Researchers from Duke University combined an FDA-approved cancer immunotherapy with gold nanostars to boost the cancer-killing abilities of both therapies, according to a study published this week in Scientific Reports.
The combination therapy cured two mice and vaccinated one against bladder cancer, the team reported.
“The ideal cancer treatment is non-invasive, safe and uses multiple approaches,” Tuan Vo-Dinh, director of the Fitzpatrick Institute for Photonics at Duke, said in prepared remarks. “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.”
The research team’s technique uses lasers and a unique type of nanoparticles, called gold nanostars, to heat up and kill tumors with the help of an immunotherapeutic drug.
“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 tumors that have spread throughout the body.”
In their study, the researchers injected cancerous cells into both hind legs of mice. To evaluate the therapy’s ability to reach tumors throughout the body, each mouse received treatment in just one of their hind legs.
The mice that received no therapy and those that received only the gold nanostar phototherapy quickly died, since the treatment did nothing to attack the tumor in the untreated leg. Mice who received just the immunotherapy initially responded well, but none survived more than 49 days, the team reported.
However, two of the five mice treated with both the immunotherapeutic and the gold nanostar survived more than 55 days.
“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.”
One mouse is still alive, the team said. It’s been a year since the mouse’s initial bout with cancer. The team even tried injecting the mouse with more cancerous cells, but the mouse’s immune system fought it off, like a vaccine would.
“This is our goal – our dream,” Vo-Dinh said.
The researchers hope to conduct a study with larger cohorts and team up with other researchers to test the therapy on mouse models of brain, breast and lung cancer.