A smarter way to screen cancer drugs just got a 3D upgrade. Uppsala University researchers adapted the Cell Painting imaging method to peer inside 3D cancer cell clusters, uncovering differences between drugs that looked identical in traditional flat cultures. Two common cancer drugs — 5-fluorouracil and olaparib — behaved distinctly in 3D, with differences tied to how each activates the p53 stress response.
Researchers at Uppsala University have given a widely used drug-screening tool a major upgrade — and it's already revealing things flat cell cultures couldn't. The team adapted Cell Painting, an imaging method that color-codes key cell structures like the nucleus and mitochondria, to work inside small 3D cancer cell clusters called minispheres. By making the clusters transparent using a simple sugar-and-glycerol solution, they could photograph individual cells deep within the spheres and measure thousands of structural details at once.
When they tested 52 cancer drugs, two — chemotherapy staple 5-fluorouracil and targeted therapy olaparib — looked nearly identical in standard flat cultures but behaved very differently in 3D. Surprisingly, 5-fluorouracil caused less DNA damage than olaparib, yet was more effective at halting cell division. Gene activity data pointed to the p53 pathway as the key differentiator, with 5-fluorouracil triggering a stronger stress response.
Key Takeaways:
Why it matters: Most drug discovery still relies on flat cell cultures, which don't reflect how cells actually behave in the body. This 3D Cell Painting approach could help researchers make better decisions earlier in drug development — potentially reducing failures down the line and improving how cancer therapies are selected and compared.
