A newly discovered gene switch may help turn chemotherapy-resistant pancreatic cancer into a treatable disease.
Researchers at Duke-NUS Medical School have discovered a molecular “switch” that determines whether pancreatic cancer cells respond to chemotherapy or resist it—a finding that could help shift some of the most treatment-resistant tumors into forms that respond better to existing drugs.
The research, published in the Journal of Clinical Investigation, explains the biological mechanism behind this switch. The results suggest that combining targeted medicines with standard chemotherapy may improve treatment results for patients whose pancreatic cancer no longer responds well to therapy.
Why Pancreatic Cancer Is So Difficult to Treat
Pancreatic cancer is one of the deadliest forms of cancer worldwide. In Singapore, it ranks as the ninth most common cancer but the fourth leading cause of cancer death. The disease is often diagnosed at a late stage and tends to respond poorly to available treatments. As a result, most patients depend on chemotherapy, which usually provides only limited benefit.
Over the past decade, scientists have learned that pancreatic tumors generally fall into two major molecular subtypes—classical and basal. Tumors in the classical subtype tend to have more organized cell structures, and patients with this form often respond better to treatment. Basal subtype tumors are more disorganized and aggressive, and they frequently resist chemotherapy.
Importantly, pancreatic cancer cells are not fixed in one subtype. They can shift between these states, moving from a more treatable form to a more resistant one. This ability to change identity is known as cancer cell plasticity.
GATA6 Gene Helps Control Tumor Aggressiveness
The Duke-NUS team focused on a gene called GATA6, which plays a key role in maintaining pancreatic cancer cells in the more structured and less aggressive classical state. When GATA6 levels are high, tumors tend to grow in a more organized pattern and are more likely to respond to chemotherapy. When GATA6 levels fall, the cells lose that structure, become more aggressive, and are more likely to resist treatment.
Professor David Virshup of Duke-NUS’s Program in Cancer & Stem Cell Biology, who led the study, said:
“We have known that pancreatic cancer cells can switch between these two states. What we didn’t understand was the mechanism driving that switch. By identifying the pathway that suppresses GATA6, we now have a clearer picture of how tumours become resistant—and potentially how to reverse that process.”
KRAS and ERK Signals Drive the Molecular Switch
The researchers traced the switch to a signaling chain inside pancreatic cancer cells. A gene called KRAS, which is mutated in nearly all pancreatic cancers, continuously instructs cells to grow. KRAS sends these signals through a partner protein known as ERK, which carries the growth message deeper into the cell.
When the ERK pathway becomes highly active, it protects another protein that reduces the production of GATA6. As GATA6 levels drop, pancreatic cancer cells lose their organized structure, shift toward a more aggressive form, and become significantly harder to treat with chemotherapy.
Blocking the Pathway Restores Chemotherapy Sensitivity
Using genetic screening, molecular studies in cancer cells, and drug treatments, the research team demonstrated that blocking the KRAS and ERK pathway removes this suppression. Once the pathway is inhibited, GATA6 levels increase again. As a result, cancer cells move back toward the more organized state and become more responsive to chemotherapy drugs.
The scientists also found that higher levels of GATA6 generally made pancreatic cancer cells more sensitive to treatment. When drugs that block the KRAS and ERK pathway were combined with standard chemotherapy, the effect was stronger than either treatment alone, but only when GATA6 was present. This suggests that GATA6 plays a crucial role in determining when combination therapies are most effective.
These results may help explain why patients whose tumors contain higher GATA6 levels often respond better to certain chemotherapy treatments. The findings also provide a biological explanation for ongoing clinical trials that are exploring new therapies aimed at KRAS and related signaling pathways.
Professor Lok Sheemei, Duke-NUS’ Interim Vice-Dean for Research, said:
“Pancreatic cancer remains one of the toughest cancers to treat. These findings provide a mechanistic explanation for why tumours respond poorly to chemotherapy and offers a rational strategy for combining targeted therapies with existing drugs.”
Implications Beyond Pancreatic Cancer
The research may also have broader implications for other cancers. Many tumors driven by KRAS mutations show similar changes in cell behavior and treatment response. Understanding how cancer cells move between different states could help scientists address treatment resistance in other forms of cancer as well.
Professor Patrick Tan, Dean and Provost’s Chair in Cancer and Stem Cell Biology at Duke-NUS, commented:
“This work demonstrates how basic science can uncover actionable insights into treatment resistance. Understanding how cancer cells switch states gives us a more strategic way to design combination treatments.”
Reference: “Oncogenic KRAS/ERK/JUNB signaling suppresses differentiation regulator GATA6 in pancreatic cancer” by Zheng Zhong, Xinang Cao, Pei-Ju Liao, Raman Sethi, Jeffrey A. Klomp, Clint A. Stalnecker, Jinmiao Chen, Yue Wan, Channing J. Der and David M. Virshup, 2 February 2026, The Journal of Clinical Investigation.
DOI: 10.1172/JCI191370
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