Cells have power plants: mitochondria, which generate energy. But when a cell turns cancerous, those plants start working for the tumor, helping it divide without restraint. Researchers took ordinary turmeric, the familiar yellow spice, and attached a chemical "address" that makes it accumulate specifically in mitochondria. The result is a drug that gets into the energy centers of tumor cells and starts a local fire.
For the test, they used fruit flies whose gut cells had Yorkie switched on. This protein forces cells to grow nonstop, much like the human protein YAP. The flies received the drug in their food for two days. Tumor burden fell in a dose-dependent way: at 30 micromoles, tumor volume shrank to what it would have been after just 24 hours of growth without the drug. In other words, the tumor wasn't merely slowed down; it was actively being destroyed.
Metabolomic analysis showed that 51 metabolites had changed: acylcarnitines, succinate, malate, and other molecules tied to disrupted energy metabolism accumulated. It's a bit like products of incomplete combustion piling up in an overloaded boiler room. The cell chokes on its own waste and can't sustain growth.
In the end, the flies that received curcumin lived longer: median survival rose from 28 to 36 days. Until now, it was unclear whether inhibiting TrxR would work against tumors with hyperactive Yorkie in a living organism. Now it's clear that it does. What's more, the fly enzyme uses cysteine instead of selenocysteine, as in mammals, yet curcumin still binds to it tightly. That opens the door to drugs that strike at a tumor's redox balance without touching healthy cells.
Drosophila thioredoxin reductase uses cysteine instead of selenocysteine, as in mammals, but retains high catalytic activity. This makes the fly enzyme a convenient model for testing inhibitors that do not depend on selenium.
Not published on arXiv. Here are its page, the PDF and the formalization: you can check it yourself, not only read our account.