Deformability of Tumor Cells versus Blood Cells

TLDR

Circulating tumor cells are rare, yet their isolation is crucial for understanding metastasis, and recent advances in single‑cell deformability measurements suggest that physical differences between tumor and blood cells could aid in their detection. The study aims to evaluate whether tumor cells differ in deformability from blood cells by measuring the time they take to traverse a microfluidic constriction. The authors performed microfluidic constriction experiments, recording passage times to quantify deformability differences between tumor and blood cells. Tumor cells that have undergone phenotypic shifts show only modest deformability changes compared to other tumor lines; in a mouse model circulating tumor cells are not more deformable than injected cells, and in metastatic prostate cancer patients some CTCs appear mechanically similar to blood cells rather than typical tumor lines.

Abstract

Abstract The potential for circulating tumor cells (CTCs) to elucidate the process of cancer metastasis and inform clinical decision-making has made their isolation of great importance. However, CTCs are rare in the blood and universal properties with which to identify them remain elusive. As technological advancements have made single-cell deformability measurements increasingly routine, the assessment of physical distinctions between tumor cells and blood cells may provide insight into the feasibility of deformability-based methods for identifying CTCs in patient blood. To this end, we present an initial study assessing deformability differences between tumor cells and blood cells, indicated by the length of time required for them to pass through a microfluidic constriction. Here, we demonstrate that deformability changes in tumor cells that have undergone phenotypic shifts are small compared to differences between tumor cell lines and blood cells. Additionally, in a syngeneic mouse tumor model, cells that are able to exit a tumor and enter circulation are not required to be more deformable than the cells that were first injected into the mouse. However, a limited study of metastatic prostate cancer patients provides evidence that some CTCs may be more mechanically similar to blood cells than to typical tumor cell lines.