Assistant Professor Shao Huilin and her research team from the Department of Biomedical Engineering and Institute for Health Innovation & Technology (iHealthtech) at the National University of Singapore (NUS) have developed a technology that is accurate, less invasive and significantly brings forward the evaluation window, by using liquid biopsies.
The technique, termed extracellular vesicle monitoring of small-molecule chemical occupancy and protein expression (ExoSCOPE), is the first of its kind in the world. It takes advantage of extracellular vesicles (EVs) secreted by cancer cells and circulating in blood as a reflective indicator of drug effectiveness in solid tumors.
"Conventional procedures such as tumor imaging are not only expensive but also delayed. For these methods, treatment effectiveness can only be determined after weeks. Using the ExoSCOPE, we can directly measure the outcomes of drug effectiveness within 24 hours of treatment initiation. This will significantly reduce the time and cost for cancer treatment monitoring," said the lead scientist Asst Prof Shao.
She added, "This method requires only a tiny amount of blood sample for the analysis and each test takes less than one hour to complete. So, it is less invasive and yet more informative. In this way, doctors could monitor a patient's response to treatment more regularly during the course of the treatment, and make timely adjustments to customize the treatment for better outcomes."
The research was first published in the scientific journal Nature Nanotechnology.
To achieve sensitive and rapid analysis of drug efficacy through blood samples, the NUS research team developed the ExoSCOPE as an integrated nanotechnology platform. It measures EVs, which are membrane vesicles of dimension at least a hundred times smaller than the diameter of human hair and invisible under conventional light microscopy. During successful cancer treatment, when a targeted cancer drug attaches to a cancer cell and interfere with tumor growth, the treated cell will release into the bloodstream EVs containing the drug.
The ExoSCOPE platform harnesses a complementary approach of chemical biology and sensor development to measure these delicate drug changes in EVs.
In a clinical trial involving 163 blood samples from 106 patients, the ExoSCOPE has shown encouraging results on lung cancer patients to enable timely evaluation of patients' targeted treatment outcomes. Compared against the gold standard of tumor volumetric imaging, which was performed at the end of the entire treatment regimen, the ExoSCOPE achieved an accuracy rate of 95 percent, but within 24 hours of treatment initiation.