RESUMO
Methoxychlor, an organochlorine pesticide, is thought to be an endocrine disrupter that affects Ca²âº homeostasis and cell viability in different cell models. This study explored the action of methoxychlor on cytosolic free Ca²âº concentrations ([Ca²âº]i) and apoptosis in HA59T human hepatoma cells. Fura-2, a Ca²âº-sensitive fluorescent dye, was applied to measure [Ca²âº]i. Methoxychlor at concentrations of 0.1-1 µM caused a [Ca²âº]i rise in a concentration-dependent manner. Removal of external Ca²âº abolished methoxychlor's effect. Methoxychlor-induced Ca²âº influx was confirmed by Mn²âº-induced quench of fura-2 fluorescence. Methoxychlor-induced Ca²âº entry was inhibited by nifedipine, econazole, SK&F96365, and protein kinase C modulators. Methoxychlor killed cells at concentrations of 10-130 µM in a concentration-dependent fashion. Chelation of cytosolic Ca²âº with 1,2-bis(2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid/AM (BAPTA/AM) did not prevent methoxychlor's cytotoxicity. Methoxychlor (10 and 50 µM) induced apoptosis concentration-dependently as determined by using Annexin V/propidium iodide staining. Together, in HA59T cells, methoxychlor induced a [Ca²âº]i rise by inducing Ca²âº entry via protein kinase C-sensitive Ca²âº-permeable channels, without causing Ca²âº release from stores. Methoxychlor also induced apoptosis that was independent of [Ca²âº]i rises.
Assuntos
Apoptose/efeitos dos fármacos , Cálcio/metabolismo , Carcinoma Hepatocelular/metabolismo , Homeostase/efeitos dos fármacos , Inseticidas/farmacologia , Neoplasias Hepáticas/metabolismo , Metoxicloro/farmacologia , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Neoplasias Hepáticas/patologiaRESUMO
Burdock (Arcticum lappa L.) root is used in folk medicine and also as a vegetable in Asian countries. In the present study, burdock root treatment significantly reduced body weight in rats. To evaluate the bioactive compounds, we successively extracted the burdock root with ethanol (AL-1), and fractionated it with n-hexane (AL-2), ethyl acetate (AL-3), n-butanol (AL-4), and water (AL-5). Among these fractions, AL-2 contained components with the most effective hypolipidemic potential in human hepatoma HepG2 cells. AL-2 decreased the expression of fatty acid synthase (FASN) and inhibited the activity of acetyl-coenzyme A carboxylase (ACC) by stimulating AMP-activated protein kinase (AMPK) through the LKB1 pathway. Three active compounds were identified from the AL-2, namely α-linolenic acid, methyl α-linolenate, and methyl oleate. These results suggest that burdock root is expected to be useful for body weight management.