New Polymer Shows Promise Against Ovarian Cancer

SAN FRANCISCO, March 28 — A new polymer derived from an antibacterial drug has unexpectedly and dramatically inhibited the growth of ovarian cancer cell lines previously thought to be resistant to drugs, according to researchers at Florida Atlantic University in Boca Raton.

Both cell lines were obtained from ovarian cancer patients previously treated by conventional chemotherapy, including the drugs cytoxan, adriamycin and cisplatin. The new polymer-drug combination inhibited the growth of one cancer cell line by 97 percent and another by 80 percent.

The findings were presented here today at the 219th national meeting of the American Chemical Society, the world’s largest scientific society. The weeklong meeting is expected to attract about 20,000 scientists from around the world.

The investigation, carried out by Charles Carraher, Ph.D., and Deborah Siegmann-Louda, Ph.D., involves modifying existing drugs by incorporating them in metal-containing polymers. In this case, the antibacterial drug cephalexin and a polymer containing tin were used. By itself, cephalexin — marketed under the names Keflex and Keftabis — not active against the cell lines tested, Carraher notes.

The new polymer’s effectiveness makes it a potential “candidate as a last-defense cancer drug,” according to the researchers.

Why the polymer is effective remains a mystery. But there appears to be a synergistic effect from the metal, according to Carraher: “When you make polymers without the metals, as far as we can tell, you don’t get much activity.”

The next step is to vary the metal and see if that has any effect on the cancer, he says. In addition to tin, the researchers have made polymers combining cephalexin with arsenic, alimony and bismuth; they are now being tested.

Carraher calls the findings “exciting,” but is quick to add a note of caution: “Nothing is a miracle cure.” More testing is needed, including animal studies. Still, Carraher believes the cell line findings are “promising” — enough so, he says, that he is reallocating resources from other research projects in his lab.

Dr. Carraher is Professor, Department of Chemistry and Biochemistry, Florida Atlantic University. He also is Associate Director, Florida Center forEnvironmental Studies.

Dr. Siegmann-Louda is Associate Professor, Department of Chemistry and Biochemistry, Florida Atlantic University.