RESUMO
Time-lapse microscopy of human lung cancer (H460) cells showed that the endogenous cannabinoid anandamide (AEA), the phyto-cannabinoid Delta-9-tetrahydrocannabinol (THC) and a synthetic cannabinoid HU 210 all caused morphological changes characteristic of apoptosis. Janus green assays of H460 cell viability showed that AEA and THC caused significant increases in OD 595 nm at lower concentrations (10-50 microM) and significant decreases at 100 microM, whilst HU 210 caused significant decreases at all concentrations. In rat heart mitochondria, all three ligands caused significant decreases in oxygen consumption and mitochondrial membrane potential. THC and HU 210 caused significant increases in mitochondrial hydrogen peroxide production, whereas AEA was without significant effect. All three ligands induced biphasic changes in either mitochondrial complex I activity and/or mitochondrial complex II-III activity. These data demonstrate that AEA, THC, and HU 210 are all able to cause changes in integrated mitochondrial function, directly, in the absence of cannabinoid receptors.
Assuntos
Apoptose/efeitos dos fármacos , Ácidos Araquidônicos/farmacologia , Agonistas de Receptores de Canabinoides , Canabinoides/farmacologia , Dronabinol/análogos & derivados , Dronabinol/farmacologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/fisiologia , Alcamidas Poli-Insaturadas/farmacologia , Carcinoma Pulmonar de Células não Pequenas , Linhagem Celular Tumoral , Complexo I de Transporte de Elétrons/efeitos dos fármacos , Complexo II de Transporte de Elétrons/efeitos dos fármacos , Complexo III da Cadeia de Transporte de Elétrons/efeitos dos fármacos , Endocanabinoides , Humanos , Peróxido de Hidrogênio/metabolismo , Neoplasias Pulmonares , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Modelos Biológicos , Consumo de Oxigênio/efeitos dos fármacosRESUMO
Time-lapse photomicroscopy of human H460 lung cancer cells demonstrated of the transient receptor potential V1 (TRPV1) channel agonists, (E)-capsaicin and resiniferatoxin, and the TRPV1 antagonists, capsazepine, and SB366791, were able to bring about morphological changes characteristic of apoptosis and/or necrosis. Immunoblot analysis identified immunoreactivity for the transient receptor potential V1 (TRPV1) channel in rat brain samples, but not in rat heart mitochondria or in H460 cells. In isolated rat heart mitochondria, all four ligands caused concentration-dependent decreases in oxygen consumption and mitochondrial membrane potential. (E)-Capsaicin and capsazepine evoked concentration-dependent increases and decreases, respectively, in mitochondrial hydrogen peroxide production, whilst resiniferatoxin and SB366791 were without significant effect. These data support the hypothesis that (E)-capsaicin, resiniferatoxin, capsazepine, and SB366791 are all mitochondrial inhibitors, able to activate apoptosis and/or necrosis via non-receptor mediated mechanisms, and also support the use of TRPV1 ligands as anti-cancer agents.