Human Bone Marrow-Derived Mesenchymal Cell Reactions to 316L Stainless Steel: An in Vitro Study on Cell Viability and Interleukin-6 Expression

Toxicity assessment and health hazard classification of stainless steels

Stainless steels are widely used iron-based alloys that contain chromium and, typically, other alloying elements. The chromium(III)-rich surface oxide of stainless steels efficiently limits the release (bioaccessibility) of their metal constituents in most physiological environments, influencing the toxicity of the alloy. Of the constituents and impurities of stainless steels, nickel and cobalt are of particular interest, primarily due to skin sensitization and repeated-dose inhalation toxicity of nickel, and (inhalation) carcinogenicity of cobalt. A review of the available toxicological data on stainless steels, and the toxicological, mechanistic, and bioaccessibility data on their constituent metals supports the low toxicity and non-carcinogenicity of stainless steels. The comparative metal release, rather than the bulk composition of stainless steels, needs to be considered when assessing their health hazard classification according to the UN Globally Harmonized System, and the corresponding EU CLP regulation. As an illustrative example, a 28-day inhalation toxicity study on stainless steel powder showed no signs of lung toxicity at exposure levels at which significant toxicity would have been expected on the basis of its bulk nickel content. This finding is associated with the low bioaccessibility of nickel from the alloy in the lungs.

Transcriptome of Two Canine Prostate Cancer Cells Treated With Toceranib Phosphate Reveals Distinct Antitumor Profiles Associated With the PDGFR Pathway

Canine prostate cancer (PC) presents a poor antitumor response, usually late diagnosis and prognosis. Toceranib phosphate (TP) is a nonspecific inhibitor of receptor tyrosine kinases (RTKs), including vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), and c-KIT. This study aimed to evaluate VEGFR2, PDGFR-β, and c-KIT protein expression in two established canine PC cell lines (PC1 and PC2) and the transcriptome profile of the cells after treatment with TP. Immunofluorescence (IF) analysis revealed VEGFR2 and PDGFR-β protein expression and the absence of c-KIT protein expression in both cell lines. After TP treatment, only the viability of PC1 cells decreased in a dose-dependent manner. Transcriptome and enrichment analyses of treated PC1 cells revealed 181 upregulated genes, which were related to decreased angiogenesis and cell proliferation. In addition, we found upregulated PDGFR-A, PDGFR-β, and PDGF-D expression in PC1 cells, and the upregulation of PDGFR-β was also observed in treated PC1 cells by qPCR. PC2 cells had fewer protein-protein interactions (PPIs), with 18 upregulated and 22 downregulated genes; the upregulated genes were involved in the regulation of parallel pathways and mechanisms related to proliferation, which could be associated with the resistance observed after treatment. The canine PC1 cell line but not the PC2 cell line showed decreased viability after treatment with TP, although both cell lines expressed PDGFR and VEGFR receptors. Further studies could explain the mechanism of resistance in PC2 cells and provide a basis for personalized treatment for dogs with PC.