genetically manipulated tumors, we confirmed that LZFPN-90 exerted target-dependent antitumor activities, affecting metabolic processes and the immune system. In conclusion, our results demonstrate the relevance of NAD+-related metabolic processes in antitumor immunity and suggest that co-targeting NAD+ metabolism and PD-L1 represents a promising therapeutic approach.
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Antígeno B7-H1 , Neoplasias , Humanos , Animales , Ratones , NAD , Neoplasias/patología , Proliferación Celular , Apoptosis , Línea Celular Tumoral , Microambiente TumoralRESUMEN
Infusion of natural killer (NK) cells is an attractive therapeutic modality in patients with cancer. However, the activity of NK cells is regulated by several mechanisms operating within solid tumors. Regulatory T (Treg) cells suppress NK cell activity through various mechanisms including deprivation of IL-2 via the IL-2 receptor alpha (CD25). Here, we investigate CD25 expression on NK cells to confer persistence in Treg cells containing solid tumor models of renal cell carcinoma (RCC). Compared with IL-2, stimulation with IL-15 increases the expression of CD25 resulting in enhanced response to IL-2 as evidenced by increased phosphorylation of STAT5. Compared with CD25dim NK cells, CD25bright NK cells isolated from IL-15 primed NK cells display increased proliferative and metabolic activity as well as increased ability to persist in Treg cells containing RCC tumor spheroids. These results support strategies to enrich for or selectively expand CD25bright NK cells for adoptive cellular therapy of NK cells.
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Carcinoma de Células Renales , Neoplasias Renales , Humanos , Linfocitos T Reguladores/metabolismo , Interleucina-15 , Interleucina-2/farmacología , Carcinoma de Células Renales/terapia , Células Asesinas Naturales , Neoplasias Renales/metabolismoRESUMEN
As a single-layer feedforward network (SLFN), extreme learning machine (ELM) has been successfully applied for classification and regression in machine learning due to its faster training speed and better generalization. However, it will perform poorly for domain adaptation in which the distributions between training data and testing data are inconsistent. In this article, we propose a novel ELM called two-stage transfer extreme learning machine (TSTELM) to solve this problem. At the statistical matching stage, we adopt maximum mean discrepancy (MMD) to narrow the distribution difference of the output layer between domains. In addition, at the subspace alignment stage, we align the source and target model parameters, design target cross-domain mean approximation, and add the output weight approximation to further promote the knowledge transferring across domains. Moreover, the prediction of test sample is jointly determined by the ELM parameters generated at the two stages. Finally, we investigate the proposed approach in classification task and conduct experiments on four public domain adaptation datasets. The result indicates that TSTELM could effectively enhance the knowledge transfer ability of ELM with higher accuracy than other existing transfer and non-transfer classifiers.
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Algoritmos , Aprendizaje AutomáticoRESUMEN
Abnormalities of the insulinlike growth factor 2 (IGF2)H19 locus with the overexpression of IGF2 are frequent findings in adrenocortical carcinoma (ACC). The present study assessed the expression of RNAs and microRNAs (miRNAs/miRs) from the IGF2H19 locus using PCRbased methods in ACC and adrenocortical adenoma (ACA). The results were associated with proteomics data. IGF2 was overexpressed in ACC, and its expression correlated with that of miR4833p and miR4835p hosted by IGF2. The downregulated expression of H19 in ACC compared to ACA correlated with miR675 expression hosted by H19. Several proteins exhibited an inverse correlation in expression and were predicted as targets of miR4833p, miR4835p or miR675. Subsets of these proteins were differentially expressed between ACC and ACA. These included several proteins involved in mitochondrial metabolism. Among the mitochondrial respiratory complexes, complex I and IV were significantly decreased in ACC compared to ACA. The protein expression of NADH:ubiquinone oxidoreductase subunit C1 (NDUFC1), a subunit of mitochondrial respiratory complex I, was further validated as being lower in ACC compared to ACA and normal adrenals. The silencing of miR4835p increased NDUFC1 protein expression and reduced both oxygen consumption and glycolysis rates. On the whole, the findings of the present study reveal the dysregulation of the IGF2H19 locus and mitochondrial respiration in ACC. These findings may provide a basis for the further understanding of the pathogenesis of ACC and may have potential values for diagnostics and treatment.
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Neoplasias de la Corteza Suprarrenal , Adenoma Corticosuprarrenal , Carcinoma Corticosuprarrenal , MicroARNs , Neoplasias de la Corteza Suprarrenal/genética , Neoplasias de la Corteza Suprarrenal/patología , Adenoma Corticosuprarrenal/metabolismo , Adenoma Corticosuprarrenal/patología , Carcinoma Corticosuprarrenal/genética , Carcinoma Corticosuprarrenal/patología , Complejo I de Transporte de Electrón/metabolismo , Humanos , Factor II del Crecimiento Similar a la Insulina/genética , Factor II del Crecimiento Similar a la Insulina/metabolismo , MicroARNs/genética , NAD/metabolismo , UbiquinonaRESUMEN
Long non-coding RNAs (lncRNAs) play important roles in cancer development and progression; however, their contributions to gastric cancer metastasis remain largely unknown. By lncRNA microarray screening, our study showed that 453 lncRNAs are dysregulated in gastric cancer tissues with or without lymph node metastasis, of which lnc-LEMGC ranks as one of the most significantly downregulated lncRNAs. Lnc-LEMGC inhibited cell migration and invasion both in vitro and in vivo, by combining with protein DNA-PKcs. Importantly, nucleotides 1300-1800 of lnc-LEMGC prevented DNA-PKcs phosphorylation of serine 2056 and partially abrogated the effects of downstream effectors, ErbB1, SRC and protein tyrosine kinase 2 (FAK), in the epidermal growth factor receptor (EGFR) pathway. The results of this study extend our knowledge of lncRNA's molecular mechanisms, in which lnc-LEMGC functions by directly suppressing the phosphorylation of its combined protein DNA-PKcs and inactivating the DNA-PKcs downstream EGFR signaling.
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Receptores ErbB/genética , Quinasa 1 de Adhesión Focal/genética , ARN Largo no Codificante/genética , Neoplasias Gástricas/genética , Familia-src Quinasas/genética , Anciano , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular/genética , Femenino , Regulación Neoplásica de la Expresión Génica/genética , Humanos , Metástasis Linfática/genética , Metástasis Linfática/patología , Masculino , Persona de Mediana Edad , Transducción de Señal/genética , Neoplasias Gástricas/patologíaRESUMEN
Interferon-gamma (IFN-γ) signaling in keratinocytes plays an important role in IFN-γ-induced skin inflammation. A novel tacrolimus topical ointment has shown remarkable efficacy in treating skin inflammation. This study explored the mechanism of tacrolimus-modulated IFN-γ signal transduction in HaCaT keratinocytes and the effects of tacrolimus on IFN-γ-associated cytokine production in HaCaT cells. Tacrolimus down-regulated the recombinant human IFN-γ (rhIFN-γ)-induced expression of IFN-γ receptor α (IFN-γRα). The IFN-γ induced expression of phosphorylated Janus kinase 2 (pJAK2) and phosphorylated signal transducer and activator of transcription-1 (pSTAT-1) was also inhibited by tacrolimus. Tacrolimus up-regulated the IFN-γ-induced expression of suppressor of cytokine signaling-1 (SOCS-1). Tacrolimus was also demonstrated to down-regulate IFN-γ-induced the secretion of chemotactic factor CXCL-8 and the expression of intercellular adhesion molecule-1 and human leucocyte antigen HLA-DR. The findings in this work indicate that the direct effects of tacrolimus on IFN-γ signaling in keratinocytes may contribute to its therapeutic efficacy as a topical ointment in the treatment of IFN-γ-dependent skin inflammation.
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Inmunosupresores/farmacología , Interferón gamma/efectos de los fármacos , Tacrolimus/farmacología , Supervivencia Celular/efectos de los fármacos , Regulación hacia Abajo/fisiología , Ensayo de Inmunoadsorción Enzimática , Antígenos HLA-DR/metabolismo , Humanos , Molécula 1 de Adhesión Intercelular/metabolismo , Interferón gamma/farmacología , Interleucina-8/metabolismo , Janus Quinasa 2/metabolismo , Queratinocitos/metabolismo , Factor de Transcripción STAT1/metabolismo , Transducción de Señal/efectos de los fármacos , Proteína 1 Supresora de la Señalización de Citocinas , Proteínas Supresoras de la Señalización de Citocinas/metabolismo , Regulación hacia Arriba/fisiologíaRESUMEN
Merkel cell carcinoma is an aggressive skin malignancy, mostly caused by Merkel cell polyomavirus (MCPyV). MCPyV T-antigens can induce mature microRNA expressions through the DnaJ domain, but its underlying mechanism is still unknown. Here, we report that the T-antigens induce protein expression and mRNA stability of DICER1, a key factor in microRNA biogenesis, through heat shock cognate 70 (HSC70). HSC70 directly interacts with the AU-rich elements (ARE) of DICER1 mRNA in both coding and 3' untranslated region in the presence of MCPyV T-antigen. The T-antigen/HSC70 interaction could induce luciferase activity of synthetic ARE-containing reporter, as well as the stability of ARE-containing mRNAs, suggesting a broader role of MCPyV T-antigens in regulating multiple mRNAs via HSC70. These findings highlight a new role for the interaction of HSC70 and MCPyV T-antigens in mRNA regulation and an undescribed regulatory mechanism of DICER1 mRNA stability and translation through its direct interaction with HSC70.
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Increasing evidence reveals that the Rho GTPase-activating protein is a crucial negative regulator of Rho family GTPase involved in tumorigenesis. The Rho GTPase-activating protein 25 (ARHGAP25) has been shown to specifically inactivate the Rho family GTPase Rac1, which plays an important role in pancreatic adenocarcinoma (PAAD) progression. Therefore, here we aimed to clarify the expression and functional role of ARHGAP25 in PAAD. The ARHGAP25 expression was lower in PAAD tissues than that in normal pancreatic tissues based on bioinformatics analysis and immunohistochemistry staining. Overexpression of ARHGAP25 inhibited cell growth of AsPC-1 human pancreatic cancer cells in vitro, while opposite results were observed in BxPC-3 human pancreatic cancer cells with ARHGAP25 knockdown. Consistently, in vivo tumorigenicity assays also confirmed that ARHGAP25 overexpression suppressed tumor growth. Mechanically, overexpression of ARHGAP25 inactivated AKT/mTOR signaling pathway by regulating Rac1/PAK1 signaling, which was in line with the results from the Gene set enrichment analysis on The Cancer Genome Atlas dataset. Furthermore, we found that ARHGAP25 reduced HIF-1α-mediated glycolysis in PAAD cells. Treatment with PF-04691502, a dual PI3K/mTOR inhibitor, hampered the increased cell growth and glycolysis due to ARHGAP25 knockdown in PAAD cells. Altogether, these results conclude that ARHGAP25 acts as a tumor suppressor by inhibiting the AKT/mTOR signaling pathway, which might provide a therapeutic target for PAAD.
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Adenocarcinoma/genética , Carcinogénesis/genética , Proteínas Activadoras de GTPasa/genética , Regulación Neoplásica de la Expresión Génica , Proteína Oncogénica v-akt/genética , Neoplasias Pancreáticas/genética , Serina-Treonina Quinasas TOR/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patología , Animales , Ciclo Celular , Línea Celular Tumoral , Proliferación Celular , Transformación Celular Neoplásica/genética , Femenino , Proteínas Activadoras de GTPasa/biosíntesis , Glucólisis/genética , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Persona de Mediana Edad , Neoplasias Experimentales , Proteína Oncogénica v-akt/biosíntesis , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patología , ARN Neoplásico/genética , ARN Neoplásico/metabolismo , Transducción de Señal , Serina-Treonina Quinasas TOR/biosíntesisRESUMEN
Background: Drug resistance is one of the biggest challenges in cancer therapy. temozolomide (TMZ) represents the most important chemotherapeutic option for glioma treatment. However, the therapeutic efficacy of TMZ remains very limited due to its frequent resistance in glioma, and the underlying mechanisms were not fully addressed. Herein, we demonstrate that the elevated expression of CD147 contributes to TMZ resistance in glioma cells, potentially through the post-translational regulation of Nrf2 expression. Methods: Cell-based assays of CD147 triggered drug resistance were performed through Edu-incorporation assay, CCK8 assay, TUNEL staining assay and flow cytometric assay. Luciferase reporter assay, protein stability related assays, co-immunoprecipitation assay were used to determine CD147 induction of Nrf2 expression through ß-TrCP dependent ubiquitin system. Finally, the effect of the CD147/Nrf2 signaling on glioma progression and TMZ resistance were evaluated by functional experiments and clinical samples. Results: Based on the analysis of clinical glioma tissues, CD147 is highly expressed in glioma tissues and positively associated with tumor malignancy. Suppression of CD147 expression increased the inhibitory effect of TMZ on cell survival in both U251 and T98G cells, whereas the gain of CD147 function blocked TMZ-induced ROS production and cell death. Mechanistic study indicates that CD147 inhibited GSK3ß/ß-TrCP-dependent Nrf2 degradation by promoting Akt activation, and subsequently increased Nrf2-mediated anti-oxidant gene expressions. Supporting the biological significance, the reciprocal relationship between CD147 and Nrf2 was observed in glioma tissues, and associated with patient outcome. Conclusions: Our data provide the first evidence that glioma resistance to TMZ is potentially due to the activation of CD147/Nrf2 axis. CD147 promotes Nrf2 stability through the suppression of GSK3ß/ß-TrCP dependent Nrf2 protein degradation, which results in the ablation of TMZ induced ROS production. As such, we point out that targeting CD147/Nrf2 axis may provide a new strategy for the treatment of TMZ resistant gliomas.
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Basigina/metabolismo , Neoplasias Encefálicas/tratamiento farmacológico , Glioma/tratamiento farmacológico , Transducción de Señal/efectos de los fármacos , Temozolomida/farmacología , Animales , Neoplasias Encefálicas/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Glioma/metabolismo , Humanos , Masculino , Ratones , Ratones Desnudos , Factor 2 Relacionado con NF-E2/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto , Proteínas con Repetición de beta-Transducina/metabolismoRESUMEN
Mutations in the miRNA enzyme gene DICER1 have been reported in several endocrine malignancies and is associated with the rare tumour-predisposing DICER1 syndrome. DICER1 mutations have been reported in subsets of follicular thyroid carcinoma (FTC), but the role of DICER1 in follicular thyroid tumorigenesis has not been extensively studied. In this study, we investigate the role of DICER1 in 168 follicular thyroid tumours and in an FTC cell line. We found rare DICER1 mutations in paediatric FTC cases and a general DICER1 down-regulation in FTCs visualized both on mRNA and protein level, especially pronounced in Hürthle cell carcinoma (HuCC). The down-regulation was also evident in follicular thyroid adenomas (FTAs), suggesting a potential early step in tumorigenesis. The expression of DICER1 was lower in FTCs of older patients in which TERT promoter mutations are more frequent. In FTCs, DICER1 down-regulation was not caused by gene copy number loss but significantly correlated to expression of the transcription factor GABPA in clinical cases. GABPA was found to bind to the DICER1 promoter and regulate DICER1 expression in vitro, as GABPA depletion in FTC cell lines reduced DICER1 expression. This in turn stimulated cell proliferation and affected the miRNA machinery, evident by altered miRNA expression. To conclude, we show that GABPA directly regulates DICER1 in FTC, acting as a tumour suppressor and displaying down-regulation in clinical samples. We also show reduced expression of DICER1 in benign and malignant follicular thyroid tumours, suggesting a potentially early tumorigenic role of this gene aberrancy.
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Adenocarcinoma Folicular/genética , ARN Helicasas DEAD-box/metabolismo , Ribonucleasa III/metabolismo , Adenocarcinoma Folicular/patología , Adulto , Anciano , Anciano de 80 o más Años , Línea Celular Tumoral , Proliferación Celular , Regulación hacia Abajo , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Background: Metastasis is the most common cause of lethal outcome in various types of cancers. Although the cell proliferation related metabolism rewiring has been well characterized, less is known about the association of metabolic changes with tumor metastasis. Herein, we demonstrate that metastatic tumor obtained a mesenchymal phenotype, which is obtained by the loss of tumor suppressor NDRG2 triggered metabolic switch to glutamine metabolism. Methods: mRNA-seq and gene expression profile analysis were performed to define the differential gene expressions in primary MEC1 and metastatic MC3 cells and the downstream pathways of NDRG2. NDRG2 regulation of Fbw7-dependent c-Myc stability were determined by immunoprecipitation and protein half-life assay. Luciferase reporter and ChIP assays were used to determine the roles of Akt and c-Myc in mediating NDRG2-dependent regulation of ASCT2 in in both tumor and NDRG2-knockout MEF cells. Finally, the effect of the NDRG2/Akt/c-Myc/ASCT2 signaling on glutaminolysis and tumor metastasis were evaluated by functional experiments and clinical samples. Results: Based on the gene expression profile analysis, we identified metastatic tumor cells acquired the mesenchymal-like characteristics and displayed the increased dependency on glutamine utilization. Further, the gain of NDRG2 function blocked epithelial-mesenchymal transition (EMT) and glutaminolysis, potentially through suppression of glutamine transporter ASCT2 expression. The ASCT2 restoration reversed NDRG2 inhibitory effect on EMT program and tumor metastasis. Mechanistic study indicates that NDRG2 promoted Fbw7-dependent c-Myc degradation by inhibiting Akt activation, and subsequently decreased c-Myc-mediated ASCT2 transcription, in both tumor and NDRG2-knockout MEF cells. Supporting the biological significance, the reciprocal relationship between NDRG2 and ASCT2 were observed in multiple types of tumor tissues, and associated with tumor malignancy. Conclusions: NDRG2-dependent repression of ASCT2 presumably is the predominant route by which NDRG2 rewires glutaminolysis and blocks metastatic tumor survival. Targeting glutaminolytic pathway may provide a new strategy for the treatment of metastatic tumors.
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Sistema de Transporte de Aminoácidos ASC/genética , Reprogramación Celular , Glutamina/metabolismo , Antígenos de Histocompatibilidad Menor/genética , Neoplasias Experimentales/genética , Proteínas Supresoras de Tumor/genética , Animales , Línea Celular Tumoral , Transición Epitelial-Mesenquimal , Regulación Neoplásica de la Expresión Génica , Humanos , Ratones Desnudos , Metástasis de la Neoplasia/genética , Neoplasias Experimentales/metabolismo , Transducción de SeñalRESUMEN
Metabolic reprogramming is a hallmark of cancer cells in response to targeted therapy. Decreased glycolytic activity with enhanced mitochondrial respiration secondary to imatinib has been shown in imatinib-sensitive gastrointestional stromal tumors (GIST). However, the role of energy metabolism in imatinib-resistant GIST remains poorly characterized. Here, we investigated the effect of imatinib treatment on glycolysis and oxidative phosphorylation (OXPHOS), as well as the effect of inhibition of these energy metabolisms on cell viability in imatinib-resistant and -sensitive GIST cell lines. We observed that imatinib treatment increased OXPHOS in imatinib-sensitive, but not imatinib-resistant, GIST cells. Imatinib also reduced the expression of mitochondrial biogenesis activators (peroxisome proliferator-activated receptor coactivator-1 alpha (PGC1α), nuclear respiratory factor 2 (NRF2), and mitochondrial transcription factor A (TFAM)) and mitochondrial mass in imatinib-sensitive GIST cells. Lower TFAM levels were also observed in imatinib-sensitive GISTs than in tumors from untreated patients. Using the Seahorse system, we observed bioenergetics diversity among the GIST cell lines. One of the acquired resistant cell lines (GIST 882R) displayed a highly metabolically active phenotype with higher glycolysis and OXPHOS levels compared with the parental GIST 882, while the other resistant cell line (GIST T1R) had a similar basal glycolytic activity but lower mitochondrial respiration than the parental GIST T1. Further functional assays demonstrated that GIST 882R was more vulnerable to glycolysis inhibition than GIST 882, while GIST T1R was more resistant to OXPHOS inhibition than GIST T1. These findings highlight the diverse energy metabolic adaptations in GIST cells that allow them to survive upon imatinib treatment and reveal the potential of targeting the metabolism for GIST therapy.
Asunto(s)
Resistencia a Antineoplásicos , Tumores del Estroma Gastrointestinal/tratamiento farmacológico , Tumores del Estroma Gastrointestinal/metabolismo , Mesilato de Imatinib/uso terapéutico , Antimicina A/farmacología , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Metabolismo Energético/efectos de los fármacos , Tumores del Estroma Gastrointestinal/genética , Tumores del Estroma Gastrointestinal/patología , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Glucólisis/efectos de los fármacos , Gosipol/farmacología , Humanos , Mesilato de Imatinib/farmacología , Oligomicinas/farmacología , Biogénesis de Organelos , Fosforilación Oxidativa/efectos de los fármacos , Fenotipo , Piruvatos/farmacologíaRESUMEN
OBJECTIVE: To investigate the effects of triptolide on the production of interferon-gamma (IFN-gamma) in human peripheral blood mononuclear cell (PBMC) and interleukin-8 (IL-8) in HaCaT keratinocytes and phosphorylation of signal transducer and activator of transcription-1 (STAT1) of IFN-gamma signal transduction pathways in HaCaT cells. METHODS: Human PBMC was induced by phytohaemagglutinin (PHA-L) and HaCaT cells were stimulated by recombinant human IFN-gamma (rhIFN-gamma). The productions of IFN-gamma and IL-8 in cells were detected by ELISA. The expression of STAT1 and its phosphorylation were analyzed by Western blot. RESULTS: Triptolide inhibited the production of IFN-gamma in human PBMC induced by PHA-L in a dose-dependent manner (P < 0.05, P < 0.01, P < 0.001) and the 50% inhibitory concentration (IC50) value was 5.96 x 10(-11) mol/L. IL-8 production in HaCaT cells induced by rhIFN-gamma in vitro was also inhibited by triptolide (P < 0.001) and the IC50 value was about 1.15 x 10(-13) mol/L. The expressions of phosphorylated STAT1 in HaCaT cells stimulated by rhIFN-gamma was inhibited by triptolide (P < 0.01) and the IC50 value was about 9.45 x 10(-11) mol/L. CONCLUSION: Triptolide can inhibit the production of IFN-gamma in human PBMC and downregulate IL-8 level in HaCaT keratinocytes induced by rhIFN-gamma. Triptolide can inhibit the phosphorylations of STAT1 of IFN-gamma signal pathway in HaCaT keratinocytes stimulated by IFN-gamma.
Asunto(s)
Antiinflamatorios no Esteroideos/farmacología , Diterpenos/farmacología , Interferón gamma/biosíntesis , Interleucina-8/biosíntesis , Leucocitos Mononucleares/efectos de los fármacos , Fenantrenos/farmacología , Factor de Transcripción STAT1/metabolismo , Compuestos Epoxi/farmacología , Humanos , Interferón gamma/farmacología , Queratinocitos/efectos de los fármacos , Queratinocitos/metabolismo , Leucocitos Mononucleares/metabolismo , FosforilaciónRESUMEN
cAMP responsive element binding protein 1 (CREB1) has been reported to be implicated in tumor development and progression of human cancers. However, the clinical significance and regulatory mechanisms of CREB1 expression in gastric cancer remain largely unknown. In the present study, immunohistochemistry was performed to detect the expression of CREB1 protein in 185 primary gastric cancer tissues, 50 secondary lymph node metastatic foci and 50 nontumorous gastric tissues. A prognostic model combining CREB1 expression with TNM tumor stage was constructed by logistic regression analysis. Regulation of CREB1 by miRNAs was investigated by luciferase reporter assay and Western blot. It was shown that CREB1 was highly expressed and correlated with lymph node metastasis, distant metastasis and tumor stage and poor outcome in gastric cancer. The prognostic model was proven to be an independent prognosis predictor and performed better than CREB1 or tumor stage alone. CREB1 was identified as a direct target of miR-27b and miR-200b, and down-regulated by miR-27b/miR-200b. We conclude that CREB1 is a promising biomarker to predict tumor metastasis and patient outcome in gastric cancer, and the miR-27b/miR-200b-CREB1 pathway may serve as a potential molecular target for the treatment of gastric cancer.