Figure 1. Gliobalastoma cells with high expression of ObR represent TMZ-resistant characteristic. (A) Flow cytometry to sort ObR+ cells in U87 gliobalastoma cells. ObR+ and ObR− cells were cultured for 72 h in the presence of indicated concentration of TMZ. MTT assay was performed to assess the anti-proliferative effects of TMZ (B), Annexin V and PI staining FACS was used to assess apoptosis of cells (C). (D) U87 cells with a low dose of TMZ in culture media for 4 wk to establish TMZ-resistant cells, and the image showed that nude mice bearing U87 and U87R cells xenografts were treated with 100 μM TMZ; 4 wk later, the xenografts were weighted. (E) The mRNA and (F) protein expression levels of ObR were elevated in U87R cells.