Photo-thermal effect enhances the efficiency of radiotherapy using Arg-Gly-Asp peptides-conjugated gold nanorods that target αvβ3 in melanoma cancer cells

Background: Thermotherapy has been known to be one of the most effective adjuvants to radiotherapy (RT) in cancer treatment, but it is not widely implemented clinically due to some limitations, such as, inadequate temperature concentrations to the tumor tissue, nonspecific and non-uniform distribution of heat. So we constructed arginine-glycine-aspartate peptides-conjugated gold nanorods (RGD-GNRs) that target the alpha(v) beta(3) Integrin (alpha v beta 3) and investigate whether the photo-thermal effect of RGD-GNRs by near infrared radiation (NIR) could enhance the efficiency of RT in melanoma cancer cells. Results: RGD-GNRs could be seen both on the surface of the cell membranes and cytoplasm of A375 cells with high expression of alpha v beta 3. After exposed to 808 nm NIR, RGD-GNRs with various concentrations could be rapidly heated up. Compared to other treatments, flow cytometric analysis indicated that RT + NIR + RGD-GNRs increased apoptosis (p < 0.001) and decreased the proportion of cells in the more radioresistant S phase (p = 0.014). Treated with NIR + RGD-GNRs, the radiosensitivity was also significantly enhanced (DMFSF2: 1.41). Conclusion: Results of the current study showed the feasibility of using RGD-GNRs for synergetic RT with photothermal therapy. And it would greatly benefit the therapeutic effects of refractory or recurrent malignant cancers.