A Protein Called Fra-2 May Explain Why KRAS Inhibitors Stop Working in Pancreatic Cancer
One of the biggest challenges in treating pancreatic cancer is that tumors often stop responding to therapy, sometimes very quickly. A new study published in PNAS (April 2026), with the contribution of the I-PCC labs Dr. Carmine Carbone, Dr. Vincenzo Corbo and Dr. Gian Luca Rampioni Vinciguerra, sheds important light on why this happens with a promising class of targeted drugs, and points toward a potential solution.
The drugs in question: KRAS inhibitors
KRAS is a gene that, when mutated, acts like a stuck accelerator, pushing cancer cells to grow and spread. A specific mutation called KRAS G12D is found in nearly half of all pancreatic cancer cases. Scientists have recently developed drugs that target this mutation directly, with MRTX-1133 being one of the most promising. Early results have been encouraging, but tumors often find ways around these drugs.
The new discovery: a protein called Fra-2
Researchers from Sapienza University of Rome and The Ohio State University found that when pancreatic cancer cells are treated with KRAS inhibitors, they activate a protein called Fra-2 as a kind of survival response, almost like the tumor's emergency backup system. Fra-2 then switches on another well-known cancer growth pathway called mTOR, helping the tumor continue to grow despite the drug.
Importantly, the team confirmed this pattern not only in laboratory cell lines, but also in animal models and in tumor tissue grown from actual patient samples (called organoids), making the findings highly relevant to real-world disease.
A possible solution: blocking Fra-2
The researchers tested whether blocking Fra-2, using an existing compound called T-5224, originally developed for rheumatoid arthritis, could restore the effectiveness of the KRAS inhibitor. The combination worked significantly better than either drug alone, and the benefit was specifically due to the Fra-2 blockade.
Why this matters for patients
This research helps explain a recurring frustration in pancreatic cancer treatment: why even promising targeted therapies eventually stop working. By identifying Fra-2 as a key driver of resistance, this study opens a new avenue for combination therapies that could keep KRAS inhibitors working longer. The fact that T-5224 has already been tested in humans and shown a good safety profile makes this combination potentially testable in clinical trials in the near future.