Can Common Antibiotics Eradicate Cancer Cells?

Study examines how side effects from commonly used antibiotics effect mitochondria of cancer cells.

A method of killing cancer stem cells using common antibiotics may offer a new highly effective treatment for the disease, a recent study suggests.

The potential treatment was inspired after Professor Michael P. Lisanti, director of the Breakthrough Breast Cancer Unit at the University of Manchester, spoke with his daughter Camilla about his cancer research. The conversation prompted Lisanti to examine how antibiotics effect the mitochondria of cancer stem cells.

"I was having a conversation with Camilla about how to cure cancer and she asked why don't we just use antibiotics like we do for other illnesses,” Lisanti said in a press release. “I knew that antibiotics can affect mitochondria and I've been doing a lot of work recently on how important they are to the growth of tumors, but this conversation helped me to make a direct link."

In a study published recently in Oncotarget, Lisanti and a team of researchers explored the potential repurposing of highly effective drugs that have been used safely for many years. Cancer stem cells, which lead to tumors and develop resistance to other types of therapy, are particularly tough to eradicate with normal treatment.

The researchers utilized 5 different types of antibiotics on the cell lines of 8 different tumor types. The study revealed 4 antibiotics that killed cancer stem cells in each test, including glioblastoma, lung cancer, prostate cancer, ovarian cancer, breast cancer, pancreatic cancer, and skin cancer.

With mitochondria believed to have descended from bacteria that joined with cells early in the evolution of life, research has found that some antibiotics used to destroy bacteria can also impact mitochondria while not having an adverse effect on humans. During laboratory testing, antibiotics did not harm normal cells. Given that these drugs are already approved for use in humans, trials for the new treatments would be easier and could save both time and money, the study noted.

"This research makes a strong case for opening new trials in humans for using antibiotics to fight cancer,” Lisanti said. “Many of the drugs we used were extremely effective, there was little or no damage to normal cells and these antibiotics have been in use for decades and are already approved by the FDA for use in humans. However, of course, further studies are needed to validate their efficacy, especially in combination with more conventional therapies."

During prior clinical trials with antibiotics for the treatment of cancer-associated infections, the drugs were found to have a positive therapeutic result on advanced or treatment-resistant cancer patients.

In patients with lung cancer, the antibiotic azithromycin increased 1-year patient survival from 45% to 75%. Bacteria-free lymphoma patients administered a 3-week course of the acne antibiotic doxycycline showed complete remission of the disease, which indicates the therapeutic effects of the drug were independent of infection, the study noted.

"As these drugs are considerably cheaper than current therapies, they can improve treatment in the developing world where the number of deaths from cancer is predicted to increase significantly over the next ten years," said study co-leader Federica Sotgia, MD.