Scientists have long been fascinated by tiny molecules called polyamines. These molecules exist in every living cell, from simple bacteria to human beings. They help cells grow, divide, and carry out many basic tasks that keep the body alive.
One of the best-known polyamines is called spermidine. In recent years, this molecule has attracted a great deal of attention because of its possible role in healthy aging. Some studies suggest that spermidine may help cells stay healthy for longer by activating a natural cleaning system inside cells.
This system, known as autophagy, removes damaged parts of the cell and recycles useful materials. By clearing out old or damaged components, autophagy helps cells function more efficiently and may slow some aspects of aging.
Because of these potential benefits, polyamines such as spermidine are sometimes described as “geroprotectors,” meaning substances that may help protect the body from the harmful effects of aging.
However, at the same time, scientists have noticed something troubling. High levels of polyamines are also often found in many types of cancer. In tumors, these molecules appear to help cancer cells grow faster and become more aggressive. This strange contradiction has puzzled researchers for many years.
How can the same molecules that seem to support healthy aging also help cancer grow?
To answer this question, scientists have been trying to understand exactly how polyamines affect the inner workings of cells. A new study led by Associate Professor Kyohei Higashi from the Faculty of Pharmaceutical Sciences at Tokyo University of Science in Japan has provided important clues. The research was published in Volume 301, Issue 8 of the Journal of Biological Chemistry.
Cancer cells behave very differently from normal cells. One major difference lies in how they produce energy. Healthy cells usually rely on mitochondria, which are often called the “power plants” of the cell. Mitochondria generate energy in an efficient way that supports normal cell activity.
Cancer cells, however, often switch to a faster but less efficient method of energy production known as glycolysis. This process breaks down sugar quickly and helps cancer cells grow rapidly, even though it produces less energy overall.
Before this study, scientists knew that polyamines were connected to cancer metabolism, but they did not fully understand how this connection worked.
To investigate, Dr. Higashi and his research team used advanced laboratory methods to examine cancer cells in detail. They worked with human cancer cell lines and carefully changed the levels of polyamines inside the cells. First, they used a drug to reduce polyamine levels. Then they added spermidine to restore them.
This allowed the scientists to observe how cancer cells responded when polyamine levels went down and then rose again.
The team used a powerful technique called proteomics, which allows researchers to measure thousands of proteins inside cells at the same time. In total, the scientists examined changes in more than 6,700 proteins.
Their results revealed an important pattern. Polyamines strongly increased glycolysis in cancer cells. In other words, these molecules pushed cancer cells toward the rapid sugar-burning process that supports fast tumor growth. The polyamines did not strongly increase mitochondrial activity, which is more commonly linked with healthy aging.
The researchers also discovered that polyamines increased the levels of several proteins connected to cancer progression. Among these were five ribosomal proteins, including RPS27A, RPL36AL, and RPL22L1. Ribosomes are tiny structures inside cells that help produce proteins, and changes in ribosomal proteins are often associated with aggressive cancers.
Another key discovery involved two closely related proteins called eIF5A1 and eIF5A2.
These two proteins are extremely similar in structure. In fact, about 84 percent of their amino acid sequences are identical. Yet they behave very differently in the body.
The scientists found that polyamines activate different pathways depending on which of these proteins is involved.
In normal cells, polyamines mainly interact with eIF5A1. This interaction supports autophagy and helps mitochondria work properly, which contributes to healthy cell maintenance and longevity.
In cancer cells, however, polyamines increase the production of eIF5A2 instead. This protein helps control how certain genes are translated into proteins and promotes rapid cell growth. As a result, cancer cells divide more quickly and tumors can expand.
The research team also discovered how polyamines increase the amount of eIF5A2 in cancer cells.
Under normal conditions, the production of eIF5A2 is limited by a small regulatory molecule known as microRNA miR-6514-5p. MicroRNAs act as natural brakes that control how much of certain proteins cells can make.
The scientists found that polyamines interfere with this control system. By weakening the effect of miR-6514-5p, polyamines allow cancer cells to produce larger amounts of eIF5A2.
This discovery helps explain why polyamines can encourage tumor growth even though they may support healthy processes in normal cells.
The findings have important implications for both cancer research and the growing interest in anti-aging supplements.
For example, some people take spermidine supplements because they believe it may promote longevity. The new research suggests that the effects of polyamines may depend heavily on the biological context.
In healthy tissues, these molecules may help maintain cell health. But in tissues that already contain cancer cells or are at risk of developing cancer, the same molecules may stimulate tumor growth.
Because of this dual effect, scientists believe more research is needed before polyamine supplements can be fully considered safe for long-term use.
At the same time, the study also points to a possible new strategy for cancer treatment. If scientists can design therapies that specifically block the cancer-related protein eIF5A2 without affecting eIF5A1, it might be possible to slow tumor growth while preserving the beneficial effects linked to healthy aging.
This would allow doctors to target cancer cells more precisely while leaving normal cells largely unaffected.
Overall, the study represents an important step forward in understanding the complex role of polyamines in human biology. It helps solve a long-standing scientific puzzle about why the same molecules can have both positive and harmful effects.
In simple terms, polyamines are not inherently good or bad. Their impact depends on the environment inside the cell and which molecular pathways they activate.
By uncovering these mechanisms, scientists now have a clearer picture of how aging and cancer processes may be connected. This knowledge could help guide the development of safer supplements, better cancer treatments, and new approaches to healthy aging.
When reviewing these findings, it becomes clear that biological systems are rarely simple. Molecules that help maintain healthy cells can sometimes be hijacked by cancer cells to support uncontrolled growth. The study highlights the importance of studying not just individual molecules, but also the context in which they operate.
Future research will need to determine how these discoveries apply to human health outside the laboratory. If researchers can learn how to carefully control the pathways involved, polyamines may one day be used in ways that maximize their benefits while minimizing their risks.
If you care about cancer, please read studies that artificial sweeteners are linked to higher cancer risk, and how drinking milk affects risks of heart disease and cancer.
For more health information, please see recent studies about the best time to take vitamins to prevent heart disease, and results showing vitamin D supplements strongly reduces cancer death.
Copyright © 2026 Knowridge Science Report. All rights reserved.
