evaluating the radiosensitization effect of hydroxyapatite nanoparticles on human breast adenocarcinoma cell line and fibroblast

Background: nanohydroxyapatite (nhap) exhibit antiproliferative effects on various cancer cells. however, to date, there are only a few studies on the radiosensitization effect of nhap. the present study aimed to investigate the possible enhancement of the radiosensitization effect of nhap on human breast adenocarcinoma cancer (mcf7) and fibroblast. methods: nhap was extracted from fish scales using the thermal alkaline method and characterized at babol university of medical sciences (babol, iran) in 2017. the antiproliferative and the radiosensitization effects of nhap were investigated by 3(4, 5-dimethylthiazol2yl)2, 5-diphenyltetrazolium bromide (mtt), clonogenic assay, and apoptosis assay. mcf7 cells and fibroblasts were incubated with different concentrations of nhap and at different periods. the mtt solution was added and the absorbance was measured at 570 nm. the mcf7 cells were exposed to 0, 1.5, 3.5, and 5 gy xray irradiation and incubated for 1014 days. the data were compared using the oneway analysis of variance (anova) followed by the post hoc tests (tukey’s method). results: the results showed that nhap significantly inhibited the growth of mcf7 cells compared with controls (p = 0.001), but the difference was not statistically significant for fibroblasts (p=0.686 at 400 µg/ml at 72 hours). after 48 hours, the proliferation of mcf7 cells and fibroblasts was inhibited by about 81% and 34% at 400 µg/ml concentration, respectively. the radiosensitization enhancement factor for mcf7 cells and fibroblasts at a dose of 3.5 gy and 100 μg/ml concentration were 1.87 and 1.3, respectively. conclusion: nhap can be considered as a breast cancer radiosensitization agent with limited damage to the surrounding healthy tissue.