Gold nanostars, shown as white spots, preferentially accumulate within a tumor and are sparse in normal tissue. Photo courtesy Duke University

Aug. 18 (UPI) -- Researchers at Duke University have successfully cured and vaccinated mice against cancer in a recent small study using nanotechnology and immunotherapy.

The study, published on Aug. 17 in Scientific Reports, combined a Food and Drug Administration-approved cancer immunotherapy treatment with a new tumor-killing nanotechnology to improve the effectiveness of both therapies.


"The ideal cancer treatment is non-invasive, safe and uses multiple approaches," said Tuan Vo-Dinh, professor of Biomedical Engineering, professor of chemistry, and director of the Fitzpatrick Institute for Photonics at Duke University, said in a news release. "We also aim at activating the patient's own immune system to eradicate residual metastatic tumors. If we can create a long-term anticancer immunity, then we'd truly have a cure."

Researchers developed the photothermal immunotherapy using lasers and gold nanostars to heat and destroy tumors in combination with an immunotherapy drug.

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The gold nanostars consist of multiple sharp spikes and are capable of capturing the laser's energy more efficiently, which allows them to work with less exposure so they are more effective deeper within tissue.

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

Researchers injected bladder cancer cells into both hind legs of a group of mice and tested several different treatments on one leg of the mice after the tumors grew.

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Mice that had not treatment at all died from the cancer as well as mice that received only the gold nanostar photothermal therapy. Mice that were treated with just the immunotherapy initially responded well but none survived more than 49 days.

However, the group treated with both the immunotherapy and the gold nanostar photothermal therapy responded very well to treatment with two of the mice being completely cured. One mice even survived nearly a year after treatment with no recurrence of cancer.

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

Researchers found that after a month when the mouse was injected with more cancerous cells, its immune system attacked and destroyed the cells showing a vaccine effect.