Cancer link leads researchers to request reassessment of zinc oxide
A study led by researchers from Nanyang Technological University (NTU), Singapore, reports that nano-sized particles of the chemical – as used in consumer products from foods to cosmetics; including sunscreens, biosensors, food additives, and pigments – can potentially lead to the development of cancer by damaging genes in the body.
Writing in the journal Biomaterials, the researchers suggested that industry may have to reassess the health impact of nano-sized zinc oxide used in everyday products. They added that more studies are required to investigate the use and concentration levels of nano- materials in consumer products, how often a consumer uses them and in what quantities.
“Currently there is a lack of information about the risks of the nano-materials used in consumer products and what they can pose to the human body,” said Dr Joachim Loo of an assistant professor NTU – who led the study.
“This study points to the need for further research in this area and we hope to work with the relevant authorities on this,” he added.
Loo and his team reported that zinc oxide activated an important anti-tumour pathway in cells – known as the p53 pathway. The researchers suggested that the activation of p53 implies a cellular response to the presence of the zinc oxide nano particles that requires an anti-tumour function.
The team proposed that p53 may act as a ‘master switch’ that leads to programmed cell death when damage is caused to DNA.
“This also suggests that in cells without robust p53, protective response can be tipped towards carcinogenesis when stimulated by DNA damage inducing agents like zinc oxide particles,” said the researchers.
Upon testing this theory, Loo and his colleagues found that indeed cells with a lack of p53 – or ones cannot generate adequate amount of functional p53 – become cancerous when exposed to zinc oxide nano particles.
Ng Kee Woei – also of PLPLPL – said the team will carry out further research to investigate the currently unknown mechanisms behind the nano- zinc oxide induced DNA damage. But what is clear, he said, is that besides causing DNA damage, nano particles can also cause other harmful effects when used in high doses.
“From our studies, we found that nano particles can also increase stress levels in cells, cause inflammation or simply kill cells,” said Ng, who added that apart from finding the cellular mechanisms behind the nano zinc oxide findings, more focused research is also expected to focus on other physiological effects and damage that nano-sized zinc oxide particles can cause.
Moving forward, the team said they hope to work with existing and new collaborative partners, to coordinate a more concerted effort towards the advancement of the fledgling field of nanotoxicology – with the aim of helping regulatory bodies formulate guidelines to protect consumer interests.
They added that they would also like to work with the European Union, to assist in unearthing the risks involving nanomaterials, and such materials should be regulated before they are made commercially available.
Volume 32, Issue 32, November 2011, Pages 8218-8225, doi: 10.1016/j.biomaterials.2011.07.036
“The role of the tumor suppressor p53 pathway in the cellular DNA damage response to zinc oxide nanoparticles”
Authors: K.W. Ng, S.P.K. Khoo, B.C. Heng, M.I. Setyawati, E.C. Tan, et al
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