Sorting and characterization of cancer cells with different migration phenotypes using a microfluidic platform

Cancer metastasis is the primary cause of poor prognosis and high mortality in patients, and the chemotactic migration of cancer cells is closely related to the metastasis process. Isolating cancer cells with different migration phenotypes is crucial for understanding the mechanisms of cancer cell migration and cancer metastasis. However, current methods for sorting cancer cells based on migration phenotypes often suffer from low efficiency, long operation times, and complex procedures. Additionally, cell migration and sorting experiments often rely on live cell imaging systems, which are generally costly and lack portability. In this study, we developed an automated microfluidic platform for sorting cancer cells based on their migration phenotypes. The platform was validated using two breast cancer cell lines, MDA-MB-231 and MCF-7, with the sorting process completed within 6.5 hours. The sorted cells with high and low migration phenotypes could be further cultured and had similar proliferative capacities. Through SMART-seq2 analysis, we identified several significantly differentially expressed genes closely related to cell migration and tumor metastasis across different migration phenotypes. Functional validation experiments revealed that the knockdown of the GADD45B gene in MDA-MB-231 cells reduced the migration rate of high-chemotactic cells. Enrichment analyses revealed that the differentially expressed genes were associated with multiple migration-related pathways, including the mitogen-activated protein kinases (MAPK) signaling pathway. Protein expression assays indicated an upregulation of phosphorylated p38 in high-chemotactic cells. In conclusion, this sorting platform provides an efficient and robust solution for investigating the migration heterogeneity of cancer cells.