Figure 1.

OSM-induced invasive potential of mouse mammary tumor cells in vitro. (A) Secreted OSM levels (ELISA) from equal numbers of cells (1 × 10⁵) and (B) semiquantitative expression of OSMRβ (RT-PCR, normalized to GAPDH expression) were compared between 66c14 and 4T1.2 mouse mammary tumor cells. (C) Bone metastatic mammary tumor 4T1.2 cells were treated with 25 ng/mL OSM and show a decreased adherent cell number over time (left) and increased cell detachment (right) when monitored for up to 10 days in culture. (D) The percentage of 4T1.2 cells that migrated through Matrigel-coated transwell plates increased with 24-hour OSM treatment. Single chambers from 3 independent experiments were analyzed; data are expressed as mean ± SEM. *P < 0.05 (t test).