A Sensor to Visualize Tumor Cells in the Body with a PET Scan

What is it about?

Imaging of cells is essential for disease diagnosis and treatment. The first step of cell imaging often involves targeted labeling of cells with self-labeling protein tags. Protein tags are polypeptide chains or small proteins that can specifically bind to a protein of interest within a cell. The tags can be attached to a probe such as a fluorescent dye so that the attached protein can be imaged and tracked. One such protein tag is the SNAP-tag. SNAP tags are advantageous because of their ability to react rapidly with benzylguanine derivatives to which a variety of probes, including fluorescence emitting ones, can be attached. Although fluorescent SNAP labels, also called substrates, are quite common, there is a dearth of radioactive substrates for use in positron emission tomography (PET). In this study, researchers have developed a sensor that can selectively attach to cancerous cells and be detected with a PET scan. To achieve this, the researchers attached an [18F]fluorine-based radioactive probe to the benzylguanine derivative. The probe behaves as a radiotracer enabling the labelled cells to be identified with a PET scan. This opens avenues for multi-scale imaging.

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Photo by Ryan Plomp on Unsplash

Photo by Ryan Plomp on Unsplash

Why is it important?

While protein tags have been successfully used to label proteins inside cells, the fluorescent dyes are not detectable in tissues deep inside the body. Imaging cells of a live subject requires surgical procedures to expose the target tissue. As a non-invasive way to image deeper tissue, researchers developed a radioactive substrate that can be attached to the SNAP-tag. With the developed sensor, labeled cells, such as tumors, can be detected with a simple full-body PET scan and offer more detailed information. KEY TAKEAWAY: The ability to visualize cells in the body is useful for detecting certain types of cells such as tumors. The radioactive SNAP-tag substrate developed in this study simplifies the imaging of cells in live subjects and eliminates the need for invasive surgical procedures.