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Posted: June 12, 2006
Nanoparticles overcome anticancer drug resistance
(Nanowerk News) Too often, chemotherapy fails to cure cancer because some tumor cells develop resistance to multiple anticancer drugs. In most cases, resistance develops when cancer cells begin expressing a protein, known as p-glycoprotein, that is capable of pumping anticancer drugs out of a cell as quickly as they cross through the cell’s outer membrane. New research from the University of Kentucky shows that nanoparticles may be able to get anticancer drugs into cells without triggering the p-glycoprotein pump.
Next, the investigators injected the nanoparticle-entrapped paclitaxel, empty nanoparticles, free paclitaxel, or saline directly into paclitaxel-resistant human colon tumors growing in mice. Nineteen days after injection, tumors in the animals treated with nanoparticle-entrapped paclitaxel were 47 percent smaller than those treated with free paclitaxel and 70 percent smaller than those in animals treated with plain nanoparticles or saline.
One surprising finding from this study was the fact that free paclitaxel had any effect at all on tumors known to be resistant to the drug. Further investigation showed that this effect was likely a result of paclitaxel’s ability to inhibit angiogenesis. The researchers concluded that nanoparticulate-entrapped paclitaxel was able to suppress tumor growth by killing tumor cells directly and through inhibition of angiogenesis.