Mecanismo antitumoral da berberina em linhagem de células U87MG de glioblastoma multiforme

Abstract

Glioblastoma multiforme (GBM) is the most prevalent tumor among gliomas. GBM cells present high pleomorphism, with undifferentiated cells, with cellular atypia and high mitotic activity, being considered as incurable tumors with the highest mortality rate among brain tumors. Berberine (BBR), an alkaloid isoquinoline, is a compound found in medicinal plants such as Coptis chinensis. Studies have been showed that BBR presents protective activity in mesenchymal cells and neurons, and antitumor properties, such as inhibition of cell proliferation, induction of cell cycle arrest, and apoptosis in breast cancer and hepatocarcinoma. The aim of this study was to investigate the antitumor effects of BBR in the GBM U87MG cells, as well as to identify whether such effects are mediated by oxidative stress and canonical apoptotic pathways. After treatment with several concentrations of BBR (10, 25, 100 and 250μM) for 24, 48 and 72 hours, the samples were analyzed by MTT assay and it was observed that BBR inhibited cell viability of U87MG cells in a concentration- and time-dependent manner. Afterwards, it was observed that BBR, starting at a concentration of 25 μM for 24hs, significantly suppressed proliferation evidenced by flow cytometry techniques, while significantly increased early apoptosis (53.5% ± 11.15 of annexin V+ propidium iodide- cells) compared to untreated cells (7.5% ± 4.6). BBR-induced apoptosis was independent on AMPK activity and did not change caspase 3 and p-p53 levels. Moreover, BBR (25μM / 24h) increased oxidative stress in U87MG cells, evidenced by high levels of reactive oxygen species, TBARS and protein carbonylation. Considering the antitumor effects of BBR in U87MG cells, it is suggest that this compound may be a potential candidate for adjuvant GBM treatment.