Figure 3

Prostate cancer cells induce sprouting of sensory nerve fibers in the bone marrow of tumor bearing femurs. High power µCT slices of bone (100 µm-thick) overlaid with confocal images (20 µm-thick) obtained from a sham femur (A) and tumor-bearing femur from mice sacrificed at early (B) and more advanced stages of the disease (C). In these images the DAPI stained nucleus of cells appear blue, the green fluorescent protein expressing (GFP) prostate cancer cells appear green, and the calcitonin gene related peptide (CGRP) sensory nerve fibers appear yellow/red. Note that in the sham mice, CGRP⁺ nerve fibers that are present in the marrow space of normal mice appear as single, nerve fibers with a highly linear morphology. As GFP⁺ prostate tumor cells proliferate and form tumor colonies (B,C), the CGRP⁺ sensory nerve fibers undergo marked sprouting which produces highly branched, disorganized and dense meshwork of sensory nerve fibers (B,C) that is never observed in the normal marrow (A).