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2.
Cell Death Discov ; 9(1): 291, 2023 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-37558683

RESUMEN

Radiotherapy resistance is an important and urgent challenge in the clinical management of esophageal squamous carcinoma (ESCC). However, the factors mediating the ESCC resistance to radiotherapy and its underlying molecular mechanisms are not fully clarified. Our previous studies have demonstrated the critical role of DNA polymerase iota (POLI) in ESCC development and progression, here, we aimed to investigate the involvement of POLI in ESCC radiotherapy resistance and elucidate the underlying molecular mechanism. We found that highly expressed POLI was correlated with shorter overall survival of ESCC patients received radiotherapy. Down-regulation of POLI sensitized ESCC to IR, prolonged γH2AX foci in nuclei and comet tails after IR. HR but not NHEJ repair is inhibited in POLI-deficient ESCC cells. POLI stabilizes RAD51 protein via competitively binding with and blocking the interaction between RAD51 and E3 ligase XIAP and XIAP-mediated ubiquitination. Furthermore, loss of POLI leads to the activation of GAS signaling. Our findings provide novel insight into the role of POLI in the development of radioresistance mediated by stabilizing RAD51 protein in ESCC.

3.
Exploration (Beijing) ; 3(2): 20220119, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37324033

RESUMEN

Ionizing radiation (IR) poses a growing threat to human health, and thus ideal radioprotectors with high efficacy and low toxicity still receive widespread attention in radiation medicine. Despite significant progress made in conventional radioprotectants, high toxicity, and low bioavailability still discourage their application. Fortunately, the rapidly evolving nanomaterial technology furnishes reliable tools to address these bottlenecks, opening up the cutting-edge nano-radioprotective medicine, among which the intrinsic nano-radioprotectants characterized by high efficacy, low toxicity, and prolonged blood retention duration, represent the most extensively studied class in this area. Herein, we made the systematic review on this topic, and discussed more specific types of radioprotective nanomaterials and more general clusters of the extensive nano-radioprotectants. In this review, we mainly focused on the development, design innovations, applications, challenges, and prospects of the intrinsic antiradiation nanomedicines, and presented a comprehensive overview, in-depth analysis as well as an updated understanding of the latest advances in this topic. We hope that this review will promote the interdisciplinarity across radiation medicine and nanotechnology and stimulate further valuable studies in this promising field.

5.
Cells ; 11(10)2022 05 16.
Artículo en Inglés | MEDLINE | ID: mdl-35626687

RESUMEN

Renal cell carcinoma (RCC) is one of the most aggressive urological malignancies and has a poor prognosis, especially in patients with metastasis. Although RCC is traditionally considered to be radioresistant, radiotherapy (RT) is still a common treatment for palliative management of metastatic RCC. Novel approaches are urgently needed to overcome radioresistance of RCC. Black phosphorus quantum dots (BPQDs) have recently received great attention due to their unique physicochemical properties and good biocompatibility. In the present study, we found that BPQDs enhance ionizing radiation (IR)-induced apoptotic cell death of RCC cells. BPQDs treatment significantly increases IR-induced DNA double-strand breaks (DSBs), as indicated by the neutral comet assay and the DSBs biomarkers γH2AX and 53BP1. Mechanistically, BPQDs can interact with purified DNA-protein kinase catalytic subunit (DNA-PKcs) and promote its kinase activity in vitro. BPQDs impair the autophosphorylation of DNA-PKcs at S2056, and this site phosphorylation is essential for efficient DNA DSBs repair and the release of DNA-PKcs from the damage sites. Consistent with this, BPQDs suppress nonhomologous end-joining (NHEJ) repair and lead to sustained high levels of autophosphorylated DNA-PKcs on the damaged sites. Moreover, animal experiments indicate that the combined approach with both BPQDs and IR displays better efficacy than monotreatment. These findings demonstrate that BPQDs have potential applications in radiosensitizing RCC cells.


Asunto(s)
Carcinoma de Células Renales , Neoplasias Renales , Puntos Cuánticos , Animales , Carcinoma de Células Renales/radioterapia , ADN/metabolismo , Reparación del ADN , Humanos , Neoplasias Renales/radioterapia , Fósforo , Polinucleótido 5'-Hidroxil-Quinasa/metabolismo , Tolerancia a Radiación
6.
Oncogene ; 41(4): 489-501, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34775484

RESUMEN

Chromosomal instability (CIN) is a driving force for cancer development. The most common causes of CIN include the dysregulation of the spindle assembly checkpoint (SAC), which is a surveillance mechanism that prevents premature chromosome separation during mitosis by targeting anaphase-promoting complex/cyclosome (APC/C). DAB2IP is frequently silenced in advanced prostate cancer (PCa) and is associated with aggressive phenotypes of PCa. Our previous study showed that DAB2IP activates PLK1 and functions in mitotic regulation. Here, we report the novel mitotic phosphorylation of DAB2IP by Cdks, which mediates DAB2IP's interaction with PLK1 and the activation of the PLK1-Mps1 pathway. DAB2IP interacts with Cdc20 in a phosphorylation-independent manner. However, the phosphorylation of DAB2IP inhibits the ubiquitylation of Cdc20 in response to SAC, and blocks the premature release of the APC/C-MCC. The PLK1-Mps1 pathway plays an important role in mitotic checkpoint complex (MCC) assembly. It is likely that DAB2IP acts as a scaffold to aid PLK1-Mps1 in targeting Cdc20. Depletion or loss of the Cdks-mediated phosphorylation of DAB2IP destabilizes the MCC, impairs the SAC, and increases chromosome missegregation and subsequent CIN, thus contributing to tumorigenesis. Collectively, these results demonstrate the mechanism of DAB2IP in SAC regulation and provide a rationale for targeting the SAC to cause lethal CIN against DAB2IP-deficient aggressive PCa, which exhibits a weak SAC.


Asunto(s)
Puntos de Control del Ciclo Celular/genética , Inestabilidad Cromosómica/genética , Mitosis/genética , Oncogenes/genética , Huso Acromático/metabolismo , Humanos , Fosforilación , Transducción de Señal , Transfección
7.
Cell Cycle ; 20(2): 211-224, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-33404279

RESUMEN

Combining targeted therapeutic agents is an attractive cancer treatment strategy associated with high efficacy and low toxicity. DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is an essential factor in DNA damage repair. Studies from us and others have revealed that DNA-PKcs also plays an important role in normal mitosis progression. Histone deacetylase (HDACs) inhibitors commonly lead to mitotic aberration and have been approved for treating various cancers in the clinic. We showed that DNA-PKcs depletion or kinase activity inhibition increases cancer cells' sensitivity to HDACs inhibitors in vitro and in vivo. DNA-PKcs deficiency significantly enhances HDACs inhibitors (HDACi)-induced mitotic arrest and is followed by apoptotic cell death. Mechanistically, we found that DNA-PKcs binds to HDAC6 and facilitates its acetylase activity. HDACi is more likely to impair HDAC6-induced deacetylation of HSP90 and abrogate HSP90's chaperone function on Aurora A, a critical mitotic kinase that regulates centrosome separation and mitotic spindle assembly in DNA-PKcs-deficient cells. Our current work indicates crosstalk between DNA-PKcs and HDACs signaling pathways, and highlights that the combined targeting of DNA-PKcs and HDACs can be used in cancer therapy. Abbreviations: DNA-PKcs, DNA-dependent protein kinase catalytic subunit, HDACs, Histone deacetylases, DSBs, DNA double-strand breaks, ATM, ataxia telangiectasia mutated, ATR, ATM-Rad3-related.


Asunto(s)
Proteína Quinasa Activada por ADN/metabolismo , Proteínas HSP90 de Choque Térmico/metabolismo , Histona Desacetilasa 6/metabolismo , Chaperonas Moleculares/metabolismo , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Proteínas de Ciclo Celular/metabolismo , División del Núcleo Celular/genética , División del Núcleo Celular/fisiología , Daño del ADN/genética , Reparación del ADN/genética , Histona Desacetilasa 6/genética , Humanos , Proteínas Supresoras de Tumor/metabolismo
8.
Oncogenesis ; 10(1): 8, 2021 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-33431808

RESUMEN

The PI3K/AKT/mTOR signaling pathway is constitutively active in PTEN-deficient cancer cells, and its targeted inhibition has significant anti-tumor effects. However, the efficacy of targeted therapies is often limited due to drug resistance. The relevant signaling pathways in PTEN-deficient cancer cells treated with the PI3K/mTOR inhibitor BEZ235 were screened using a phosphokinase array, and further validated following treatment with multiple PI3K/AKT/mTOR inhibitors or AKT knockdown. The correlation between PTEN expression levels and STAT3 kinase phosphorylation in the tissue microarrays of gastric cancer patients was analyzed by immunohistochemistry. Cell proliferation and clonogenic assays were performed on the suitably treated PTEN-deficient cancer cells. Cytokine arrays, small molecule inhibition and knockdown assays were performed to identify related factors. PTEN-deficient tumor xenografts were established in nude mice that were treated with PI3K/AKT/mTOR and/or STAT3 inhibitors. PTEN deficiency was positively correlated with low STAT3 activity. PI3K/mTOR inhibitors increased the expression and secretion of macrophage migration inhibitory factor (MIF) and activated the JAK1/STAT3 signaling pathway. Both cancer cells and in vivo tumor xenografts showed that the combined inhibition of PI3K/AKT/mTOR and STAT3 activity enhanced the inhibitory effect of BEZ235 on the proliferation of PTEN-deficient cancer cells. Our findings provide a scientific basis for a novel treatment strategy in cancer patients with PTEN deficiency.

9.
Toxicol Appl Pharmacol ; 387: 114855, 2020 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-31830491

RESUMEN

Vanillin is a natural compound endowed with antioxidant and anti-mutagenic properties. We previously identified the vanillin derivative VND3207 with strong radio-protective and antioxidant effects and found that VND3207 confers survival benefit and protection against radiation-induced intestinal injury (RIII) in mice. We also observed that VND3207 treatment enhanced the expression level of the catalytic subunit of the DNA-dependent protein kinase (DNA-PKcs) in human lymphoblastoid cells with or without γ-irradiation. DNA-PKcs is a critical component of DNA double strand break repair pathway and also regulates mitotic progression by stabilizing spindle formation and preventing mitotic catastrophe in response to DNA damage. In the present study, we found that VND3207 protected intestinal epithelial cells in vitro against ionizing radiation by promoting cell proliferation and inhibiting cell apoptosis. In addition, VND3207 promoted DNA-PKcs activity by increasing autophosphorylation at S2056 site. Consistent with this, VND3207 significantly decreased the number of γH2AX foci and mitotic catastrophe after radiation. DNA-PKcs deficiency abolished these VND3207 radio-protective effects, indicating that DNA-PKcs activation is essential for VND3207 activity. In conclusion, VND3207 promoted intestinal repair following radiation injury by regulating the DNA-PKcs pathway.


Asunto(s)
Benzaldehídos/farmacología , Proteína Quinasa Dependiente de GMP Cíclico Tipo I/metabolismo , Proteína Quinasa Activada por ADN/metabolismo , Mucosa Intestinal/efectos de los fármacos , Traumatismos Experimentales por Radiación/prevención & control , Protectores contra Radiación/farmacología , Animales , Apoptosis/efectos de los fármacos , Apoptosis/efectos de la radiación , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Proliferación Celular/efectos de la radiación , Proteína Quinasa Activada por ADN/genética , Células Epiteliales/efectos de los fármacos , Células Epiteliales/patología , Células Epiteliales/efectos de la radiación , Rayos gamma/efectos adversos , Humanos , Mucosa Intestinal/citología , Mucosa Intestinal/patología , Mucosa Intestinal/efectos de la radiación , Mutación con Pérdida de Función , Masculino , Ratones , Fosforilación/efectos de los fármacos , Traumatismos Experimentales por Radiación/patología , Protectores contra Radiación/uso terapéutico
10.
Nanotoxicology ; 13(10): 1409-1421, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31589482

RESUMEN

Graphene quantum dots (GQDs) have gained significant attention in various biomedical applications. The physicochemical properties of these nanoparticles, including toxic effects, are largely determined by their surface modifications. Previous studies have demonstrated high in vitro cytotoxicity of the hydroxylated GQDs (OH-GQDs). The focus of this study was on the intestinal toxicity of OH-GQDs. Briefly, C57BL/6J mice were given daily oral gavage of 0.05, 0.5 or 5 mg/kg OH-GQD for 7 days, and the indices of intestinal damage were evaluated. Higher doses of the OH-GQDs caused significant intestinal injuries, such as enhanced intestinal permeability, shortened villi and crypt loss. The number of Lgr5+ intestinal stem cells also decreased dramatically upon OH-GQDs exposure, which also inhibited the Ki67+ proliferative progenitor cells. In addition, an increased number of crypt cells harboring the oxidized DNA base 8-OHdG and γH2AX foci were also detected in the intestines of OH-GQD-treated mice. Mechanistically, the OH-GQDs up-regulated both total and phosphorylated p53. Consistent with this, the average number of TUNEL+ and cleaved caspase-3+ apoptotic intestinal epithelial cells were significantly increased after OH-GQDs treatment. Finally, a 3-dimensional organoid culture was established using isolated crypts, and OH-GQDs treatment significantly reduced the size of the surviving intestinal organoids. Taken together, the intestinal toxicity of the OH-GQDs should be taken into account during biomedical applications.


Asunto(s)
Apoptosis/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Grafito/toxicidad , Mucosa Intestinal/efectos de los fármacos , Puntos Cuánticos/toxicidad , Células Madre/efectos de los fármacos , Administración Oral , Animales , Apoptosis/genética , Proliferación Celular/genética , Daño del ADN , Grafito/química , Hidroxilación , Mucosa Intestinal/patología , Intestino Delgado/efectos de los fármacos , Intestino Delgado/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Estrés Oxidativo/efectos de los fármacos , Permeabilidad , Puntos Cuánticos/química , Células Madre/patología , Propiedades de Superficie , Proteína p53 Supresora de Tumor/genética
11.
Free Radic Biol Med ; 145: 223-236, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31580946

RESUMEN

The intestine is a highly radiosensitive tissue that is susceptible to structural and functional damage due to systemic as well as localized radiation exposure. Unfortunately, no effective prophylactic or therapeutic agents are available at present to manage radiation-induced intestinal injuries. We observed that the vanillin derivative VND3207 improved the survival of lethally irradiated mice by promoting intestinal regeneration and increasing the number of surviving crypts. Pre-treatment with VND3207 significantly increased the number of Lgr5+ intestinal stem cells (ISCs) and their daughter cells, the transient Ki67+ proliferating cells. Mechanistically, VND3207 decreased oxidative DNA damage and lipid peroxidation and maintained endogenous antioxidant status by increasing the level of superoxide dismutase and total antioxidant capacity. In addition, VND3207 maintained appropriate levels of activated p53 that triggered cell cycle arrest but were not sufficient to induce NOXA-mediated apoptosis, thus ensuring DNA damage repair in the irradiated small intestinal crypt cells. Furthermore, VND3207 treatment restores the intestinal bacterial flora structures altered by TBI exposure. In conclusion, VND3207 promoted intestinal repair following radiation injury by reducing reactive oxygen species-induced DNA damage and modulating appropriate levels of activated p53 in intestinal epithelial cells.


Asunto(s)
Benzaldehídos/farmacología , Microbioma Gastrointestinal/genética , Proteínas Proto-Oncogénicas c-bcl-2/genética , Receptores Acoplados a Proteínas G/genética , Proteína p53 Supresora de Tumor/genética , Animales , Antioxidantes/farmacología , Benzaldehídos/química , Linaje de la Célula/efectos de los fármacos , Linaje de la Célula/efectos de la radiación , Microbioma Gastrointestinal/efectos de la radiación , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/efectos de la radiación , Humanos , Intestinos/efectos de los fármacos , Ratones , Estrés Oxidativo/efectos de los fármacos , Exposición a la Radiación/efectos adversos , Traumatismos por Radiación/genética , Traumatismos por Radiación/prevención & control , Tolerancia a Radiación/genética , Transducción de Señal/efectos de la radiación , Células Madre/efectos de los fármacos
12.
Cancer Sci ; 109(12): 3783-3793, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30281878

RESUMEN

The p53-inducible gene 3 (PIG3) is one of the p53-induced genes at the onset of apoptosis, which plays an important role in cell apoptosis and DNA damage response. Our previous study reported an oncogenic role of PIG3 associated with tumor progression and metastasis in non-small cell lung cancer (NSCLC). In this study, we further analyzed PIG3 mRNA expression in 504 lung adenocarcinoma (LUAD) and 501 lung squamous cell carcinoma (LUSC) tissues from The Cancer Genome Atlas database and we found that PIG3 expression was significantly higher in LUAD with lymph node metastasis than those without, while no difference was observed between samples with and without lymph node metastasis in LUSC. Gain and loss of function experiments were performed to confirm the metastatic role of PIG3 in vitro and to explore the mechanism involved in its oncogenic role in NSCLC metastasis. The results showed that PIG3 knockdown significantly inhibited the migration and invasion ability of NSCLC cells, and decreased paxillin, phospho-focal adhesion kinase (FAK) and phospho-Src kinase expression, while its overexpression resulted in the opposite effects. Blocking FAK with its inhibitor reverses PIG3 overexpression-induced cell motility in NSCLC cells, indicating that PIG3 increased cell metastasis through the FAK/Src/paxillin pathway. Furthermore, PIG3 silencing sensitized NSCLC cells to FAK inhibitor. In conclusion, our data revealed a role for PIG3 in inducing LUAD metastasis, and its role as a new FAK regulator, suggesting that it could be considered as a novel prognostic biomarker or therapeutic target in the treatment of LUAD metastasis.


Asunto(s)
Adenocarcinoma del Pulmón/genética , Carcinoma de Células Escamosas/genética , Péptidos y Proteínas de Señalización Intracelular/genética , Neoplasias Pulmonares/genética , Proteínas Proto-Oncogénicas/genética , Transducción de Señal , Regulación hacia Arriba , Células A549 , Adenocarcinoma del Pulmón/metabolismo , Adulto , Anciano , Animales , Carcinoma de Células Escamosas/metabolismo , Línea Celular Tumoral , Movimiento Celular , Femenino , Quinasa 1 de Adhesión Focal/metabolismo , Regulación Neoplásica de la Expresión Génica , Humanos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Neoplasias Pulmonares/metabolismo , Metástasis Linfática , Masculino , Ratones , Persona de Mediana Edad , Invasividad Neoplásica , Trasplante de Neoplasias , Fosforilación , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas pp60(c-src)/metabolismo
13.
Toxicol Sci ; 164(1): 339-352, 2018 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-29669094

RESUMEN

Graphene quantum dots (GQDs) have attracted significant interests due to their unique chemical and physical properties. In this study, we investigated the potential effects of hydroxyl-modified GQDs (OH-GQDs) on the human esophageal epithelial cell line HET-1A. Our data revealed significant cytotoxicity of OH-GQDs which decreased the viability of HET-1A in a dose and time-dependent manner. The moderate concentration (25 or 50 µg/ml) of OH-GQDs significantly blocked HET-1A cells in G0/G1 cell cycle phase. An increased percentage of γH2AX-positive and genomically unstable cells were also detected in cells treated with different doses of OH-GQDs (25, 50, and 100 µg/ml). Microarray data revealed that OH-GQDs treatment down-regulated genes related to DNA damage repair, cell cycle regulation and cytoskeleton signal pathways indicating a novel role of OH-GQDs. Consistent with the microarray data, OH-GQDs disrupted microtubule structure and inhibited microtubule regrowth around centrosomes in HET-1A cells. In conclusion, our findings provide important evidence for considering the application of OH-GQDs in biomedical fields.


Asunto(s)
Daño del ADN , Células Epiteliales/efectos de los fármacos , Esófago/efectos de los fármacos , Grafito/toxicidad , Microtúbulos/efectos de los fármacos , Puntos Cuánticos/toxicidad , Ciclo Celular/efectos de los fármacos , Ciclo Celular/genética , Línea Celular , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/genética , Reparación del ADN/genética , Relación Dosis-Respuesta a Droga , Regulación hacia Abajo , Células Epiteliales/patología , Esófago/patología , Regulación de la Expresión Génica/efectos de los fármacos , Grafito/química , Humanos , Hidroxilación , Microtúbulos/ultraestructura , Puntos Cuánticos/química , Factores de Tiempo
14.
Toxicol Appl Pharmacol ; 348: 76-84, 2018 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-29679654

RESUMEN

Esophageal squamous cell carcinoma (ESCC) is the most common form of esophageal cancer in China. Since chemotherapy is the standard clinical intervention for advanced ESCC, the development of highly effective and minimal/non-toxic drugs is essential to improve the clinical outcome and prognosis of the patients. A novel derivative of vanillin, 6-bromine-5-hydroxy-4-methoxybenzaldehyde (BVAN08), has been recently reported to activate different cell death pathways in cancer cells. In this study, we demonstrate that BVAN08 exhibits a potent anti-proliferation effect on ESCC cells (TE-1 and ECA-109) by inhibiting the expression of PLK1, an important mitotic kinase. Consistent with this, BVAN08 induces mitotic arrest and chromosomal misalignment in ESCC cells. The disruption of microtubule nucleation around centrosomes is also observed in BVAN08 treated ESCC cells. Furthermore, BVAN08 enhances radio-sensitivity of ESCC cells by prolonging DNA damage repair. These findings underscore the potential value of BVAN08 in cancer therapeutics and demonstrate the underlying mechanism by which BVAN08 induces mitotic catastrophe and enhances radio-sensitivity in ESCC cells.


Asunto(s)
Antineoplásicos/farmacología , Benzaldehídos/farmacología , Carcinoma de Células Escamosas/terapia , Proteínas de Ciclo Celular/antagonistas & inhibidores , Proliferación Celular/efectos de los fármacos , Quimioradioterapia , Neoplasias Esofágicas/terapia , Mitosis/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Proto-Oncogénicas/antagonistas & inhibidores , Tolerancia a Radiación/efectos de los fármacos , Carcinoma de Células Escamosas/enzimología , Carcinoma de Células Escamosas/patología , Proteínas de Ciclo Celular/metabolismo , Línea Celular Tumoral , Centrosoma/efectos de los fármacos , Centrosoma/patología , Daño del ADN , Reparación del ADN/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Neoplasias Esofágicas/enzimología , Neoplasias Esofágicas/patología , Carcinoma de Células Escamosas de Esófago , Humanos , Microtúbulos/efectos de los fármacos , Microtúbulos/patología , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Transducción de Señal/efectos de los fármacos , Factores de Tiempo , Quinasa Tipo Polo 1
15.
Nucleic Acids Res ; 46(4): 1847-1859, 2018 02 28.
Artículo en Inglés | MEDLINE | ID: mdl-29309644

RESUMEN

The DNA-dependent protein kinase (DNA-PK), consisting of the DNA binding Ku70/80 heterodimer and the catalytic subunit DNA-PKcs, has been well characterized in the non-homologous end-joining mechanism for DNA double strand break (DSB) repair and radiation resistance. Besides playing a role in DSB repair, DNA-PKcs is required for the cellular response to replication stress and participates in the ATR-Chk1 signaling pathway. However, the mechanism through which DNA-PKcs is recruited to stalled replication forks is still unclear. Here, we report that the apoptosis mediator p53-induced protein with a death domain (PIDD) is required to promote DNA-PKcs activity in response to replication stress. PIDD is known to interact with PCNA upon UV-induced replication stress. Our results demonstrate that PIDD is required to recruit DNA-PKcs to stalled replication forks through direct binding to DNA-PKcs at the N' terminal region. Disruption of the interaction between DNA-PKcs and PIDD not only compromises the ATR association and regulation of DNA-PKcs, but also the ATR signaling pathway, intra-S-phase checkpoint and cellular resistance to replication stress. Taken together, our results indicate that PIDD, but not the Ku heterodimer, mediates the DNA-PKcs activity at stalled replication forks and facilitates the ATR signaling pathway in the cellular response to replication stress.


Asunto(s)
Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Replicación del ADN , Proteína Quinasa Activada por ADN/metabolismo , Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/metabolismo , Proteínas Nucleares/metabolismo , Secuencias de Aminoácidos , Animales , Línea Celular , Cricetinae , Proteína Quinasa Activada por ADN/química , Humanos , Autoantígeno Ku/fisiología , Proteínas Nucleares/química , Puntos de Control de la Fase S del Ciclo Celular , Transducción de Señal , Estrés Fisiológico , Rayos Ultravioleta
16.
Cancer Sci ; 108(12): 2503-2510, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28905458

RESUMEN

An aberrantly elevated expression of DNA polymerase ι (Pol ι) is significantly associated with poor prognosis of patients with esophageal squamous cell carcinoma (ESCC), yet the mechanisms behind this phenomenon remain obscure. Based on the RNA-Seq transcriptome and real-time PCR analysis, we identified ETS-1 as a candidate gene involved in Pol ι-mediated progression of ESCC. Wound-healing and transwell assay indicated that downregulation of ETS-1 attenuates Pol ι-mediated invasiveness of ESCC. Signaling pathway analysis showed that Pol ι enhances ETS-1 phosphorylation at threonine-38 through the Erk signaling pathway in ESCC cells. Kaplan-Meier analysis, based on 93 clinical tissue samples, revealed that ETS-1 phosphorylation at threonine-38 is associated with poor prognosis of ESCC patients. The present study thus demonstrates that phosphorylation of ETS-1 is a critical event in the Pol ι-induced invasion and metastasis of ESCC.


Asunto(s)
Carcinoma de Células Escamosas/patología , ADN Polimerasa Dirigida por ADN/metabolismo , Neoplasias Esofágicas/patología , Proteína Proto-Oncogénica c-ets-1/metabolismo , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/mortalidad , Movimiento Celular , Neoplasias Esofágicas/metabolismo , Neoplasias Esofágicas/mortalidad , Carcinoma de Células Escamosas de Esófago , Humanos , Estimación de Kaplan-Meier , Invasividad Neoplásica/patología , Fosforilación , ADN Polimerasa iota
17.
Int J Med Sci ; 14(5): 452-461, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28539821

RESUMEN

Objectives: 4E-BP1 is a family member of eIF4E binding proteins (4E-BPs) which act as the suppressors of cap-dependent translation of RNA via competitively associating with cap-bound eIF4E. RNA translation regulation is an important manner to control the cellular responses to a series of stress conditions such as ionizing radiation (IR)-induced DNA damage response and cell cycle controlling. This study aimed to determine the mechanism of 4E-BP1 stabilization and its potential downstream target(s) in the response to IR. Methods: PI3Ks kinase inhibitors were used to determine the signaling control of 4E-BP1 phosphorylation and protein stability. shRNA strategy was employed to silence the expression of 4E-BP1 in HeLa and HepG2 cells, and determine its effect on the irradiation-induced CHK2 phosphorylation. The protein degradation/stability was investigated by western blotting on the condition of blocking novel protein synthesis by cycloheximide (CHX). Results: The phosphorylation of 4E-BP1 at Thr37/46 was significantly increased in both HepG2 and HeLa cells by ionizing radiation. Depression of 4E-BP1 by shRNA strategy resulted in an incomplete G2 arrest at the early stage of 2 hours post-irradiation, as well as a higher accumulation of mitotic cells at 10 and 12 hours post-irradiation as compared to the control cells. Consistently, the CHK2 phosphorylation at Thr68 induced by IR was also attenuated by silencing 4E-BP1 expression. Both PI3K and DNA-PKcs kinase inhibitors significantly decreased the protein level of 4E-BP1, which was associated with the accelerated degradation mediated by ubiquitination-proteasome pathway. Conclusion: PI3K kinase activity is necessary for maintaining 4E-BP1 stability. Our results also suggest 4E-BP1 a novel biological role of regulating cell cycle G2 checkpoint in responding to IR stress in association with controlling CHK2 phosphorylation.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/genética , Quinasa de Punto de Control 2/genética , Fosfatidilinositol 3-Quinasas/genética , Fosfoproteínas/genética , Biosíntesis de Proteínas/genética , Proteínas de Ciclo Celular , Puntos de Control de la Fase G2 del Ciclo Celular/efectos de la radiación , Regulación de la Expresión Génica/efectos de la radiación , Células HeLa , Células Hep G2 , Humanos , Fosforilación/efectos de la radiación , Biosíntesis de Proteínas/efectos de la radiación , Proteínas Proto-Oncogénicas c-akt/genética , ARN Interferente Pequeño/genética , Radiación Ionizante , Transducción de Señal/genética , Transducción de Señal/efectos de la radiación
18.
J Exp Clin Cancer Res ; 36(1): 39, 2017 03 04.
Artículo en Inglés | MEDLINE | ID: mdl-28259183

RESUMEN

BACKGROUND: Non-small cell lung cancer (NSCLC) is the most commonly diagnosed type of lung cancer that is associated with poor prognosis. In this study we explored the potential role of p53-induced gene 3 (PIG3) in the progression of NSCLC. METHODS: Immunohistochemistry was used to determine the expression levels of PIG3 in 201 NSCLC patients. We performed in vitro studies and silenced endogenous PIG3 by using specific siRNAs that specific target PIG3. Immunofluorescent staining was performed to determine the effect of PIG3 on mitotic progression in NSCLC cells. The growth rates of microtubules were determined by microtubule nucleation analysis. Cell proliferation and chemosensitivity were analyzed by CCK8 assays. Annexin V staining and ß-galactosidase activity analysis were used to evaluate PIG3 deficiency-related apoptosis and senescence, respectively. RESULTS: PIG3 expression levels negatively correlated with overall survival and disease-free survival of NSCLC patients. Knock down of PIG3 resulted in repressed proliferation of NSCLC cells and increased aberrant mitosis, which included misaligning and lagging chromosomes, and bi- or multi-nucleated giant cells. In addition, PIG3 contributed to mitotic spindle assembly by promoting microtubule growth. Furthermore, loss of PIG3 sensitized NSCLC cells to docetaxel by enhancing docetaxel-induced apoptosis and senescence. CONCLUSIONS: Our results indicate that PIG3 promotes NSCLC progression and therefore suggest that PIG3 may be a potential prognostic biomarker and novel therapeutic target for the treatment of NSCLC.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Neoplasias Pulmonares/genética , Mitosis , Proteínas Proto-Oncogénicas/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Progresión de la Enfermedad , Supervivencia sin Enfermedad , Docetaxel , Femenino , Silenciador del Gen , Humanos , Péptidos y Proteínas de Señalización Intracelular/genética , Neoplasias Pulmonares/metabolismo , Masculino , Persona de Mediana Edad , Pronóstico , Proteínas Proto-Oncogénicas/genética , Análisis de Supervivencia , Taxoides/farmacología , Adulto Joven
19.
Oncotarget ; 7(38): 62340-62351, 2016 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-27694690

RESUMEN

Radiotherapy is promising and effective for treating prostate cancer but the addition of a tumor cell radiosensitizer would improve therapeutic outcomes. PC-1/PrLZ, a TPD52 protein family member is frequently upregulated in advanced prostate cancer cells and may be a biomarker of aggressive prostate cancer. Therefore, we investigated the potential role of PC-1/PrLZ for increasing radioresistance in human prostate cancer cell lines. Growth curves and survival assays after g-ray irradiation confirmed that depletion of endogenous PC-1/PrLZ significantly increased prostate cancer cell radiosensitivity. Irradiation (IR) increased PC-1/PrLZ expression in a dose- and time-dependent manner and increased radiosensitivity in PC-1/PrLZ-suppressed cells was partially due to decreased DNA double strand break (DBS) repair which was measured with comet and gH2AX foci assays. Furthermore, depletion of PC-1/PrLZ impaired the IR-induced G2/M checkpoint, which has been reported to be correlate with radioresistance in cancer cells. PC-1/PrLZ-deficient cells exhibited higher level of autophagy when compared with control cells. Thus, specific inhibition of PC-1/PrLZ might provide a novel therapeutic strategy for radiosensitizing prostate cancer cells.


Asunto(s)
Autofagia/efectos de la radiación , Roturas del ADN de Doble Cadena/efectos de la radiación , Reparación del ADN/efectos de la radiación , Proteínas de Neoplasias/efectos de la radiación , Neoplasias de la Próstata/radioterapia , Tolerancia a Radiación , Línea Celular Tumoral , Relación Dosis-Respuesta en la Radiación , Puntos de Control de la Fase G2 del Ciclo Celular/efectos de la radiación , Rayos gamma , Histonas/metabolismo , Histonas/efectos de la radiación , Humanos , Masculino , Microscopía Fluorescente , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Fosforilación , Próstata/citología , Próstata/efectos de la radiación , Neoplasias de la Próstata/patología , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Regulación hacia Arriba
20.
Nucleic Acids Res ; 44(18): 8842-8854, 2016 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-27568005

RESUMEN

Defects in kinetochore-microtubule (KT-MT) attachment and the spindle assembly checkpoint (SAC) during cell division are strongly associated with chromosomal instability (CIN). CIN has been linked to carcinogenesis, metastasis, poor prognosis and resistance to cancer therapy. We previously reported that the DAB2IP is a tumor suppressor, and that loss of DAB2IP is often detected in advanced prostate cancer (PCa) and is indicative of poor prognosis. Here, we report that the loss of DAB2IP results in impaired KT-MT attachment, compromised SAC and aberrant chromosomal segregation. We discovered that DAB2IP directly interacts with Plk1 and its loss inhibits Plk1 kinase activity, thereby impairing Plk1-mediated BubR1 phosphorylation. Loss of DAB2IP decreases the localization of BubR1 at the kinetochore during mitosis progression. In addition, the reconstitution of DAB2IP enhances the sensitivity of PCa cells to microtubule stabilizing drugs (paclitaxel, docetaxel) and Plk1 inhibitor (BI2536). Our findings demonstrate a novel function of DAB2IP in the maintenance of KT-MT structure and SAC regulation during mitosis which is essential for chromosomal stability.


Asunto(s)
Puntos de Control del Ciclo Celular , Inestabilidad Cromosómica , Cinetocoros/metabolismo , Microtúbulos/metabolismo , Huso Acromático/metabolismo , Proteínas Activadoras de ras GTPasa/metabolismo , Animales , Puntos de Control del Ciclo Celular/efectos de los fármacos , Puntos de Control del Ciclo Celular/genética , Proteínas de Ciclo Celular/antagonistas & inhibidores , Proteínas de Ciclo Celular/metabolismo , Línea Celular Tumoral , Aberraciones Cromosómicas , Segregación Cromosómica , Técnicas de Inactivación de Genes , Humanos , Ratones , Mitosis/efectos de los fármacos , Mitosis/genética , Fosforilación , Unión Proteica , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Serina-Treonina Quinasas/metabolismo , Transporte de Proteínas , Proteínas Proto-Oncogénicas/antagonistas & inhibidores , Proteínas Proto-Oncogénicas/metabolismo , Interferencia de ARN , Moduladores de Tubulina/farmacología , Proteínas Activadoras de ras GTPasa/genética , Quinasa Tipo Polo 1
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