Fig. 3

IGF-1 secreted by osteoclasts promotes the proliferation of IGF-1R-expressing nasopharyngeal carcinoma cells. a GSEA of the “Bone mineralization” and “Bone morphogenesis” gene modules in NPC patients of GSE180272 with metastasis or non-metastasis. b Representative TRAP staining of osteoclasts along the tumor-bone interface of bone metastases. c CCK8 assay of cell lines with/without treatment of CM from murine bone marrow–derived osteoclasts (OC) for 48 h, with/without IGF-1 neutralizing antibody (1 μg/mL) or rIGF-1(100 ng/mL). d Secretion level of IGF-1 and IGF-2 in osteoclasts and tumor cells. e IGF-1R and IGF-1 immunostaining of bone metastases from NPC patients. f IGF-1 secretion of osteoclasts after treatment with control normal medium or CM from 5-8F or BM3 with or without CSF2 knockdown. g GM-CSF secretion in 5-8F and BM3 cells with/without CSF2 knockdown. h Osteoclastogenesis assays from murine bone marrow when the bone marrow was treated with CM from 5-8F or BM3 with or without CSF2 knockdown. (“ns” indicates P > 0.05, “*” represents P < 0.05, “**” represents P < 0.01,“***” represents P < 0.001 and “****” represents P < 0.0001, Scar bar = 50 μm.)