Researchers have developed an experimental way to turn a chemical made by cancer cells into a weapon against them. Instead of delivering toxic drugs throughout the body, the method uses carbon monoxide naturally released by tumor cells to manufacture anticancer compounds directly inside those cells. The study was published in Nature Communications.
Carbon monoxide is best known as a poisonous gas, but many cancer cells produce it in unusually large amounts. The team exploited this by delivering a compound called a palladacycle into cells. A palladacycle is a molecule built around palladium, a metal that acts as a catalyst. When enough carbon monoxide is present, the palladacycle reacts with the gas to form phenanthridinone, an organic molecule with toxic derivatives already used in anticancer drugs.
There was one major obstacle. Inside cells, a natural substance called glutathione rapidly deactivates the palladium catalyst and stops the reaction. To protect it, the researchers enclosed the palladacycle within albumin, a protein commonly found in blood, which shields the catalyst as it travels through the bloodstream and into cells.
Selective drug production in lab tests
The scientists exposed cultured human liver, cervical, breast, and lung cancer cells to the albumin and palladacycle complex for 48 hours, and also tested a noncancerous cell line. After 48 hours, phenanthridinone was detected in the cancer cells but not in the normal cells. A refined version of the system allowed the newly formed drug to separate from the carrier and move freely through the cell. In cultured liver cancer cells, the toxic compound formed inside the cells and damaged them. The drug was not produced in blood, the researchers believe, because carbon monoxide in the bloodstream is mostly attached to hemoglobin, the protein that carries oxygen, making it unavailable for the reaction.
The work matters because conventional chemotherapy often damages healthy tissue along with tumors, causing serious side effects. A system that builds a drug only where a tumor's own chemistry is active could attack cancer while sparing healthy cells. The research is still at an early laboratory stage, and the team plans to test the approach in animal models. If successful, the strategy could lead to a new class of treatments that use substances already present in the body to synthesize drugs exactly where they are needed.