Gold nanoparticles and immunotherapy provide surprising results

Posted on 2017-08-21

Two approaches that kill cancer have teamed up to become an effective duo. Gold nanostars and immunotherapy are being used together in an effort to provide a non-invasive cancer treatment which has produced an unexpectedly pleasant result.

Photothermal thermal therapy uses tiny, gold nano-stars which are inserted into a tumour. Then, a laser is used to heat up the nanostars, heating the tips to a point it can kill the cancerous cells. 

"The nanostar spikes work like lightning rods, concentrating the electromagnetic energy at their tips," said Vo-Dinh. "We've experimented with these gold nanostars to treat tumours before, but we wanted to know if we could also treat tumours we didn't even know were there or distant and undetectable tumours that have spread throughout the body."

For the trial, the researchers used mice and injected them with bladder cancer cells into both hind legs. The control group had no treatment and died very quickly. One group had the photothermal treatment used in one of their legs, and all died as the second leg was left untreated. The third group were treated with an immunotherapy drug to hinder PD-L1 interaction, resulting in the mice remaining alive for up to 49 days. The final group received both immunotherapy and photothermal therapy, resulting in two of them being completely cured.

"When a tumour dies, it releases particles that trigger the immune system to attack the remnants," said Vo-Dinh. "By destroying the primary tumour, we activated the immune system against the remaining cancerous cells, and the immunotherapy prevented them from hiding."

Although small and only studied on mice, this proof-of-concept experiment shows a lot of promise for future trials. One mouse displayed an immunity to cancer after the experiment. A year passed and the mouse was still alive and kicking, even after another injection of cancer. It was observed that the mice's own immune system could fight off cancer by itself.

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