The anticancer properties of iron core–gold shell nanoparticles in colorectal cancer cells

Ya-Na Wu,1 Ping-Ching Wu,1 Li-Xing Yang,1 Kyle R Ratinac,2 Pall Thordarson,4 Kristina A Jahn,2 Dong-Hwang Chen,3 Dar-Bin Shieh,1,5,6 Filip Braet2,7 1Institute of Oral Medicine and Department of Stomatology, National Cheng Kung University Hospital, College of Medicine, Tainan, Taiwan; 2Australian Centre for Microscopy and Microanalysis, University of Sydney, Sydney, NSW, Australia; 3Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan; 4School of Chemistry, University of New South Wales, Sydney, NSW, Australia; 5Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan, Taiwan; 6Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, Taiwan; 7School of Medical Sciences (Discipline of Anatomy and Histology), The Bosch Institute, University of Sydney, Sydney, NSW, Australia Abstract: Previously, iron core–gold shell nanoparticles (Fe@Au) have been shown to possess cancer-preferential cytotoxicity in oral and colorectal cancer (CRC) cells. However, CRC cell lines are less sensitive to Fe@Au treatment when compared with oral cancer cell lines. In this research, Fe@Au are found to decrease the cell viability of CRC cell lines, including Caco-2, HT-29, and SW480, through growth inhibition rather than the induction of cell death. The cytotoxicity induced by Fe@Au in CRC cells uses different subcellular pathways to the mitochondria-mediated autophagy found in Fe@Au-treated oral cancer cells, OECM1. Interestingly, the Caco-2 cell line shows a similar response to OECM1 cells and is thus more sensitive to Fe@Au treatment than the other CRC cell lines studied. We have investigated the underlying cell resistance mechanisms of Fe@Au-treated CRC cells. The resistance of CRC cells to Fe@Au does not result from the total amount of Fe@Au internalized. Instead, the different amounts of Fe and Au internalized appear to determine the different response to treatment with Fe-only nanoparticles in