DA-125, a novel anthracycline derivative showing high-affinity DNA binding and topoisomerase II inhibitory activities, exerts cytotoxicity via c-Jun N-terminal kinase pathway.
OBJECTIVE
DA-125 [(8S,10S)-8-(3-Aminopropanoyloxyacetyl)-10-[(2,6-dideoxy-2-fluoro-alpha-L-talopyranosyl) oxy]-7,8,9,10-tetrahydro-6,8,11-trihydroxy-1-methoxy-5,12-naphthacene-dione hydrochloride] is a novel anthracycline derivative with anticancer activity. In the present study, we compared the cytotoxicity of DA-125 with that of doxorubicin in H4IIE rat hepatoma cells and investigated the mechanistic basis. Because activation of MAP kinases, in particular c-Jun N-terminal kinase (JNK), is implicated in apoptotic cell death, the signaling pathways responsible for DA-125-induced apoptosis were studied.


METHODS
Cytotoxicity and apoptosis were measured in H4IIE cells and cells were stably transfected with a dominant-negative mutant of JNK1 (JNK1-) by MTT and TUNEL assays. Inhibition of topoisomerase II activity was determined in vitro. Drug accumulation and DNA binding affinity were determined by fluorescence spectroscopy.


RESULTS
The cytotoxicity of DA-125 was greater than that of doxorubicin (IC50 11.5 vs 70 microM). DA-125 induced apoptosis with 30-fold greater potency than doxorubicin. Inhibition of topoisomerase II by DA-125 was fourfold greater. The presence of excess beta-alanine, a DA-125 moiety, failed to alter cytotoxicity and accumulation of DA-125, indicating that the improved cytotoxicity of DA-125 did not result from the beta-alanine moiety. Greater cellular accumulation of DA-125 correlated with its high-affinity DNA binding. Although neither PD98059 nor SB203580 altered the degree of cytotoxicity induced by DA-125, JNK1 cells exhibited about a twofold greater viability than control cells. DA-125-induced apoptosis was also decreased in JNK1- -transfected cells.


CONCLUSIONS
DA-125 potently inhibited topoisomerase II activity and induced apoptosis by a high rate of prooxidant production. DA-125 exhibited high-affinity DNA binding with improved cellular drug accumulation. Apoptosis induced by DA-125 involved the pathway of JNK1, but not ERK1/2 or p38 kinase.
Kim
S G
SG
College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, South Korea. sgk@snu.ac.kr
Sung
M
M
Kang
K W
KW
Kim
S H
SH
Son
M H
MH
Kim
W B
WB
D000818:Animals; D000970:Antineoplastic Agents / Q000378:metabolism / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy / Q000378:metabolism; D004273:DNA, Neoplasm / Q000378:metabolism*; D004317:Doxorubicin / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases; D008113:Liver Neoplasms / Q000188:drug therapy / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism; D051381:Rats; D059005:Topoisomerase II Inhibitors; D014407:Tumor Cells, Cultured; D015091:beta-Alanine / Q000378:metabolism
D000970:Antineoplastic Agents; D004273:DNA, Neoplasm; D004791:Enzyme Inhibitors; D059005:Topoisomerase II Inhibitors; D015091:beta-Alanine; C090816:7-O-(2,6-Dideoxy-2-fluoro-alpha-talopyranosyl)adriamycinone- 14-beta-alaniate hydrochloride; D004317:Doxorubicin; D009195:Peroxidase; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases