Doers, Dreamers, Trailblazers

New nanomedicines offer small solutions to the big problem of cancer

From studies about what causes it to personal stories of friends and family battling it -- cancer is a disease we all think about. Treatments are often harsh and sometimes as destructive as the cancer itself. The financial impact can match the emotional one, as treatments can last years and cost thousands. But some researchers have started to think smaller to solve this big problem by engineering molecular-level treatments.

These nanomedicines, as they're called, could revolutionize cancer treatment using the way the body naturally reacts to different treatment strategies. Ultimately, nanomedicines could be used to eradicate specific cancers quickly, with few side effects and smaller cost.

"The body is going to treat nano-size objects differently than it will objects of other sizes," explained Eric Simanek, professor of chemistry and the department chair of chemistry and biochemistry at Fort Worth's Texas Christian University. The small nature of the particles allows medicines to affect specific parts of the human body, including problem areas like cancerous tumors.

"The goal is to translate simple polymer chemistry into an opportunity to change the human condition," he said.

Nanotechnology allows scientists to target drug delivery on the molecular level, and this is especially important when treating cancer.

Cancer drugs are "wonderfully poisonous molecules," said Simanek. But the challenge with such drugs is that they not only target and poison tumors, they target and poison healthy tissue.

"Cancer patients undergoing chemo will lose hair. Their muscles will atrophy. There are a number of horrific side effects," Simanek said. "One of the goals of nanomedicines is to take advantage of the poisons that exist and target them specifically to the tumor to reduce side effects."

There are a number of approaches to achieving this level of specificity. One strategy is to tie the drug to a protein, typically an antibody, designed to home in on cancerous tumors. Drugs that attach to specific targets will cut side effects and increase chances of a cure.

Another method, which Simanek is pursuing using different chemical compounds, is to change the size of the drug to optimize how the body absorbs it. "Since atoms aren't balloons and they can't be inflated, we tie the cancer drug to a larger carrier, a polymer carrier," he said. Doing so can narrow the ways the body reacts to it, and ultimately pinpoint where it ends up, he said.

Larger is relative, of course: The field of nanomedicines works on a scale that measures about two to three nanometers to a few hundred nanometers, said Simanek.

For reference, a strand of hair is about 100,000 nanometers wide, while a cancerous cell is 10 times smaller. The target of cancer drugs, typically proteins are 1000 times smaller still, or about 10 nm, the size of the nanomedicines that Simanek and others are creating.

Studying and manipulating something so small requires work from many disciplines, including chemistry, biology, physics and molecular biology, said Simanek.

As the chemists, Simanek's team takes the first steps. "Our job is to make sure we're making what we say we're making and characterize the materials thoroughly," he said.

Then, Simanek and TCU partner with collaborators around the world and close to home, including the University of Texas Southwestern Medical Center, a prominent biomedical research institute.

"Our work has progressed through understanding the basic chemistry of the system, to understanding how to attach drugs and how those drugs may or may not fall off, to how to make these materials compatible in more sophisticated models of disease," said Simanek.

After leaving his lab, these nanomedicines are tested in other labs on cells and in some cases, mice, to make sure they function in a way that is expected. Ultimately, Simanek said, the molecules he has crafted in the lab could treat people with cancer. Currently, chemotherapeutic nanomedicines are in various stages of testing, including clinical trials.

The results have been encouraging: Simanek's most sophisticated molecules have seemingly cured human prostate cancer in mice. While this study is ongoing and all clinical factors have not been fully explored, this represents an important step in the research. Next steps will involve improving the medicine's effectiveness to move it closer to clinical relevance.

The dream, said Simanek, is that nanomedicines used to treat cancer could be taken like a vitamin tablet, with few side effects. "That is the perfect situation," he said.

Ultimately, nanomedicines could be used to treat a number of conditions, not just cancer.

"Since cancer has so many side effects, the opportunity for nanomedicines is great," Simanek said. "But I don't think any disease is immune from the impact of nanomedicines."

--Jamie Van Bergen for TCU

Copyright © 2016, Los Angeles Times
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