Toxicoproteomic evaluation of carbon nanomaterials in vitro

Our plain-English summary of Toxicoproteomic evaluation of carbon nanomaterials in vitro, by H. Haniu, Y. Matsuda, Y. Usui, et al (Journal of Proteomics, 2011).

The study

• Authors: H. Haniu, Y. Matsuda, Y. Usui, K. Aoki, M. Shimizu, N. Ogihara, K. Hara, M. Okamoto, S. Takanashi, N. Ishigaki, K. Nakamura, H. Kato, N. Saito
• Journal: Journal of Proteomics
• Published: 2011;74(12):2703-12
• Type of article: Review
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Carbon nanotubes (CNTs) have already been successfully implemented in various fields, and they are anticipated to have innovative applications in medical science. However, CNTs have asbestos-like properties, such as their nanoscale size and high aspect ratio (>100). Moreover, CNTs may persist in the body for a long time. These properties are thought to cause malignant mesothelioma and lung cancer. However, based on conventional toxicity assessment systems, the carcinogenicity of asbestos and CNTs is unclear. The reason for late countermeasures against asbestos is that reliable, long-term safety assessments have not yet been developed by toxicologists. Therefore, a new type of long-term safety assessment, different from the existing methods, is needed for carbon nanomaterials. Recently, we applied a proteomic approach to the safety assessment of carbon nanomaterials. In this review, we discuss the basic concept of our approach, the results, the problems, and the possibility of a long-term safety assessment for carbon nanomaterials using the toxicoproteomic approach.

Copyright © 2011 Elsevier B.V. All rights reserved.

In plain English

This article is a review of using proteomics, measuring changes in many cell proteins at once, to judge the long-term safety of carbon nanomaterials. These include carbon nanotubes, which the authors describe as having asbestos-like properties. The review first listed earlier animal and cell studies by other researchers, and the authors described their results as conflicting. It then described the authors' own earlier experiments. In those, human monoblastic leukemia cells (U937) were exposed for 96 hours to carbon black and to three grades of multi-wall carbon nanotubes: As-grown, HTT1800 and HTT2800. The last two had been heat-treated to remove iron and polycyclic aromatic hydrocarbons. As-grown nanotubes significantly inhibited cell growth. The heat-treated grades tended to inhibit growth, but this was not statistically significant. Carbon black did not affect growth. Protein levels changed in cells treated with HTT1800, HTT2800 or carbon black, and two changes were shared by all three. The authors noted that evidence linking such protein changes to chronic toxicity is lacking. They concluded that it is not yet clear whether carbon nanomaterials will be hazardous.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Review; it summarizes published toxicity studies by others and the authors' own earlier proteomic experiments in cultured cells
• Who was studied: In the authors' own experiments described in the review: cultured human monoblastic leukemia cells (U937), n=4
• Exposure: Three grades of multi-wall carbon nanotubes (As-grown, HTT1800 and HTT2800; HTT1800 and HTT2800 were heat-treated above 1800 °C in argon to remove iron and polycyclic aromatic hydrocarbons) and carbon black (particle diameter 85 nm), for 96 hours
• Main results:
  • The review tabulated earlier in vivo and in vitro toxicity studies of carbon nanotubes by other groups. The authors described their results as conflicting.
  • As-grown multi-wall carbon nanotubes significantly inhibited proliferation of U937 cells (n=4).
  • In cells exposed to HTT1800 and HTT2800, proliferation tended to be inhibited, but this was not statistically significant compared with control (n=4).
  • Carbon black did not affect cell proliferation.
  • The expression of many proteins was altered in cells treated with HTT1800, HTT2800 or carbon black.
  • Altered expression of two proteins was shared by cells treated with any of the three carbon materials (HTT1800, HTT2800, carbon black).
  • Proteins that function in cell proliferation and transcription changed only in cells exposed to multi-wall carbon nanotubes with impurities.
  • Annexin A2 was increased by multi-wall carbon nanotubes but decreased by carbon black.
• The authors' conclusion: The authors concluded that, based on currently available toxicoproteomics, it is not yet clear whether carbon nanomaterials will be hazardous in applications including medical sciences.
• Limitations the authors state:
  • The authors did not draw conclusions about toxicity from protein functions, because evidence linking known functions of altered proteins to chronic toxicity is lacking.
  • Chronic toxicity cannot be predicted because there is insufficient information on how chronic disease relates to changes in protein expression.
  • The 2-DE/MS method used may not allow quantitative comparison of low-abundance proteins.

Topics

Medical terms in this study, explained in our Lexicon: Aspect Ratio (Length-to-diameter ratio), Mesothelioma, Lung Cancer.

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