Scientists have developed a new way of treating cancer with iron nanoparticles, which were able to kickstart the immune system into attacking tumors in groups of mice.
In the study, macrophages (white blood cells) fought back against spreading tumors after a dose of iron nanoparticles, stopping the cancer from taking hold.
In addition to shrinking existing tumors in mice, the treatment stopped cancer tumors from spreading through the body, according to researchers from Stanford University and Oregon Health & Science University.
The researchers used ferumoxytol for their tests, an iron supplement already available commercially for the treatment of anemia, where the body doesn't have enough iron naturally.
Originally the idea was to use the iron nanoparticles as a kind of Trojan horse, sneaking chemotherapy into tumors. As it turned out, though, the control group of mice – which were given iron without chemo drugs – showed the best results in terms of tumor suppression.
Follow-up tests conducted in cells in a dish determined that it was the macrophages that were battling the cancer after receiving the iron – ordinarily, these macrophages stop attacking tumors and start helping their growth, once the tumors reach a certain size.
The researchers think the iron and macrophages were able to somehow restart cell apoptosis (natural programmed cell death) inside tumors. While the treatment isn't strong enough to remove cancer on its own, it could be if used in combination with existing drugs.
The dose of ferumoxytol used in the tests was similar to a safe dose given in the treatment of anemia, with the anti-cancer effect from each dose seeming to last for around three weeks.
In subsequent tests, the team noticed iron nanoparticles having a suppressive effect on cancer metastasis – where tumors spread to nearby tissues and organs – and found the treatment reduced tumor size when given before the cancers were introduced.
Now the researchers want to work out ways in which this could benefit humans as a complement to existing chemotherapy.
While the results have only been seen so far in mice, the team hopes the iron nanoparticles might be able help while patients recover between doses of chemo – or perhaps clean up remaining tumor cells after surgery. The researchers concluded in the study published in the Nature Nanotechnology.