Fluorescence probes capable of selective molecular imaging of living cancer cells are reported in a paper online this week in Nature Medicine. The method reduces ‘noise’ from healthy cells and could potentially be adapted to other cancer specific molecules.
A goal of cancer diagnosis is to develop tumour-imaging techniques that have sufficient specificity and sensitivity. To achieve this, minimizing the background signal from healthy tissues is crucial. Yasuteru Urano and his colleagues achieve highly specific cancer visualization within the body by developing a probe that becomes fluorescent after its entry into the cell by sensing the acidic pH change characteristic of a certain part of the cell, known as lysosomes. The authors attached their pH-activated probe to a cancer-targeting antibody and showed that it was useful to image lung cancer cells in mice.
The probe was highly specific for tumours with minimal background signal. Furthermore, because the acidic pH in lysosomes disappears in dying or dead cells, only living cancer cells were successfully visualized. The design concept developed in this paper can in principle be adapted to any cancer-specific, cell surface?targeting molecule that enters a cell through lysosomes.