Russian Scientists Discover Hidden Target of Cancer Drug, Paving Way for Less Toxic Therapy

Scientists reveal irinotecan's hidden weapon against cancer cells

Researchers from ITMO University have, for the first time, conducted a detailed study of the molecular mechanisms behind irinotecan—a widely used anticancer drug—and identified a previously unknown protein target in cancer cells. According to a statement from the university's press service to TASS, this breakthrough could serve as the foundation for developing more effective and safer versions of the medication.

The scientists found that the well-known cancer drug works not through a single mechanism, but via two distinct pathways. It not only disrupts the division of cancer cells but also affects a specific protein that is particularly abundant in malignant tumors.

"By blocking this protein with an existing drug, we could selectively halt the progression of various cancers," explained Olga Volkova of ITMO University. "This would make treatment gentler on patients—for example, by reducing the required radiation dose."

The drug itself is derived from a natural source. It was developed based on a compound extracted from the bark of the Chinese happy tree (Camptotheca acuminata). Previously, it was believed that the medication simply inhibited cell proliferation, which is why it has been successfully used to treat certain cancers, including those of the intestine and lungs.

In a study supported by the Russian Science Foundation, the researchers hypothesized that the drug might also interact with the same "harmful" protein commonly found in tumors. To test this theory, they turned to computer modeling.

Using specialized software, the team created precise virtual models of the molecules and simulated their interactions. First, they measured how strongly the drug binds to the protein, then assessed the stability of the resulting complex. The calculations revealed that the drug binds to the target protein even more effectively than expected—and does so at very low concentrations. These findings were later confirmed in real laboratory experiments.