A major cancer-driving gene in pancreatic cancer appears to switch off an important marker that helps determine how aggressive the disease is and how it responds to treatment.
Researchers have discovered that abnormal activity in the KRAS signalling pathway, which is present in most pancreatic cancers, suppresses a gene called GATA6. The gene plays an important role in keeping pancreatic tumor cell differentiation – meaning they behave more like normal cells and tend to respond better to treatment.
Pancreatic cancer can be divided into two broad molecular types. Tumors with high levels of GATA6 belong to the classical subtype, which generally shows better responses to therapy and improved survival. Tumors with low GATA6 levels tend to fall into the basal-like subtype, which is more aggressive and harder to treat.
The new research, published in the Journal of Clinical Investigation, shows how the KRAS pathway helps push tumors toward the more aggressive state.
The team found that when the KRAS pathway is highly active, it stabilizes another protein called JUNB that acts like a switch and turns down the activity of the GATA6 gene. As a result, GATA6 levels drop and tumor cells lose features associated with the more favorable classical subtype.
When the KRAS pathway was blocked in laboratory experiments, JUNB levels fell and GATA6 activity increased. This shift pushed cancer cells back toward the more differentiated state.
These findings help explain why pancreatic tumors can look and behave differently even though most carry the same KRAS mutation. Differences in how strongly the KRAS pathway is activated may determine how much GATA6 is produced and, therefore, which subtype of tumor develops.
The study also suggests possible implications for treatment. Increasing GATA6 levels made pancreatic cancer cells more sensitive to certain chemotherapy drugs, especially oxaliplatin, which is part of the commonly used FOLFIRINOX treatment regimen.
In experiments, drugs that block the KRAS signaling pathway worked particularly well when combined with oxaliplatin. The combination slowed tumor growth more effectively than either treatment alone.
Although the findings still need further validation in clinical settings, they point to a possible strategy for improving therapy. Treatments that reduce KRAS signaling could potentially restore GATA6 activity, making tumors more responsive to chemotherapy.
More broadly, the work highlights how understanding the molecular switches that control tumor behavior may help guide both diagnosis and treatment decisions in pancreatic cancer.
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