Researchers stumble onto a new role for breast cancer drug
Tamoxifen stops immune cells from destroying injured eye cells in mice
When the eyes of her mice looked normal, Xu Wang was certain she had done something wrong. She was blasting the mice with blinding light to study how a specific gene affected the animals’ response to eye injury. All the mice were given the drug tamoxifen. Half were engineered to respond to the drug by disabling the gene — a step that would protect their eyes. The control mice, with all genes intact, should have lost sight as photo-receptors — the light-sensitive cells in the retina — died.
Instead, the retinas of the control mice looked just fine. “I was kind of despondent because it didn’t agree with our hypothesis,” Wang says. She and her mentor, Wai Wong, both ophthalmologists at the National Eye Institute in Bethesda, Md., could have started over with another kind of mouse. But they decided to do the test again. And again.