03 December 2010

Nanoshells Provide Golden "Touch" in Killing Breast Tumors

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Gold nanoparticles have shown promise as miniature thermal scalpels that when irradiated with near-infrared light are capable of cooking tumors to death

Now, a team of investigators from The Methodist Hospital, Baylor College of Medicine, and The University of Texas M. D. Anderson Cancer Center have found that gold nanoshells can be used to deliver just a little heat to breast tumor cells already treated with radiation, boosting the killing power of both therapies. Indeed, as the investigators report in the journal Science Translational Medicine, the combination therapy not only shrank the tumors but dramatically decreased the population of cancer stem cells. This study was led by Jeffrey Rosen and Jenny C. Chang.

According to Baylor College of Medicine graduate student Rachel Atkinson, this was a serendipitous discovery. "I stumbled on this when I was a first-year graduate student. I was working with radiation and cancer stem cells, which are resistant to chemotherapy and radiation therapy. I had treated my cells with radiation and left them over the weekend. When I returned on Monday, I was disappointed because my cancer stem cells were dead and the normal cells were fine." She opened the incubator and her glasses fogged, giving her a clue that the temperature had gone up over the weekend. That was the clue that heat plus radiation appeared to be effective against the stubborn stem cells.

Ms. Atkinson repeated her experiment with different kinds of tumor cells and was about to publish her data when she learned of a group at M.D. Anderson that used nanoshells to deliver hyperthermia and to sensitize tumors to radiation therapy. These original studies had demonstrated hyperthermia delivered through nanoshells increases perfusion of tumors with oxygen and also focally disrupts the blood supply to tumors, both of which enhance the effectiveness of radiation. The Baylor and M.D. Anderson groups decided to collaborate to determine what effect heat delivered by the nanoshells would have in highly resistant tumors in mice. For their study, Ms. Atkinson chose two aggressive breast tumors that represent one of the worst breast cancer types - triple negative breast cancer, which lacks crucial receptors that can make it targetable with specific drugs. She also worked with mice that had human tumors of the same type.

(Nanotechwire)

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