Carbon nanoparticles charge up old cancer treatment to powerful effect

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Carbon nanoparticles are galloping to the rescue once again. Scientists are exploring their use as a booster ingredient to enhance the effectiveness of an existing treatment for head-and-neck cancer. Their idea worked in mice, killing even more tumors combined with radiation than without the nanotech.

Rice University and University of Texas/MD Anderson Cancer Center researchers came up with the approach, and their study--the culmination of 6 years of work--is published in the journal ACS Nano. Co-lead researcher James Tour, a Rice chemist, came up with the idea in a pretty sad situation, talking with colleague and Nobel laureate Richard Smalley, who died in 2005 of leukemia. After Smalley's death, Tour began to develop it further with Jeffrey Myers, a professor of head-and-neck surgery at MD Anderson.

Their model amounts to improving both the delivery and safety of a tried-and-true cancer treatment that also happens to be pretty toxic to healthy tissue. Doctors traditionally use Taxol, a combination of paclitaxel and Cetuximab, to treat head-and-neck cancers as well as lung, ovarian and breast cancers. But paclitaxel doesn't mix with water, so the compounds are blended with the castor oil-based compound known as Cremophor EL, which delivers the treatment to patients intravenously. It gets the job done, but Cremaphor and paclitaxel are both toxic to nearby healthy cells, the researchers note.

Enter non-toxic carbon nanoparticles, specifically, "hydrophilic carbonic clusters functionalized with polyethylene glycol" or PEG-HCC. By mixing them instead of the Cremaphor with the paclitaxel and Cetuximab, the treatment becomes water-soluble and appears to target tumors more effectively than traditional Taxol. Researchers think that the paclitaxel--the chemotherapy drug in the combo--makes the cancer cells more sensitive to radiation. Then the PEG-HCC/Cetuximab combo boosts how much of the paclitaxel is delivered to cancer cells for the killing blow.

The idea here is that the effectiveness of the new approach would allow doctors to reduce how much of the chemotherapy drug is needed to get the job done. And doing away with the Cremophor eliminates much of the issues with toxicity. What's more, the delivery system could work for other cancers or diseases. But there are lots of issues ahead. More funding and research are necessary to explore this in people and test it for other indications in animals to see if the delivery tech works consistently. Additional studies are also important to make sure the nanotech used here isn't ultimately toxic to people.

A similar drug is in the marketplace, but why aren't more patients using it? Celgene's ($CELG) Abraxane is a chemotherapy cancer drug that combines paclitaxel with albumin nanoparticles, but the researchers claim it hasn't taken over more than 10 percent of the market since its introduction more than 6 years ago, even though it "shows promise."

- here's the release
- check out the journal abstract

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