One way of bypassing the immune system to deliver drugs to a tumor site is to use the immune system itself as a delivery mechanism. And now researchers at Stanford University have unexpectedly found that nanoparticle-encased drugs injected into mice entered immune cells called monocytes, which then carry the treatment to the correct site.Senior author Bryan Smith
The scientists developed carbon nanotubes that they expected to reach a tumor on their own, but after visualizing the particles' behavior in mice, they found that monocytes, which are known to fuel diseases like cancer, according to the university, carried the nanoparticles straight to the tumor. And they "were taken up with unprecedented selectivity," according to senior researcher Bryan Smith as reported by the Stanford Daily.
"Here, we show that, in addition to conventional nanoparticle-uptake mechanisms, single-walled carbon nanotubes … significantly enhance the number of … monocytes reaching the tumor," lead author Sanjiv Gambhir, Smith and their team wrote in the abstract published in the journal Nature Nanotechnology. "… The remarkable selectivity of this tumor-targeting mechanism demonstrates an advanced immune-based delivery strategy for enhancing tumour delivery with substantial penetration."
In the future, Gambhir hopes to advance the system enough to be able to remove a patient's own immune cells, load them with the nanoparticles, and release them back into the bloodstream to reach their target.