Cancer Immune System Weapon Study Reveals Breakthrough
- In a move described as a promising breakthrough in immunotherapy, researchers at Weill Cornell Medical College have revealed how tumors drain the immune system's energy, specifically targeting T...
- The study centers on the observation that T cells, the immune system's primary cancer fighters, become tired during prolonged exposure to tumors.
- "We've known for some time that CD47 on cancer cells helps them evade the immune system," explains dr.
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Tumor ‘Energy Drain’ Identified: new Immunotherapy Target discovered
In a move described as a promising breakthrough in immunotherapy, researchers at Weill Cornell Medical College have revealed how tumors drain the immune system’s energy, specifically targeting T cells, and how this process can be stopped to preserve T cell effectiveness in fighting cancer. The findings, published in Nature Immunology on November 20, 2023, identify a previously unknown mechanism by which tumors suppress the immune response.
The Energy Drain: How Tumors Exhaust T Cells
The study centers on the observation that T cells, the immune system’s primary cancer fighters, become tired during prolonged exposure to tumors. Researchers found that cancer cells exploit a molecular signal – the CD47 protein – to induce this exhaustion. Crucially, the team discovered that T cells *themselves* produce CD47, and its levels increase dramatically as the T cells become depleted. This creates a feedback loop where the T cells contribute to their own weakening.
“We’ve known for some time that CD47 on cancer cells helps them evade the immune system,” explains dr. Shahin Rafii, a senior author of the study and director of the Cancer Immunology and Immunotherapy Center at Weill Cornell Medicine.”But what we didn’t realize is that T cells also express CD47, and that this expression is a key driver of their exhaustion.” Weill Cornell News
CD47: The ‘Don’t Eat Me’ Signal and its Role in T Cell exhaustion
CD47 is often referred to as the “don’t eat me” signal because it binds to a receptor on immune cells, preventing them from attacking the cancer cell. The Weill Cornell team’s research demonstrates that when T cells are depleted, thay upregulate CD47 production.This increased CD47 then interacts with its receptor, SIRPα, on other immune cells, effectively signaling the T cells to shut down and conserve energy. This energy conservation,while beneficial for the T cell’s survival in the short term,ultimately hinders its ability to effectively kill cancer cells.
Mouse Model Experiments Confirm Findings
To validate their findings, the researchers conducted experiments on mice. Animals genetically engineered to lack CD47 on their T cells developed slower-growing tumors compared to control mice. This suggests that blocking CD47 signaling on T cells coudl be a viable strategy for enhancing the effectiveness of cancer immunotherapy.
| Group | CD47 Expression on T Cells | Tumor Growth Rate |
|---|---|---|
| control Mice | Normal | Fast |
| CD47-deficient Mice | Absent | Slow |
Implications for Immunotherapy
Current immunotherapies, such as checkpoint inhibitors, aim to unleash the immune system’s ability to fight cancer.However, these therapies don’t always work, and many patients develop resistance. The discovery of the CD47-mediated energy drain provides a potential explanation for this resistance. If tumors can effectively deplete T cells,even checkpoint inhibitors may be unable to restore their function.
“This research suggests that we need to think beyond simply blocking