RESUMEN
Apoptosis, the cell's natural mechanism for death, is a promising target for anticancer therapy. Both the intrinsic and extrinsic pathways use caspases to carry out apoptosis through the cleavage of hundreds of proteins. In cancer, the apoptotic pathway is typically inhibited through a wide variety of means including overexpression of antiapoptotic proteins and under-expression of proapoptotic proteins. Many of these changes cause intrinsic resistance to the most common anticancer therapy, chemotherapy. Promising new anticancer therapies are plant-derived compounds that exhibit anticancer activity through activating the apoptotic pathway.
Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Caspasas/genética , Curcumina/farmacología , Regulación Neoplásica de la Expresión Génica , Terapia Molecular Dirigida , Neoplasias/tratamiento farmacológico , Animales , Apoptosis/efectos de los fármacos , Carcinogénesis/efectos de los fármacos , Carcinogénesis/genética , Carcinogénesis/metabolismo , Carcinogénesis/patología , Caspasas/metabolismo , Línea Celular Tumoral , Proteína Ligando Fas/genética , Proteína Ligando Fas/metabolismo , Humanos , Ratones , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patología , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Transducción de Señal , Proteína X Asociada a bcl-2/genética , Proteína X Asociada a bcl-2/metabolismo , Receptor fas/genética , Receptor fas/metabolismoRESUMEN
PURPOSE: Andrographolide is a diterpenoid lactone isolated from Andrographis paniculata (King of Bitters), an herbal medicine used in Asia. It has been reported to have anti-inflammatory, antihypertensive, antiviral, and immune-stimulant properties. Furthermore, it has been shown to inhibit cancer cell proliferation and induce apoptosis in leukemia and solid tumor cell lines. EXPERIMENTAL DESIGN: We studied the Burkitt p53-mutated Ramos cell line, the mantle cell lymphoma (MCL) line Granta, the follicular lymphoma (FL) cell line HF-1, and the diffuse large B-cell lymphoma (DLBCL) cell line SUDHL4, as well as primary cells from patients with FL, DLBCL, and MCL. RESULTS: We found that andrographolide resulted in dose- and time-dependent cell death as measured by MTT. Andrographolide significantly increased reactive oxygen species (ROS) production in all cell lines. To determine mechanism of cell death, we measured apoptosis by Annexin V/propidium iodide in the presence and absence of the antioxidant N-acetyl-l-cysteine (NAC), the glutathione (GSH)-depleting agent buthionine sulfoxamine (BSO), or caspase inhibitors. We found that apoptosis was greatly enhanced by BSO, blocked by NAC, and accompanied by poly(ADP-ribose) polymerase cleavage and activation of caspase-3, caspase-8, and caspase-9. We measured BAX conformational change and mitochondrial membrane potential, and using mouse embryonic fibroblast (MEF) Bax/Bak double knockouts (MEF(Bax-/-/Bak-/-)), we found that apoptosis was mediated through mitochondrial pathways, but dependent on caspases in both cell lines and patient samples. CONCLUSIONS: Andrographolide caused ROS-dependent apoptosis in lymphoma cell lines and in primary tumor samples, which was enhanced by depletion of GSH and inhibited by NAC or the pan-caspase inhibitor Z-VAD-FMK. Further studies of diterpenoid lactones in lymphoma are warranted.
Asunto(s)
Andrographis/química , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Diterpenos/farmacología , Linfoma/tratamiento farmacológico , Linfoma/patología , Mitocondrias/efectos de los fármacos , Animales , Antineoplásicos/química , Antineoplásicos/aislamiento & purificación , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Diterpenos/química , Diterpenos/aislamiento & purificación , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Fibroblastos/citología , Fibroblastos/efectos de los fármacos , Humanos , Linfoma/metabolismo , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Ratones , Ratones Noqueados , Mitocondrias/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Factores de TiempoRESUMEN
Mantle cell lymphoma (MCL) is characterized by translocation t(11;14)(q13;q32), aggressive clinical behaviour, and poor patient outcomes following conventional chemotherapy. New treatment approaches are needed that target novel biological pathways. All trans retinoic acid (ATRA) is a key retinoid that acts through nuclear receptors that function as ligand-inducible transcription factors. The present study evaluated cell killing effects of ATRA-enriched nanoscale delivery particles, termed nanodisks (ND), on MCL cell lines. Results show that ATRA-ND induced cell death more effectively than naked ATRA (dimethyl sulphoxide) or empty ND. ATRA-ND induced reactive oxygen species (ROS) generation to a greater extent than naked ATRA. The antioxidant, N-acetylcysteine, inhibited ATRA-ND induced apoptosis. Compared to naked ATRA, ATRA-ND enhanced G1 growth arrest, up-regulated p21and p27, and down regulated cyclin D1. At ATRA concentrations that induced apoptosis, expression levels of retinoic acid receptor-alpha (RARalpha) and retinoid X receptor-gamma (RXRgamma) were increased. Compared to naked ATRA, ATRA-ND significantly stimulated transcriptional activity of RARA in a model carcinoma cell line. Furthermore, the RAR antagonist, Ro 41-5253, inhibited ATRA-ND induced ROS generation and prevented ATRA-ND induced cell growth arrest and apoptosis. In summary, incorporation of ATRA into ND enhanced the biological activity of this retinoid in cell culture models of MCL.