title: Zinc adaptation and resistance to cadmium toxicity in mammalian cells: molecular insight by proteomic analysis.
abstract: To identify proteins involved in cellular adaptive responses to zinc, a comparative proteome analysis between a previously developed high zinc- and cadmium-resistant human epithelial cell line (high zinc-resistant HeLa cells, HZR) and the parental HeLa cells has been carried out. Differentially produced proteins included cochaperones, proteins associated with oxido-reductase activities, and ubiquitin. Biochemical pathways to which these proteins belong were probed for their involvement in the resistance of both cell lines against cadmium toxicity. Among ER stressors, thapsigargin sensitized HZR cells, but not HeLa cells, to cadmium toxicity more acutely than tunicamycin, implying that these cells heavily relied on proper intracellular calcium distribution. The similar sensitivity of both HeLa and HZR cells to inhibitors of the proteasome, such as MG-132 or lactacystin, excluded improved proteasome activity as a mechanism associated with zinc adaptation of HZR cells. The enzyme 4-hydroxyphenylpyruvate dioxygenase (HPPD) was overproduced in HZR cells as compared to HeLa cells. It transforms HPP to homogentisate in the second step of tyrosine catabolism. Inhibition of HPPD decreased the resistance of HZR cells against cadmium, but not that of HeLa cells, suggesting that adaptation to zinc overload and increased HPP removal are linked in HZR cells.
authors.affiliation: CEA, DSV, IRTSV, Laboratoire de Chimie et Biologie des Métaux, Grenoble, France.
authors.forename: Estelle
authors.initials: E
authors.lastname: Rousselet
authors.forename: Alain
authors.initials: A
authors.lastname: Martelli
authors.forename: Mireille
authors.initials: M
authors.lastname: Chevallet
authors.forename: Hélène
authors.initials: H
authors.lastname: Diemer
authors.forename: Alain
authors.initials: A
authors.lastname: Van Dorsselaer
authors.forename: Thierry
authors.initials: T
authors.lastname: Rabilloud
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Moulis
mesh_terms: D015111:4-Hydroxyphenylpyruvate Dioxygenase / Q000378:metabolism; D002104:Cadmium / Q000737:chemistry / Q000494:pharmacology / Q000633:toxicity*; D002105:Cadmium Poisoning / Q000378:metabolism; D002256:Carbonic Anhydrases / Q000378:metabolism; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D015180:Electrophoresis, Gel, Two-Dimensional; D004847:Epithelial Cells / Q000166:cytology; D006367:HeLa Cells; D006801:Humans; D020543:Proteome; D040901:Proteomics / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013778:Tetrazolium Salts / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology; D015032:Zinc / Q000737:chemistry*
chemical_list: D020543:Proteome; D013778:Tetrazolium Salts; D013844:Thiazoles; D002104:Cadmium; D015111:4-Hydroxyphenylpyruvate Dioxygenase; D002256:Carbonic Anhydrases; C022616:thiazolyl blue; D015032:Zinc