MM progression is attenuated by STING inhibition. (A) 5TGM1 cells (1 × 10⁶) transduced with rLV.EF1.mCherry-Mito9 lentivirus (5TGM1^LUCI+) were injected into KaLwRij mice. (B) In vivo imaging of mice engrafted with 5TGM1^{(GFP+ LUCI+)} on days 19 and 27, representing before and after H-151 (750 nM) treatment, respectively. (C) Bioluminescence, before and after treatment, was quantified using ImageJ (n = 6 in each group). Data indicate mean ± SD. Statistics presented as Wilcoxon test. (D) Mice were euthanized at 27 days. (E) BM was harvested for flow cytometry 5TGM1 engraftment and FACS-purified for BM macrophages. RNA was extracted for analysis by qRT-PCR of GBP2, IFIT3, and IRF7. (F) BM cells were analyzed for GR1, F4/80, CD115, LY6G, CD11b, CD86, and CD206 expression and used to identify resident BM macrophages (BM MΦ) (GR1⁻, CD115^lo/int, and F4/80⁺) and MM-infiltrating macrophages (IF MΦ) (Ly6G⁻ and CD11b⁺). The gating strategy is shown. (G) Cell counts of BM MΦ and IF MΦ from treated mice. Data indicate mean ± SD. Statistics presented as Kruskal-Wallis test with Dunn post hoc multiple comparisons test. ∗P < .05; ∗∗P < .01.