title: Lidamycin induces marked G2 cell cycle arrest in human colon carcinoma HT-29 cells through activation of p38 MAPK pathway.
abstract: Lidamycin (LDM), a member of the enediyne antibiotic family, is presently undergoing phase I clinical trials in P.R. China. In this study, we investigated the mechanisms of LDM-induced cell cycle arrest in order to support its use in clinical cancer therapy. Using human colon carcinoma HT-29 cells, we observed that LDM induced G2 cell cycle arrest in a time- and dose-dependent manner. LDM-induced G2 arrest was associated with increasing phosphorylation of Chk1, Chk2, Cdc25C, Cdc2 and expression of Cdc2 and cyclin B1. In addition, cytoplasmic localization of cyclin B1 was also involved in LDM-induced G2 arrest. Moreover, we found that p38 MAPK pathway contributed to LDM-induced G2 arrest. Inhibition of p38 MAPK by its inhibitor SB203580 not only attenuated LDM-induced G2 arrest but also potentiated LDM-induced apoptosis, which was accompanied by decreasing phosphorylation of Cdc2 and increasing expression of FasL and phosphorylation of JNK. Finally, we demonstrated that cells at G1 phase were more sensitive to LDM. Together, our findings suggest that p38 MAPK signaling pathway is involved in LDM-induced G2 arrest, at least partly, and a combination of LDM with p38 MAPK inhibitor may represent a new strategy for human colon cancer therapy.
authors.affiliation: Institute of Medicinal Biotechnology, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100050, P.R. China.
authors.forename: Xia
authors.initials: X
authors.lastname: Liu
authors.forename: Chunjing
authors.initials: C
authors.lastname: Bian
authors.forename: Kaihuan
authors.initials: K
authors.lastname: Ren
authors.forename: Haixia
authors.initials: H
authors.lastname: Jin
authors.forename: Baowei
authors.initials: B
authors.lastname: Li
authors.forename: Rong-Guang
authors.initials: RG
authors.lastname: Shao
mesh_terms: D000617:Aminoglycosides / Q000494:pharmacology*; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D053281:Enediynes / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D016195:G2 Phase / Q000187:drug effects*; D006801:Humans; D048051:p38 Mitogen-Activated Protein Kinases / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000617:Aminoglycosides; D000903:Antibiotics, Antineoplastic; D053281:Enediynes; C058024:C 1027; D048051:p38 Mitogen-Activated Protein Kinases