Roles of mitochondrial, mitogen-activated kinase and STAT3 signaling pathways in the apoptosis of EPDMNQ- and ENDMNQ-treated Hep3B cells. Detection of p-ERK, p-JNK, p-p38, p-STAT3, Bax, Bcl-2, cle-PARP and cle-caspase-3 protein expression in (A) EPDMNQ- and (B) ENDMNQ-treated Hep3B cells by western blot analysis. ***P<0.001 vs. untreated control groupl. EPDMNQ, 2,3-dihydro-2,3-epoxy-2-propylsulfonyl-5,8-dimethoxy-1,4-naphthoquinone; ENDMNQ, 2,3-dihydro-2,3-epoxy-2-nonylsulfonyl-5,8-dimethoxy-1,4-naphthoquinone; Bcl-2, B-cell lymphoma 2; Bax, Bcl-2-associated X protein; cle, cleaved; PARP, poly (adenosine 5-diphosphate-ribose) polymerase; p, phosphorylated; p38, p38 mitogen-activated protein kinase; JNK, c-Jun N-terminal kinase; ERK, extracellular signal regulated kinase; STAT3, signal transducer and activator of transcription 3.