Fig. 4.

CX3CL1 expression in tumour cells is associated with p16/p21-dependent tumour progression. a Amount of soluble CX3CL1 in the indicated conditioned medium, as measured by enzyme-linked immunosorbent assay. Data were normalised to cell number. SCT cells were retrovirally transduced to express shRNA targeting Cx3cl1 or a scrambled control shRNA. LLC-CX3CL1 indicates Cx3cl1-transduced LLC cells. b The growth curve of CX3CL1-overexpressing LLC cells in WT and p16/p21-DKO mice. c, d Tumour size in WT (c) and SCID-beige (d) mice injected with SCT-shScramble, SCT-shCx3cl1#1 and SCT-shCx3cl1#4. e, f Representative flow cytometry plots of CD45⁺CD11b⁺-gated (e) and CD45⁺-gated (f) cells in tumours from WT mice 2 weeks after inoculation with Cx3cl1-knockdown or control SCT cells. Cells were labelled with CD45, CD11b, Ly6C and Ly6G (e) and CD45 and CD8 (f) antibodies. Graphs indicate CD11b⁺Ly6C^highLy6G⁻ (Mo-MDSC) (e) and CD3⁺CD8⁺ (CD8⁺ T cell) populations (f) among CD45⁺ cells. g SCT growth curve in WT mice intraperitoneally injected every other day with anti-CX3CL1 antibody (4 µg per mouse) or isotype control rat IgG (4 µg per mouse) from day 10 to 23; data are presented as the mean ± SEM. The statistical significance was determined by Student’s t-test; **p < 0.01 and ***p < 0.001; NS not significant