Comparison of the sensitivity of different toxicological endpoints in Caco-2 cells after cadmium chloride treatment.
The human colorectal adenocarcinoma cell line Caco-2 is a widely used in vitro model of the intestinal barrier. Cadmium chloride (CdCl(2)) is a highly toxic metal compound, ubiquitous in the biosphere, able to enter the food chain and to reach the intestinal epithelium, causing structural and functional damages. The aim of this work was to characterise cadmium toxicity in Caco-2 cells and, in particular, to compare the sensitivity of different endpoints revealing damage both on the epithelial barrier and at the cellular or molecular level. After 24-h exposure of the cells to CdCl(2), lactate dehydrogenase (LDH) leakage showed cadmium-induced cell toxicity, significant from 25 microM CdCl(2) and above, and analysis of different cell death pathways indicated the presence of necrosis after treatment with 50 microM CdCl(2). At the molecular level, we observed an increase in the protective protein heat shock protein 70 (HSP70), starting at 10 microM CdCl(2). At the barrier level, transepithelial electrical resistance (TEER) decreased while paracellular permeability (PCP) significantly increased after the treatment, showing an EC(50) of 6 and 16 microM CdCl(2), respectively, and indicating the loss of barrier integrity. In conclusion, our data reveal that CdCl(2) toxicity in Caco-2 cells can be detected at the barrier level at very low concentrations; also, HSP70 was shown to be a sensitive marker for detecting in vitro cadmium-induced toxicity.
Boveri
Monica
M
ECVAM, Institute for Health and Consumer Protection, Joint Research Centre, European Commission, Via Enrico Fermi 1, 21020 Ispra (Va), Italy. monica.boveri@jrc.it
Pazos
Patricia
P
Gennari
Alessandra
A
Casado
Juan
J
Hartung
Thomas
T
Prieto
Pilar
P
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D015153:Blotting, Western; D018938:Caco-2 Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D019256:Cadmium Chloride / Q000633:toxicity*; D016923:Cell Death / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D017097:Electric Impedance; D005434:Flow Cytometry; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis / Q000096:biosynthesis*; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000032:analysis / Q000378:metabolism; D018613:Microscopy, Confocal
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018840:HSP70 Heat-Shock Proteins; D007770:L-Lactate Dehydrogenase; D019256:Cadmium Chloride