- Sunday, Sep 13, 2009
As a logistics officer in the U.S. Marine Corps during the U.S.-led invasion of Iraq, Kimberly Homan specialized in leading convoys and directing supplies and equipment to where they needed to be.
Now a Ph.D. graduate in Biomedical Engineering, the former captain is involved in a different kind of battle: fighting and treating one of the most deadly diseases, pancreatic cancer. Homan is researching a nanotechnology approach to image and treat this devastating type of cancer.
"The five-year mean survival rate for pancreatic cancer is only 5 percent," Homan says. "You get it, and you are all but given a death sentence — that can be changed."
Her work (under the supervision of Associate Professor Stanislav Emelianov and Lisa Brannon-Peppas, adjunct professor and vice president of scientific operations at Appian Labs) recently was awarded a two-year, $400,000 grant from the National Institutes of Health (NIH). Specifically, she is working with a new type of imaging: photoacoustic imaging to zero in on the tumor in the pancreas. She builds nanoparticle contrast agents that augment this imaging system by highlighting the presence of a pancreatic tumor in photoacoustic images.
Since receiving the NIH grant, the team's work related to pancreatic cancer has been presented at many conferences, published in a 2012 ACS Nano publication, and featured in a chapter of a book titled Nanoimaging.
These nano-agents can seek out cancer cells by recognizing their unique characteristics. Briefly, the nanoparticles can be outfitted with an antibody that specifically binds with receptors that are abundant on the surface of cancer cells, but not on healthy cells. Once injected in the bloodstream, these nano-agents then will circulate and bind to cancer cells. Photoacoustic imaging can then be used to detect the presence of these nano-agents in the tumor.
It's sneaky, but cancer itself is a devious disease.
Homan, who spent six years in the Marines and then enrolled at UT, says tumors recruit blood vessels early in their growth process. In cancer's haste to survive, however, these vessels are built in a disorganized manner. That vasculature, or arrangement of blood vessels, actually assists nanoparticles accumulate in cancer because unlike normal blood vessels the vasculature feeding cancer is porous, providing thousands of holes from which nanoparticles — circulating in the bloodstream — can infiltrate the tumor.
Homan is also working on encapsulating drugs in these nano-agents. She hopes that site-specific delivery of these multifunctional nano-agents through the bloodstream to cancer will lessen the side effects of chemotherapy and increase survival rates.
A large obstacle Homan will have to address is in the delivery of the nanoparticles through the bloodstream because the immune system views the nanoparticles as foreign invaders and can attack them.
"We have to find ways to evade the immune system," Homan says. "We can add polymers to the surface of the nanoparticles, and this layer minimizes recognition by the immune system. It can be a pretty difficult challenge."
But it's one she has readily accepted.
"The Marine Corps was the best of times and the worst of times — a roller coaster ride. This is more of a long walk up a steep hill," Homan says of her current research.
But the climb, the former Marine says, is worth every step to give pancreatic cancer patients a fighting chance. Something her previous career taught her.
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