DMXAA Causes Tumor Site-Specific Vascular Disruption in Murine Non-Small Cell Lung Cancer, and like the Endogenous Non-Canonical Cyclic Dinucleotide STING Agonist, 2′3′-cGAMP, Induces M2 Macrophage Repolarization (original) (raw)
Figure 3
Exposure to either DMXAA or 2′3′-cGAMP repolarized M2 macrophages towards an M1 phenotype in vitro.
(A) Triplicate samples of non-polarized macrophages (Mφ), M1-, and M2-polarized macrophages were exposed to 20 µg/ml DMXAA for 24 hours in vitro and RNA transcript levels measured by qRT-PCR. DMXAA down-regulated Arg-1 and Fizz1 expression, while increasing expression of iNOS and IL-12p40. (B) Shows reciprocal changes in Arg-1 and iNOS expression in M2 cells in response to increasing concentrations of DMXAA (N = 3). (C) RNA transcripts were also taken from triplicate samples of M2-polarized macrophages exposed to 20 or 40 µg/ml 2′3′-cGAMP plus LF2000 for 6 and 24 hours in vitro. LF2000 alone served as the control (designated as ‘M2 alone’ in the graphs). 2′3′-cGAMP led to down-regulation of Arg-1 and Fizz1, and dramatic increases in iNOS and IL-12p40 expression in a dose-dependent manner. (D) IFN-β induction provided an indication of STING activation in response to 2′3′-cGAMP, with strong inductions at 6 hours that returned to baseline by 24 hours (*p<0.05, **p<0.01, ***p<0.001).