title: Cadmium-transformed cells in the in vitro cell transformation assay reveal different proliferative behaviours and activated pathways.
abstract: The in vitro Cell Transformation Assay (CTA) is a powerful tool for mechanistic studies of carcinogenesis. The endpoint is the classification of transformed colonies (foci) by means of standard morphological features. To increase throughput and reliability of CTAs, one of the suggested follow-up activities is to exploit the comprehension of the mechanisms underlying cell transformation. To this end, we have performed CTAs testing CdCl2, a widespread environmental contaminant classified as a human carcinogen with the underlying mechanisms of action not completely understood. We have isolated and re-seeded the cells at the end (6weeks) of in vitro CTAs to further identify the biochemical pathways underlying the transformed phenotype of foci. Morphological evaluations and proliferative assays confirmed the loss of contact-inhibition and the higher proliferative rate of transformed clones. The biochemical analysis of EGFR pathway revealed that, despite the same initial carcinogenic stimulus (1μM CdCl2 for 24h), transformed clones are characterized by the activation of two different molecular pathways: proliferation (Erk activation) or survival (Akt activation). Our preliminary results on molecular characterization of cell clones from different foci could be exploited for CTAs improvement, supporting the comprehension of the in vivo process and complementing the morphological evaluation of foci.
authors.affiliation: Department of Biotechnology and Biosciences, University of Milan Bicocca, Piazza della Scienza 3, 20126 Milan, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Forcella
authors.affiliation: Department of Earth and Environmental Sciences, University of Milan Bicocca, Piazza della Scienza 1, 20126 Milan, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Callegaro
authors.affiliation: Department of Earth and Environmental Sciences, University of Milan Bicocca, Piazza della Scienza 1, 20126 Milan, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Melchioretto
authors.affiliation: Institute for Health and Consumer Protection, DG JRC, European Commission, Via Enrico Fermi 2749, 21027 Ispra, Varese, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Gribaldo
authors.affiliation: Istituto Cantonale di Patologia, Via in Selva 24, 6601 Locarno, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Frattini
authors.affiliation: Department of Statistics, Computer Science, Applications, University of Florence, Viale Morgagni 59, 50100 Florence, Italy.
authors.forename: F M
authors.initials: FM
authors.lastname: Stefanini
authors.affiliation: Department of Biotechnology and Biosciences, University of Milan Bicocca, Piazza della Scienza 3, 20126 Milan, Italy. Electronic address: paola.fusi@unimib.it.
authors.forename: P
authors.initials: P
authors.lastname: Fusi
authors.affiliation: Department of Earth and Environmental Sciences, University of Milan Bicocca, Piazza della Scienza 1, 20126 Milan, Italy. Electronic address: chiara.urani@unimib.it.
authors.forename: C
authors.initials: C
authors.lastname: Urani
mesh_terms: D000818:Animals; D001681:Biological Assay; D019256:Cadmium Chloride / Q000633:toxicity*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002471:Cell Transformation, Neoplastic / Q000187:drug effects*; D066246:ErbB Receptors / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D051379:Mice; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism
chemical_list: C541485:EGFR protein, mouse; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt; D019256:Cadmium Chloride
keywords: Cadmium; Carcinogenesis; Epidermal growth factor receptor pathway; In vitro cell transformation assay