When oncologists began using the first KRAS inhibitors to treat certain lung cancers in 2021, it felt like a turning point. The mutations these drugs target — in the KRAS gene, which functions like a growth on-off switch in cells — are among the most common drivers of cancer, particularly in the lungs, pancreas, and colon. For the first time, patients had a treatment that could lock those overactive proteins in an inactive state and slow tumor growth.
But a frustrating pattern emerged: even when the drug worked, a small population of stubborn cancer cells often survived. These cells, called drug-tolerant persister cells, or DTPs, would linger after treatment, sometimes contributing to relapse months or years later.
Now, researchers from Chiba University in Japan have discovered something that may change that picture. Their findings, published in the journal Communications Biology, reveal that DTPs are not simply dormant cells passively weathering the storm. They undergo significant biological changes, reshaping their metabolism and becoming critically dependent on a specific nutrient-processing pathway to survive.
The study was led by Associate Professor Shigeki Aoki, along with researchers Hiroki Furukawa, Professor Kousei Ito, Dr. Keitaro Umezawa, and Dr. Yuchen Sun. Working with laboratory models of KRAS-mutant non-small cell lung cancer and pancreatic ductal adenocarcinoma, the team found that these surviving cells stop multiplying and adopt features resembling cellular senescence — but unlike truly dormant cells, they can bounce back once treatment stops, regaining their ability to grow and potentially trigger relapse.
The key discovery came when the researchers examined how DTPs adapt. Rather than simply waiting out the treatment, these cells rewire their internal machinery. They become heavily dependent on glutamine metabolism and lysosome-associated functions — cellular processes involved in nutrient processing and waste recycling. In other words, they trade one survival strategy for another.
Here is where the finding becomes genuinely hopeful: that very dependence creates a vulnerability. By blocking glutamine metabolism and lysosome functions, the researchers were able to reduce DTP survival during KRAS inhibitor treatment. In other words, the same adaptation that helps these cells persist also exposes a weakness that can be exploited.
"The central message of our study is that the same adaptive process that allows cancer cells to survive KRAS-targeted therapy may also expose a new weakness," said Aoki. "Targeting this weakness could provide a strategy to eliminate residual KRAS-mutant cancer cells after KRAS inhibition, prevent relapse at its source, and ultimately move KRAS-targeted therapy closer to curative treatment."
The implications could extend well beyond the laboratory. If future therapies can combine KRAS inhibitors with agents that target glutamine metabolism, oncologists might one day eliminate the residual cells that currently allow cancer to return — transforming what is now a chronic condition requiring ongoing management into something closer to a curative outcome.