Microfluidic Cell Deformability Assay for Rapid and Efficient Kinase Screening with the CRISPR‐Cas9 System

Herein we report a CRISPR‐Cas9‐mediated loss‐of‐function kinase screen for cancer cell deformability and invasive potential in a high‐throughput microfluidic chip. In this microfluidic cell separation platform, flexible cells with high deformability and metastatic propensity flowed out, while stiff cells remained trapped. Through deep sequencing, we found that loss of certain kinases resulted in cells becoming more deformable and invasive. High‐ranking candidates identified included well‐reported tumor suppressor kinases, such as chk2, IKK‐α, p38 MAPKs, and DAPK2. A high‐ranking candidate STK4 was chosen for functional validation and identified to play an important role in the regulation of cell deformability and tumor suppression. Collectively, we have demonstrated that CRISPR‐based on‐chip mechanical screening is a potentially powerful strategy to facilitate systematic genetic analyses.