Credit: PNAS
Biomedical engineers have reported that daisy-shaped, nanoscale structures can deliver a cocktail of drugs directly to cancer cells.
The “nanodaisies” effectively delivered a 2-drug combination in a range of cell lines, including the leukemia cell line HL-60.
The drug-delivery vehicles also proved effective in a mouse model of lung cancer.
Zhen Gu, PhD, of North Carolina State University and the University of North Carolina at Chapel Hill, and his colleagues detailed these results in Biomaterials.
“We found that this technique was much better than conventional drug-delivery techniques at inhibiting the growth of lung cancer tumors in mice,” Dr Gu said.
“And based on in vitro tests in 9 different cell lines, the technique is also promising for use against leukemia, breast, prostate, liver, ovarian, and brain cancers.”
To make the “nanodaisies,” the researchers begin with a solution that contains a polymer called polyethylene glycol (PEG). The PEG forms long strands that have much shorter strands branching off to either side.
The researchers directly link the anticancer drug camptothecin (CPT) onto the shorter strands and introduce the anticancer drug doxorubicin (Dox) into the solution.
PEG is hydrophilic, but CPT and Dox are hydrophobic. As a result, the CPT and Dox cluster together in the solution, wrapping the PEG around themselves. This results in a daisy-shaped drug cocktail, only 50 nanometers in diameter, that can (in theory) be injected into a cancer patient.
Once injected, the nanodaisies float through the bloodstream until they are absorbed by cancer cells. In fact, one of the reasons the researchers chose to use PEG is because it has chemical properties that prolong the life of the drugs in the bloodstream. Once in a cancer cell, the drugs are released.
“Both drugs attack the cell’s nucleus but via different mechanisms,” said study author Wanyi Tai, PhD, who was previously a researcher in Dr Gu’s lab but is now at the University of Washington in Seattle.
“Combined, the drugs are more effective than either drug is by itself,” Dr Gu added. “We are very optimistic about this technique and are hoping to begin preclinical testing in the near future.”
