Radiosensitizing effect of mesoporous silica-encapsulated gold nanorods on human triple-negative breast cancer cells

Abstract

Objective To investigate the radiosensitizing effect of mesoporous silica-encapsulated gold nanorods (GNRs@mSiO2) combined with 6 MV X-ray on human triple-negative breast cancer MDA-MB-231 cells and its possible mechanism. Methods A transmission electron microscope was used to analyze the morphology and intracellular distribution of GNRs@mSiO2. An atomic absorption spectrophotometer was used to evaluate the uptake of GNRs@mSiO2 by cells. The CCK-8 assay was used to measure the cytotoxicity of different concentrations of GNRs@mSiO2. The colony formation assay was used to determine the effect of GNRs@mSiO2 on the radiosensitivity of cells. Flow cytometry was used to measure the cell cycle, apoptosis, and the level of reactive oxygen species. Between-group comparison was made by paired t test. Results The uptake of GNRs@mSiO2 by MDA-MB-231 cells reached a peak value at 24 h, which was (7.09±0.26)-fold higher than that in the control group and significantly higher than those in other groups (P=0.002-0.014). After exposure to 12.5-50.0μg/ml GNRs@mSiO2 for 24 h, more than 90% of the cells remained alive. The D0, Dq, and SF2 values in the GNRs@mSiO2+ irradiation group were lower than those in the irradiation alone group, yielding a sensitization enhancement radio of 1.27(radio of SF2 values). The apoptosis rate was (30.4±0.68)% in the GNRs@mSiO2+ irradiation group. The proportion of cells in G2/M phase was (31.25±0.75)% in the GNRs@mSiO2+ irradiation group, which was significantly higher than those in other groups (P=0.003-0.033). Conclusions Mesoporous silica-encapsulated gold nanorods can effectively enhance the radiosensitivity of human triple-negative breast cancer MDA-MB-231 cells to 6 MV X-ray. Key words: Mesoporous silica-encapsulated gold nanorods; Radiosensitivity; Triple-negative breast cancer cell lines