Environmental Carcinogenesis and Risk Assessment, Environmental Protection and Health Prevention Agency - Emilia-Romagna Region (ER-EPA), Viale Filopanti 22, 40126 Bologna, Italy.
Toxicol In Vitro. 2010 Jun;24(4):1292-300. doi: 10.1016/j.tiv.2010.03.003. Epub 2010 Mar 11.
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.
人类致癌风险的预测主要基于动物实验。然而，在过去的 20 年中，科学界非常关注符合共同道德和伦理价值观的替代策略。新的欧洲化学品法规 REACH（Reg. EC 1907/2006）仅要求在不得已的情况下在脊椎动物中进行新的研究。REACH 要求开发经过验证的体外方案，这些方案可以在中长期内替代动物生物测定。体外细胞转化测定（CTA）被提议作为体内致癌性测试的替代方法。该测定方法被列入 REACH（Reg. EC 440/2008）接受方法清单。BALB/c 3T3 模型是最著名的 CTA 之一，被认为是筛选单一化学物质或复杂混合物致癌性预测的有用工具。在这项研究中，我们使用了改良的方案来突出三种单一化合物（雌二醇、硫唑嘌呤和苯并[a]芘）以及两种多氯联苯混合物（已知或疑似人类致癌物）的转化潜力。我们还评估了抗氧化剂α-硫辛酸（ALA）的活性，ALA 是一种有前途的肿瘤化学预防剂。当 BALB/c 3T3 细胞暴露于 EE、AZA-T 或苯并[a]芘以及 PCBs 处理时，转化频率显着增加。相反，ALA 并没有引起焦点发生的任何增加。我们的结果证实了改良方案区分致癌化合物的适用性，并支持使用 BALB/c 3T3 细胞转化测定作为预测人类致癌风险的替代方法。
