Nowadays,
radiotherapy is one of the most effective treatments for
breast cancer. In order to overcome the radioresistance of
cancer cells, radio-sensitizing agents can be used combined with irradiation to increase the therapeutic efficiency.
Curcumin can enhance the radiosensitivity of
cancer cells and decrease their viability by the accumulation of these cells in the G2 phase. The encapsulation of
curcumin in a nanoniosomal delivery system increases aqueous solubility and bioavailability, resulting in increased radio sensitivity. The present study aimed to enhance the radio-sensitizing effect of the
curcumin-containing nanoniosome (Cur-Nio) when combined with irradiation. Thus,
curcumin (0.5 mg ml-1) was loaded on a PEGylated nanoniosome containing
Tween 60,
cholesterol,
DOTAP, and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-poly(ethylene glycol) (
DSPE-PEG) (at ratios of 70:30:10:5, respectively) by the thin-film hydration method. The particle size, zeta potential, entrapment efficiency, and drug-release rate of formulated nanoniosomes were determined. In order to assess cytotoxicity and apoptosis, different doses of irradiation along with various concentrations of free
curcumin and Cur-Nio (single or in combination with irradiation) were treated with
breast cancer cells. The particle size and zeta potential of Cur-Nio were reported to be 117.5 nm and -15.1 mV, respectively. The entrapment efficiency (EE%) and loading capacities were 72.3% and 6.68%, respectively. The drug-release rate during 6 h was 65.9%. Cell survival in the presence of
curcumin at doses of 1 and 3 Gy showed a significant reduction compared with cells irradiated at 48 h and 72 h (p < 0.000). Also, the rate of cytotoxicity and apoptosis was significantly higher in cells treated with the combination of
curcumin-containing nanoniosomes and irradiation in comparison with those treated with free
curcumin. These findings indicate that the efficacy of pre-treatment with Cur-Nio as a radiosensitizer during
radiotherapy enhances irradiation-induced
breast cancer cell apoptosis and is a useful strategy to increase the effectiveness of
breast cancer therapy.