title: The redox antimalarial dihydroartemisinin targets human metastatic melanoma cells but not primary melanocytes with induction of NOXA-dependent apoptosis.
abstract: Recent research suggests that altered redox control of melanoma cell survival, proliferation, and invasiveness represents a chemical vulnerability that can be targeted by pharmacological modulation of cellular oxidative stress. The endoperoxide artemisinin and semisynthetic artemisinin-derivatives including dihydroartemisinin (DHA) constitute a major class of antimalarials that kill plasmodium parasites through induction of iron-dependent oxidative stress. Here, we demonstrate that DHA may serve as a redox chemotherapeutic that selectively induces melanoma cell apoptosis without compromising viability of primary human melanocytes. Cultured human metastatic melanoma cells (A375, G361, LOX) were sensitive to DHA-induced apoptosis with upregulation of cellular oxidative stress, phosphatidylserine externalization, and activational cleavage of procaspase 3. Expression array analysis revealed DHA-induced upregulation of oxidative and genotoxic stress response genes (GADD45A, GADD153, CDKN1A, PMAIP1, HMOX1, EGR1) in A375 cells. DHA exposure caused early upregulation of the BH3-only protein NOXA, a proapototic member of the Bcl2 family encoded by PMAIP1, and genetic antagonism (siRNA targeting PMAIP1) rescued melanoma cells from apoptosis indicating a causative role of NOXA-upregulation in DHA-induced melanoma cell death. Comet analysis revealed early DHA-induction of genotoxic stress accompanied by p53 activational phosphorylation (Ser 15). In primary human epidermal melanocytes, viability was not compromised by DHA, and oxidative stress, comet tail moment, and PMAIP1 (NOXA) expression remained unaltered. Taken together, these data demonstrate that metastatic melanoma cells display a specific vulnerability to DHA-induced NOXA-dependent apoptosis and suggest feasibility of future anti-melanoma intervention using artemisinin-derived clinical redox antimalarials.
authors.affiliation: College of Pharmacy & Arizona Cancer Center, Department of Pharmacology and Toxicology, University of Arizona, 1515 North Campbell Avenue, Tucson, AZ 85724, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Cabello
authors.forename: Sarah D
authors.initials: SD
authors.lastname: Lamore
authors.forename: Warner B
authors.initials: WB
authors.lastname: Bair
authors.forename: Shuxi
authors.initials: S
authors.lastname: Qiao
authors.forename: Sara
authors.initials: S
authors.lastname: Azimian
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Lesson
authors.forename: Georg T
authors.initials: GT
authors.lastname: Wondrak
mesh_terms: D000962:Antimalarials / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D037621:Artemisinins / Q000494:pharmacology*; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D019610:Cytoprotection / Q000187:drug effects / Q000235:genetics; D004249:DNA Damage / Q000235:genetics; D004354:Drug Screening Assays, Antitumor; D004789:Enzyme Activation / Q000187:drug effects; D004817:Epidermis / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D015894:Genome, Human / Q000235:genetics; D006801:Humans; D007502:Iron Chelating Agents / Q000494:pharmacology; D008544:Melanocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*; D008545:Melanoma / Q000235:genetics / Q000473:pathology* / Q000648:ultrastructure; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D009362:Neoplasm Metastasis; D020411:Oligonucleotide Array Sequence Analysis; D010084:Oxidation-Reduction / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
chemical_list: D000962:Antimalarials; D000975:Antioxidants; D037621:Artemisinins; D007502:Iron Chelating Agents; C498702:PMAIP1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; C039060:artenimol; D053148:Caspase 3