title: Cantharidin induces G2/M phase arrest and apoptosis in human colorectal cancer colo 205 cells through inhibition of CDK1 activity and caspase-dependent signaling pathways.
abstract: Cantharidin (CTD) is a traditional Chinese medicine and an effective component isolated from blister beetle, and it has been demonstrated to have anticancer, antibiotic, antivirus activities and immune-regulated functions. It has been reported that CTD induces cell cycle arrest and apoptosis in many cancer cell types. However, there are no reports showing that CTD would induce cell cycle arrest and apoptosis in human colorectal cancer colo 205 cells. In this study, we studied colo 205 cells which were treated with CTD and demonstrated its molecular mechanisms in apoptosis. CTD induced growth inhibition, G2/M phase arrest and apoptosis in colo 205 cells. The IC50 is 20.53 µM in CTD-treated colo 205 cells. DAPI/TUNEL double staining and Annexin V assays were used to confirm the apoptotic cell death in colo 205 cells after CTD exposure. CTD caused G2/M arrest, down-regulated CDK1 activity, decreased Cyclin A, Cyclin B, CDK1 and increased CHK1 and p21 protein levels. Colorimetric assays also indicated that CTD triggered activities of casapse-8, -9 and -3 in colo 205 cells. Moreover, CTD increased ROS production and decreased the level of mitochondrial membrane potential (ΔΨm) in colo 205 cells. Consequently, CTD-induced growth inhibition was significantly attenuated by N-acetylcysteine (NAC, a scavenger). CTD stimulated the protein levels of Fas/CD95, the caspase-3 active form, cytochrome c and Bax, but suppressed the protein levels of pro-caspase-8, pro-caspase-9 and Bcl-2, determined by Western blot analysis. Based on our observations, we suggest that CTD is able to induce G2/M phase arrest and apoptosis in colo 205 cells through inhibition of CDK1 activity and caspase-dependent signaling pathways.
authors.affiliation: Department of Biological Science and Technology, China Medical University, Taichung 404, Taiwan, ROC.
authors.forename: Wen-Wen
authors.initials: WW
authors.lastname: Huang
authors.forename: Shih-Wei
authors.initials: SW
authors.lastname: Ko
authors.forename: Huei-Yann
authors.initials: HY
authors.lastname: Tsai
authors.forename: Jing-Gung
authors.initials: JG
authors.lastname: Chung
authors.forename: Jo-Hua
authors.initials: JH
authors.lastname: Chiang
authors.forename: Kuan-Tin
authors.initials: KT
authors.lastname: Chen
authors.forename: Yen-Chen
authors.initials: YC
authors.lastname: Chen
authors.forename: Hung-Yi
authors.initials: HY
authors.lastname: Chen
authors.forename: Yuh-Fung
authors.initials: YF
authors.lastname: Chen
authors.forename: Jai-Sing
authors.initials: JS
authors.lastname: Yang
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D016203:CDC2 Protein Kinase / Q000037:antagonists & inhibitors*; D002193:Cantharidin / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D015179:Colorectal Neoplasms; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D010718:Phosphatidylserines / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D010718:Phosphatidylserines; D017382:Reactive Oxygen Species; D016203:CDC2 Protein Kinase; D020169:Caspases; D002193:Cantharidin