Matrigel Invasion Assay for MMP Activity

Twenty four-well Matrigel invasion chambers were incubated with DQ-collagen IV (Invitrogen, Life Technologies) diluted in serum-free DMEM at a final concentration of 20 ng/ml at 37 °C in dark overnight. The chambers were briefly rinsed with serum-free DMEM. 1 × 10⁴cells were seeded into each invasion chamber in the presence or absence of pcDNA-ERβ and siRNA-ERβ. Cells were then incubated in a CO2 incubator at 37 °C for 4 h. Proteolytic degradation of DQ-collagen IV in the BM was imaged with fluorescence microscopy. When DQ-collagen IV was de-gradated by the MMPs secrete by cells, the clipped DQ-collagen may show fluorescence. A brighter fluorescence present the higher invasion ability. A study by Chen H et al. also described the protocol [27 (link)].