A series of molecular probes that could allow doctors to tailor treatments to individual cancer patients has been developed by chemists in the US and Australia. A team led by Bradley Smith at the University of Notre Dame and Katrina Jolliffe at the University of Sydney, prepared a series of fluorescent peptides that bind selectively to dying cells. 

Many cancer medicines kill tumour cells by triggering them to shut down in a programmed way, a process known as apoptosis. Smith and Jolliffe's peptide probes recognise apoptotic cells, and so can show whether a drug is acting effectively.

The probe works by detecting phosphatidylserine (PS), which appears on the cell surface during the early stages of apoptosis. Because the probe operates instantaneously and can be monitored by fluorescence microscopy, Smith suggests it will make an ideal marker in high throughput cancer drug discovery. 

The probes could be developed into imaging agents to detect apoptosis in the body during cancer treatment, said Smith. Tom Fyles, an expert in cell membrane sensors at the University of Victoria in Canada, agrees. 'This is a great example of how synthetic molecular recognition elements can rapidly grow into truly practical imaging tools,' he said. 

Imaging will enable doctors to test each patient's response to a cancer drug and adjust their treatment accordingly, said Smith, but the probe's future applications could extend further than cancer treatment. 'Apoptosis is also a key process in the cardiovascular system. Another long-term aim of this work is to develop minimally invasive, PS-selective agents that can detect cardiovascular disease in patients,' he said.

James Mitchell Crow