Comparative study of the effect of neutrons emitted from neutron source 241Am-Be and curcumin on MCF-7 breast cancer cells in 3D culture medium
Authors: zargan Sajedeh , borough Mehdi salehi , zargan Jamil , shayesteh Mohsen , Haji Noor Mohammadi Ashkan , Mousavi Mohsen , Alikhani Hani Keshavarz 
Published: January 2022

Introduction

Cancer is one of the major medical problems threatening human health. Breast cancer is the most prevalent type of cancer in women. Reports indicate that treatments such as surgery, chemotherapy, biotherapy, and radiotherapy play a limited but important role in treating the disease. For more efficient treatment, new treatment strategies have been evolved based on combination therapy in which two or more different methods are exploited for this aim. In the present study, a combination therapy based on radiotherapy (using neutron radiation emitted from a 241Am-Be neutron source) and biotherapy (using curcumin) is applied to investigate the treatment efficiency of MCF-7 breast cancer in a three-dimensional culture medium.

materials and methods

The neutron dose rate in the 241Am-Be source was measured using BF3 detection and MCNPX simulation methods, and then the results of both methods were compared. MTT, neutral red uptake assay, nitric oxide, glutathione assay, catalase, cytochrome c, comet assay, and caspase-3 were used to determine the effect and type of mortality due to neutron effect as well as the combined effect of neutron and curcumin in cancer cells.

Results

Calculating the fast neutron flux around the source with two methods of simulation with MCNPX and detection with BF3 showed that with increasing distance from the source, the fast neutron flux decreased exponentially. The results of neutron dose rate measurement in the 241Am-Be source also showed that if the test cells in the vial are located at a distance of 22 cm from the inlet of the collimator and are exposed to neutron radiation for 5, 10, 15, and 20 hours, the neutron dose received by breast cancer cells will be 3, 6, 9, and 12 mGy/h, respectively.

The results of cytotoxicity due to neutron irradiation as well as the combined effect of neutron and curcumin (80 μM concentration) showed that neutron irradiation with or without curcumin at 5, 10, 15, and 20 hours reduced the survival of tumor cells. According to the results, the rate of apoptosis due to the neutron effect at irradiation times has increased with increasing time. Statistical analysis also showed that the rate of apoptosis due to the combined effect of neutrons and curcumin was not significant compared to the effect of neutrons only. The results of studying the effect of neutrons and the combination of neutrons and curcumin on the production of nitric oxide, catalase, and GSH also showed that curcumin has an antioxidant effect by reducing the amount of nitric oxide and increasing the production of catalase and glutathione in cells. However, neutrons, alone, lacked this effect.

Conclusion

Overall, this study showed that the neutron source 241Am-Be with the applied doses was able to destroy the c–o, and c–h bonds of curcumin, resulting in cell death and apoptosis induction in breast cancer cells. It was caused by neutron radiation. On the other hand, according to the results of the comet assay and caspase-3 experiments, although neutrons induced apoptosis in breast cancer cells, the death rate due to necrosis was much higher than apoptosis. Due to the significant anti-cancer effect of curcumin in 3D culture, the use of this molecule before or after neutron therapy is recommended.

Highlights

The results of neutron dose rate measurement in the 241Am-Be source showed that if the test cells in the vial are located at a distance of 22 cm from the inlet of the collimator and are exposed to neutron radiation for 5, 10, 15, and 20 hours, the neutron dose received by breast cancer cells will be 3, 6, 9, and 12 mGy/h, respectively.

The results of cytotoxicity due to neutron irradiation as well as the combined effect of neutron and curcumin (80 μM concentration) showed that neutron irradiation with or without curcumin at 5, 10, 15, and 20 hours reduced the survival of tumor cells.

According to the results, the rate of apoptosis due to the neutron effect at irradiation times has increased with increasing time. The results of studying the effect of neutrons and the combination of neutrons and curcumin on the production of nitric oxide, catalase, and GSH also showed that curcumin has an antioxidant effect by reducing the amount of nitric oxide and increasing the production of catalase and glutathione in cells. However, neutrons, alone, lacked this effect.

this study showed that the neutron source 241Am-Be with the applied doses was able to destroy the c–o, and c–h bonds of curcumin, resulting in cell death and apoptosis induction in breast cancer cells. It was caused by neutron radiation.

according to the results of the comet assay and caspase-3 experiments, although neutrons induced apoptosis in breast cancer cells, the death rate due to necrosis was much higher than apoptosis.