New research from the Tokyo University of Science has uncovered a troubling paradox: compounds widely promoted for their anti-aging benefits may also accelerate cancer cell growth. The study, published recently, sheds light on how naturally occurring chemicals called polyamines – including spermidine and putrescine – interact with cancer cells at a molecular level, potentially fueling tumor proliferation.
The Double-Edged Sword of Polyamines
Polyamines are essential for all life, playing a crucial role in cell growth and protein synthesis. Prior research has shown that spermidine can extend lifespan and improve cognitive function in animal models, leading to its inclusion in many over-the-counter health supplements. However, these same compounds have also been linked to cancer progression. This new study aimed to understand how polyamines influence cancer cells, particularly their ability to thrive even without adequate oxygen.
“Changes in polyamine metabolism are correlated with various pathologies, including cancer and age-related conditions,” the researchers wrote.
The study’s findings are significant because they reveal a direct mechanism by which cancer cells exploit polyamines to fuel rapid growth.
eIF5A2: The Key to Cancer’s Exploitation of Polyamines
Researchers investigated cervical and breast cancer cells, discovering that polyamines boost levels of a protein called eIF5A2. This protein is nearly identical to another, eIF5A1, which is vital for healthy cell function. However, eIF5A2 appears to be crucial for cancer cell proliferation. Polyamines promote eIF5A2 production by suppressing a natural regulator called miR-6514-5p.
When polyamines or eIF5A2 were removed from cancer cells in the lab, tumor growth slowed dramatically. Reintroducing spermidine restored the cancer’s growth rate, confirming the compound’s role in tumor progression. This suggests that cancer cells can hijack the benefits of polyamines to expand, once initial biological malfunctions have occurred.
Normal vs. Cancer Cells: A Critical Distinction
Biochemist Kyohei Higashi explains the difference: in healthy tissues, polyamines activate mitochondria through autophagy with the help of eIF5A1. In cancer cells, polyamines promote eIF5A2, which alters gene expression to facilitate uncontrolled growth. This distinction is critical, as it suggests that targeting eIF5A2 could be a selective approach to cancer treatment.
Implications for Future Cancer Therapies
This research does not prove that spermidine causes cancer. It shows that cancer cells can exploit polyamines to accelerate growth. The findings offer promising new targets for drug development. Disrupting the interaction between eIF5A2 and ribosomes could potentially halt cancer progression without harming healthy cells.
The discovery of eIF5A2’s role in cancer proliferation provides researchers with a specific molecular target, raising the probability of effective new cancer treatments. However, extensive research is needed to ensure these treatments do not harm normal cells. As the study was conducted in a lab, further investigation is required before these findings can be applied clinically.
“Our findings reveal an important role for eIF5A2, regulated by polyamines and miR-6514-5p, in cancer cell proliferation, suggesting that the interaction between eIF5A2 and ribosomes, which regulate cancer progression, is a selective target for cancer treatment.”
