To invade healthy tissues and continue growing, aggressive cancers mimic and circumvent the body’s native piping system of veins and arteries. Through this process, known as vasculogenic mimicry (VM), tumor cells form fluid-conducting channels that transport blood, oxygen, and nutrients directly to the growing tumor.
This behavior enables tumor metastasis and tissue invasion, lowering patient survival rates. But despite VM’s wide-ranging consequences in one-third of all cancers, its exact mechanism is unknown, which makes it difficult to target as a treatment for the disease it enables.
A recent study from researchers at the University of Notre Dame remedies this knowledge gap. Katharine White, a cancer biologist, and Donny Hanjaya-Putra, a biomolecular engineer, teamed up to investigate the cancer microenvironment that drives VM formation and found that the microenvironment altered pH inside cancer cells, and VM formation is pH-dependent.
Further, the White research group identified the molecule responsible for VM’s pH-dependent formation: Beta-catenin, a multi-functional protein that controls gene expression, cell-cell adhesion, and development. The work opens the door to the discovery of new, life-saving treatments for VM. Their findings were published in Cell Death & Disease.
“Ultimately, this work can pave the way for new therapeutic strategies that target VM’s pH-sensitivity, offering a novel approach to cancer treatment that complements existing therapies,” White said.
In gel models, VM depends on pH, not tumor stiffness
White, the Clare Boothe Luce Assistant Professor in the Department of Chemistry and Biochemistry, studies how pH dynamics regulate proteins, pathways, and cell behaviors. As specialists in the role of pH in driving disease, researchers in the White Lab study how changes in proton concentration affect the behavior of proteins, cells, and whole tissue environments.
“It’s now widely accepted that pH is dysregulated in cancer cells compared to healthy cells, and pH differences could drive many of the behaviors that are hallmarks of cancer,” said White, who is a faculty affiliate of the Harper Cancer Research Institute.
To study VM outside of the body, however, White needed a good model – a system that could imitate the behavior of the cancer microenvironment, to the extent possible, outside of patient tissues while being more reproducible and controllable for research. Hanjaya-Putra, an associate professor in the Department of Aerospace and Mechanical Engineering and affiliate of the Bioengineering Graduate Program and the Harper Cancer Research Institute, contributed his expertise in biomimetic materials—substances that imitate biological tissues—to help develop these lab-bench models.
A known driver of VM is an increased stiffness of the structure that holds cells together. To form tissues, cells are surrounded by the extracellular matrix (ECM): a three-dimensional network of proteins and sugars that provides necessary support. In cancer, this ECM is stiffened, which is one reason why tumors are harder than the surrounding normal tissue and can be felt as a lump. In order to investigate the effect of matrix rigidity on VM, the researchers developed two gel-based models that could be tuned across the spectrum of soft, mimicking normal tissue, to stiff, mimicking the cancer microenvironment.
With the hydrogels prepared, the White Lab added cancer cells to both soft and stiff gels and measured the pH of the cells on each. They found that pH was significantly lower for the cells on the stiff gel compared to the soft gel.
Further, the cells on the stiff model squished together to form craters and hills, a precursor to full-fledged VM, while the cells on soft matrix remained flat and smooth, appearing like cobblestones. While promising, the correlation between low pH and stiffness-driven VM did not reveal pH as the cause.
“If there exists a direct causal relationship between matrix stiffness lowering the pH of the cancer cells and driving VM, then we should be able to raise the pH of the cells and see the stiffness response, VM, disappear,” said Leah Lund, a recent doctoral graduate from the White Lab, who led the study. “And so we tested that.”
The researchers raised the pH of the cells plated on the stiff matrix with a special ionic treatment. As pH was raised, the tense, uneven VM precursor relaxed into a flat pane of cells. The reverse was true, too. When the pH of cells plated on the soft model was lowered, the cells formed the same proto-VM peaks and crevices seen when plated on the stiff model.
“If VM only depends on the stiffness of the environment around the tumor, changing the pH would have had no effect on the shape of the cells,” Lund said. “Instead, pH appears to be responsible for the change in cell arrangement.”
A single protein is a key controller of VM
When pH changes drive major reorganization of cells, as was observed in the study of VM, a specific protein is likely responsible. To determine the culprit for the pH-sensitivity of VM, the researchers zeroed in on two proteins that previous studies had linked to VM formation: FOXC2 and beta-catenin.
Lund and colleagues repeated a previous experiment, placing lung cancer cells on stiff gel and increasing the pH, but this time, they also measured activity of Beta-catenin and FOXC2, respectively. While a loss of VM-like peaks and valleys was again observed, FOXC2 activity remained unchanged, while beta-catenin activity plummeted.
“It appears that pH regulates beta-catenin, which in turn regulates the level of VM,” White said. “We saw a decrease in VM formation at high pH because beta-catenin ceases to function above a certain pH point and, in turn, that loss of function wipes out the ability of the cells to achieve VM.”
To verify this link between VM formation and beta-catenin, the researchers repeated the original pH-raising experiment again, but this time introduced a molecule that rescues the beta-catenin activity even when the protein’s activity is dampened by pH. At high pH, with beta-catenin activity restored and unable to be repressed by the high pH of the cells, VM formation remained high.
“A rigid environment alone is not enough to drive the formation of vasculogenic mimicry,” White said. “In reality, low pH stabilizes beta-catenin and is necessary for the VM behavior to develop and persist on stiff environments.”
“Beta-catenin is the final piece in this puzzle of VM activity that will really have an impact,” added Lund. “Correlation is one thing, but we managed to find the link between pH and VM via the actual protein responsible.”
Next steps: Graduating from 2-D models to cancer treatments
With the link established between beta-catenin and VM, the protein can be targeted to treat the aggressive cancers that change their shape to mimic vascular networks. For example, a drug that modulates the pH of cancer cells or eliminates beta-catenin activity could reduce VM and the key pathways it provides for the tumor to receive nutrients, thereby weakening the tumor itself.
In addition, “tumors that develop VM are more resistant to chemotherapeutic drugs and traditional immunotherapies, so finding a way to change how these cells respond to that stiff and dysregulated environment is very important for patients,” White said.
For lead author Lund, the translation of experiments in the lab to treatments in the clinic is personal. Lund’s mother was fighting her second battle against breast cancer while Lund was discerning which lab to join as a new doctoral student at the University.
“At the time I was doing rotations and deciding which lab and what research I wanted to devote my PhD studies to, cancer was at the forefront of my personal life,” Lund said. “She’s now in remission two times over, but my mom’s second diagnosis was a huge motivator for this research.”
In order to reach the treatment stage, however, the interaction between beta-catenin, stiffness, and pH needs to be better understood. The White and Hanjaya-Putra Labs are developing three-dimensional models for these interactions, which will more closely mimic patient tumors. They will use these models to better observe how the VM networks form and interact with the surrounding normal cells and immune cells that come to fight the cancer.
“Aggressive cancers have devastating effects on patients and families,” White said. “With a better understanding of the complicated processes that drive metastasis and drug resistance, we can develop better treatments and deliver better outcomes.”
The National Institutes of Health and American Cancer Society provided funding support for this study. Learn more about cancer research at Notre Dame by visiting the Harper Cancer Research Institute’s website.
Modified images from the study appear courtesy of the White Lab, University of Notre Dame. Originally published in Cell Death & Disease (2025) under CC BY 4.0.
Originally published at research.nd.edu by Erin Fennessy on March 23, 2026.