A common antibiotic used to treat urinary tract infections has shown to slow and even stop the growth of breast and bladder cancer cells, according to researchers at Johns Hopkins University School of Medicine.

The findings show that the antibiotic, nitroxoline, blocks the formation of new blood vessels that fuel tumors, and could become a potential therapeutic agent for cancer.

"Angiogenesis, the growth of new blood vessels, plays an important role in tumor growth and metastasis, so inhibiting angiogenesis is a promising strategy for developing new anticancer drugs," Dr. Jun O. Liu, a professor of pharmacology and molecular sciences at Johns Hopkins said in a press release.

The research team tested more than 177,000 chemical compounds and drugs for their ability to block the activity of a protein to inhibit the formation of new blood vessels. Nitroxoline blocked more than 99 percent of the blood vessels at a low and safe concentration.

When tested in mice, the nitroxoline treatment reduced breast cancer cell tumor volume by 60 percent and bladder cancer cell tumor by more than 50 percent.

The study appears in the December issue of the Journal of the National Cancer Institute.

Click here to read the full study.