Figure 3

Figure 3

HNCCs labelled with GNPs show decreased in vitro colony forming potential 10 days post radiation. A colony formation assay (CFA) was used to determine the potential of GNP-labelled or unlabelled (NoNP) cancer cells to form colonies 10 days after radiation with the STB or DTB. (a) GNP-labeled Detroit-562 and FaDu cells irradiated with the DTB exhibit decreased colony formation potential compared to NoNP-labeled cells with STBR (both p = 0.045). With DTBR, GNP-labeled Detroit-562 cells formed fewer colonies than NoNP-labeled cells (p = 0.0001). GNP-labeled FaDu cells also demonstrated decreased colony forming potential with DTBR compared to STBR (p = 0.017). GNP-labelled HSC-3 cells formed fewer colonies with both DTB and STB radiation compared to unlabeled (NoNP) cells treated with DTBR (p = 0.025 and p = 0.045, respectively). Lastly, with NoNPs, STBR treated Detroit-562 cells formed fewer colonies than cells with DTBR (p = 0.0001). Panc1 cells exhibited a similar trend in the reduction of colonies in GNP-labeled groups with DTBR compared to other treatment groups, but the results were not significant. (b) Representative bright-field images of GNP-labeled HSC-3 cells fixed and stained with Crystal Violet in Petri plates receiving no radiation (No RT), STBR or DTBR. Results are presented as the fold change of surviving fraction (SF) means ± standard error of the mean, SF = (# of colonies/(plating efficiency (PE) × # of colonies seeded)) × 100. Fold changes were made relative to unirradiated control cells, p* < 0.05, p** < 0.01, p*** < 0.001 for significant decreases in colony forming potential. Significance between groups was tested using one-way analysis of variance (ANOVA) with a Tukey multiple comparisons test (n = 3). GNP gold nanoparticles, NoNP no nanoparticles, HNCC head and neck cancer cells, STB(R) standard target beam (radiation), DTB(R) diamond target beam (radiation).