Research Paper Volume 13, Issue 4 pp 4999—5019

Figure 6. HOXB9 mediates degradation of endothelial junctional proteins by upregulating MMP9. (A) Experimental design of the HUVEC/NSCLC co-culture system. (B) Western blotting analysis and gray level analysis showing restored expression of junctional proteins (ZO-1, claudin-5 and VE-cadherin) in HUVECs co-cultured with BrM3 cells in which HOXB9 or MMP9 were silenced. (C) Analysis of MMP9 and HOXB9 co-expression in primary NSCLC and matched brain metastases from the GSE74706 dataset (p = 0.024, r = 0.598). (D) Western blotting analysis and gray level analysis of MMP9 and HOXB9 expression in parental NSCLC cell lines and corresponding BrM3 cells. (E, F) Western blot analysis, gray level analysis and qPCR assays of MMP9 expression in H1915 cells transfected with MMP9-siRNA or control siRNA. (G) Western blotting analysis and gray level analysis of MMP9 and HOXB9 expression in H1915 cells in which HOXB9 or MMP9 were silenced. *p < 0.05, **p < 0.01, ***p < 0.001.