According to a new study at the Johns Hopkins University School of Medicine, drug acriflavine, used in the 1930s for treating gonorrhea, has now been found beneficial in battling cancer.
Researchers have found that acriflavine has the previously unknown ability to halt the growth of new blood vessels.
"Often times we are surprised that a drug known to do something else has another hidden property," said Dr. Jun Liu, a professor of pharmacology and molecular sciences at Johns Hopkins and author on the study.
Preliminary tests showed that mice engineered to develop cancer had no tumor growth if treated with daily injections of acriflavine.
"As cancer cells rapidly divide, they consume considerable amounts of oxygen. To continue growing, a tumor must create new blood vessels to deliver oxygen to the tumor cells," said Dr. Gregg Semenza.
Acriflavine stops blood vessel growth by inhibiting the function of the protein hypoxia-inducible factor (HIF)-1, which was discovered by Semenza's team in 1992.
When HIF-1 senses that the surrounding environment is low in oxygen, it turns on genes necessary for building new vessels.
Though essential for normal tissue growth and wound healing, HIF-1 is also turned on by cancers to obtain the oxygen they need to survive.
Most importantly, in order for HIF-1 to work, two subunits must bind together like puzzle pieces.
To visualize protein binding, scientists engineered a cell line so that when the HIF-1 subunits came together, they would cause the cell to light up like a firefly.
They then tested each of the more than 3,000 drugs in the John Hopkins drug library and found that Acriflavine did turn out the light and further studies confirmed that it was binding directly to HIF-1.
"Mechanistically, this is the first drug of its kind. It is acting in a way that is never seen for this family of proteins," said Liu.
Liu hopes that acriflavine can one day be incorporated into chemotherapy cocktails, one drug among many that help fight cancer.
The study has been published in the Proceedings of the National Academy of Sciences.