Fig. 5: Thiostrepton induces macrophages into proinflammatory state and enhances antitumor activity in vitro.

a Volcano plot showing changes in transcription in hMDMs induced by thiostrepton (n = 2). hMDMs were treated with 2.5 μM thiostrepton for 24 h followed by RNA-seq. DEGs (orange) were identified by edgeR⁵⁶ at P < 0.05 with at least two fold-change. Data for genes that were not classified as differentially expressed are plotted in black. Filled dots show upregulated (red) and downregulated (blue) genes. b GO enrichment analysis of DEGs induced by thiostrepton. c GSEA of transcriptional response to thiostrepton. d Thiostrepton inhibits the development and function of TAMs in vitro. Mouse BMMs were cultured in normal medium with or without 2.5 μM thiostrepton for 24 h (group 1), or cultured in B16F10 tumor cell conditioned medium (CM) with or without 2.5 μM thiostrepton for 24 h (group 2), or cultured with B16F10 tumor cell CM for 24 h first and then treated with 2.5 μM thiostrepton for another 24 h (group 3). The transcript levels of the indicated genes were quantified by qPCR. Data are presented as mean ± sd from four independent samples per group in two independent experiments. *P < 0.05, **P < 0.01 and ***P < 0.001 by two-sided T-test between untreated and treated groups are indicated. e Thiostrepton enhances antitumor activities of macrophages. Mouse BMMs were cultured with or without thiostrepton for 24 h, and then cocultured with equal number of B16F10 melanoma cells for 12 h. The number of tumor cells was quantified by flow cytometry after subtracting macrophages from total number of cells. Data are presented as mean ± sd from three independent experiments. P values by two-sided T-test are indicated.