US researchers have developed nanoparticles that target chemotherapy drugs directly at tumours.

US chemists and medical researchers have developed nanoparticles that target chemotherapy drugs directly at tumours. The researchers claim that the same technique could be used to develop nanoparticle-based treatments for a wide range of other diseases.   


© Omid Farokhzad / Robert Langer

Chemotherapy drugs work by impairing cell division and are effective treatments for early-stage tumours, when cancer cells are rapidly multiplying. But they also produce a range of unpleasant side effects. Targeting chemotherapy drugs directly at the tumour would increase effectiveness and reduce side effects.   

The researchers from Harvard Medical School and the Massachusetts Institute of Technology developed a range of nanoparticles (around 150nm in diameter) made of the biodegradable polymer poly(d,l-lactic-co-glycolic acid) and poly(ethylene glycol). They encapsulated the chemotherapy drug docetaxel in these nanoparticles and attached artificial RNA strands known as aptamers to the surface of each particle.   

Different aptamers bind to specific proteins, and the researchers attached an aptamer that could bind to prostate-specific membrane antigen (PSMA), which is expressed on the surface of prostate cancer cells. The researchers found that the nanoparticles bound to PSMA and were taken up by prostate cancer cells in vitro, where the nanoparticles would dissolve to release the docetaxel.   

The researchers investigated whether this strategy would reduce tumour growth, by injecting the nanoparticles into mice with prostate cancer. ’A single injection of our nanoparticles completely eradicated the tumours in five of the seven treated animals,’ said Omid Farokhzad of Harvard Medical School, ’and the remaining animals also had significant tumour reduction.’   

By incorporating different drugs and attaching different compounds, these nanoparticles could be adapted to help treat many other diseases, say the researchers.   

Jon Evans