Figure 7

Increased migration and differentiation. (A through G) Increased differentiation of mast cells (MCs) from bone marrow (BM)-derived hematopoeitic precursors in arthritic versus nonarthritic mice with breast cancer (BC). Significant increase in MC count in (A) ± tumor-bearing SKG (*P < 0.05; **P < 001) and (C) arthritic C57BL/6 and PyV MT (*P < 0.05; **P < 001) mice (10 mice). (B, D) Representative images of MCs at 400× magnification. (E, F) Flow-cytometric analysis of percentage of cells expressing cKit receptor (CD117) on MCs. (G) Representative image of toluidine staining for MCs (1,000× magnification). (H, I) Increased migration of tumor cells toward MCs derived from arthritic tumor-bearing mice. Significant increase in migration of 4T1 and PyV MT cells toward the MCs from tumor-bearing arthritic mice (BMMCs) (**P < 001 and *P < 0.05). (H, I) Treatment of tumor cells with anti-SCF antibody or MCs with anti-c-Kit antibody decreased the migration of tumor cells toward mast cells. Pretreatment of 4T1 and PyV MT cells with anti-SCF antibody or adding anti-c-Kit antibody to the MCs in the lower chamber significantly decreased the migration of the tumor cells toward the MCs (*P < 0.05; **P < 0.01; ***P < 0.001).