American scientists have discovered two cancer drugs that can slow down or treat the neurodegenerative effects occurring in the brains of Alzheimer's patients. These drugs are already used for other cancer treatments, ensuring their safety. They showed therapeutic effects in animal experiments, and patients using them for other reasons had a lower actual risk of developing Alzheimer's disease.
Researchers from the Gladstone Institutes and the University of California, San Francisco (UCSF) announced on the 22nd that they confirmed the effectiveness of the breast cancer treatment drug "letrozole (generic name)" and the colorectal and lung cancer treatment drug "irinotecan" for treating Alzheimer's disease.
Alzheimer's disease is a condition that damages cells and impairs cognitive functions such as memory and learning due to the accumulation of abnormal proteins inside and outside neurons. Although treatments have emerged that reduce abnormal proteins to delay dementia effects, they have limitations as they can cause severe side effects such as brain swelling or bleeding.
The research team utilized existing study data analyzing how Alzheimer's disease alters gene expression in single human brain cells. Gene expression refers to the process by which proteins are produced according to DNA genetic information, governing various biological phenomena. Using this data, the research team examined the gene expression patterns occurring in the brain neurons of Alzheimer's patients and the surrounding cells (glial cells).
The research team identified 86 substances among over 1,300 compounds, including FDA-approved drugs and researcher-created compounds, that acted in opposition to the effects of Alzheimer's disease on brain cells. They found substances that prevent the progression of Alzheimer's disease at the cellular level. Of these, 25 exhibited this action across various cell types in the brain.
Among the substances identified by the research team, only 10 were FDA-approved drugs. The most effective were letrozole, a breast cancer treatment, and irinotecan, a colorectal and lung cancer treatment. The researchers predicted that letrozole would treat Alzheimer's disease at the neuronal level, while irinotecan would prevent damage to glial cells.
The research team conducted experiments using both drugs on mice with Alzheimer's disease. As a result, it was confirmed that the amount of abnormal protein clumps and brain degeneration decreased, and memory was even restored. Evidence was also found that humans could experience the same effects.
After analyzing medical data from over 1.4 million patients aged 65 and older, the research team confirmed that those who took the two drugs for treatment of other diseases actually had a lower risk of developing Alzheimer's disease.
Marina Sirota, co-corresponding author and director of the Bakar Computational Health Sciences Institute at UCSF (a professor of pediatrics), said, 'I am pleased to have found a potential combination therapy for Alzheimer's disease based on FDA-approved drugs.'
Yadong Huang, another corresponding author and director of the Gladstone Research Center for Translational Evolution (a professor at UCSF), noted, 'We will soon be able to directly test combination therapy on Alzheimer's patients,' adding that he hopes it can be quickly applied as a practical solution for millions of Alzheimer's patients.
The results of this study were published in the international journal "Cell" on this day.
References
Cell(2025), DOI:
https://doi.org/10.1016/j.cell.2025.06.035