RESUMEN
Background: NRAGE (neurotrophin receptor-interacting melanoma antigen-encoding gene homolog) has a complex role and regulates cell growth in different tumor cells. Although NRAGE was been discovered for more than 10 years ago, the function of NRAGE in hepatoblastoma (HB) cells is currently unknown. Materials and Methods: The expression of NRAGE was detected by reverse transcription-quantitative polymerase chain reaction assay or western blotting assay. Cellular apoptosis was analyzed to estimate the effect of NRAGE under radiation. The ability of clonogenic capacity was evaluated to confirm the influence of proliferation for NRAGE by radiation. The immunofluorescence assay was used to further study the expression of NRAGE under radiation. A nude mouse tumor xenograft model was constructed to confirm the effect of NRAGE deficiency under radiation conditions in vivo. Results: The authors determined that deletion of NRAGE significantly inhibited HB cell proliferation in vitro and in vivo, and NRAGE knockdown apparently sensitized HB cells to ionizing radiation (IR). Further mechanistic studies revealed that NRAGE plays a critical role in homologous recombination by inhibiting the expression of RNF8 (ring finger protein 8) and BARD1 (BRCA1 associated RING domain 1) and the recruitment of RAD51. Conclusions: The authors demonstrated that downregulation of NRAGE sensitizes HB cell lines to IR in vitro and in vivo. It provides a promising therapeutic strategy for HB patients by specifically targeting NRAGE.
Asunto(s)
Antígenos de Neoplasias/biosíntesis , Hepatoblastoma/genética , Hepatoblastoma/radioterapia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/radioterapia , Proteínas de Neoplasias/biosíntesis , Reparación del ADN por Recombinación , Animales , Antígenos de Neoplasias/genética , Apoptosis/efectos de la radiación , Línea Celular Tumoral , Proliferación Celular/efectos de la radiación , Regulación hacia Abajo , Técnicas de Silenciamiento del Gen , Células HEK293 , Células Hep G2 , Hepatoblastoma/metabolismo , Hepatoblastoma/patología , Xenoinjertos , Humanos , Péptidos y Proteínas de Señalización Intracelular/antagonistas & inhibidores , Péptidos y Proteínas de Señalización Intracelular/biosíntesis , Péptidos y Proteínas de Señalización Intracelular/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Masculino , Ratones , Ratones Desnudos , Proteínas de Neoplasias/genética , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Transfección , Proteínas de Motivos Tripartitos/antagonistas & inhibidores , Proteínas de Motivos Tripartitos/biosíntesis , Proteínas de Motivos Tripartitos/genética , Proteínas Supresoras de Tumor/antagonistas & inhibidores , Proteínas Supresoras de Tumor/biosíntesis , Proteínas Supresoras de Tumor/genética , Ubiquitina-Proteína Ligasas/antagonistas & inhibidores , Ubiquitina-Proteína Ligasas/biosíntesis , Ubiquitina-Proteína Ligasas/genéticaAsunto(s)
Hepatoblastoma/radioterapia , Neoplasias Hepáticas/radioterapia , Terapia de Protones , Preescolar , Femenino , Hepatoblastoma/diagnóstico por imagen , Hepatoblastoma/mortalidad , Humanos , Neoplasias Hepáticas/diagnóstico por imagen , Neoplasias Hepáticas/mortalidad , Imagen por Resonancia Magnética , Terapia de Protones/efectos adversos , Radiografía , Dosificación Radioterapéutica , Sobrevida , SobrevivientesRESUMEN
The expression of the DNA mismatch repair proteins hMSH2 and hMLH1 and p21(waf1) the cyclin G1 inhibitor, may determine response of adult cancers to anti-cancer drugs, that include alkylating agents and platinum-based drugs. The role of DNA mismatch repair proteins (hMSH2 and hMLH1) and p21(waf1) in pediatric tumor responses to chemotherapy and irradiation is described in the present study of 23 pediatric solid cancers (4 wilms' tumors, 9 neuroblastomas, 3 hepatoblastomas, 3 lymphomas and 4 sarcomas) using immunohistochemical methods. Immunostaining was scored for intensity (0-3) and extent (0-3). Most tumors stained strongly for hMSH2 and weakly or negative for hMLH1. All the hMLH1 negative tumors (1 wilms', 1 hepatoblastoma, 1 sarcoma, 2 lymphomas and 2 neuroblastomas) achieved complete response. p21(waf1) negative and positive tumors achieved relatively similar treatment response. The results suggest that the expression of DNA mismatch repair proteins hMLH1 and hMSH2, and p21(waf1) do not influence individual cancer responses to treatment and the results may reflect the use of multiple drugs and irradiation that cause many different types of DNA damage.
Asunto(s)
Disparidad de Par Base , Ciclinas/metabolismo , Reparación del ADN , Proteínas de Unión al ADN , Inhibidores Enzimáticos/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Adaptadoras Transductoras de Señales , Antineoplásicos/uso terapéutico , Proteínas Portadoras , Niño , Preescolar , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Hepatoblastoma/tratamiento farmacológico , Hepatoblastoma/genética , Hepatoblastoma/metabolismo , Hepatoblastoma/radioterapia , Humanos , Técnicas para Inmunoenzimas , Lactante , Linfoma/tratamiento farmacológico , Linfoma/genética , Linfoma/metabolismo , Linfoma/radioterapia , Homólogo 1 de la Proteína MutL , Proteína 2 Homóloga a MutS , Neoplasias/tratamiento farmacológico , Neoplasias/genética , Neoplasias/radioterapia , Neuroblastoma/tratamiento farmacológico , Neuroblastoma/genética , Neuroblastoma/metabolismo , Neuroblastoma/radioterapia , Proteínas Nucleares , Sarcoma/tratamiento farmacológico , Sarcoma/genética , Sarcoma/metabolismo , Sarcoma/radioterapia , Resultado del Tratamiento , Tumor de Wilms/tratamiento farmacológico , Tumor de Wilms/genética , Tumor de Wilms/metabolismo , Tumor de Wilms/radioterapiaRESUMEN
UNLABELLED: Radionuclide therapy is currently used in the treatment of some malignancies, including hepatocellular carcinoma. The effects of external beam radiotherapy are improved by combining it with chemotherapy. The aim of this study was to determine whether such a synergistic effect could be demonstrated in vitro with internal radiation therapy. METHODS: HepG2 cells were cultured from Day 0 to Day 8 under the following conditions: exposure for 4 hr on Day 2 to increasing concentrations of 5-fluorouracil (5FU), doxorubicin or cisplatin (CDDP); exposure from Day 2 to Day 8 to increasing concentrations of 131-iodide; exposure on Day 2 to low-toxicity doses of drugs for 4 hr, followed by exposure to 131I at increasing concentrations; and exposure to increasing concentrations of 131I from Day 2 to Day 8, with exposure for 4 hr on Day 6 to the drugs. Cell toxicity was assessed by enzyme release (lactate dehydrogenase and aspartate aminotransferase) in the culture medium and on cell survival (protein and tetrazolium dye test). All cultures were run in triplicate. RESULTS: A dose- and time-dependent toxicity was demonstrated with doxorubicin and CDDP but not with 5FU. When HepG2 cells were exposed to 131I, the toxicity was rather low, but significant, and was time- and dose-dependent. Treating these cells with combination radiotherapy and chemotherapy resulted in a toxicity that was significantly greater than that with 131I or chemotherapy drugs alone. CONCLUSION: The radiosensitivity of HepG2 cells is low; combining a chemotherapeutic drug with a radiotherapeutic agent improves the radiosensitivity in a synergistic fashion. This combination is thus able to strengthen the therapeutic effect of internal radiation therapy in different malignancies, particularly in hepatocellular carcinoma.