The surface layer in question is called the glycocalyx. It is a dense coating made from sugar-containing molecules attached to proteins and lipids, collectively known as glycoconjugates. Although the glycocalyx is found on healthy cells as well as cancer cells, tumors can remodel it into a more substantial barrier. A thickened glycocalyx can physically interfere with contact between cancer cells and immune cells, while also altering the molecular signals that immune cells use to determine whether a cell should be attacked.

Kevin Tharp, a cancer researcher at Sanford Burnham Prebys and the study’s lead and corresponding author, began investigating this process by considering the mechanical environment surrounding tumors. Primary tumors are often stiffer than the normal tissues around them. This stiffness exerts physical stress on cells and can change how they generate energy, communicate with their surroundings and respond to nutrients. Tharp’s team hypothesized that these mechanical forces could influence tumor metabolism in ways that ultimately reshape the cancer cell surface.

To test the idea, the researchers grew cells under laboratory conditions designed to mimic either soft, normal tissue or the stiffer environment found near a primary tumor. They also compared conventional cell-culture media with a newer formulation intended to more closely reproduce the nutrient composition of human blood and tissues. Each medium was tested under normal glucose levels and under elevated glucose conditions resembling hyperglycemia, the high-blood-sugar state associated with diabetes and metabolic syndrome.

The combinations produced sharply different cellular responses. Mechanical stiffness, nutrient composition and glucose availability influenced the proteins made by the cells, the metabolites accumulating inside them and the structure of their glycocalyx. Excess glucose increased the thickness of the surface coating most clearly when cells were grown in physiological, human-like medium. The result suggests that conventional laboratory media may conceal important aspects of tumor biology by exposing cells to nutrient mixtures that differ substantially from those encountered in the body.

The team next examined how glucose metabolism could provide the raw materials needed to construct glycoconjugates. Glucose is not simply burned for energy; its carbon atoms can also be diverted into biochemical pathways that generate sugars and other components used to decorate proteins and lipids. When the researchers altered glucose metabolism, the composition of the glycocalyx changed. Cells grown in conventional medium and those grown in physiological medium developed distinctly different glycoconjugate profiles, and hyperglycemia further modified the molecular architecture of their outer coatings.

Proteomic analyses then highlighted HSF1 as a central regulator of the response. HSF1 is best known as a stress-response protein that helps cells survive high temperatures, toxic conditions and other forms of damage. It is also associated with breast cancer progression and metastasis. In the new experiments, the protein appeared to connect the physical and metabolic conditions of the tumor microenvironment with the production of cell-surface sugars.

The researchers found that hyperglycemia enhanced cancer cells’ ability to avoid immune detection when HSF1 was present and when the cells were grown under conditions designed to resemble the tumor microenvironment. Blocking HSF1 prevented the glucose-associated thickening of the glycocalyx. Using scanning angle interference microscopy, the scientists were able to measure changes in the surface layer and show that inhibiting HSF1 reduced the protective coating that otherwise formed under high-glucose conditions.

This mechanism offers a possible explanation for how elevated blood sugar could worsen cancer outcomes. Epidemiological studies have linked diabetes, metabolic syndrome and hyperglycemia with increased cancer risk and poorer results after treatment, but the biological reasons have remained incompletely understood. The new findings suggest that high glucose may do more than fuel tumor growth: in the right mechanical and nutritional environment, it may help cancer cells construct a molecular shield against immune surveillance.

The work does not establish that lowering blood sugar or blocking HSF1 will automatically improve outcomes for people with cancer, and the researchers emphasize that further studies are needed in animal models and clinical settings. However, the results create a potential therapeutic strategy. Drugs that inhibit HSF1, or treatments that interfere with glycocalyx assembly, could theoretically expose tumor cells to immune cells and make them more vulnerable to immunotherapies. Such an approach may be particularly valuable against metastatic disease, where immune evasion is a defining obstacle. The study also underscores why cancer metabolism experiments must account for both the physical properties of tumors and the complex nutrient conditions inside the human body.

Subject of Research: Cells

Article Title: The microenvironment dictates glyco-immune surveillance via HSF1-mediated metabolism

News Publication Date: 7 August 2026

Web References: https://sbpdiscovery.org/scientists/kevin-tharp-phd/; https://doi.org/10.1126/sciadv.aeb1136

References: Tharp et al., “The microenvironment dictates glyco-immune surveillance via HSF1-mediated metabolism,” Science Advances, DOI: 10.1126/sciadv.aeb1136

Image Credits: Kevin Tharp, Sanford Burnham Prebys

Keywords: cancer, cancer immunology, cancer immunotherapy, glycocalyx, hyperglycemia, HSF1, heat shock factor 1, tumor microenvironment, immune evasion, cancer metabolism, immune surveillance

The liver is a particularly favorable site for metastasis because it is metabolically active and continuously processes nutrients, including fatty acids. Cancer cells arriving in the organ encounter an environment that can provide both energy and molecular signals supporting their survival. Although scientists have increasingly recognized that tumors use local nutrients to grow, the new study examines a less understood question: how does the liver’s nutrient-rich environment influence the battle between metastatic cancer cells and immune cells?

The researchers focused on palmitate, a saturated fatty acid found naturally in the liver and used by cells in several essential biological processes. One of those processes is palmitoylation, a reversible chemical modification in which palmitate is attached to proteins. Palmitoylation can change a protein’s stability, location, or interactions with other molecules, allowing cells to fine-tune signaling pathways. In metastatic cancer cells, the team found that palmitate was attached to laminin-511 through the activity of DHHC17, an enzyme belonging to a family of palmitoyltransferases that regulate protein modification.

Laminin-511 is part of the extracellular matrix, the network of proteins surrounding cells. It helps organize tissue structure and can influence how cells move, attach, invade neighboring tissues, and establish new tumors. The researchers found that palmitoylation made laminin-511 more stable. As a result, metastatic cancer cells were able to produce a more persistent molecular environment around them, one capable of influencing nearby immune cells rather than merely supporting the physical growth and movement of the tumor.

The most important effect was observed in neutrophils. These white blood cells are best known for rapidly responding to infections, but they can also recognize and destroy cancer cells under the right conditions. Their behavior, however, is highly dependent on signals from the surrounding tissue. When exposed to laminin-511 modified by the cancer-cell palmitoylation pathway, neutrophils became less effective at attacking tumor cells. Instead, they showed an increased tendency to produce neutrophil extracellular traps, or NETs.

NETs are web-like structures made from DNA and antimicrobial proteins that neutrophils release to capture and immobilize pathogens. In cancer, however, NETs can have harmful effects. They may shield tumor cells from immune attack, support their attachment to tissues, and create conditions that promote metastatic growth. The study indicates that palmitate-driven stabilization of laminin-511 pushes neutrophils away from direct antitumor activity and toward a state that can assist the tumor.

To test whether DHHC17 was responsible for this immune suppression, the researchers manipulated the enzyme in experimental models of liver metastasis. Reducing DHHC17 activity weakened the pathway that stabilizes laminin-511 and led to smaller metastatic lesions. Crucially, the effect depended on the presence of neutrophils. This finding suggests that DHHC17 is not simply promoting cancer-cell growth in isolation; rather, metastatic cells use the enzyme and its downstream effects on laminin-511 to interfere with immune destruction.

The results reveal a form of immune evasion in which cancer cells do not need to eliminate neutrophils to benefit from them. Instead, they reshape the local molecular environment and redirect the cells’ behavior. “Rather than acting directly on the cancer cell alone, this pathway allows tumor cells to disarm neutrophils and undermine one of the body’s natural defense mechanisms against cancer,” said first author Anke Vandekeere of the VIB-KU Leuven Center for Cancer Research. The discovery adds to growing evidence that the extracellular matrix is an active participant in cancer progression, not simply a structural framework surrounding tumors.

The findings also raise the possibility that targeting palmitoylation could produce a dual therapeutic effect. Inhibiting DHHC17 or related components of the pathway might reduce tumor-promoting signals from laminin-511 while restoring the ability of neutrophils to kill metastatic cells. Such an approach would differ from strategies designed to remove neutrophils altogether. A previous clinical trial testing neutrophil depletion did not improve immunotherapy outcomes in patients with solid tumors, suggesting that reprogramming these immune cells may be more effective than eliminating them.

The study was an experimental investigation conducted in animals, so its therapeutic implications remain to be tested in human patients. Nevertheless, it offers a mechanistic explanation for how the liver’s metabolic environment can influence immune behavior during metastasis. By identifying DHHC17, palmitoylated laminin-511, and neutrophil dysfunction as connected parts of the same process, the researchers have highlighted a potential vulnerability in liver metastases. Future therapies that block this pathway could help transform neutrophils from tumor accomplices back into active defenders against metastatic cancer.

Subject of Research: Animals

Article Title: Palmitate promotes liver metastases by decreasing neutrophil antitumour behaviour

News Publication Date: 5 August 2026

Web References: https://doi.org/10.1038/s42255-026-01582-0

References: Nature Metabolism, DOI: 10.1038/s42255-026-01582-0

Keywords: Liver metastases, palmitate, palmitoylation, DHHC17, laminin-511, neutrophils, NETs, cancer immunology, immune evasion, tumor microenvironment, metastatic cancer, liver cancer research