rNDV-p53 promotes and activates anti-apoptotic proteins. (A) p53, p21 and caspase-3 levels in U251 cells following treatment with rNDV-p53, rNDV-EGFP or controls. (B) Bcl-2, Bim and Bax expression in U251 cells following treatment with rNDV-p53, rNDV-EGFP or controls. (C) rNDV-p53 treatment for 24 h promoted U251 cell apoptosis at an MOI of 5, compared with rNDV-EGFP and control treated cells. (D) TUNEL-positive U251 cells incubated for 48 h with rNDV-p53, rNDV-EGFP or control (MOI=5; magnification, ×40). **P<0.01 vs. control. rNDV, recombinant Newcastle disease virus; EGFP, enhanced green fluorescent protein; Bcl-2, B cell lymphoma-2; Bim, Bcl-2 like 11; Bax, Bcl-2 associated X; MOI, multiplicity of infection.