Researchers from Duke University have developed a new DNA-based tool to identify cancer cells. Their system is a DNA circuit. DNA binding to specific cell markers produces a signal if and only if two specific proteins are present, helping to improve specificity and reduce false positives in cancer cell detection. The researchers also hope that one day their DNA circuits can be delivered to cancer patients and help signal to the immune system to destroy tagged cancer cells.
Cancer cell detection in the body is a complex challenge, because cancer cells express many different biochemical markers. Prior work detecting cancer can be prone to false alarms, whereby noncancerous cells are mistakenly identified as cancer cells. To address this challenge, the Duke researchers designed a DNA circuit that creates a signal only if a specific combination of cell markers are present.
The DNA circuit works as follows: first, DNA strands bind to the cancer cell surface markers. The marker-binding DNA strand binds a second strand of DNA that forms a hairpin. Adding a third “initiator” strand of DNA causes one of the hairpins to open, which in turn triggers a chain reaction until the last hairpin is opened and the circuit signals that the cell is cancerous.
Testing their microscopic device, the researchers found it can detect leukemia cells and identify them from other cancer cells within a matter of hours. The device can be adapted to detect other cell surface proteins, and one day, may help signal to the immune system to destroy tagged cancer cells.
Study in Journal of the American Chemical Society: Programming DNA-Based Biomolecular Reaction Networks on Cancer Cell Membranes