Molecular research on carcinogens continues to expand, and includes studies focused on comparing the molecular level impacts of both amphibole and chrysotile fibers. Set out below is a poster presentation abstract from a poster presented at a 2013 meeting of the American Association for Cancer Research (AACR). The researchers include Michele Carbone, Haining Yang, and Harvey Pass.
The abstract is pasted below and online here. Both plaintiff and defense lawyers will find something they like in the words of the abstract.
"Crocidolite is considered the most oncogenic asbestos type. Chrysotile accounts for >90% of asbestos used worldwide, however its capacity to induce MM is still debated. We linked crocidolite carcinogenesis to the release of High-Mobility Group Box-1 protein (HMGB1) and activation of downstream genes (TNF-α and NF-{kappa}B). We compared the carcinogenicity of crocidolite and chrysotile in primary human mesothelial cells (HM). Microarray analyses of HM exposed to crocidolite or chrysotile identified 57 genes that were significantly induced or repressed. Forty-eight hours after exposure we observed induction of HMGB1 and NF-{kappa}B targeted genes and E-cadherin and SFRP4 down-regulation. In vitro, both crocidolite and chrysotile induced HMGB1 and TNF-α secretion, induced β-catenin nuclear translocation and caused HM death and epithelial-mesenchymal transition in surviving cells. Five weeks from exposure these effects were sustained in HM exposed to crocidolite; the expression of these genes had returned to normal in HM exposed to chrysotile. Soon after injection, serum HMGB1 levels were elevated in mice injected with either crocidolite or chrysotile, and remained elevated 10 weeks post-injection only in mice injected with crocidolite. Our results show that chrysotile induces the same intracellular signaling elicited by crocidolite, however these effects are transient. Accordingly, HM exposure to chrysotile in the presence of TNF-α or in co-culture with macrophages, induced foci formation with a lower transforming efficiency compared to crocidolite.
[abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3588. doi:10.1158/1538-7445.AM2013-3588
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