Fig. 6

Ovatodiolide treatment suppresses the M2 TAM polarization. a Macrophage progenitor cells, THP-1 cells, were cultured under M2 macrophage conditional medium with and without the treatment of ovatodiolide (OV, 14 μM, 48 h). Real-time PCR analysis demonstrated that the addition of OV significantly decreased the M2 markers including ARG1 and CD23 while not affecting M1 polarization in the differentiated macrophages. b Western blot analysis of OV-treated macrophages demonstrated decreased YAP1, NF-kB, phosphorylated-Akt/Akt, and IL-6. THP-1 served as a control for M2 TAMs. The minus sign indicates M2 TAMs without OV treatment while the plus sign indicates M2 TAMs treated with OV (14 μM, 48 h). c IL-6 addition simulates the presence of M2 TAMs promoted colon tumorigenic profiles including enhanced Kras, b-catenin, YAP1, NF-kB, and Atk/mTOR signaling; the addition of OV significantly reversed IL-6 induced tumorigenic profiling. d The addition of IL-6 markedly enhanced the formation of colon spheres in both cell lines, and the OV treatment suppressed it. e OV treatment markedly reduced IL-6-induced CD133+ cell population in both HCT116 and DLD-1 cell lines. f The combination index (CI) analysis showed that 5-FU and OV synergistically inhibited both DLD-1 and HCT116 cell viability. Synergism (CI < 1, shown in bold font), additive effect (CI = 1), and antagonism (CI > 1). All experiments were performed in triplicates