Scientists have developed an experimental cancer treatment that manufactures its own toxic drug inside cancer cells, potentially sparing healthy tissue.
Researchers at Japan’s RIKEN institute have discovered a clever way to exploit one of cancer’s unusual metabolic characteristics: many cancer cells naturally produce higher levels of carbon monoxide than healthy cells.
Led by chemist Katsunori Tanaka, the team developed a system that uses this gas to trigger the production of cancer-killing compounds directly inside cells.
The technology combines a palladium-based catalyst with albumin, a protein naturally found in blood. Albumin protects the catalyst as it enters cells. Once inside, the catalyst uses carbon monoxide to produce compounds called phenanthridinones, some of which have anticancer activity.
In laboratory experiments, researchers detected drug-producing reactions in liver, cervical, breast, and lung cancer cell lines, with substantially less activity in healthy cells.
A modified version also successfully produced a toxic compound inside liver cancer cells, suppressing their growth.
Why is this important? Conventional chemotherapy can damage healthy tissues alongside tumors. This approach could eventually help concentrate toxic drug production where it is needed most, potentially reducing unwanted side effects.
However, the research remains at an early stage. The treatment has only been tested in laboratory-grown cells, and healthy cells were not completely unaffected. Animal studies and human clinical trials are still needed to establish its safety and effectiveness.
Source: Kawai, M., et al. (2026). Harnessing endogenous carbon monoxide for cancer-selective drug synthesis. Nature Communications.