Figure 1.

IKKβ inhibition increases macrophage tumoricidal activity. (A) WT, MyD88^−/−, TLR-2^−/−, and TLR-4^−/− or mock, IKKβ^DN or IKKβ^f/f, and IKKβ^Δ BMDMs were co-cultured with ID8-Luc in a modified Boyden chamber without direct cell–cell contact for 72 h. In addition, CD11b⁺-selected TAMs from the ascites of ID8 tumor–bearing mice were mock (TAM_mock) or IKKβ^DN infected (TAM_DN). Invasion of ID8-Luc cells was assessed by luciferase activity in the lower part of the chamber. Macrophages deleted in MyD88, IL-1R, or IKKβ significantly reduce ID8-Luc invasion (P < 0.01; t test with Welch's correction). Data are represented as mean ± SEM of n = 6. Representative data are shown from at least three independent experiments. (B) ID8 cells were co-cultured with IKKβ-targeted BMDMs or TAMs and respective control cells. Fluorescence caspase 3/7 activity was assessed after 0, 3, and 6 h. Co-culture with IKKβ^DN and IKKβ^Δ BMDMs or TAMs expressing IKKβ^DN (TAM_DN) significantly increases caspase 3/7 activity in ID8 cells (P < 0.01; t test with Welch's correction). Data are represented as mean ± SD of n = 6. Representative data are shown from at least three independent experiments. (C) [¹¹¹In]oxine release assay after a 24-h co-culture of ¹¹¹In-labeled ID8 cells with mock, IKKβ^DN, TAM_DN or IKKβ^f/f, and IKKβ^Δ macrophages. ¹¹¹In-release in cell-free culture supernatants was measured after 24 h with a scintillation counter. IKKβ-targeted macrophages promote increased cytotoxicity. Data are represented as mean of n = 3. Representative data are shown from at least three independent experiments.