Fig 1: Myeloma cell integrin a6 regulates osteoblast differentiation via the ITGA6-LAMA4-EGFR complex. (A–C) Co-immunoprecipitation of ITGA6 (A), LAMA4 (B) or EGFR (C) in myeloma cells ARP-1 or RPMI8226 cocultured with MSCs. (D) Myeloma cells were transfected with His-tagged integrin a6 and MSCs were transfected with GFP-tagged EGFR. Coimmunoprecipitation of His (left panel) or GFP (right panel) in myeloma cells and MSCs coculture system. (E) Shown is the summarized data of Alizarin red S staining of MSCs, which were pre-treated with IgG control or 2 µg/ml of anti-EGFR neutralize antibody and then co-cultured with or without ARP-1 or RPMI8226 cells for 14 days. (F) Shown is numbers of multinuclear (=3) TRAP+ cells in preOCs that were pre-treated with IgG control or 2 µg/ml of anti-EGFR neutralize antibody and then co-cultured with or without ARP-1 or RPMI8226 cells for 7 days. Data shown as averages ± SD is a representative of three independent experiments. **P < 0.01. ***P < 0.001. ****P < 0.0001. P values were determined using one-way ANOVA. (G) Depiction of integrin a6-mediated signaling pathways in myeloma cells and MSCs.