RESUMEN
The hallmark of chronic myeloid leukemia (CML) is the abnormal activity of p210(Bcr-Abl) kinase. Selective kinase inhibitors such as imatinib or nilotinib have been established successfully for the treatment of CML. Despite high rates of clinical response, CML patients can develop resistance to these kinase inhibitors mainly due to point mutations within the Abl kinase domain of the fusion protein. Previously, we reported that a crude extract of the mushroom Daedalea gibbosa inhibited kinase activity of Bcr-Abl kinase. Here we report on the identification of the active component of Daedalea gibbosa, oleic acid, which inhibited Bcr-Abl kinase autophosphorylation in Ba/F3 cells and exhibited anti-CML activity in a BCR/ABL-positive mouse model.
Asunto(s)
Agaricales/química , Antineoplásicos/uso terapéutico , Proteínas de Fusión bcr-abl/antagonistas & inhibidores , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Ácido Oléico/uso terapéutico , Extractos Vegetales/uso terapéutico , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Animales , Cromatografía Líquida de Alta Presión , Femenino , Leucemia Mielógena Crónica BCR-ABL Positiva/enzimología , Ratones , Ratones Desnudos , Ácido Oléico/aislamiento & purificación , Fosforilación/efectos de los fármacos , Células Precursoras de Linfocitos B/efectos de los fármacosRESUMEN
OBJECTIVE: The anti-inflammatory action of low-dose methoxetrate (MTX) in the treatment of rheumatoid arthritis (RA) appears to be partially impaired by folate supplementation. Here we investigated whether a folate excess impairs monocyte differentiation, a putative anti-inflammatory action of low-dose MTX. METHODS: Monocyte differentiation of U937 promonocytic cells was assessed by CD11b and CD14 immunostaining and fluorescent absorbent cell sorting (FACS) analysis. Cell proliferation and viability were determined by cell counts and trypan-blue staining, respectively. Nuclear apoptosis was assessed by 7-actinomycin staining. Cells were treated with 10(-10)-10(-6) M MTX in the presence or absence of folinic acid. Exposure to 1,25-OH-vitamine D(3) and TGF-beta served as a positive control of monocyte differentiation in U937 cells. RESULTS: Low-dose MTX-induced monocyte differentiation was marginal when compared with 1,25-OH-D(3) + TGF-beta treatment. Low-dose MTX inhibited cell proliferation, induced apoptosis, and reduced cell viability. All the antiproliferative, cytotoxic, and monocyte differentiating effects of MTX were completely reversed by folinic acid. CONCLUSIONS: Monocyte differentiation is part of the folate-dependent MTX actions.