FIGURE 4.
shRNA‐mediated ICAM1 gene silencing inhibited bone metastasis in mice. A, shICAM1 inhibited ICAM1 gene expression in BM cells. B, Effects of shICAM1 on the proliferation of BM cells. Representative images and quantification of migration (C) and invasion (D) in shICAM1 cells and the parental BM TNBC cell line (N = 3). E, shICAM1 inhibited bone metastasis in mice. Except for the cell density of 0.5 × 106 cells/mouse for BM and shICAM1 BM cells, the rest of the procedure was conducted as described in Figure 3J (N = 3). shICAM1 decreased bone metastasis, as detected by X‐ray (F) and PET‐CT (G) imaging, in tumor‐bearing mice 4 weeks after tumor cell injection. The X‐ray images were finally processed with a color inversion algorithm. H, shICAM1 reduced tumor cell growth in bone metastases in tumor‐bearing mice (N = 3). I, IHC analysis of ICAM1 expression in bone metastases formed from BM and shICAM1 BM cells. *p < 0.05, **p < 0.01 vs. the shCtrl group. ICAM1, intercellular adhesion molecule 1; IHC, immunohistochemical; TNBC, triple‐negative breast cancer