title: MAPK regulation and caspase activation are required in DMNQ S-52 induced apoptosis in Lewis lung carcinoma cells.
abstract: 6-(1-Hydroxyimino-4-methylpentyl)5,8-dimethyoxy 1,4-naphthoquinone S-52 (DMNQ S-52) was reported to have cytotoxic activity against L1210 leukemia cells. In the present study, we investigated the apoptotic mechanism of DMNQ S-52 in vitro and in vivo in murine solid cancer cells. DMNQ S-52 exerted cytotoxicity against Lewis lung carcinoma (LLC) cells (IC50=12.3 microM). DMNQ S-52 increased Annexin V positive cell population in a concentration-dependent manner. DMNQ S-52 also induced apoptosis through caspase-mediated pathway, including activation of caspase-3, cleavage of Poly(ADP-ribose) polymerase (PARP) and decreased expression of Bcl-2 in LLC cells in a time and concentration-dependent fashion. DMNQ S-52 activated the phosphorylation of c-Jun N-terminal kinase (JNK) and p38 as well as abrogated the expression of extracellular signal-regulated kinase (ERK) in a time-dependent manner at 10 microM. Similarly, cell proliferation inhibition by DMNQ S-52 was masked by caspase inhibitor Z-Asp-Glu-Val-Asp-fluoromethylketone (Z-VAD-FMK), JNK inhibitor SP600125 and p38 inhibitor SB203580, but not by MEK inhibitor U0126. Furthermore, i.p. administration of DMNQ S-52 at 5 mg/kg resulted in a potent inhibition of the growth of LLC cells implanted on the right flank of C57BL/6 mice compared to untreated control. Immunohistochemical analysis revealed the decreased tumor cell proliferation and increased tumor cell apoptosis in DMNQ S-52 treated tumor sections using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) and proliferation cell nuclear antigen (PCNA). Taken together, these findings demonstrate that DMNQ S-52 may exhibit anti-tumor activity by inducing apoptosis via caspases and mitogen activated protein (MAP) kinase-dependent pathways.
authors.affiliation: Department of Oncology, Graduate School of East-West Medical Science, Kyunghee University, 1 Seochun-ri, Kiheung-eup, Yongin 449-701, South Korea.
authors.forename: Soo Jin
authors.initials: SJ
authors.lastname: Lee
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Sakurai
authors.forename: Keiichi
authors.initials: K
authors.lastname: Koizumi
authors.forename: Gyu Yong
authors.initials: GY
authors.lastname: Song
authors.forename: Yong Soo
authors.initials: YS
authors.lastname: Bae
authors.forename: Hyung-Min
authors.initials: HM
authors.lastname: Kim
authors.forename: Kyung-Sun
authors.initials: KS
authors.lastname: Kang
authors.forename: Young-Joon
authors.initials: YJ
authors.lastname: Surh
authors.forename: Ikuo
authors.initials: I
authors.lastname: Saiki
authors.forename: Sung Hoon
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000818:Animals; D017304:Annexin A5 / Q000032:analysis; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects*; D018827:Carcinoma, Lewis Lung / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D020169:Caspases / Q000502:physiology*; D049109:Cell Proliferation / Q000187:drug effects; D004789:Enzyme Activation; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology*; D009285:Naphthoquinones / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: C509842:6-(1-hydroxyimino-4-methylpentyl)-5,8-dimethoxy-1,4-naphthoquinone; D017304:Annexin A5; D000970:Antineoplastic Agents; D009285:Naphthoquinones; D020928:Mitogen-Activated Protein Kinases; D020169:Caspases