2.8. Transwell Invasion and Migration Assay

The capacity of MCF‐7 and MDA‐MB‐231 cells to migrate and invade was examined with cell migration and transwell assays transwell chambers (BD Bioscience). MCF‐7 cells and MDA‐MB‐231 cells were cultured in 150 μL of the serum‐free medium then planted into the superior chamber, along with 600 μL DMEM and 10% fetal bovine serum filled into the inferior chamber. The day before invasion test, 20 μL of Matrigel (BD Bioscience) was placed inside the upper chambers. After incubated for 24 h, cells at the interior bottom of the superior lumen were carefully wiped away, cells crossed the bottom membrane were immobilized in 4% paraformaldehyde with 15 min, carried on dyeing with 0.1% crystal violet with another 15 min. At last, we used an electronic microscope for image collection and counting.