What If Cancer Holds the Key to New Treatments for Alzheimer’s Disease?

The enemy of our enemy can become our friend. Scientists may have discovered a new way to treat Alzheimer’s disease, which is linked to the development of cancer.

Researchers at Huazhong University of Science and Technology in China studied mice that developed human cancers. They found that these mice were protected from Alzheimer’s disease, likely due to a protein produced by the cancer cells known as cystatin-C, or cystatin-C. Researchers say the research could lead to new treatments for a currently incurable form of dementia.

“These findings provide a major conceptual advance in cancer neuroscience and lay the groundwork for therapeutic approaches that differ from current amyloid-reducing strategies,” the authors wrote in their paper, published this month in the journal Cell.

Strange heated rivalry

Through their work, the team hoped to uncover a strange phenomenon documented by previous studies: people who are diagnosed with cancer are less likely to develop Alzheimer’s disease later on. What’s even more surprising is that this pattern goes both ways, with people with Alzheimer’s disease appearing to be less likely to develop cancer.

They conducted experiments on mice susceptible to Alzheimer’s disease. They gave mice (via transplantation) different types of cancer taken from humans: lung, colon, and prostate cancer. Compared to the control group, the cancer-bearing mice did not develop a high level of amyloid plaques in their brains, a key biomarker for Alzheimer’s disease.

The researchers then went looking for a specific reason behind this protection. They eventually found that the cancer cells in these mice were producing significant amounts of Cys-C, and that the protein was able to travel through the bloodstream, bypass the blood-brain barrier, and reach the brain.

In subsequent experiments in mice, they found evidence that Cys-C can bind to amyloid oligomers, toxic clumps of amyloid that are precursors to plaques. Cys-C also appears to activate microglia, specialized immune cells in the brain, via a receptor called TREM2. Furthermore, it appears that these activated microglia were better at clearing amyloid plaques.

When they gave Alzheimer’s mice additional amounts of Cys-C, the mice became better at solving mazes, indicating improved cognition and memory.

What does it all mean?

This research, although impressive, is still in its early days. More studies will be needed to see if the effects of CysC against Alzheimer’s can be seen in humans rather than mice, for example. Even if this work pays off, no one is suggesting we should try to get cancer as a way to avoid Alzheimer’s in the future.

However, the findings certainly provide more places for scientists to start looking for the next treatment for Alzheimer’s disease, whether it be in activating Kis-C, activating TREM2, or other compounds produced by cancer cells. This is more help we urgently need. It is estimated that at least 7 million Americans currently have Alzheimer’s disease, a number that could nearly double over the next few decades. Even the best drugs today only slow the progression of the disease, which is still 100% fatal.