WASHINGTON, Dec. 16 (UPI) -- Breast cancer drug Anastrozole, sold as Arimidex, may also inhibit the growth of lung cancer, say researchers at University of California at Los Angeles in the December 15 issue of Cancer Research.
Breast cancer grows more rapidly in the presence of estrogen, according to Lead Researcher Olga Weinberg, who is a medical student at Vanderbuilt University. Arimidex stops the body from producing estrogen by blocking aromatase, an enzyme the body uses to make the hormone, she explained.
The research team looked at whether anastrozole would be effective against lung cancer because data had already been published showing that some lung cancer cells also use estrogen to grow.
Weinberg said that the investigators identified aromatase in laboratory-produced lung cancer cell lines and also tested for the enzyme in 53 non-small cell lung cancer specimens.
They found that 88 percent of the specimens from women and 86 percent of those from men came up strongly positive.
They tested both the cell lines and the specimens to make sure the aromatase was actively producing estrogen, and when those tests came back positive as well, decided to see what anastrozole would do.
They started with the cell lines, where a 48-hour application of the drug shut down aromatase activity and slowed tumor growth in the laboratory. The next step was to implant human lung cancer cells into mice and administer the drug. After 21 days, the tumors of mice that were being treated with anastrozole were 90 percent smaller than the tumors of mice that did not receive the medication.
Minetta Liu, a physician at the Vincent T. Lombardi Comprehensive Cancer Center, told United Press International she thought the study was well-constructed and supported the further evaluation of aromatase as a potential target for lung cancer therapy. She added that she thought the results were "exciting" because the aromatase inhibitors have proven their value in breast cancer treatment.
Robert Siegel, director of the Division of Hematology/Oncology at George Washington University Medical Center, was also impressed but more cautious.
"Aromatase inhibitors have low toxicity and are very useful therapeutic agents for treating hormone-sensitive breast cancer," Siegel told UPI. "Lung cancer is a horrible disease and I appreciate the researchers' novel approach to treating it, as well as the creativity and ingenuity they used in testing an off-the-shelf drug; but this discovery is not ready for primetime yet.
He argued that, "The sidewalk is paved with studies that worked well in mice but didn't pan out in people. We won't know whether this discovery will be useful until it's tested in humans."
Siegel added that, since the aromatase inhibitors are already FDA-approved, clinical trials using them for treatment would likely be easy to launch.
