RESUMEN
The complexity of the expressed breast milk feeding process in the neonatal intensive care unit was not fully appreciated until we used a healthcare failure mode and effect analysis. This approach identified latent risks and provided semiquantitative estimates of the effectiveness of recommendations. Findings demonstrated nursing interruptions and multitasking requirements contributed to risk, emphasizing the need for focused and isolated expressed breast milk handling to improve patient safety and outcomes.
Asunto(s)
Enfermería de Cuidados Críticos/normas , Unidades de Cuidado Intensivo Neonatal/normas , Errores Médicos/prevención & control , Leche Humana , Garantía de la Calidad de Atención de Salud/métodos , Extracción de Leche Materna , Femenino , Humanos , Recién Nacido , Minnesota , Seguridad del Paciente , Mejoramiento de la Calidad , Medición de RiesgoRESUMEN
Interleukin-12 (IL-12) has shown significant antitumor activity in several preclinical animal tumor models. Our previous studies showed that IL-12 inhibited tumor growth in human osteosarcoma and Ewing's sarcoma animal model. Decreased Fas expression in osteosarcoma increased the lung metastatic potential. In this study, we further examined the mechanism of IL-12 antitumor activity and showed that IL-12 significantly increased Fas expression in both human osteosarcoma cells LM7 and Ewing's sarcoma cells TC71. Up-regulation of Fas expression increased their sensitivity to Fas-induced cell apoptosis. Constructs of the Fas promoter linked to a luciferase reporter gene were used to determine the promoter activity. IL-12 increased Fas promoter activity 4.2- and 4.9-fold in TC71 and LM7 cells, respectively. Time course studies have shown that recombinant IL-12 stimulated Fas promoter activity at 2 hours, reached the peak level at 4 hours, and then declined at 24 hours. To investigate whether IL-12 specifically enhanced Fas promoter activity, we determined whether another gene (E1A) was able to stimulate Fas promoter activity. We also evaluated effect of IL-12 on the topoisomerase IIalpha promoter. The results indicated that E1A but not IL-12 stimulated topoisomerase IIalpha promoter activity. E1A failed to increase Fas promoter activity. We also found that kappaB-Sp1 element at position -295 to -286 in Fas promoter was essential for IL-12-induced activation, and nuclear factor-kappaB transcription factor was activated after IL-12 treatment in TC71 cells. These results indicate that IL-12 up-regulates Fas expression in human osteosarcoma and Ewing's sarcoma by enhancing Fas promoter activity. Understanding this mechanism may lead to new therapeutic approaches for the treatment of sarcoma involving the use of IL-12.
Asunto(s)
Neoplasias Óseas/metabolismo , Interleucina-12/fisiología , Osteosarcoma/metabolismo , Regiones Promotoras Genéticas , Sarcoma de Ewing/metabolismo , Receptor fas/biosíntesis , Animales , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/metabolismo , Apoptosis , Línea Celular Tumoral , ADN-Topoisomerasas de Tipo II/genética , ADN-Topoisomerasas de Tipo II/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Genes Reporteros , Humanos , Luciferasas de Luciérnaga/genética , Ratones , FN-kappa B/metabolismo , Regulación hacia Arriba , Receptor fas/genéticaRESUMEN
Cyclophosphamide (CY) and its derivative ifosfamide are alkylating agents used to treat osteosarcoma (OS). The purpose of these studies was to determine whether alkylating agents affect the expression of Fas ligand (FasL) and whether interleukin 12 enhances the sensitivity of human OS cells to alkylating agents. 4-Hydroperoxycyclophosphamide (4-HC), the preactivated CY compound, and 4-hydroperoxydidechlorocloclophosphamide (4-HDC), its nonalkylating analogue, human OS LM6 cells, and a clone of cells derived by transfection with the interleukin 12 gene (LM6-#6) were used for these studies. Incubation of LM6 and LM6-#6 with 10 micro M 4-HC increased the expression of FasL mRNA (2.5- and 3.0-fold, respectively). By contrast, 4-HDC, Adriamycin (ADR), cisplatin (CDP), and methotrexate (MTX) had no effect on FasL mRNA expression. Increased FasL expression after treatment with 4-HC was also demonstrated by immunohistochemistry and flow cytometry. Drug-induced FasL was functional and mediated cell death. We examined the effect of FasL up-regulation by 4-HC on LM6 and LM6-#6 cells. Flow cytometry showed that LM6-#6 cells expressed 2.2-fold more Fas than LM6 cells. Cytotoxicity of 4-HC, 4-HDC, ADR, CDP, and MTX on LM6, LM6-neo, and LM6-#6 were quantified. Colony-forming assay revealed an IC(50) of 2.10 micro M for 4-HC in LM6-neo cells compared with 0.41 micro M in LM6-#6 cells. The IC(50) for 4-HDC, ADR, CDP, and MTX were not significantly different between the two cell lines. We concluded that the increased expression of Fas enhanced LM6-#6 sensitivity to 4-HC. These data indicate that Fas/FasL may be involved in the cytotoxic pathway of CY. Combining biological agents with chemotherapeutic agents that have complementary Fas/FasL pathway actions may offer new therapeutic alternatives.
Asunto(s)
Ciclofosfamida/análogos & derivados , Ciclofosfamida/farmacología , Interleucina-12/fisiología , Glicoproteínas de Membrana/metabolismo , Osteosarcoma/tratamiento farmacológico , Receptor fas/metabolismo , Antineoplásicos/farmacología , Línea Celular Tumoral , Separación Celular , Cisplatino/farmacología , Relación Dosis-Respuesta a Droga , Doxorrubicina/farmacología , Proteína Ligando Fas , Citometría de Flujo , Humanos , Inmunohistoquímica , Concentración 50 Inhibidora , Interleucina-12/metabolismo , Metotrexato/farmacología , ARN Mensajero/metabolismo , Factores de Tiempo , Transfección , Regulación hacia ArribaRESUMEN
PURPOSE: The process of metastasis requires the single tumor cell that seeds the metastatic clone to complete a complex series of steps. Identifying factors responsible for these steps is essential in developing and improving targeted therapy for metastasis. Resistance to receptor-mediated cell death, such as the Fas/Fas ligand pathway, is one mechanism commonly exploited by metastatic cell populations. EXPERIMENTAL DESIGN AND RESULTS: LM7, a subline of the SAOS human osteosarcoma cell line with low Fas expression, was selected for its high metastatic potential in an experimental nude mouse model. When transfected with the full-length Fas gene (LM7-Fas), these cells expressed higher levels of Fas than the parental LM7 cells or LM7-neo control-transfected cells. These cells were also more sensitive to Fas-induced cell death than controls. When injected intravenously into nude mice, the LM7-Fas cell line produced a significantly lower incidence of tumor nodules than control cell lines. Lung weight and tumor nodule size were also decreased in those mice injected with LM7-Fas. Levels of Fas were quantified in osteosarcoma lung nodules from 17 patients. Eight samples were Fas negative, whereas the remaining 9 were only weakly positive compared with normal human liver (positive control). CONCLUSIONS: Our results demonstrate that altering Fas expression can impact the metastatic potential of osteosarcoma cells. We conclude that the increase of Fas on the surface of the LM7 osteosarcoma cells increased their sensitivity to Fas-induced cell death in the microenvironment of the lung, where Fas ligand is constitutively expressed. Thus, loss of Fas expression is one mechanism by which osteosarcoma cells may evade host resistance mechanisms in the lung, increasing metastatic potential. Fas may therefore be a new therapeutic target for osteosarcoma.
Asunto(s)
Apoptosis , Neoplasias Pulmonares/prevención & control , Osteosarcoma/metabolismo , Receptor fas/metabolismo , Animales , Neoplasias Óseas/metabolismo , Neoplasias Óseas/patología , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundario , Masculino , Ratones , Ratones Desnudos , Osteosarcoma/patología , Timidina/metabolismoRESUMEN
A complex series of steps must take place to allow for a single cell to metastasize. Identifying factors responsible for these steps is essential in developing targeted therapy. We developed series of osteosarcoma cell lines with differing metastatic potentials. We used them to investigate mechanisms of metastasis and possible therapeutic targets for osteosarcoma metastasis to the lung in a nude mouse model. No correlation was found between epidermal growth factor receptor (EGFR), insulin-like growth factor receptor inhibitor (IGF-I-R), gelatinase, p53, metalloproteinase 9 (MMP 9), platelet derived growth factor receptor (PDGF-R), vascular endothelial growth factor (VEGF) and c-met expression and metastatic potential as measured by Northern analysis. By contrast, Fas expression inversely correlated with metastatic potential, and manipulation of Fas expression altered the metastatic phenotype of the cell. Our data indicate that fas gene expression may offer a new therapeutic target for the treatment of metastatic osteosarcoma in the lung.