Effects of human arylamine N-acetyltransferase I knockdown in triple-negative breast cancer cell lines.
Bottom Line: The expression of Snail increased when NAT1 was knocked down, while other genes associated with mesenchymal to epithelial transition (vimentin, cytokeratin-18, and Twist) did not show any changes.By contrast, both N-cadherin and β-catenin were significantly reduced.When MDA-MB-231 cells expressing shRNA were injected in vivo into BALB/c nu/nu nude mice, a significant reduction in the number of colonies that formed in the lungs was observed.
Affiliation: School of Biomedical Sciences, University of Queensland, St Lucia, Queensland, 4072, Australia.Show MeSH
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Mentions: Invading breast cancer cells display a motile phenotype and a gene expression profile that includes extracellular proteases that degrade the surrounding tissue matrix 26. Invasion also has been associated with the transition from an epithelial phenotype to a more mesenchymal phenotype 27 and therapeutic strategies that induce the epithelial phenotype have been suggested as a means to prevent metastatic disease 28. Here, we investigated whether the reduced cell invasiveness following NAT1 knockdown in MDA-MB-231 cells was associated with mesenchymal–epithelial transition (MET) by examining several well-characterized MET markers (Fig.3A). There were no differences in cytokeratin-18 or vimentin expression (Fig.3B), and neither Twist nor E-cadherin was detected in control or shNAT1 cells (Fig.3A). By contrast, there was a significant increase in Snail expression while both N-cadherin and β-catenin were significantly decreased following NAT1 knockdown (Fig.3B). Both N-cadherin and β-catenin have been associated with breast cancer invasiveness 29–31 and are the targets for novel anticancer therapies 32,33. In MDA-MB-231 cells, β-catenin is mainly localized to the nucleus (Fig.3C). Upon NAT1 knockdown, there appeared to be a decrease in the nuclear content of this protein (Fig.3C).
Affiliation: School of Biomedical Sciences, University of Queensland, St Lucia, Queensland, 4072, Australia.