The cells in our bodies contain a scaffolding material called cytoskeleton, which determines the cell's mechanical properties. This includes its ability to deform under stress, and in response to processes like cell-division. If the cytoskeleton is damaged, cell-division is affected, too.
It has been known since 1998 that some diseases like cancer are capable of causing such damage to the cytoskeleton, rendering cells softer and smoother. Thus, testing for susceptibility to deformation in cells could be a technique to screen for cancer.
Now, researchers from the University of California, Los Angeles (UCLA) have devised an instrument called a deformability cytometer (DC) to accomplish this. This instrument comprises a network of channels each about half the width of a human hair. A solution containing cells to be tested was pumped through them, from opposing sides toward a four-way intersection. At the intersection, cells from each channel bounced off the opposing stream and then exited.
According to the researchers’ paper, which appeared in Science Translational Medicine on November 20, the inertial forces during deflection deform the cells. This is captured by a high-speed camera at 1,000 cells per second. The images are then studied for the extent of deformation: more it is during impact, less rigid the cells are, pointing to damaged cytoskeletons.
With 119 samples, DC was able to accurately classify 63 per cent of the samples as positive or negative results. Moreover, 16 samples among the 119 were chosen because they couldn’t be properly diagnosed; the DC was able to provide conclusive diagnoses for 8 of them. Finally, 10 out of 17 samples that tested negative for cancer by classical techniques were corrected to be positive.
As Dr. Dino di Carlo, an associate professor in the Department of Bioengineering, UCLA, who was involved in the study, wrote in an email, “We are now extending the measurements with the system by capturing up to 500,000 frames per second.”
When the DC was first built in 2012 at UCLA, it was used to study the mechanical properties of different cells and how they changed when swollen, which could happen in patients with AIDS or whose bodies were rejecting transplanted organs.
The researchers note that the technique is well-suited to studying malignant pleural effusions (MPE), a fluid that accumulates around lungs in cancer patients and contains immune cells, cells from the chest wall lining, and low concentrations of cancer cells.
Dr. di Carlo said they would have to conduct larger tests with more varied samples before this instrument entered hospitals. As Jochen Guck, from the Cavendish Laboratory, University of Cambridge, noted in an article in the same journal, “The authors did not test any MPE samples from patients with non-small cell lung cancer” — one of the most common causes of MPE.
