Disrupting DNA Repair May Help Defeat Drug-Resistant Cancer

Cancer’s ability to adapt is one of its most dangerous characteristics, especially when tumors stop responding to life-saving drugs. But a new study in Natural communications suggests that even drug-resistant cancers may have a hidden weakness.

Instead of directly targeting genetic mutations, researchers have found a way to dismantle the very system that cancer cells rely on to survive. By disrupting the machinery that repairs damaged DNA, scientists were able to make resistant tumors vulnerable again, potentially opening the door to treatments that stopped working.

“This study demonstrates that controlling the stability of DNA repair proteins can have a direct impact on cancer cell survival. It also highlights a new therapeutic direction to overcome drug resistance,” co-corresponding author Myung Kyungjae said in a press release.

A new strategy to fight drug-resistant cancer

Many modern cancer therapies, including PARP inhibitors, are designed to exploit a key vulnerability: cancer cells’ reliance on DNA repair. These treatments work by overwhelming tumor cells with damage that they cannot repair. But over time, some cancers adapt, reestablish their repair system and become resistant.

This new research takes a different approach to exploitation. Instead of trying to get ahead of genetic changes in cancer, researchers targeted the stability of proteins responsible for DNA repair.

Using a specialized screening method, the team identified a small molecule called UNI418. When introduced into cancer cells, UNI418 significantly reduces levels of critical DNA repair. Without these proteins, cancer cells lost their ability to recover from DNA damage, even if they had previously developed resistance.

“We identified a mechanism in which key DNA repair proteins are actively degraded inside the cell,” explained co-corresponding author Lee Joo-Young. “This provides a new way to regulate homologous recombination beyond genetic mutations.”

The result is a kind of forced vulnerability. When exposed to this treatment, even resilient cancer cells become responsive to treatments again, providing a potential avenue to expand the effectiveness of existing therapies.

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What is DNA repair?

An important aspect of this new treatment is a process called homologous recombination, which is a precise way in which cells repair their broken DNA. It relies on specialized proteins to precisely restore damaged genetic material.

Under normal conditions, this system is essential for healthy cells. But for cancer cells, it becomes a survival tool.

Tumor cells experience constant stress and DNA damage as they grow rapidly. Their ability to repair this damage allows them to survive treatments that would otherwise destroy them. This is why therapies targeting DNA repair are so effective, but only for a limited time.

What makes this new finding different is that, rather than completely blocking repair pathways, UNI418 triggers a natural protein removal system inside the cell. This system targets key repair proteins to destroy them, effectively dismantling the repair process from the inside out.

As these proteins disappear, cancer cells are left exposed and unable to deal with the accumulated damage.

What this means for the future of cancer treatment

This research highlights a broader shift in the way scientists think about cancer treatment. Instead of simply targeting genes, as in previous cancer treatments, this new process controls the proteins produced by those genes.

And the treatment is proving effective. In laboratory experiments, UNI418 not only improved treatment outcomes, but also restored effectiveness in cancers that had already become resistant to treatment.

“By weakening the DNA repair system, we can resensitize tumors that have become resistant to existing therapies. This suggests a new strategy to increase the effectiveness of PARP inhibitors,” Kyungjae said.

If future studies can replicate these laboratory findings in clinical patients, this approach could help extend the lifespan of existing cancer therapies and offer new hope to people facing drug-resistant forms of cancer.

This article does not offer medical advice and should be used for informational purposes only.

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