Scientists have linked a widely-used antidepressant drug to cancer research — with early research showing a significant improvement. Researchers from the University of California in Los Angeles discovered that selective serotonin reuptake inhibitors (best known for the role they play in the brain) can significantly enhance the ability of T cells to fight cancer.
“It turns out SSRIs don’t just make our brains happier; they also make our T cells happier — even while they’re fighting tumors. These drugs have been widely and safely used to treat depression for decades, so repurposing them for cancer would be a lot easier than developing an entirely new therapy,” the UCLA Health website quoted senior senior author Lili Yang as saying.
The research team had first started investigating the role of serotonin in fighting cancer after noticing that immune cells isolated from tumors had higher levels of serotonin-regulating molecules. The researchers tested SSRIs in mouse and human tumour models representing melanoma, breast, prostate, colon, and bladder cancer — with the results published this week in the journal Cell. They found that SSRI treatment reduced average tumour size by over 50 per cent and made the cancer-fighting T cells more effective at killing cancer cells.
They had focused initially on MAO-A — an enzyme that breaks down serotonin and other neurotransmitters, including norepinephrine and dopamine. The team soon turned its attention to an alternative called SERT because MAOIs have safety concerns, including serious side effects and interactions with certain foods and medications. Unlike MAO-A, another researcher on the team explained, SERT has only one job — to transport serotonin.
Notably, combining SSRIs with existing cancer therapies also improved treatment outcomes. The researchers said that the combination significantly reduced tumor size in all treated mice and even achieved complete remission in some cases.