Gold nanoparticle radio-sensitization of MCF-7 breast cancer cells.
Janic B, Brown S, Bagher-Ebadian H, Liu F, Mao G, Chetty I, Movsas B, and Wen N. Gold nanoparticle radio-sensitization of MCF-7 breast cancer cells. Med Phys 2017; 44(6):3063-3064.
Purpose: Nanoparticles are structures 1-100 nm in size explored for their application in cancer diagnosis and treatment. Our long-term plan is to develop nanoparticles that will simultaneously serve as imaging and radiosensitization probes. In the current study, we explore the ability of gold nanoparticles (AuNP), of two different sizes, to increase the sensitivity of breast cancer cells to three different megavoltage (MV) X-rays. Methods: The effect of 4 and 14 nm diameter AuNPs on MCF-7 cell's viability and response to radiation was studied. Cells were incubated for 6 and 24 hours with 4 and 14 nm AuNP at two different concentrations. Cells were irradiated using 4 Gy X-rays of 2.5 flattening filter free (FFF), 6 or 10FFF MV energies. Cells were then allowed to grow for 3 or 7 days after which cell proliferation was analyzed by MTT assay. For viability studies, the proliferation of non-irradiated cells exposed to AuNP alone was assessed. Results: AuNP alone was not toxic to MCF-7 cells. Radio-sensitization, in contrast, was significant and most evident 7 days after irradiation. In cells incubated for 6 h with 4 nm AuNP, a significant dose enhancement of 27% and 31% was observed at 6 and 10 MV, respectively. Under the same conditions, 14 nm AuNP induced a significant enhancement of 49% at 6 MV and 37% at 10 MV. In cells incubated for 24 h with 4 nm AuNP, a significant dose enhancement of 18% was detected using 2.5 and 10 MV X-rays, while 14 nm AuNP induced 52% significant dose enhancement at 2.5 MV only. Conclusion: AuNP radiosenzitization of MCF-7 cells was most pronounced 7 days after irradiation at all energies investigated, especially after 2.5 MV X-rays. The magnitude of radiosensitization was dependent on AuNP size, concentration and incubation time. The lack of significant cytotoxicity in the absence of radiation provides a platform for further exploring AuNP radiosensitizing potential.