Differential Regulation of Methylation-Regulating Enzymes by Senescent Stromal Cells Drives Colorectal Cancer Cell Response to DNA-Demethylating Epi-Drugs

Figure 1

Effect of fibroblasts and their conditioned medium on HCT116 DNA demethylation in 2D cultures. (a) Representative images showing RFP nuclear fluorescence but no EGFP fluorescence in the untreated control, and changes in EGFP fluorescence following DAC treatment in HCT116 monocultures or cocultures with BJ. 20x objective; scale bar: 100 μm. Graphs showing a significant increase in EGFP intensity in HCT116 cocultured with normal nonirradiated (non-IR) BJ and 1-week-irradiated (1-wk-IR) sBJ fibroblasts in comparison to HCT116 monocultures following treatment with different concentrations of DAC and AZA. Data are mean ± SEM, , , compared to HCT116 monocultures. (b) A significant increase in EGFP intensity of HCT116 cells cocultured with 3-week-irradiated (3-wk-IR) sBJ or sMRC-5 cells following treatment with 1 μM DAC. (c) Schematic diagram of the setup of conditioned medium culture and graph showing no effect of sBJ or sMRC-5 conditioned medium on EGFP intensity following treatment of HCT116 monocultures with 1 μM DAC. Data are mean ± SEM, n = 2–4.

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