Antibiotics reveal a new way to fight cancer

Osaka, Japan – Cancer cells grow and spread by hiding from the body’s immune system. Immunotherapy allows the immune system to find and attack hidden cancer cells, helping cancer patients live longer lives. However, many patients get little or no benefit from these revolutionary treatments.

Immune checkpoint inhibitors are the most used immunotherapies. They work by recognizing and blocking proteins that cancer cells use to hide from the immune system. However, cancer cells that don’t have these proteins use different ways to hide. Since patients with these cancers don’t respond to immune checkpoint inhibitors, researchers are keen to develop new immunotherapies with different targets.

In a study published in the Journal for ImmunoTherapy of Cancer, researchers from Osaka University have discovered that tetracycline antibiotics help the immune system to find cancer cells in a way that is different from current immunotherapies. These antibiotics stimulate immune cells, known as T lymphocytes, to attack and destroy cancer cells.

“We investigated the tetracycline antibiotic minocycline in blood and tumor tissue from lung cancer patients,” says lead author Mari Tone. “We found that minocycline enhanced the antitumor activity of T lymphocytes by targeting galactin-1, which is an immunosuppressive protein produced by cancer cells.”

The team found that galactin-1 helps cancer cells hide from the immune system by preventing cytotoxic T lymphocytes from reaching the tumor. After treatment with tetracycline, galactin-1 was no longer able to stop the T lymphocytes from attacking the tumor. Blocking galactin-1 might just be the key to new cancer treatments.

“These antibiotics have a different mechanism of action from immune checkpoint inhibitors and other immunotherapies used to treat cancer,” says corresponding author Kota Iwahori. “We hope this research will lead to the development of new drugs that target different immune pathways and can benefit people with cancer, particularly those who don’t benefit from current immunotherapies.”

Tetracycline antibiotics have been used to treat patients with infectious diseases for many years worldwide. Now, these old drugs may point the way to new immunotherapies for cancer patients who currently have few treatment options.

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The article, “Tetracyclines enhance anti-tumor T cell immunity via the Zap70 signaling pathway,” was published in Journal for ImmunoTherapy of Cancer at DOI: http://doi.org/10.1136/jitc-2023-008334.

About Osaka University
Osaka University was founded in 1931 as one of the seven imperial universities of Japan and is now one of Japan's leading comprehensive universities with a broad disciplinary spectrum. This strength is coupled with a singular drive for innovation that extends throughout the scientific process, from fundamental research to the creation of applied technology with positive economic impacts. Its commitment to innovation has been recognized in Japan and around the world, being named Japan's most innovative university in 2015 (Reuters 2015 Top 100) and one of the most innovative institutions in the world in 2017 (Innovative Universities and the Nature Index Innovation 2017). Now, Osaka University is leveraging its role as a Designated National University Corporation selected by the Ministry of Education, Culture, Sports, Science and Technology to contribute to innovation for human welfare, sustainable development of society, and social transformation.
Website: https://resou.osaka-u.ac.jp/en