Scientists have developed a new way to deliver vaccines, using unique 'stealth' nanoparticles, that successfully stifled tumour growth in mice.
Cancer vaccines have recently emerged as a promising approach for killing tumour cells before they spread. But so far, most clinical candidates have not worked that well.
Now, scientists have developed a new way to deliver vaccines that successfully stifled tumour growth when tested in laboratory mice. And the key is in the vaccine's unique stealthy nanoparticles.
Researchers Hiroshi Shiku, Naozumi Harada and colleagues explain in the journal American Chemical Society (ACS) Nano that most cancer vaccine candidates are designed to flag down immune cells, called macrophages and dendritic cells, that signal "killer" T cells to attack tumours.
The problem is that approaches based on targeting these generally circulating immune cells have not been very successful.
But recent research has suggested that a subset of macrophages only found deep inside lymph nodes could play a major role in slowing cancer.
Shiku's team wanted to see if stealthy nanoparticles they had developed and clinically tested in patients might hold the answer.
The researchers injected the nanoparticles into mice. They found that the particles, which have no electric charge or surface molecules that would attract the attention of circulating immune cells, were able to enter the mice's lymph nodes.
But once inside the lymph nodes' core, the special kind of macrophage engulfed the particles. When molecules for signalling killer T cells were put inside the nanoparticles, they hindered tumour growth far better than existing vaccines.
