Natural Killer Cells Stay Battle-Ready in Obesity-Linked Cancer Terrain

Natural killer cells are the immune system’s front-line assassins, capable of recognising and destroying tumour cells without the prior sensitisation that other immune cells require. In obesity, however, these cells frequently lose their edge, becoming sluggish and dysfunctional in ways that help cancers take hold. Now a team of researchers at Trinity College Dublin and St. James’s Hospital has delivered an encouraging message for the field of cellular immunotherapy: a laboratory-grown natural killer cell line called KHYG-1 can withstand direct exposure to the tumour and omental microenvironments of patients with obesity-associated oesophagogastric adenocarcinoma, retaining much of its cancer-killing capacity even in conditions that would exhaust ordinary immune cells.

The study, published in the Journal of Cancer Research and Clinical Oncology, set out to answer a deceptively simple question. If natural killer cells are to be used as a living drug against oesophagogastric adenocarcinoma, a cancer whose incidence is rising steeply in parallel with obesity, will they still work once they arrive in the patient’s body? The tumour microenvironment is a chemically hostile neighbourhood, saturated with immunosuppressive metabolites, cytokines and lipids, and in patients with obesity the omentum, a fatty apron of visceral adipose tissue draped over the abdominal organs, adds its own inflammatory and lipid-rich milieu. Any adoptive cell therapy must not only survive these conditions but also navigate them, migrating to the tumour rather than being lured elsewhere.

To model this terrain in the laboratory, the researchers collected tissue from patients undergoing surgery for oesophagogastric adenocarcinoma and prepared conditioned media, nutrient-rich fluids in which pieces of tumour or omental adipose tissue had been cultured. These adipose-conditioned media and tumour-conditioned media recapitulate the soluble cocktail of signalling molecules, chemokines, fatty acids and metabolites that a therapeutic cell would encounter in vivo. The team then bathed KHYG-1 cells in these fluids and measured what happened to their phenotype and function using flow cytometry, a technique that reads the fluorescent signatures of proteins on and inside individual cells.

The central finding was one of resilience. Neither the adipose-conditioned media nor the tumour-conditioned media derived from patients with obesity significantly suppressed the effector function of KHYG-1 cells. In other words, the cells’ capacity to kill was not meaningfully blunted by the soluble factors secreted by either the fat or the tumour. This stands in contrast to the well-documented dysfunction seen in natural killer cells taken from the blood and tissues of patients with obesity and cancer, and it suggests that KHYG-1 cells, an immortalised human natural killer cell line widely used as a research model and a candidate for cellular therapy, carry an intrinsic resistance to the immunosuppressive pressures of this disease setting.

Intriguingly, the study also found that exposure to the conditioned media altered the expression of phenotypic and functional markers on the KHYG-1 cells, and that adipose-conditioned media actually increased their killing capacity. Rather than being worn down by the fatty environment, the cells appeared in some respects to be primed by it. The researchers compared KHYG-1 cells with natural killer cells derived from the peripheral blood of healthy donors, providing a benchmark against which the cell line’s robustness could be judged. The comparison matters because blood-derived natural killer cells are the more conventional starting material for adoptive cell therapy, and their known susceptibility to obesity-associated dysfunction is precisely the problem a cell line such as KHYG-1 might sidestep.

Function, however, is only half the battle. A therapeutic cell that cannot find the tumour is a weapon without a target. The team therefore tested whether KHYG-1 cells could migrate towards the chemical signals emanating from omental fat and tumour tissue, using a Boyden chamber assay, a classic technique in which cells are placed in an upper chamber and their movement through a membrane towards chemoattractants in a lower chamber is counted. The result was a cautionary one. KHYG-1 cells migrated in significantly higher numbers towards the chemotactic signals of the omentum than towards those of the tumour. In a patient’s abdomen, where the omentum lies in close anatomical proximity to oesophagogastric tumours, this bias could draw therapeutic cells into fat tissue rather than into the malignancy they are meant to attack.

This migratory misdirection is not a trivial technicality. Obesity-associated cancers arise in a landscape where visceral adipose tissue is abundant, and the chemokine gradients produced by omental fat can act as siren songs for immune cells. The Dublin group’s data suggest that erroneous homing towards the omentum would present a genuine challenge for the effective delivery of KHYG-1 cells to oesophagogastric tumours in living patients. Yet the study did not stop at identifying the problem; it also pointed towards a solution rooted in the chemistry of attraction.

When the researchers supplemented the tumour-conditioned media with IP-10, a chemokine also known as interferon-gamma-inducible protein 10 that is naturally produced during inflammatory responses and is known to attract natural killer cells through the CXCR3 receptor, the chemoattraction of KHYG-1 cells to the tumour environment increased. This proof-of-principle experiment supports the concept of chemokine profile remodelling: deliberately reshaping the signalling landscape of the tumour microenvironment so that therapeutic cells are guided towards the cancer rather than into the surrounding fat. Such remodelling could be achieved through local delivery of chemokines, oncolytic viral vectors engineered to secrete attractants, or other strategies that physicians and bioengineers are already exploring in related contexts.

The broader significance of the work lies in its ex vivo rigour. By using patient-derived materials rather than simplified cell culture systems, the study captured a realistic snapshot of the obesity-associated cancer environment, and by testing both function and migration it addressed the two properties that determine whether adoptive cell therapy can succeed. Oesophagogastric adenocarcinoma carries a poor prognosis, and patients with obesity face compounded immunological disadvantages, making the search for effective immunotherapies in this population particularly urgent. The findings suggest that KHYG-1 cells, or cell lines and engineered derivatives modelled on them, could form the basis of therapies that augment anti-tumour immunity where the patient’s own natural killer cells have faltered.

Considerable work remains before any clinical translation. The experiments were conducted outside the body, and the full complexity of the in vivo environment, including vascular trafficking, stromal barriers and interactions with other immune populations, cannot be fully reproduced in a dish. The authors themselves emphasise that the migratory bias towards omentum will need to be overcome, likely through the chemokine-remodelling approaches their data support. Nonetheless, the study offers a dual gift to the field: evidence that a candidate therapeutic cell can retain its cytotoxic potency in one of the most immunologically challenging disease settings, and a mechanistically grounded roadmap for steering those cells to where they are needed most. For a cancer whose burden grows with the global obesity epidemic, that combination of resilience and navigability may prove to be exactly what the next generation of natural killer cell therapies requires.

Subject of Research: The functional resilience and migratory behaviour of KHYG-1 natural killer cells in the tumour and omental microenvironments of obesity-associated oesophagogastric adenocarcinoma.

Article Title: KHYG-1 cells retain functionality following exposure to the tumour and omental microenvironments of patients with obesity-associated cancer

Article References: Marion, C., Barry, J. C., Mylod, E., Smith, L., Menon, M. S., O’Connor, N., Butler, C., Deac, O. M., Donohoe, C. L., Elliott, J. A., Lowery, M., Reynolds, J. V., Lysaght, J., & Conroy, M. J. (2026). KHYG-1 cells retain functionality following exposure to the tumour and omental microenvironments of patients with obesity-associated cancer. Journal of Cancer Research and Clinical Oncology. https://doi.org/10.1007/s00432-026-06617-3

Image Credits: AI Generated

DOI: 10.1007/s00432-026-06617-3

Keywords: natural killer cells, KHYG-1, oesophagogastric adenocarcinoma, obesity, tumour microenvironment, omentum, chemokines, IP-10, cell migration, immunotherapy, cancer research, adoptive cell therapy