<b>Results:</b> While the population of LY6C<sup>hi</sup> monocytes was increased in non-treated tumor-bearing mice, the treatment with ATL-1 diminished the population of LY6C<sup>hi</sup> monocytes in spleen, blood and bone marrow, decreasing macrophage infiltration into the tumor and reducing the M2 markers expression on TAMs.
Treatment effects were determined by assessment of tumor growth, proliferation (Ki67-staining), angiogenesis (CD31-staining), metastasis (immunostaining), EMT markers (western blot), stromal components collagen type I, Itgb1 and FSP1 (immunostaining) and chemotherapeutic efficacy (5FU).
In consistent with the results in vitro, ATL-1 inhibited tumor growth, protein expressions of Stat3, SP1 and PDK1, and induced phosphorylation of ERK1/2 in vivo.
Analysis of human neuroblastoma tumors also confirmed the presence of αFAP- and FSP-1-positive cells in the tumor stroma, and their presence correlated with that of M2 tumor-associated macrophages.