Switching on PPARD in CAR T cells slowed or stopped colorectal tumor growth in lab models
Cold Spring Harbor Laboratory researchers activated PPARD in immune cells and saw colorectal tumor growth slow or stop in lab models. The Nature Immunology paper uses CAR T cells, a format already used to treat certain cancers.
The Scientist · Science desk
What happened
- PPARD is a transcription factor that helps regulate how cells burn fat for energy.
- Work began in mice with colorectal cancer, where tumor cells used PPARD for their own activity but activating it in immune cells tilted the surroundings toward immune attack.
- For the human-relevant tests, the team engineered CAR T cells with PPARD activated and ran them against patient-derived organoids and cultured cancer cells, in dishes and implanted into mice.
- The team also reported promising results in breast cancer, ovarian cancer and melanoma.
Why it matters
- What it limits constraint The approach has not yet been proven in patients, so safety and benefit in people remain open questions.
- What's now possible capability Fat metabolism becomes a setting that could be adjusted in engineered T cells, which the release suggests could strengthen existing immunotherapy strategies.
- What doesn't add up contradiction PPARD supports tumor cells and also arms immune cells, so the direction of the effect depends on which cell carries the activation.
The CAR T step is the clinically closer test, since those cells are already used to treat certain cancers [7]. Three different kinds of target make three different tests, and agreement among them says more than any single positive would [3].
Semir Beyaz, a Cold Spring Harbor assistant professor, framed the work as a parallel between tumor cells and immune cells. "We hypothesized that the fitness determinants of cancer and our immune cells may not be so different," he said [10]. The effect, in his telling, is metabolic. "It's all about cell fitness," Beyaz said. "What cells eat affects who they are. When immune cells burn more fat, they become more fit for fighting cancer." [11]
The thing this doesn't tell you is how large the effect was. "Slowed or stopped" spans a wide range [4]. The ScienceDaily write-up of the Cold Spring Harbor release does not say which models fell where, how many animals were in each group, what the comparison arm was, or how PPARD was switched on.
The other three cancers rest on a one-line description. We would treat colorectal as the tested case and the rest as early signals.
The release says colorectal cancer was the initial focus because of its growing toll on younger adults, and describes it as the top cause of cancer death in people younger than 50 [8]. People whose disease is hard to treat often run short of options once chemotherapy and newer immunotherapy fail [9]. The findings appear in Nature Immunology [6].
What to watch
- The full Nature Immunology data: tumor measurements, group sizes, comparison arms and the method used to activate PPARD.
- Whether the breast, ovarian and melanoma results are shown with CAR T cells in the same detail as the colorectal work.
- Any plan to test PPARD-activated cells in patients, since that is the step the release says has not happened.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence40
- Adoption
- Not scored
- Hype gap+30
- Incentives55
- Confidence50
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
PPARD (peroxisome proliferator-activated receptor delta) is a transcription factor that helps regulate how cells burn fat for energy, meaning it controls the activity of genes involved in important cellular processes.
- [2]
Beyaz and colleagues began with mice with colorectal cancer and found that cancer cells use PPARD to support their own activity, while activating the same protein in immune cells shifted the surrounding environment toward one favoring the immune system's attack on cancer.
- [3]
The team activated PPARD in engineered CAR T cells and tested them against organoids grown from patient tissue and against human cancer cells cultured in laboratory dishes and implanted into mice.
- [4]
Across the experiments, the PPARD-activated CAR T cells slowed or stopped tumor growth.
- [5]
The approach has not yet been proven in patients.
- [6]
The findings were published in Nature Immunology.
- [7]
CAR T cell therapies are already used to treat certain cancers.
- [8]
Colorectal cancer was the initial focus because of its growing toll on younger adults, and the release calls it the leading cause of cancer-related death among people under 50.
- [9]
Many patients with difficult-to-treat forms of colorectal cancer have limited options, particularly when chemotherapy and newer immunotherapy treatments fail.
- [10]
"We hypothesized that the fitness determinants of cancer and our immune cells may not be so different," he said.
- [11]
"It's all about cell fitness," Beyaz said. "What cells eat affects who they are. When immune cells burn more fat, they become more fit for fighting cancer."
- [12]
The team also confirmed promising results in other cancers, including breast cancer, ovarian cancer and melanoma.
- [13]
The results suggest that changing how immune cells process energy could make existing immunotherapy strategies more effective.
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Sources
1 independent publisher whose own reporting we read for this story.
- sciencedaily.comA protein that fuels cancer could also be the key to fighting it
1 article · October 15, 2026
Topics and entities
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Topics
- Cancer immunotherapyFollow
- Colorectal cancerFollow
- Cellular metabolismFollow
- CAR-T cell therapyFollow
Entities
- Nature ImmunologyFollow
- Cold Spring Harbor LaboratoryFollow
- Semir BeyazFollow
- PPARDFollow