BALB/c 3T3 cell transformation assay for the prediction of carcinogenic potential of chemicals and environmental mixtures.
The prediction of the carcinogenic risk for humans is mostly based on animal experiments. For the last 20 years, however, the scientific community has paid great attention to alternative strategies in compliance with common moral and ethical values. The new European chemical regulation REACH (Reg. EC 1907/2006) requires the performance of new studies in vertebrates only as a last resort. REACH asks for the development of validated in vitro protocols that can replace, in the medium to the long term, animal bioassays. An in vitro cell transformation assay (CTA) is proposed as an alternative to in vivo carcinogenicity testing. This assay is reported in the list of accepted methods for REACH (Reg. EC 440/2008). The BALB/c 3T3 model represents one of the most well-known CTAs and is regarded as a useful tool to screen single chemicals or complex mixtures for carcinogenicity prediction. In this study we used a modified protocol to highlight the transforming potential of three single compounds, ethinylestradiol (EE), azathioprine (AZA-T), melphalan, and two polychlorinated biphenyls (PCBs) mixtures, which are known or suspected to be human carcinogens. We also evaluated the activity of the antioxidant alpha-lipoic acid (ALA), a promising tumor chemopreventive. A significant increase in transformation frequency was observed when the BALB/c 3T3 cells were exposed to EE, AZA-T or melphalan as well as after PCBs treatment. On the contrary, ALA did not induce any increase of foci occurrence. Our results confirm the suitability of the improved protocol to discriminate carcinogenic compounds and support the use of BALB/c 3T3 cell transformation assay as a possible alternative to predict carcinogenic risk to humans.
Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency - Emilia-Romagna Region (ER-EPA), Viale Filopanti 22, 40126 Bologna, Italy.
Maria Grazia
MG
Mascolo
Stefania
S
Perdichizzi
Francesca
F
Rotondo
Elena
E
Morandi
Angela
A
Guerrini
Paola
P
Silingardi
Monica
M
Vaccari
Sandro
S
Grilli
Annamaria
A
Colacci
D000818:Animals; D001379:Azathioprine / Q000633:toxicity; D041702:BALB 3T3 Cells; D015197:Carcinogenicity Tests / Q000379:methods*; D002273:Carcinogens / Q000633:toxicity*; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced*; D004785:Environmental Pollutants / Q000633:toxicity; D004997:Ethinyl Estradiol / Q000633:toxicity; D008558:Melphalan / Q000633:toxicity; D051379:Mice; D011078:Polychlorinated Biphenyls / Q000633:toxicity
D002273:Carcinogens; D004785:Environmental Pollutants; D004997:Ethinyl Estradiol; D011078:Polychlorinated Biphenyls; D001379:Azathioprine; D008558:Melphalan