Journal: International Journal of Molecular Sciences
Article Title: The Blockade of Tumoral IL1β-Mediated Signaling in Normal Colonic Fibroblasts Sensitizes Tumor Cells to Chemotherapy and Prevents Inflammatory CAF Activation
doi: 10.3390/ijms22094960
Figure Lengend Snippet: ( A ) colony forming assay of CCCL in transwell coculture with NCF. ( B ) quantification of colonies: Blocking the IL1β-mediated crosstalk between cocultures of NCF (upper 24 mm transwell chamber) and colorectal cancer cell lines (lower transwell chamber) with a neutralizing IL1β antibody sensitizes cancer cells to L-OHP. ( C ) Such IL1β blocking altered the composition of conditioned media (affecting IL1β targets), as illustrated in the bar graphs, where the neutralizing antibody affected the IL1β itself and IL6, as a surrogate marker of the IL1β response (grey bars), both soluble factors determined by ELISA in a mixture of coculture supernatants before 10% FBS reconstitution (proportional volume of the different CM from NCF with either DLD1, HT29, or HCT116 cells). ( D ) Western blot of HT29 cells cultured with control CM (Ø) or IL1β-stimulated NCF-conditioned medium (10 ng/mL of IL1β) or same condition with the addition of a polyclonal neutralizing antibody against IL1β (2 µg/mL). FBS-free DMEM/F12 was used to generate conditioned medium after 48 h NCFs culture with or without the presence of the neutralizing antibody. Such conditioned media were then used to stimulate JAK2, STAT3, or AKT in HT29 cells for 1 h or 3 h. Quantification of phosphoproteins for three independent experiments was performed normalizing first for total JAK2, STAT3, or AKT and then normalizing for Tubulin (data expressed as arbitrary units). Statistical significance was assessed using non-parametric Kruskal–Wallis + Dunn’s multiple comparison test. ( E ) In 48 h experiments, the same conditioned media were reconstituted at 10% FBS. We evaluated JAK/STAT target proteins, Cyclin D1, and cMyc. ( F ) Overview of the experiment: to confirm paracrine signaling mediated by tumor cell-derived IL1β, we cocultured NCFs and HT29 cells with a defective secretion of IL1β, (silenced by means of shRNA) or transfected with a mock vector or wild-type as controls (75 mm transwell inserts, 3µm pore-size). As a positive control, we added IL1β to cocultures with HT29-shIL1β and NCFs. Culture conditions were: 2 × 10 6 cells tumor cells in the lower chamber and fibroblasts in the upper chamber (10 6 cells) in FBS-free DMEMF12. After 48 h, we harvested the conditioned medium and reconstituted the 10% FBS. As illustrated in ( G ), the conditioned medium obtained from cocultured NCFs and IL1β-deficient tumor cells (Ht29shIL1β) yielded lower IC 50 values in dose–response assays compared with the other experimental conditions tested ( p < 0.0001; survival is reported as %). The conditioned media obtained from cocultures of NCF and HT29-shIL1β cells with the exogenous addition of IL1β restored the IC 50 values of cocultured with HT29 wild-type cells. Each dose–response curve corresponds to the mean of three independent experiments of six technical replicates each. Differences between dose–response curves were compared with extra sum-of-squares F test (Log IC 50 ). ( H ) Real-Time PCR of the aforementioned cocultured NCF’s reported that the inhibition of the IL1β-mediated crosstalk between HT29shIL1β cells and fibroblasts induced a myofibroblastic phenotype in NCFs, with increased expression of ACTA2, CNN1, PDPN, and MYH11, while inflammatory markers were diminished, evidenced by decrease in IL6, LIF, and CCL2 (Kruskal–Wallis test; adjusted P values after Dunn’s multiple comparison test).
Article Snippet: For the NCF migration assay, IL1β (10 ng/mL) or IL1β plus IL1β neutralizing antibody (R&D Systems AF-201-NA) were added (2 μg/mL).
Techniques: Blocking Assay, Marker, Enzyme-linked Immunosorbent Assay, Western Blot, Cell Culture, Control, Comparison, Derivative Assay, shRNA, Transfection, Plasmid Preparation, Pore Size, Positive Control, Real-time Polymerase Chain Reaction, Inhibition, Expressing