Abstract Uveal melanoma (UM) originating in the eye and metastasizing to the liver is associated with poor prognosis and has only one approved therapeutic option. We hypothesized that liver-borne growth factors may contribute to UM growth. Therefore, we investigated the role of insulin-like growth factor −1 and its receptor (IGF-1/IGF-1R) signaling in UM. We found that the insulin receptor substrate −1 (IRS-1) is overexpressed in UM cells and tumors. Since we previously observed that IGF-1R antibody therapy was not clinically effective in UM, we investigated the potential of NT157, a small molecule inhibitor of IRS-1/2 in blocking this pathway in UM. NT157 treatment in UM cells resulted in reduced cell survival and migration, and increased apoptosis. This treatment also significantly inhibited UM tumor growth in vivo , in the chicken egg chorioallantoic membrane (CAM) and subcutaneous mouse models, validating the in vitro effect. Mechanistically, through reverse phase protein array (RPPA), we identified significant proteomic changes in the PI3K/AKT pathway, a downstream mediator of IGF-1 signaling, with NT157 treatment. Together, these results suggest that NT157 inhibits cell survival, migration in vitro and tumor growth in vivo via inhibiting IGF-1 signaling in UM.

Targeting IRS-1/2 in uveal melanoma inhibitsin vitrocell growth, survival and migration, andin vivotumor growth