 Fluorescence in Live Cancer Cells Only
2009/08/12
The development of molecules that selectively light up only in live cancer cells was announced in the December 7, 2008, online version of British science journal Nature Medicine. The development of the compound was achieved by a joint research team involving Professor Yasuteru Urano of the Graduate School of Pharmaceutical Sciences, University of Tokyo; chief researcher Hisataka Kobayashi of the National Cancer Institute in the United States; and medical equipment manufacturer Olympus.
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While lysosomes are mildly acidic in living cells, they are neutral in dead cells. Using this property, only live cancern cells can be made to fluoresce.
With earlier types of fluorescent probes, only small amounts were absorbed by cancer cells, with the result that the probe molecules were also scattered near the cancer cells and also spread throughout the body. This made it difficult to reliably detect small cancerous cells.
The new technique uses the fact that lysosomes are weakly acidic compared with the surrounding environment to resolve this problem.
In an experiment described in the journal, a fluorescent probe was introduced in mice in which lung cancer had been produced using breast cancer cells. One day later a fluorescent endoscope was used to detect and remove murine tumors of less than 1 millimeter. It was also demonstrated that the fluorescence stopped after the cancer cells were removed.
With the advances in positron emission tomography (PET) and magnetic resonance imaging (MRI) in recent years it has become easier to discover cancer, and detection can be done with higher precision. However, more than 80% of cancer deaths today are from metastasis, and the identification and removal of minute tumors produced by these metastases currently depends in large part on the skill and experience of the surgeon.
Using this new technique, it will become possible to easily discover small tumors on the millimeter scale. Moreover, since live cancer cells can be made to selectively fluoresce, endoscopic techniques can be incorporated into surgery, facilitating the task and enabling the confirmation of the status and location of tumors in real time. (Koji Fujiyoshi)
Related Websites
- National Cancer Institute (NCI) in the United States
http://www.cancer.gov/newscenter/pressreleases/HER2imagingKobayashi/
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