Measuring Biomechanical Properties of Cancer Cells Using a High-Throughput Microfluidic Platform and Their Correlation with Surface Rheology and Internal Elasticity
Biomarkers are intended to provide critical information to characterize the type/severity of the cancer, with the ultimate goal of providing information about treatment. However, their use in diagnostic applications is limited because they require the expensive and time consuming use of molecular probes. By using a technique that is label free and requires a simple and inexpensive microfluidic chip, we can capitalize on acute phenotypic differences that result from overexpression of glycoproteins that change the surface rheology of cells. Previous studies have shown that metastatic tumors overexpress bulky glycoproteins such as MUC1 which contributes to cancerous cell growth, adhesion, and survival. In our study, we quantified MUC1 expression in various cancer cell lines using flow cytometry and correlated this expression with the ability of cells to deform under shear forces during deformability cytometry experiments. Comparing the deformability data of cells from the same cell lines but with different levels of MUC1 expression provided compelling evidence that surface rheology effects can be captured using this technique. It has also been shown that the nucleus plays an important role in determining cell deformability vis-a-vis internal elasticity. Therefore, we also measured the nucleus size of these cell lines with fluorescence microscopy and compared the area of the nucleus to the area of the cytoplasm. Comparing the ratio of these two measurements in each cell line with the deformability values confirmed that nucleus size is indeed the key factor determining cell elasticity and must be accounted for when considering deformability and MUC1 expression.