UF researchers: ‘Nanotrain' holds promise for targeting only cancer cells
Published: Friday, May 3, 2013 at 1:48 p.m.
Last Modified: Friday, May 3, 2013 at 4:58 p.m.
The body is often compared to a system of highways, and a new potential way of delivering cancer therapy builds on that analogy: The "DNA nanotrain" developed by University of Florida researchers can both target cancer cells and deliver the right drugs to kill them.
"(The train) has many boxcars, each one loaded with effective drugs," said professor Weihong Tan, a UF professor of chemistry, physiology and functional genomics who worked on developing the nanotrain. "A very smart engine can bring the train to where the cancer cells are."
Tan explained that the novel cancer-drug delivery system uses aptamers — molecules that are often compared to antibodies in how they can target cancer cells. Aptamers are smaller than antibodies and can more efficiently deliver drugs to cancer cells.
Aptamers also can be used to discover the unknown biomarkers of cancer cells, thereby decoding them so the right drugs can be delivered to the cancer cells.
"You will be able to generate an aptamer to recognize those unknown biomarkers … to elucidate the biomarkers," said Tan, who also works with the UF Shands Cancer Center and the UF Genetics Institute.
Guizhi Zhu, a UF doctoral student who worked with Tan on a study of the nanotrain published last week in the Proceedings of the National Academy of Sciences, said another advantage of the nanotrain is that it is made of DNA — perfectly biodegradable, unlike other nanotechnologies in cancer therapies that place inorganic materials in the body for a long time.
Because of the biocompatibility of the drug delivery system, higher amounts of the drugs can stay in the body for a longer amount of time, Zhu added.
"If the nanotrain reaches the cancer cells, it binds to the cancer cells and holds the structure at the tumor site," Zhu said. "The direct benefit of this is that the drug can stay there for a much longer time, which will have a higher therapeutic effect."
The recent study was in mice models, and both Tan and Zhu say they still need to do more detailed animal studies before attempting to use this drug delivery system in humans.
Clinical application could be many years away. Still, the mice in the study who received drugs via the nanotrain had less tumor growth and fewer side effects than those who were treated without the nanotrain.
For Dr. Carmen Allegra, a hematologist and oncologist and the associate director for clinical and translational research at the UF&Shands Cancer Center, the prospects of the nanotrain one day being used in the clinic are very exciting.
"It's kind of the holy grail of chemotherapy," Allegra said. "For years, we've had chemotherapy that can kill anything. The problem is getting it to the right cells."
Allegra added that the nanotrain targets cancer cells specifically — without causing "collateral damage" to other cells; the train itself also can be loaded up with a high drug load.
Allegra cited the cancer drug TDM-1, a successful drug for advanced breast cancer, as using a similar approach: combining a monoclonal antibody with chemotherapy to first target cancer cells and then deliver the drug to them.
Allegra said part of the novelty of the nanotrain is that it can be loaded with either an imaging agent to find the cancer cells, or cytotoxic drugs.
Either way, the nanotrain is powerful, Allegra added.
"Instead of the toxin being the magic bullet, it's the delivery system."
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