Golden Chemistry
Barrios studies how metals work in the body
By Eva Emerson
At age nine, Amy Barrios liked chemistry. Her parents bought her a biology kit.
It wasn’t until she received her Ph.D. that she got the chemistry set
she always wanted, says Barrios, the newest member of the USC College
chemistry department.
Perhaps her parents knew something: Barrios combines interests in the
chemical world of atoms and the biological world of cells in her
research on the chemistry of metals within the body. Metals are
critical in many of the body’s proteins. Iron ions, for example, are a
key ingredient in hemoglobin, which carries oxygen in blood. The
anti-cancer drug cisplatin, which helped cyclist Lance Armstrong beat
testicular cancer, contains platinum.
One of her three research projects focuses on gold, a main ingredient
in a last resort drug used for rheumatoid arthritis (RA) patients who
fail other treatments. Although effective, gold has unwanted side
effects.Auranofin, the gold-containing drug, targets the body’s joints,
slowing the disease process. Barrios speculates that auranofin
interferes with enzymes called cathespins thought to play a role in RA
and osteoporosis. Cathespins cut up and clear away proteins no longer
needed in the cell. Gone awry, the enzymes may damage healthy proteins
such as the collagen in joints.
“We’re trying to figure out if gold inhibits these enzymes,” says
Barrios, the Gabilan Assistant Professor of Chemistry. Understanding
the drug’s mechanism could lead to a drug that’s more efficient and has
fewer side effects. “That’s a big undertaking—not something I expect to
accomplish anytime soon.”
In another investigation, Barrios researches the dramatic differences
in zinc levels found in healthy and malignant prostate cells. She aims
to create a zinc-sensitive molecule to use with magnetic resonance
imaging technology to better diagnose prostate cancer.
In a third project, Barrios hopes to characterize enzymes called
protein tyrosine phosphatases, important in cellular signaling pathways
such as the one that controls insulin levels. Genomic studies reveal
120 genes encoding for these enzymes, but how they differ isn’t known.
By figuring that out, Barrios hopes to reveal new ways to battle
diabetes mellitus, which some link to overactive phosphatases.
Inhibiting the enzymes could
lead to new treatments.
Barrios is a welcome addition to the department, says chemistry chair
and professor Hanna Reisler. “She’s bringing us new expertise in the
field of pharmaceutical chemistry.”
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