Fig. 3. Effect of phosphatase and tensin homologous (PTEN) knockout (PTEN-KO) on the resistance to NL101. (a) The 3-‍(4,5-dimethylthiazol-2-yl)‍-2,5-diphenyltetrazolium bromide (MTT) assay in cell lines exposed to NL101 and/or VO-OHpic trihydrate (PTEN inhibitor) for 48 h. (b) The clustered regularly interspaced short palindromic repeats (CRISPR)‍-mediated PTEN depletion was confirmed by western blot. (c, d) MTT assays of PTEN-wild type (WT) (control) and knockout (KO) cell lines exposed to NL101 for 48 h at the indicated doses, and the corresponding the half maximal inhibitory concentration (IC₅₀) values. (e) The levels of poly-‍(ADP-ribose) polymerase-1 (PARP-1), phosphorylated γ-H2A.X, and phosphorylated protein kinase B (p-AKT) (S473) in PTEN-WT and PTEN-KO cell lines treated with NL101 for 24 h were determined by western blot. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and total AKT were used as controls. Data (a, c) are expressed as mean±standard deviation (SD) (n=4). ^** P<0.01, ^*** P<0.001.