Human cancers may be influenced by ancient viruses that have been integrated into our DNA for millions of years.
Researchers at the University of Colorado Boulder have revealed that endogenous retroviruses, long considered inactive DNA, play a crucial role in activating genes related to tumor growth. This discovery opens up new avenues for improving cancer treatments.
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Endogenous retroviruses make up about 8% of the human genome. They are the result of viral infections that occurred in our primate ancestors tens of millions of years ago. These viral DNA sequences integrated into reproductive cells, passing on from generation to generation. For a long time, these DNA fragments were perceived as harmless, lacking the ability to cause diseases. However, recent research has revealed that they can act as switches, activating nearby genes, and playing a role in human evolution, notably in the development of the placenta and the immune response.
The study published in
Science Advances showed that these retroviruses might also contribute to cancer growth. By analyzing genomic data from 21 types of cancers, researchers discovered high activity of a particular lineage of endogenous retrovirus called LTR10. This retrovirus, which infected primates around 30 million years ago, was particularly active in several types of cancers, such as lung and colon cancers. In-depth analyses revealed that LTR10 was active in about one-third of patients with colorectal cancer.
To confirm these findings, scientists used CRISPR technology to deactivate LTR10 in cancer cells. This led to the inactivation of critical genes involved in cancer development.
Experiments conducted on mice also showed that suppressing this retrovirus improved the effectiveness of treatments aimed at reducing tumors. Edward Chuong, the study's lead author, emphasized that understanding the origin of these switches could allow for better targeting of current treatments and the discovery of new therapies.
In conclusion, this study suggests that endogenous retroviruses, long considered inactive, may play a significant role in the emergence and persistence of modern cancers. Continuing research in this field could pave the way for major therapeutic advancements.
Article author: Cédric DEPOND