Effect of TWSG1 and BMP7 on Mammary Cell Migration

Objectives:   Twisted gastrulation (TWSG1) is an extracellular bone morphogenetic protein (BMP) modulator. Twsg1 knockout mice exhibit craniofacial defects, and females experience a delay in ductal elongation within the mammary gland. Twsg1 is detected in normal mouse mammary glands as well as invasive human breast cancer. However, its role in mammary epithelial cells remains unknown. As a first step, we set out to examine how TWSG1 modulates the migratory behavior of mammary epithelial cells.

Methods:   Mouse (HC11) and human (MCF10A) normal mammary epithelial cells were treated with recombinant BMP7 and TWSG1 proteins for 18 hours, and the migratory behavior was evaluated using a scratch assay. The effect of each treatment on the expression of BMP target genes Msx1 and Msx2 was determined using Q-PCR.

Results:   In both human and mouse mammary cells, BMP7 increased migration and Msx1 and Msx2 expression. The migration was dose-dependent, with the most migration occurring at 50 ng/mL. In contrast, TWSG1 decreased migration and Msx1 and Msx2 expression, with an optimal dose of 500 ng/mL.

Conclusions:   BMP7 promotes normal mammary epithelial cell migration and Msx1 and Msx2 expression, while TWSG1 inhibits normal mammary epithelial cell migration and Msx1 and Msx2 expression in vitro. These results show that TWSG1 has an effect on mammary epithelial cells, and further experiments on human breast cancer cell lines should deepen our understanding of this effect.