DCA enhanced the cytotoxicity of PENAO in GBM cells. (A, B, C and D) Percentage of apoptotic cells (Annexin V positive) after 24 hr treatment with PENAO (3, 4 and 5 μM), 20 mM DCA, and their combination. (E) The expression of cleaved PARP (c-PARP) in GBM cells (LN229, DBTRG, U87 and BAH1) after treatments with 5 μM PENAO, 20 mM DCA and their combination. Western blots presented are representative of 3 independent experiments. (F) The percentage of GBM cells (LN229, DBTRG, U87 and BAH1) with depolarized mitochondria after 16 hr treatment with PENAO, DCA and the combination. Results are presented as means ± s.d. of three experiments. *p < 0.05, **p < 0.01, ***p < 0.001, #p < 0.01 vs PENAO.