Fig. 6. Effect of CXCR1 knockdown on OS cell survival in vivo and immunohistochemistry of CXCR1 and p-Akt.

a Survival of Saos2-lung-M cells in vivo at 0, 4, and 8 h after CXCR1 knockdown. b Quantification of luciferase intensity. c Tissue sections were prepared from OS pulmonary metastases from nude mice at week 4. Hematoxylin and eosin staining of tumors, and immunohistochemical staining for CXCR1 and p-Akt expression. d Quantification of positive staining. Results are expressed as the mean density of positive staining. e Schematic of the proposed mechanisms of enhanced OS resistance to anoikis via IL-8/CXCR1/Akt signaling. According to the results of this study, MSC-secreted IL-8 and autocrine IL-8 of OS itself upregulate p-Akt expression through CXCR1 activation, resulting in enhanced OS cell resistance to anoikis and the promotion of lung metastasis. Data are presented as mean ± standard deviation *p < 0.05 and ***p < 0.001. Each group contained 10 animals