title: Dihydroartemisinin accelerates c-MYC oncoprotein degradation and induces apoptosis in c-MYC-overexpressing tumor cells.
abstract: Artemisinin and its derivatives (ARTs) are effective antimalarial drugs and also possess profound anticancer activity. However, the mechanism accounted for its distinctive activity in tumor cells remains unelucidated. We computed Pair wise Pearson correlation coefficients to identify genes that show significant correlation with ARTs activity in NCI-55 cell lines using data obtained from studies with HG-U133A Affymetrix chip. We found c-myc is one of the genes that showed the highest positive correlation coefficients among the probe sets analyzed (r=0.585, P<0.001). Dihydroartemisinin (DHA), the main active metabolite of ARTs, induced significant apoptosis in HL-60 and HCT116 cells that express high levels of c-MYC. Stable knockdown of c-myc abrogated DHA-induced apoptosis in HCT116 cells. Conversely, forced expression of c-myc in NIH3T3 cells sensitized these cells to DHA-induced apoptosis. Interestingly, DHA irreversibly down-regulated the protein level of c-MYC in DHA-sensitive HCT116 cells, which is consistent to persistent G1 phase arrest induced by DHA. Further studies demonstrated that DHA accelerated the degradation of c-MYC protein and this process was blocked by pretreatment with the proteasome inhibitor MG-132 or GSK 3beta inhibitor LiCl in HCT116 cells. Taken together, ARTs might be useful in the treatment of c-MYC-overexpressing tumors. We also suggest that c-MYC may potentially be a biomarker candidate for prediction of the antitumor efficacies of ARTs.
authors.affiliation: Division of Anti-tumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Rd., Shanghai 201203, PR China.
authors.forename: Jin-Jian
authors.initials: JJ
authors.lastname: Lu
authors.forename: Ling-Hua
authors.initials: LH
authors.lastname: Meng
authors.forename: Uma T
authors.initials: UT
authors.lastname: Shankavaram
authors.forename: Cai-Hua
authors.initials: CH
authors.lastname: Zhu
authors.forename: Lin-Jiang
authors.initials: LJ
authors.lastname: Tong
authors.forename: Guang
authors.initials: G
authors.lastname: Chen
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Lin
authors.forename: John N
authors.initials: JN
authors.lastname: Weinstein
authors.forename: Jian
authors.initials: J
authors.lastname: Ding
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D037621:Artemisinins / Q000494:pharmacology*; D045744:Cell Line, Tumor; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects; D016193:G1 Phase / Q000187:drug effects; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors; D000071679:Glycogen Synthase Kinase 3 beta; D045325:HCT116 Cells; D018922:HL-60 Cells; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology; D018021:Lithium Chloride / Q000494:pharmacology; D051379:Mice; D041681:NIH 3T3 Cells; D016271:Proto-Oncogene Proteins c-myc / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D000962:Antimalarials; D037621:Artemisinins; D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D016271:Proto-Oncogene Proteins c-myc; C039060:artenimol; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D038362:Glycogen Synthase Kinase 3; D018021:Lithium Chloride; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde