RESUMEN
Methylmercury (MeHg) is an environmental neurotoxic substance, which can easily cross the blood-brain barrier, causing irreversible damage to the human central nervous system. Reactive oxygen species (ROS) are involved in various ways of intracellular physiological or pathological processes including neuronal apoptosis. This study attempted to explore the role of ROS-mediated poly ADP-ribose polymerase (PARP)/apoptosis-inducing factor (AIF) apoptosis signaling pathway in the process of MeHg-induced cell death of human neuroblastoma cells (SH-SY5Y). Here, we found that SH-SY5Y cells underwent apoptosis in response to MeHg, which was accompanied by the increased levels of ROS and calcium ion, and the activation of caspase cascades and PARP. Inhibiting the production of ROS can reduce the apoptosis rate to a certain extent. PARP/AIF apoptotic pathway is independent of caspase dependent signaling pathway and regulates it. In conclusion, these results suggest that ROS mediated activation of caspase pathway and PARP/AIF signaling pathway are involved in MeHg induced apoptosis, and these two pathways interact with each other.
Asunto(s)
Compuestos de Metilmercurio , Neuroblastoma , Adenosina Difosfato Ribosa/farmacología , Apoptosis , Factor Inductor de la Apoptosis/metabolismo , Factor Inductor de la Apoptosis/farmacología , Caspasas/metabolismo , Humanos , Compuestos de Metilmercurio/toxicidad , Poli(ADP-Ribosa) Polimerasa-1/metabolismo , Inhibidores de Poli(ADP-Ribosa) Polimerasas/farmacología , Poli(ADP-Ribosa) Polimerasas/metabolismo , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Aggressive cancer cells gain robust tumor vascular mimicry (VM) capability that promotes tumor growth and metastasis. VE-cadherin is aberrantly overexpressed in vasculogenic cancer cells and regarded as a master gene of tumor VM. Although microRNAs (miRNAs) play an important role in modulating tumor angiogenesis and cancer metastasis, the miRNA that targets VE-cadherin expression in cancer cells to inhibit tumor cell-mediated VM is enigmatic. In this study, we found that miR-27b levels are negatively co-related to VE-cadherin expression in ovarian cancer cells and tumor cell-mediated VM, and demonstrated that miR-27b could bind to the 3'-untranslated region (3'UTR) of VE-cadherin mRNA. Overexpression of miR-27b in aggressive ovarian cancer cell lines Hey1B and ES2 significantly diminished intracellular VE-cadherin expression; convincingly, the inhibitory effect of miR-27b could be reversed by miR-27b specific inhibitor. Intriguingly, miR-27b not only effectively suppressed ovarian cancer cell migration and invasion, but also markedly inhibited formation of ovarian cancer cell-mediated capillary-like structures in vitro and suppressed generation of functional tumor blood vessels in mice. Together, our study suggests that miR-27b functions as a new inhibitor of ovarian cancer cell-mediated VM through suppression of VE-cadherin expression, providing a new potential drug candidate for antitumor VM and anti-ovarian cancer therapy.
Asunto(s)
Antígenos CD/genética , Cadherinas/genética , MicroARNs/genética , Neoplasias Ováricas/irrigación sanguínea , Neoplasias Ováricas/genética , Regiones no Traducidas 3' , Animales , Línea Celular Tumoral , Movimiento Celular , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Ratones , Invasividad Neoplásica , Trasplante de NeoplasiasRESUMEN
Lung cancer is a leading lethal disease with a 5-year survival rate of only 16%. Inadequate potent anti-cancer drugs appear to be a bottleneck in the treatment of lung cancer; hence, how to develop effective anti-lung cancer therapeutics is an urgent problem. In this study, we aim to explore a novel compound with potent anti-lung cancer effect and study its anti-cancer mechanisms. We found that triptonide at very low concentrations of 5-10â¯nM caused a marked suppression of cell proliferation and colony formation of lung cancer cells. More interestingly, triptonide also robustly inhibited the lung cancer cell formation of tumor spheres, and reduced the stemness and tumorigenicity of the sphere-forming cells. In vivo studies showed that administration of triptonide significantly inhibited the tumor growth with low toxicity. Molecular mechanistic studies revealed that triptonide significantly decreased expression of the Gli1 at both mRNA and protein levels by repressing Gli1 gene promoter activity. Additionally, triptonide reduced the levels of cancer stem cell key signaling protein sonic hedgehog (Shh), but increased the amount of Ptch1, a protein binding to SMO to diminish the Shh signal transduction, thus inhibition of the Shh-Gli1 signaling pathway. Together, our findings show that triptonide effectively inhibits lung cancer cell growth, stemness, and tumorigenicity, and support the notion that triptonide is a new Shh-Gli1 signaling inhibitor and a novel anti-lung cancer drug candidate for further developing effective lung cancer therapeutics.
Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Proliferación Celular/efectos de los fármacos , Proteínas Hedgehog/metabolismo , Neoplasias Pulmonares/tratamiento farmacológico , Transducción de Señal/efectos de los fármacos , Triterpenos/farmacología , Proteína con Dedos de Zinc GLI1/metabolismo , Células A549 , Animales , Relación Dosis-Respuesta a Droga , Regulación hacia Abajo , Femenino , Proteínas Hedgehog/genética , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Ratones Desnudos , Células Madre Neoplásicas/efectos de los fármacos , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/patología , Receptor Patched-1/metabolismo , Fenotipo , Ensayos Antitumor por Modelo de Xenoinjerto , Proteína con Dedos de Zinc GLI1/genéticaRESUMEN
Foodborne pathogen contamination is a major safety issue for many foods and is causing concern worldwide. In this study, a detection system based on magnetic separation, multiplex PCR (MPCR) and capillary electrophoresis (CE) technologies was developed for the simultaneous detection of four foodborne pathogens. Magnetic separation technology is used to rapidly capture pathogenic bacteria in food samples, and then a combination of MPCR and CE can be used to greatly increase detection sensitivity. The detection limit for bacterial DNA reached 10-5 -10-7 ng µL-1 and in the analysis of mocked food samples, the assay showed good sensitivity for bacterial detection ranging from 101 to 105 CFU mL-1 with excellent specificity. Compared to similar detection methodologies, this technique avoids the need for time-consuming enrichment cultures, is more sensitive, and can be used to assay simultaneously four foodborne pathogens.
Asunto(s)
Electroforesis Capilar , Reacción en Cadena de la Polimerasa Multiplex , ADN Bacteriano/genética , Microbiología de Alimentos , Fenómenos Magnéticos , Sensibilidad y EspecificidadRESUMEN
Cancer cells are defective in DNA repair, so they experience increased DNA strand breaks, genome instability, gene mutagenesis, and tumorigenicity; however, multiple classic DNA repair genes and pathways are strongly activated in malignant tumor cells to compensate for the DNA repair deficiency and gain an apoptosis resistance. The mechanisms underlying this phenomenon in cancer are unclear. We speculate that a key DNA repair gene or signaling pathway in cancer has not yet been recognized. Here, we show that the lipogenic liver X receptor (LXR)-sterol response element binding factor-1 (SREBF1) axis controls the transcription of a key DNA repair gene polynucleotide kinase/phosphatase (PNKP), thereby governing cancer cell DNA repair and apoptosis. Notably, the PNKP levels were significantly reduced in 95% of human pancreatic cancer (PC) patients, particularly deep reduction for sixfold in all of the advanced-stage PC cases. PNKP is also deficient in three other types of cancer that we examined. In addition, the expression of LXRs and SREBF1 was significantly reduced in the tumor tissues from human PC patients compared with the adjacent normal tissues. The newly identified LXR-SREBF1-PNKP signaling pathway is deficient in PC, and the defect in the pathway contributes to the DNA repair deficiency in the cancer. Strikingly, further diminution of the vulnerable LXR-SREBF1-PNKP signaling pathway using a small molecule triptonide, a new LXR antagonist identified in this investigation, at a concentration of 8 nM robustly activated tumor-suppressor p53 and readily elevated cancer cell DNA strand breaks over an apoptotic threshold, and selectively induced PC cell apoptosis, resulting in almost complete elimination of tumors in xenograft mice without obvious complications. Our findings provide new insight into DNA repair and apoptosis in cancer, and offer a new platform for developing novel anticancer therapeutics.
Asunto(s)
Apoptosis , Reparación del ADN , Lipogénesis , Receptores X del Hígado/metabolismo , Neoplasias/patología , Neoplasias/terapia , Transducción de Señal , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/metabolismo , Animales , Apoptosis/efectos de los fármacos , Apoptosis/genética , Carcinogénesis/efectos de los fármacos , Carcinogénesis/genética , Carcinogénesis/patología , Línea Celular Tumoral , Roturas del ADN de Doble Cadena/efectos de los fármacos , Reparación del ADN/efectos de los fármacos , Reparación del ADN/genética , Enzimas Reparadoras del ADN/deficiencia , Enzimas Reparadoras del ADN/genética , Enzimas Reparadoras del ADN/metabolismo , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Lipogénesis/efectos de los fármacos , Lipogénesis/genética , Ratones Desnudos , Mitosis/efectos de los fármacos , Modelos Biológicos , Neoplasias/genética , Fosfotransferasas (Aceptor de Grupo Alcohol)/deficiencia , Fosfotransferasas (Aceptor de Grupo Alcohol)/genética , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transducción de Señal/efectos de los fármacos , Transcripción Genética/efectos de los fármacos , Triterpenos/farmacología , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
An amendment to this paper has been published and can be accessed via a link at the top of the paper.