Stanford scientists turn a cancer driver into a kill switch
A Stanford-designed molecule turns a major lymphoma-promoting protein against cancer cells, activating their own self-destruct machinery instead of simply blocking tumor growth. In mice, the treatment completely eliminated aggressive human lymphoma tumors within 11 days, although much more testing is needed before it could reach patients.
Key points
- Stanford researchers created TCIP3, a two-part molecule that turns BCL6 against lymphoma cells.
- Twice-daily TCIP3 eliminated aggressive lymphoma tumors in mice within 11 days.
- The compound is not yet ready for human use and needs further refinement and testing.
Stanford Medicine researchers have developed a two-part molecule that turns a major driver of B-cell lymphoma against the cancer cells that depend on it. In mice, twice-daily treatment with the experimental compound caused aggressive lymphoma tumors to disappear within 11 days.
The study, published in Cell, was led by graduate student Meredith Nix and postdoctoral scholar Sai Gourisankar. Senior authors include Gerald Crabtree, Nathanael Gray, Stephen Hinshaw and Michael Green of MD Anderson Cancer Center.
How the molecule works
The compound, called TCIP3, uses chemically induced proximity to connect BCL6 with either of two proteins, P300 and CBP. One side of TCIP3 binds to BCL6, while the other side binds P300 or CBP, which add acetyl marks to nearby proteins.
This rewiring not only removes BCL6's suppression of cell-death genes but also actively drives their expression. Nix compared the difference to easing off a car's brake versus flooring the accelerator.
We're trying to essentially fight cancer with its cause -- taking the driving force of the cancer and then rewiring it to activate cell death mechanisms
— Gerald Crabtree
Structural findings and next steps
Structural analysis revealed that TCIP3 acts as a molecular glue, anchoring the proteins together and forming additional stabilizing contacts. Using this information, chemists made the connection between the molecule's two halves more rigid, producing a compound that killed lymphoma cells at very low concentrations in the laboratory.
In mice implanted with human lymphoma cells, TCIP3 eliminated tumors by 11 days with no obvious toxicity. The compound also wiped out germinal centers, suggesting possible applications for autoimmune diseases like rheumatoid arthritis and myasthenia gravis. However, TCIP3 still requires chemical refinement and testing in additional animal species before human trials can be considered.
