MMP-1 and MMP-13 knockdown reduces invasive features in MCF-7 cells with Pit-1 overexpression, and in MDA-MB-231 cells. (A-B) Wound-healing assay in (A) MCF-7 cells with Pit-1 overexpression (pRSV-hPit-1), and knockdown of MMP-1 (shMMP-1(1) and shMMP-1(2)) and MMP-13 (shMMP-13(1) and shMMP-13(2)); (B) MDA-MB-231 cells with knockdown of Pit-1 (siPit-1), MMP-1 (shMMP-1(1) and shMMP-1(2)), and MMP-13 (shMMP-13(1) and shMMP-13(2)). Distance between the wound edges was measured at 48 hours in three different assays, and data are represented as mean ± SD; ns = not significant. (C-D) Cell motility through uncoated filters (migration) at 24 hours in control MCF-7 cells (pRcRSV), Pit-1-overexpressing MCF-7 cells (pRSV-hPit-1), and Pit-1-overexpressing and knockdown of MMP-1 or MMP-13 MCF-7 cells (pRSV-hPit-1 + shMMP-1 or −13). (E-F) Cell motility through matrigel-coated filters at 48 hours in control cells, cells transfected with the pRSV-hPit-1 vector, and cells transfected with pRSV-hPit-1 and knockdown of MMP-1 (Pit-1 + shMMP-1) or MMP-13 (Pit-1 + shMMP-13). Numbers represent mean ± SD. Scale bar: 100 μm. MMP-1, matrix metalloproteinase-1; MMP-13, matrix metalloproteinase-13; Pit-1, POU class 1 homeobox 1.