Characterization of a HER-2 targeted silica-gold nanoshells for breast cancer radio-photothermal therapy

The combination of nanoparticles (NPs) with X-ray radiation, laser and chemotherapy offers a promising strategy to enhance breast cancer (BC) treatment efficacy. This study investigates the therapeutic potential of Trastuzumab-loaded Au@SiO₂ nanoshells (TZ-Au@SiO₂ NSs) for SKBr-3 (HER-2⁺) and MCF-7 (HER-2^-) BC cells.

Au and SiO₂ NPs were prepared via the citrate reduction and sol-gel method, respectively. TZ-Au@SiO₂ NSs were formed by conjugating TZ to Au@SiO₂ NSs. Nano-complex characterization was performed using FT-IR, DLS, TEM, SEM, UV-Vis, XRD, and drug loading efficiency analysis. Cell viability was assessed using the MTT assay after treatment with Au@SiO₂ NSs, TZ, TZ-Au@SiO₂ NSs, NIR laser (808 nm), and X-ray radiation (6 MV, 2 Gy). Moreover, gene expression was analyzed using RT-qPCR to measure apoptosis-related genes.

The synthesized TZ-Au@SiO₂ NSs (around 70 nm) presented significant ability of temperature increase. The combination of TZ-Au@SiO₂ NSs with laser and X-ray radiation resulted in a significant decrease in cell viability. In SKBR-3 cells, TZ-Au@SiO₂ NSs alone reduced viability from 100 % to 71.5 % at 200 μg/mL. After laser treatment, viability decreased to 46 % at the highest dose (350 J/cm²), while X-ray radiation reduced the viability to 63 %. The combined treatment with laser + X-ray resulted in 50 % viability in SKBR-3 and 57 % in MCF-7 cells. Gene expression analysis revealed upregulation of TP53, indicating the induction of apoptosis.

TZ-Au@SiO₂ NSs significantly enhance the cytotoxic effects of X-ray radiation and photothermal-chemotherapy, especially in SKBR-3 BC cells, suggesting their potential as effective radio-sensitizers and photo-sensitizers for improved BC treatment.