RESUMEN
OBJECTIVE: Telomere length-related genes (TLRGs) play an important role in multiple tumors; however, there is a lack of systematic reporting about their relevance in non-small cell lung cancer (NSCLC). This study investigated the relation between TLRG gene expression and the immunotherapeutic response of patients with NSCLC. MATERIALS AND METHODS: Differentially expressed TLRGs in tumor tissues and normal tissues were screened using Gene Expression Omnibus (GEO) datasets. A univariate Cox regression analysis was performed to identify the optimal prognosis-related genes. A prognostic risk model was constructed by using least absolute shrinkage, selection operator, and multivariate Cox regression analysis results. The model was then evaluated by a Kaplan-Meier analysis, functional enrichment annotation, and a receiver operating characteristic curve analysis; after which, it was validated in the TCGA dataset. The model was used to predict immunotherapeutic response and drug sensitivity. RESULTS: An 18-gene prognostic signature was developed and used to stratify NSCLC patients into a low- or high-risk group in GEO cohorts. Patients in the low-risk group had better survival possibilities than those in the high-risk group, and showed significantly higher overall survival times in the TCGA cohort. The risk score was identified as an independent prognostic factor, when compared with other clinical factors. ssGSEA scores showed that the risk model was mainly linked to cancer- and immune-related pathways. Importantly, the candidate risk model was linked to tumor immunity and predicted a patient's response to PDL-1 blockade immune therapy. Several potential drugs that might target this model were identified. CONCLUSIONS: This study provides broad molecular signatures that can be used in further functional and therapeutic studies of the telomere system, and also represents an integrated approach for characterizing key protein complexes when creating a prognosis and identifying new targets for cancer immunotherapy.
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Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Biomarcadores de Tumor/genética , Carcinoma de Pulmón de Células no Pequeñas/diagnóstico , Carcinoma de Pulmón de Células no Pequeñas/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Inmunidad , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/genética , Pronóstico , Telómero/genéticaRESUMEN
BACKGROUND: Distant metastasis is the major cause of cancer-related death, and epithelial-to-mesenchymal transition (EMT) has a critical role in this process. Accumulating evidence indicates that EMT can be regulated by microRNAs (miRNAs). miR-29c has been implicated as a tumor suppressor in several human cancers. However, the role of miR-29c in the progression of colorectal cancer (CRC) metastasis remains largely unknown. PATIENTS AND METHODS: The expression of miR-29c was examined by qRT-PCR in a cohort of primary CRC (PC) and distant liver metastasis (LM) tissues. A series of in vivo and in vitro assays were carried out in order to elucidate the functions of miR-29c and the molecular mechanisms underlying the pathogenesis of metastatic CRC. RESULTS: miR-29c was markedly downregulated in PCs with distant metastasis and determined to be an independent predictor of shortened patient survival. But LM tissues showed higher levels of miR-29c than that in PC tissues. In CRC cells, miR-29c dramatically suppressed cell migration and invasion abilities in vitro and cancer metastasis in vivo. In addition, miR-29c inhibited EMT and negatively regulated Wnt/ß-catenin signaling pathway. Guanine nucleotide binding protein alpha13 (GNA13) and protein tyrosine phosphatase type IVA (PTP4A) were identified as direct targets of miR-29c, which acted through ERK/GSK3ß/ß-catenin and AKT/GSK3ß/ß-catenin pathways, respectively, to regulate EMT. Furthermore, significant associations between miR-29c, its target genes (GNA13 and PTP4A) and EMT markers were validated in both PC and LM tissues. CONCLUSION: Our findings highlight the important role of miR-29c in regulating CRC EMT via GSK-3ß/ß-catenin signaling by targeting GNA13 and PTP4A and provide new insights into the metastatic basis of CRC.
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Proteínas de Ciclo Celular/biosíntesis , Neoplasias Colorrectales/genética , Proteínas de la Membrana/biosíntesis , MicroARNs/genética , Proteínas Tirosina Fosfatasas/biosíntesis , beta Catenina/genética , Proteínas de Ciclo Celular/genética , Línea Celular Tumoral , Movimiento Celular/genética , Neoplasias Colorrectales/patología , Transición Epitelial-Mesenquimal/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Glucógeno Sintasa Quinasa 3/genética , Glucógeno Sintasa Quinasa 3 beta , Humanos , Proteínas de la Membrana/genética , Metástasis de la Neoplasia , Proteínas Tirosina Fosfatasas/genética , Vía de Señalización WntRESUMEN
Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer, and is also highly resistant to conventional chemotherapy treatments. In this study, we report that Longikaurin A (LK-A), an ent-kaurane diterpenoid isolated from the plant Isodon ternifolius, induced cell cycle arrest and apoptosis in human HCC cell lines. LK-A also suppressed tumor growth in SMMC-7721 xenograft models, without inducing any notable major organ-related toxicity. LK-A treatment led to reduced expression of the proto-oncogene S phase kinase-associated protein 2 (Skp2) in SMMC-7721 cells. Lower Skp2 levels correlated with increased expression of p21 and p-cdc2 (Try15), and a corresponding decrease in protein levels of Cyclin B1 and cdc2. Overexpression of Skp2 significantly inhibited LK-A-induced cell cycle arrest in SMMC-7721 cells, suggesting that LK-A may target Skp2 to arrest cells at the G2/M phase. LK-A also induced reactive oxygen species (ROS) production and apoptosis in SMMC-7721 cells. LK-A induced phosphorylation of c-Jun N-terminal kinase (JNK), but not extracellular signal-regulated kinase and P38 MAP kinase. Treatment with, the JNK inhibitor SP600125 prevented LK-A-induced apoptosis in SMMC-7721 cells. Moreover, the antioxidant N-acetylcysteine prevented phosphorylation of both JNK and c-Jun. Taken together, these data indicate that LK-A induces cell cycle arrest and apoptosis in cancer cells by dampening Skp2 expression, and thereby activating the ROS/JNK/c-Jun signaling pathways. LK-A is therefore a potential lead compound for development of antitumor drugs targeting HCC.
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Antineoplásicos Fitogénicos/farmacología , Apoptosis/efectos de los fármacos , Carcinoma Hepatocelular/tratamiento farmacológico , Diterpenos de Tipo Kaurano/farmacología , Puntos de Control de la Fase G2 del Ciclo Celular/efectos de los fármacos , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Neoplasias Hepáticas/tratamiento farmacológico , Proteínas Proto-Oncogénicas c-jun/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Proteínas Quinasas Asociadas a Fase-S/metabolismo , Transducción de Señal/efectos de los fármacos , Animales , Proteína Quinasa CDC2 , Carcinoma Hepatocelular/enzimología , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patología , Ciclina B/metabolismo , Ciclina B1/metabolismo , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/metabolismo , Quinasas Ciclina-Dependientes , Relación Dosis-Respuesta a Droga , Regulación hacia Abajo , Células Hep G2 , Humanos , Proteínas Quinasas JNK Activadas por Mitógenos/antagonistas & inhibidores , Neoplasias Hepáticas/enzimología , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patología , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Fosforilación , Inhibidores de Proteínas Quinasas/farmacología , Proto-Oncogenes Mas , Proteínas Quinasas Asociadas a Fase-S/genética , Factores de Tiempo , Transfección , Carga Tumoral/efectos de los fármacos , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The enhancer of zeste homolog 2 (EZH2) is upregulated and has an oncogenic role in several types of human cancer. However, the abnormalities of EZH2 and its underlying mechanisms in the pathogenesis of nasopharyngeal carcinoma (NPC) remain unknown. In this study, we found that high expression of EZH2 in NPC was associated closely with an aggressive and/or poor prognostic phenotype (P<0.05). In NPC cell lines, knockdown of EZH2 by short hairpin RNA was sufficient to inhibit cell invasiveness/metastasis both in vitro and in vivo, whereas ectopic overexpression of EZH2 supported NPC cell invasive capacity with a decreased expression of E-cadherin. In addition, ablation of endogenous Snail in NPC cells virtually totally prevented the repressive activity of EZH2 to E-cadherin, indicating that Snail might be a predominant mediator of EZH2 to suppress E-cadherin. Furthermore, co-immunoprecipitation (IP), chromatin IP and luciferase reporter assays demonstrated that in NPC cells, (1) EZH2 interacted with HDAC1/HDAC2 and Snail to form a repressive complex; (2) these components interact in a linear fashion, not in a triangular fashion, that is, HDAC1 or HDAC2 bridge the interaction between EZH2 and Snail; and (3) the EZH2/HDAC1/2/Snail complex could closely bind to the E-cadherin promoter by Snail, but not YY1, to repress E-cadherin. The data provided in this report suggest a critical role of EZH2 in the control of cell invasion and/or metastasis by forming a co-repressor complex with HDAC1/HDAC2/Snail to repress E-cadherin, an activity that might be responsible, at least in part, for the development and/or progression of human NPCs.
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Cadherinas/genética , Proteínas de Unión al ADN/metabolismo , Histona Desacetilasa 1/metabolismo , Histona Desacetilasa 2/metabolismo , Neoplasias Nasofaríngeas/metabolismo , Factores de Transcripción/metabolismo , Adulto , Animales , Secuencia de Bases , Línea Celular Tumoral , Proteínas de Unión al ADN/genética , Proteína Potenciadora del Homólogo Zeste 2 , Femenino , Regulación Neoplásica de la Expresión Génica , Histona Desacetilasa 1/genética , Histona Desacetilasa 2/genética , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Persona de Mediana Edad , Datos de Secuencia Molecular , Complejos Multiproteicos/metabolismo , Neoplasias Nasofaríngeas/genética , Neoplasias Nasofaríngeas/patología , Invasividad Neoplásica , Metástasis de la Neoplasia , Complejo Represivo Polycomb 2 , Regiones Promotoras Genéticas/genética , Unión Proteica , Interferencia de ARN , Proteínas Represoras/metabolismo , Factores de Transcripción de la Familia Snail , Factores de Transcripción/genéticaRESUMEN
Telomere maintenance is essential for cancer growth. Induction of telomere dysfunction, for example, by inhibition of telomeric proteins or telomerase, has been shown to strongly enhance cancer cells' sensitivity to chemotherapies. However, it is not clear whether modulations of telomere maintenance constitute cancer cellular responses to chemotherapies. Furthermore, the manner in which anti-cancer drugs affect telomere function remains unknown. In this study, we show that anthracyclines, a class of anti-cancer drugs widely used in clinical cancer treatments, have an active role in triggering telomere dysfunction specifically in telomerase-positive cancer cells. Anthracyclines interrupt telomere maintenance by telomerase through the downregulation of PinX1, a protein factor responsible for targeting telomerase onto telomeres, thereby inhibiting telomerase association with telomeres. We further demonstrate that anthracyclines downregulate PinX1 by inducing this protein degradation through the ubiquitin-proteasome-dependent pathway. Our data not only reveal a novel action for anthracyclines as telomerase functional inhibitors but also provide a clue for the development of novel anti-cancer drugs based on telomerase/telomere targeting, which is actively investigated by many current studies.