Fig. 5
Treatment with ATRA retards tumor growth, prolongs survival, decreases tumor metastasis, and reduces M2 macrophage infiltration in LL2 tumor-bearing mice. a and b Tumor volume (a) and survival curves (b) of tumor-bearing mice (n = 6 in the solvent group; n = 7 in the ATRA group;). c Gross appearance of lungs (upper left panels), histology of tumor nodules in the lungs (lower left panels) (× 40 magnification, scale bar = 200 μm), and numbers of tumor nodules in individual mice with horizontal lines denoting means ± SEM (n = 5 to 6) (right panel) at day 35 after LL2 tumor cell inoculation. C57BL/6 mice were subcutaneously inoculated with LL2 cells (5 × 105) at day 0 and treated intratumorally with ATRA (10 mg/kg) at days 10, 11, 13, 14, 25, 26, 28, and 29. d-f Immunohistochemical detection of Oct4, M-CSF, and CD206 in tumor tissues of mice after treatment with ATRA or solvent. Immunohistochemical staining of lung tissues (left panels) (× 200 magnification) and quantification of immunoreactive intensities of Oct4 (d), M-CSF (e), and CD206 (f) in AEC-positive areas (right panels) at day 15 after tumor cell inoculation (n = 6 in the solvent group; n = 4 to 5 in the ATRA group). Negative control slides stained with isotype control IgG. C57BL/6 mice were subcutaneously inoculated with LL2 cells (5 × 105) at day 0 and treated intratumorally with ATRA (10 mg/kg) at days 10, 11, 13, 14. Results are representative of two independent experiments. Scale bar, 50 μm