FIGURE 3.

Bone metastatic MDA‐MB‐231BM (BM) cells with high bone metastases have higher levels of ICAM1. A, ICAM1 mRNA expression in the TCGA BRCA cohort was analyzed using UALCAN (http://ualcan.path.uab.edu/index.html; N = 833). B, ICAM1 protein expression in the Clinical Proteomic Tumor Analysis Consortium (CPTAC) BRCA cohort was analyzed using UALCAN (N = 108). C, mRNA expression levels of ICAM1 in GSE25055. D, Differences in the overall survival (OS) of patients with breast cancer in the high and low ICAM1 expression groups in the GSE25055 cohort (N = 310). E, Process for establishing the MDA‐MB‐231BM (BM) TNBC cell line with high bone metastatic activity. F, Protein and mRNA expression levels of ICAM1 in BM cells and the parental cells (N = 3). G, Comparison of cell proliferation between two TNBC cell lines. Representative images and quantitative analysis of migration (H) and invasion (I) in BM TNBC cells and its parental cells (N = 3). J, ICAM1 promoted bone metastasis detected by bioluminescence imaging (BLI) in TNBC cell–bearing mice. Cell suspensions (1 × 10⁷ cells/ml) were prepared, and 1 × 10⁶ cells (0.1 ml/mouse) were injected into the left ventricles of mice. In vivo BLI was used to monitor tumor cell proliferation in mice 2 h after injection and weekly thereafter. The signal intensity was normalized to the signal at 2 h post injection. The MDA‐MB‐231 parental cell group and the BM cell group contained eight and seven mice, respectively. ICAM1 promoted bone metastasis, as detected by X‐ray (K) and PET‐CT (L) imaging, in tumor‐bearing mice 4 weeks after tumor cell injection. M, ICAM1 reduced the survival of tumor‐bearing mice. N, ICAM1 increased tumor cell growth in bone metastases in tumor‐bearing mice (N = 3). O, ICAM1 promoted bone destruction (TRAP⁺ cells) in tumor‐bearing mice (N = 3). P, Immunohistochemical (IHC) analysis of ICAM1 in bone metastases formed from two different bone metastatic cell lines. *p < 0.05, **p < 0.01 vs. the Par or nTNBC group. ICAM1, intercellular adhesion molecule 1; TNBC, triple‐negative breast cancer