Extended Data Fig. 4: Intracellular and extracellular cGAMP from cancer cell lines.
a, cGAS expression of 4T1-luc WT and 4T1-luc shcGAS analyzed by western blot (full scan of blot available in Source Data). Intracellular cGAMP (chromatograms and quantification displayed) in 4T1-luc WT and shcGAS cells without exogenous stimulation. Concentration reported in units of molecules/cell and nM (estimated using cell volume = 4 pL). IS = internal standard. Data are from 1 experiment; 2 cell culture replicates are plotted. b, Extracellular cGAMP produced by MC38 cells over 48 hours. At time 0, cells were refreshed with media supplemented with 50 μM STF-1084. Line depicts linear regression. Data are from one experiment representative of two independent validations; 2 cell culture replicates are plotted with a bar representing the mean. c, Chromatograms for E0771, Panc02, and NMuMG cell lysate from LC-MS/MS. E0771 cell lysate was spiked with 40 nM cGAMP to determine limit of quantification. IS = internal standard. Data are representative of 2 independent validations. d, cGAS and STING expression of 4T1-luc, MC38, E0771, Panc02, and Neuro-2a cell lines analyzed by western blot (full scan of blot available in Source Data). Data are representative of 3 independent validations. e, Cell viability of cancer cell lines 4T1-luc and E0771 measured by lactate dehydrogenase extracellular activity compared to intracellular activity. At time 0, cells were left untreated or treated with IR (8 Gy or 20 Gy) and refreshed with media supplemented with 50 μM STF-1084. Data are from 1 experiment representative of two independent validations; 2 cell culture replicates are plotted with a bar representing the mean.
