Gold Particles Significantly Boost Focus of Radiation Therapy

Cancer cells (A) treated with gold alone (dark areas) take up far less gold than cells with gold delivered by pHLIPs (B). C and D are cellular close-up with pHLIP-delivered gold. Images: Reshetnyak and Andreev/URI

A team from Brown University and the University of Rhode Island has developed a new technique to radically improve how radiation therapy acts on cancer cells. The method uses gold nanoparticles that are delivered to cancer cells using so-called pH Low-Insertion Peptides (pHLIP), compounds that are attracted to acidic environments. Since cancer cells tend to be more acidic than healthy ones, pHLIPs accumulate around tumor sites.

The team attached gold nanoparticles to the pHLIPs and injected the compound into laboratory samples of tumor tissue. They showed that the cancer cells had a 24% lower survival rate than cells irradiated without the injection, and 21 percent lower when injecting just the gold particles without the pHLPs. The next step is to test the technology on animal cancer models, hopefully leading to clinical applications of the technology in humans. Not only is there potential for more precise tumor targeting, but the radiation dose delivered to patients may be reduced significantly thanks to the pHLP delivered nanoparticles.

From the study in Proceedings of the National Academy of Sciences:

Damage from radiation and gold nanoparticles depends in part on the Auger effect, which is very localized; thus, it is important to place the gold nanoparticles on or in the cancer cells. In this work, we use the pH-sensitive, tumor-targeting agent, pH Low-Insertion Peptide (pHLIP), to tether 1.4-nm gold nanoparticles to cancer cells. We find that the conjugation of pHLIP to gold nanoparticles increases gold uptake in cells compared with gold nanoparticles without pHLIP, with the nanoparticles distributed mostly on the cellular membranes. We further find that gold nanoparticles conjugated to pHLIP produce a statistically significant decrease in cell survival with radiation compared with cells without gold nanoparticles and cells with gold alone.

Study in Proceedings of the National Academy of Sciences: Enhancement of radiation effect on cancer cells by gold-pHLIP…

Source: Brown University…