New cancer diagnostic technique developed

Researchers have devised a new molecular sensor that can detect high levels of lactate - a telltale sign of cancer - in individual cells.
Cancer cells break down sugars and produce the metabolic acid lactate at a much higher rate than normal cells. This phenomenon signals that cancer is present, via diagnostics such as PET scans, and possibly offers an avenue for novel cancer therapies.
Now, a team of Chilean researchers at The Centro de Estudios Cientificos (CECs), with the collaboration of Carnegie's Wolf Frommer, has devised a molecular sensor that can detect levels of lactate in individual cells in real time.

Prior to this advance, no other measurement method could non-invasively detect lactate in real time at the single-cell level.
The work, published in the journal PLOS ONE, is a boon to understanding how different types of cells go awry when cancer hits.
"Over the last decade, the Frommer lab at Carnegie has pioneered the use of Forster Resonance Energy Transfer, or FRET, sensors to measure the concentration and flow of sugars in individual cells with a simple fluorescent colour change," said Alejandro San Martin, lead author of the study.

"Using the same underlying physical principle and inspired by the sugar sensors, we have now invented a new type of sensor based on a transcriptional factor. A molecule that normally helps bacteria to adapt to its environment has now been tricked into measuring lactate for us," Martin said.

"Standard methods to measure lactate are based on reactions among enzymes, which require a large number of cells in complex cell mixtures," said Felipe Barros, leader of the project.
"This makes it difficult or even impossible to see how different types of cells are acting when cancerous. Our new technique lets us measure the metabolism of individual cells, giving us a new window for understanding how different cancers operate," Barros said in a statement.
Researchers turned the sensor on in three cell types: normal brain cells, tumour brain cells, and human embryonic cells. The sensor was able to quantify even very low concentrations of lactate, providing an unprecedented sensitivity and range of detection.

The researchers found that the tumour cells produced lactate 3-5 times faster than the non-tumour cells.
"The high rate of lactate production in the cancer cell is the hallmark of cancer metabolism," said Frommer.