A Novel Strategy for Inducing the Antitumor Effects of Triterpenoid Compounds: Blocking the Protumoral Functions of Tumor-Associated Macrophages via STAT3 Inhibition
Figure 1
Effects of natural compounds on macrophage activation. A schematic drawing of the compound screening process (a). HMDMs (5 104 cells per well in a 96-well plate) were incubated with natural compounds (30 μM) for 24 hours after treatment with IL-10 (20 nM) for two days, after which the CD163 expression was determined using Cell-ELISA (b). HMDMs (5 × 104 cells per well in a 96-well plate) were stimulated with LPS (100 ng/mL) for 24 hours after incubation with 30 μM of corosolic acid (CA) and 30 μM of oleanolic acid (OA) for 24 hours in the presence of TCS, after which the level of IL-10 secretion was determined using ELISA (c). HMDMs (5 × 104 cells per well in a 96-well plate) were incubated with the indicated concentrations of corosolic acid (CA) and oleanolic acid (OA) for 24 hours, after which the cell viability was determined using a WST-8 assay (d). Chemical structures of corosolic acid (CA) and oleanolic acid (OA) (e). HMDMs (5 × 104 cells per well in a 96-well plate) were incubated with 30 μM of corosolic acid (CA) and 30 μM of oleanolic acid (OA) for 24 hours after treatment with U373 glioblastoma-derived tumor cell supernatant (TCS) for two days, after which the CD163 expression was determined using Cell-ELISA (f). HMDMs (5 × 104 cells per well in a 96-well plate) were stimulated with LPS (100 ng/mL) for 24 hours after incubation with 30 μM of corosolic acid (CA) and 30 μM of oleanolic acid (OA) for 24 hours in the presence of TCS, after which the level of IL-12 secretion was determined using ELISA (g). HMDMs were incubated with 30 μM of corosolic acid (CA) or oleanolic acid (OA) for three hours after treatment with IL-10 (20 nM) or TCS for 24 hours, after which the levels of phosphorylated STAT3, STAT3, and -actin were determined using a Western blot analysis (h). The data are presented as the mean ± SD. *, ** versus control.
