Disguising Drugs As Platelets To Target Cancer

Disguising Drugs As Platelets To Target Cancer
On the left is the schematic design of the TRAIL/Dox loaded
platelet membrane-coated nanogel delivery system. The TRAIL
is attached on the surface of membrane and Dox is loaded in the
core of nanogel. On the right is a transmission electron
microscope image of the drug delivery system. Black is the
synthetic core nanogel, the outside shell is the platelet
 membrane. (Credit: Quanyin Hu)
Researchers have for the first time developed a technique that coats anticancer drugs in membranes made from a patient's own platelets, allowing the drugs to last longer in the body and attack both primary cancer tumors and the circulating tumor cells that can cause a cancer to metastasize. The work was tested successfully in an animal model, and published in the journal Advanced Materials.
 
Here's how the process works. Blood is taken from a patient - a lab mouse in the case of this research - and the platelets are collected from that blood. The isolated platelets are treated to extract the platelet membranes, which are then placed in a solution with a nanoscale gel containing the anticancer drug doxorubicin (Dox), which attacks the nucleus of a cancer cell. The solution is compressed, forcing the gel through the membranes and creating nanoscale spheres made up of platelet membranes with Dox-gel cores. These spheres are then treated so that their surfaces are coated with the anticancer drug TRAIL, which is most effective at attacking the cell membranes of cancer cells.
 
When released into a patient's bloodstream, these pseudo-platelets can circulate for up to 30 hours - as compared to approximately six hours for the nanoscale vehicles without the coating.
 
When one of the pseudo-platelets comes into contact with a tumor, three things happen more or less at the same time. First, the P-Selectin proteins on the platelet membrane bind to the CD44 proteins on the surface of the cancer cell, locking it into place. Second, the TRAIL on the pseudo-platelet's surface attacks the cancer cell membrane. Third, the nanoscale pseudo-platelet is effectively swallowed by the larger cancer cell. The acidic environment inside the cancer cell then begins to break apart the pseudo-platelet - freeing the Dox to attack the cancer cell's nucleus.
 
In a study using mice, the researchers found that using Dox and TRAIL in the pseudo-platelet drug delivery system was significantly more effective against large tumors and circulating tumor cells than using Dox and TRAIL in a nano-gel delivery system without the platelet membrane.
 
The researchers now plan to do additional pre-clinical testing, and think the technique also could be used to deliver other drugs, such as those targeting cardiovascular disease.
 
Based on material originally posted by North Carolina State University.