Fig. 5.

Neutrophil depletion is permissive for bone metastatic but not non-metastatic prostate cancer growth in bone but lose cytotoxicity with tumor progression. a Top, PAIII cells were injected intratibially into SCID Beige mice (n = 5/group) and treated with anti-Ly6G (1A8) or isotype control antibody. Bioluminescence is shown in representative images (left). Graph represents change in bioluminescence/growth rate from day of neutrophil depletion start at Day 3 (right). Arrow in graph denotes start of neutrophil depletion. Bottom, bioluminescence of luciferase-expressing LNCaP cells. LNCaP-luc were injected intratibially into SCID Beige mice (n = 5/group) and neutrophil depletion started 3 days post-tumor inoculation. Arrow indicates start of treatment. b C42B cells (or saline as a control) were injected intratibially into male SCID Beige mice and mice euthanized at Weeks 1, 2 and 4 post-injection for isolation of bone neutrophils. Control neutrophils (from saline-injected tibia; denoted as NØs) and tumor-associated neutrophils (TANs) were cultured ex vivo with LNCaP and C42B cell lines for 24 h and counted via Trypan Blue Exclusion assay. Graphs show percent change in cell number after 24 h of culture with neutrophils. Asterisks denote statistical significance (*p < 0.05, **p < 0.01, ***p < 0.001)