Activating PPARD in immune cells turns a cancer-fueling protein into a tumor-fighting weapon
Cold Spring Harbor scientists boosted fat-burning in CAR T cells by activating PPARD, slowing or stopping colorectal tumor growth in lab and mouse models.
Summary
Researchers at Cold Spring Harbor Laboratory found that a protein known to help cancer cells grow can be repurposed to help immune cells destroy tumors. The protein, PPARD, regulates how cells burn fat for energy. Cancer cells use it to fuel themselves, but when the team activated it in immune cells, those cells burned more fat and became better at attacking cancer. In mice with colorectal cancer, this shifted the tumor environment in favor of the immune response. The scientists then activated PPARD in engineered CAR T cells and tested them against colorectal cancer organoids, cultured human cancer cells, and tumors implanted in mice. The treated cells slowed or stopped tumor growth. The work, published in Nature Immunology, may eventually help patients whose cancers resist chemotherapy and current immunotherapies. It remains early-stage, preclinical research, and it has not been tested in people.
Detailed Summary
Colorectal cancer has become the leading cause of cancer-related death among people under 50, and many patients run out of options when chemotherapy and newer immunotherapies fail. A new study from Cold Spring Harbor Laboratory suggests that the metabolic state of immune cells could be a lever for improving treatment.
The work centers on PPARD, short for peroxisome proliferator-activated receptor delta. This transcription factor controls genes involved in fat burning. Cancer cells use PPARD to support their own growth, which would normally make it an unattractive target to activate. Semir Beyaz and colleagues found that the opposite is true in immune cells. In mice with colorectal cancer, activating PPARD in immune cells pushed the tumor environment toward one that favored immune attack. As Beyaz put it, cells that burn more fat become more fit for fighting cancer.
The team then applied the idea to CAR T cells, engineered immune cells that are already approved for certain blood cancers. They activated PPARD in the CAR T cells and tested them in several models of human colorectal cancer: patient-derived organoids, cultured human cancer cells, and cancer cells implanted in mice. Across these experiments, the PPARD-activated cells slowed or stopped tumor growth. The approach also showed promise against breast cancer, ovarian cancer, and melanoma.
The central insight is that cancer cells and immune cells face the same chemical and physical constraints, so a metabolic pathway that helps one can be harnessed to strengthen the other. Reprogramming immune cell metabolism could make existing immunotherapies work better, particularly in tumors that currently resist them.
There is no practical step for patients yet. The evidence comes from laboratory dishes, organoids, and mouse models, and the approach has not been tested in humans. Safety, durability, and the risk of PPARD activation also feeding tumor cells all need study. Human trials would be required before any clinical use.
Key Findings
- PPARD supports fat burning in cancer cells but, when activated in immune cells, shifts the tumor environment toward immune attack.
- Activating PPARD in CAR T cells slowed or stopped tumor growth in colorectal cancer organoids, cell cultures, and mouse models.
- Immune cells that burn more fat became more effective tumor fighters, linking cellular metabolic fitness to anticancer immunity.
- The approach also showed promise against breast cancer, ovarian cancer, and melanoma in laboratory experiments.
- The findings are preclinical and have not yet been tested in human patients.
Methodology
This is a ScienceDaily news report based on a Cold Spring Harbor Laboratory press release about a Nature Immunology paper. The evidence comes from preclinical work: mouse models, patient-derived organoids, and cultured human cancer cells. The source is credible, but the article is a secondary summary of the primary study.
Study Limitations
The article is truncated and excerpts only part of the results, and the findings in breast, ovarian, and melanoma models are mentioned without detail. Mouse and organoid results often fail to translate to humans, and safety and off-target effects of PPARD activation are not addressed. Readers should check the original Nature Immunology paper for effect sizes, models used, and controls.
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