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BACKGROUND AND PURPOSE: Non-small-cell lung cancer (NSCLC) accounts for up to 80-85% of all lung cancers and has a disappointing prognosis. Flavonoids exert anticancer properties, mostly involving stimulation of ROS production without significant toxicity to normal cells. This study was aimed to delineate the effect of diosmetin, a natural flavonoid, on NSCLC cells and its ability to enhance the antitumour activity of paclitaxel. EXPERIMENTAL APPROACH: NSCLC cells, normal cell lines HLF-1 and BEAS-2B, and immunodeficient mice were chosen as models to study the effects of diosmetin. Changes in cell viability, apoptosis, and ROS were analysed by MTT assay, flow cytometry assay, and fluorescent probe DCFH-DA. Expression of proteins and mRNA was determined by Western blotting and real-time RT-PCR. Growth of xenografted tumours was measured. Spleens and other vital organs were analysed with histological and immunohistochemical techniques. KEY RESULTS: Diosmetin induced selective apoptotic death in NSCLC cells but spared normal cells, via ROS accumulation. Diosmetin induced ROS production in NSCLC cells probably via reducing Nrf2 stability through disruption of the PI3K/Akt/GSK-3ß pathway. The in vitro and in vivo xenograft studies showed that combined treatment of diosmetin and paclitaxel synergistically suppressed NSCLC cells. Histological analysis of vital organs showed no obvious toxicity of diosmetin, which matched our in vitro findings. CONCLUSIONS AND IMPLICATIONS: Diosmetin selectively induced apoptosis and enhanced the efficacy of paclitaxel in NSCLC cells via ROS accumulation through disruption of the PI3K/Akt/GSK-3ß/Nrf2 pathway. Therefore, diosmetin may be a promising candidate for adjuvant treatment of NSCLC.
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Antineoplásicos Fitogénicos/farmacología , Apoptosis/efectos de los fármacos , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Flavonoides/farmacología , Neoplasias Pulmonares/tratamiento farmacológico , Factor 2 Relacionado con NF-E2/antagonistas & inhibidores , Paclitaxel/farmacología , Antineoplásicos Fitogénicos/química , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/patología , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Flavonoides/química , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Estructura Molecular , Factor 2 Relacionado con NF-E2/metabolismo , Paclitaxel/química , Especies Reactivas de Oxígeno/análisis , Especies Reactivas de Oxígeno/metabolismo , Relación Estructura-ActividadRESUMEN
Platelet-derived growth factor receptors (PDGFRs) are abundantly expressed by stromal cells in the non-small cell lung cancer (NSCLC) microenvironment, and in a subset of cancer cells, usually with their overexpression and/or activating mutation. However, the effect of PDGFR inhibition on lung cancer cells themselves has been largely neglected. In this study, we investigated the anticancer activity of CP-673451, a potent and selective inhibitor of PDGFRß, on NSCLC cell lines (A549 and H358) and the potential mechanism. The results showed that inhibition of PDGFRß by CP-673451 induced a significant increase in cell apoptosis, accompanied by ROS accumulation. However, CP-673451 exerted less cytotoxicity in normal lung epithelial cell line BEAS-2B cells determined by MTT and apoptosis assay. Elimination of ROS by NAC reversed the CP-673451-induced apoptosis in NSCLC cells. Furthermore, CP-673451 down-regulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) probably through inhibition of PI3K/Akt pathway. Rescue of Nrf2 activity counteracted the effects of CP-673451 on cell apoptosis and ROS accumulation. Silencing PDGFRß expression by PDGFRß siRNA exerted similar effects with CP-673451 in A549 cells, and when PDGFRß was knockdowned by PDGFRß siRNA, CP-673451 produced no additional effects on cell viability, ROS and GSH production, Nrf2 expression as well as PI3K/Akt pathway activity. Specifically, Nrf2 plays an indispensable role in NSCLC cell sensitivity to platinum-based treatments and we found that combination of CP-673451 and cisplatin produced a synergistic anticancer effect and substantial ROS production in vitro. Therefore, these results clearly demonstrate the effectiveness of inhibition of PDGFRß against NSCLC cells and strongly suggest that CP-673451 may be a promising adjuvant chemotherapeutic drug.
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Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Apoptosis/efectos de los fármacos , Bencimidazoles/farmacología , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Cisplatino/farmacología , Neoplasias Pulmonares/tratamiento farmacológico , Factor 2 Relacionado con NF-E2/metabolismo , Quinolinas/farmacología , Receptor beta de Factor de Crecimiento Derivado de Plaquetas/antagonistas & inhibidores , Células A549 , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/patología , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Sinergismo Farmacológico , Regulación Neoplásica de la Expresión Génica , Glutatión/metabolismo , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Estrés Oxidativo/efectos de los fármacos , Fosfatidilinositol 3-Quinasa/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Interferencia de ARN , Especies Reactivas de Oxígeno/metabolismo , Receptor beta de Factor de Crecimiento Derivado de Plaquetas/genética , Receptor beta de Factor de Crecimiento Derivado de Plaquetas/metabolismo , Transducción de Señal/efectos de los fármacosRESUMEN
Acetaminophen (APAP) overdose-induced acute liver damage is mostly due to overwhelmingly increased oxidative stress. Nuclear factor-erythroid 2-related factor2 (Nrf2) plays an important role in alleviating APAP hepatic toxicity. Shikonin (SHK) enhances Nrf2 in multiple lines of normal cells. Nevertheless, whether SHK protects against APAP-induced liver toxicity remains undefined. This study found SHK defended APAP-induced liver toxicity, as well as reversed the levels of serum alanine/aspartate aminotransferases (ALT/AST), liver myeloperoxidase (MPO) activity, and reactive oxygen species (ROS), while it enhanced the liver glutathione (GSH) level in APAP-treated mice. SHK rescued the cell viability and GSH depletion, but neutralized oxidative stress in APAP-treated human normal liver L-02 cells. Mechanically, SHK increased Nrf2 expression in the exposure of APAP at the protein level but not at the mRNA level. Inhibition of Nrf2 blocked the SHK effect in APAP-treated hepatocytes. Furthermore, SHK improved Nrf2 stability through stimulating PI3K/Akt pathway, thus inhibiting GSK-3ß. In vivo studies confirmed the close correlation of liver protection of SHK against APAP and Akt/GSK-3ß/Nrf2 pathway. In conclusion, this study reveals that SHK prevents APAP hepatotoxicity by upregulation of Nrf2 via PI3K/Akt/GSK-3ß pathway. Therefore, SHK may be a promising candidate against APAP-induced liver injury.