The National Cancer Institute’s Alliance for Nanotechnology in Cancer describes a significant advance toward personalized nanotech treatments for cancer. The effectiveness of treatment with multifunctional nanoparticles was studied using human breast tumors grown in rats lacking an immune system (to prevent the rats rejecting the foreign tumors) so that the variation in the effectiveness of treatment could be compared among individual breast tumors. From “Nanoparticle reports on drug delivery to breast tumors, predicts response to therapy“
One of the hallmarks of many nanoparticle-based anticancer therapeutics and imaging agents is that they accumulate in tumors thanks to the fact that they are small enough to escape from the bloodstream through the leaky blood vessels that surround tumors. And although many if not most tumors are surrounded by leaky blood vessels, the extent of that leakiness varies widely among tumors. As a result, the effectiveness of a given nanoparticle-based therapeutic also might vary from patient to patient in a way that is now impossible to predict.
A research team headed by Ravi Bellamkonda, Ph.D., the Georgia Institute of Technology, appears to have hit on a solution to the problem of determining how much of a nanoparticle drug is actually making it into breast tumors. The team’s approach, which is described in a paper in the journal Biomaterials [abstract], involves adding an approved x-ray contrast agent to a drug-loaded nanoparticle and then using standard mammography to quantify how much of the nanoparticle accumulates in a particular breast tumor. These results hold promise for personalizing breast cancer therapy.
…When the researchers monitored the nanoparticles for 3 days after injection, they observed that there was wide variability in the amount of nanoparticle that they could observe in different tumors. Some tumors rapidly accumulated significant levels of the nanoparticle, whereas other tumors showed a slow and low uptake. More importantly, the investigators noted that those animals that showed rapid uptake of the nanoparticles, as visualized using mammography 3 days after dosing, survived significantly longer than did those animals with a slower uptake.
One way to compensate for variations in capillary permeability in different tumors might be to decorate nanoparticles with molecules that specifically target tumor cells, as in this post from last week.
—Jim
