Cancer drug resistance remains one of the most devastating barriers in oncology. It causes treatments to fail and enables cancers to metastasize, leading to aggressive tumors at distant sites. Consequently, several research groups worldwide are focused on uncovering the mechanisms behind this resistance and identifying ways to block it.
UVA Researchers Trace Resistance to EMT Pathways
At the University of Virginia, scientists investigating pancreatic ductal adenocarcinoma (PDAC) uncovered elusive signaling pathways that drive resistance. Their findings, published in Science Signaling, reveal that drug resistance stems from a dynamic cellular transformation process and an unexpected signaling backup system that sustains it.
Using Information Theory to Uncover Hidden Signals
To decode these complex interactions, the team used information theory—specifically a concept called mutual information—to identify which signaling molecules trigger drug resistance. This mathematical approach helped them pinpoint the key pathways involved in pancreatic cancer’s evasive behavior.
Pancreatic Ductal Adenocarcinoma: A Difficult Disease to Treat
PDAC accounts for up to 90% of pancreatic cancer cases, according to the U.S. National Institutes of Health. Treatment is notoriously difficult because the disease is often diagnosed late and rapidly develops resistance to therapy, regardless of where patients receive care.
EMT: The Central Driver of Drug Resistance
Lead author Dr. Michelle Barbeau explains that specific signaling molecules initiate a process called epithelial–mesenchymal transition (EMT). During EMT, cancer cells shift from stationary epithelial cells to migratory, spindle-shaped mesenchymal cells. This transformation increases invasiveness, boosts drug efflux mechanisms, and enables cells to evade chemotherapy.
ERK Emerges as the Dominant EMT Signal
As reported by medicalxpress, the research team discovered that variations in signaling activity largely activate EMT. They identified the kinase enzyme ERK as the primary driver. Yet, ERK is not the only molecule at work. Using mutual information, researchers confirmed ERK’s dominant role and linked its activity directly to the onset of EMT in individual cancer cells.
Heterogeneity Complicates Treatment
Barbeau’s team found that EMT does not occur uniformly. Instead, tumors display a mix of cell types—from stationary epithelial cells to fully transformed mesenchymal cells. Some cells exist in hybrid states, further complicating treatment. Importantly, they observed that greater EMT heterogeneity correlates with poorer patient outcomes.
A Backup System: JNK Steps In When ERK Is Blocked
When researchers inhibited ERK in the lab, another kinase, JNK, unexpectedly took over to drive EMT. This redundancy highlights how pancreatic cancer cells adapt quickly, making them exceptionally difficult to treat. Additional factors, including growth factor exposure, also influence whether a cell undergoes EMT.
Why EMT Makes Cancer More Lethal
EMT increases metastasis, enables cells to travel and seed new tumors, and contributes to the development of drug-resistant cancer stem cells. While epithelial cancer cells tend to proliferate, mesenchymal cells spread, invade, and endure even the harshest therapies.
Identifying Pathways to Improve Treatment Response
Despite these challenges, the findings offer hope. By identifying the signaling pathways behind EMT, researchers can propose effective drug combinations that counteract chemoresistance. Barbeau notes that modulating these pathways may significantly improve therapeutic outcomes.
A Global Challenge With a High Mortality Rate
Pancreatic cancer remains one of the deadliest cancers, with a five-year survival rate of only 10–13%. Globally, around 500,000 people are diagnosed each year, and nearly the same number die—largely due to late diagnosis and limited treatment options.
ERK Inhibitors May Reduce Chemoresistance
The research concludes that adding ERK inhibitors to PDAC treatment strategies could lessen EMT-driven drug resistance. While more work is needed, this approach may offer a promising avenue to improve survival in one of the world’s most challenging cancers.