Fig. 7

Reduced metastasis and enhanced anti-tumor immunity by miRNA mimics. a qRT-PCR of miR-130a and −145 in the plasma and Gr-1⁺CD11b⁺ cells (left), as well as TβRII in Gr-1⁺CD11b⁺ cells (right) from 4T1 tumor-bearing mice (n = 6/each time point) at indicated times after systemic delivery of miRNA mimics through TVI. b qRT-PCR of miR-130a (left) or miR-145 (right) in Gr-1⁺CD11b⁺ myeloid cells, CD3⁺ lymphocytes, and CD19⁺ B cells sorted from peripheral blood of mice (n = 3) 24 h after injection of miRNA mimics. c Metastasis nodule counts from mice that received miR control, miR-130a, and miR-145 mimics as a single agent or in combination with Paclitaxel (PAC) (n = 13). d Flow cytometry of IFNγ⁺CD8⁺ cells from spleens of TCR-HA transgenic mice co-cultured (ex vivo) with Gr-1⁺CD11b⁺ cells from 4T1 tumor-bearing mice that were treated with miR-130a or miR-145 mimics. e Upper panels: miRNA in situ hybridization: miR-145 mimic distribution (green) in metastatic lungs of 4T1 tumor-bearing mice 12 h after miR mimic injection, with DAPI (blue), CD11b (red), and E-cadherin (Magenta). Scale bar: 20 μm. Lower panel: the quantitative data of miRNA mean fluorescent intensity in myeloid cells or tumor cells in metastatic lung of mice with miRNA mimic injections (n = 23–30). f Flow cytometry of IFNγ⁺CD8⁺ T cells at metastasized lung from mice treated with miR-130a or miR-145 mimics (n = 3). g CD8 T cell proliferation assay: flow cytometry of CSFE-labeled CD8⁺ T cells from splenocytes of TCR-HA transgenic mice co-cultured with sorted Gr-1⁺CD11b⁺ myeloid cells from the spleen of mice treated with miR-130a or miR-145 mimic injection (left), with quantitative data (right). h CTL assays: flow cytometry of 4T1.2 tumor cells (Sytox blue positive are dead) expressing HA co-cultured with splenocytes from TCR-HA transgenic mice and Gr-1⁺CD11b⁺ cells from the spleen of mice treated with miR-130a or miR-145, quantitative data (right). The percentage of targeted dead tumor cells = total dead cells minus dead cells from single culture of tumor cells, myeloid cells, and splenocytes. i Number of metastasis in 4T1 tumor-bearing mice treated with miR mimics with CD4 or CD8α neutralizing antibody or IgG control. The data are presented as mean ± SEM, and Student’s t test was performed. *p < 0.05, **p < 0.01, ***p < 0.001