Its anti-migratory effects are mediated by angiomotin (Amot), one of angiostatin receptors [ 11].
To verify if the inhibition of the migratory effect was due to the presence of IGFBP7 in CM, we repeated the growth assays using a recombinant IGFBP7 (rIGFBproteintein.
In wound-healing assays, an increased migratory effect was observed in rhBDNF-treated cells compared with untreated cells, and those treated with K252a followed by rhBDNF inhibited the migratory effect in all three cell lines tested.
Such a migratory effect was further impaired by Ribavirin, suggesting that the combination of this drug with TRAP1 blockade may efficiently counteract a fundamental step in the metastatic cascade.
These anti-migratory effects were accompanied by downregulation of MMPs, as reported previously (Baumann et al, 2009).
No additive anti-migratory effect was observed in response to simultaneous inhibition of JAM-A, Rap1 and β1-integrin, suggesting that they lie in a linear migratory pathway.
Given that TGFβ enhanced cyclin D1 and p21 expression and complex formation in these human metastatic breast cancer cells, we investigated whether the TGFβ pro-migratory effect is mediated through cyclin D1.
As the EC50 value of salinomycin in PC-3 cells in response to 48-h exposure was higher than 1 μ, the salinomycin-induced anti-migratory effect is not due to inhibition of cell proliferation.
We have previously shown that TGFβ's pro-migratory and invasive effects are mediated through the induction of p21 in highly migratory triple negative breast cancer cells [ 44].
Previous studies have indicated that during breast cancer progression, TGFβ cytostatic responses are lost while pro-migratory and pro-invasive effects are maintained [ 56].
Thus, our results indicate that, although Cdc42/PAK/LIMK and p38/MK2/Hsp25 pathways are both required for the BMP-2 migratory effects, BMP-2 is able to activate both routes mostly independently since the blockage of one pathway does not alter its ability to stimulate the other one (Fig. 9).
