Secretome profiling of heterotypic spheroids suggests a role of fibroblasts in HIF-1 pathway modulation and colorectal cancer photodynamic resistance

LAMBERTI, MARÍA JULIA; RETTEL, MANDY; KRIJGSVELD, JEROEN; RIVAROLA, VIVIANA ALICIA; RUMIE VITTAR, NATALIA BELÉN

Cellular Oncology

Springer

Año: 2019 p. 1 - 24

2211-3428

AbstractPurpose Previous analyses of the tumor microenvironment (TME) have resulted in a concept that tumor progression may dependon interactions between cancer cells and its surrounding stroma. An important aspect of these interactions is the ability of cancercells to modulate stroma behavior, and vice versa, through the action of a variety of soluble mediators. Here, we aimed to identifysoluble factors present in the TME of colorectal cancer cells that may affect relevant pathways through secretome profiling.Methods To partially recapitulate the TME and its architecture, we co-cultured colorectal cancer cells (SW480, TC) with stromalfibroblasts (MRC-5, F) as 3D-spheroids. Subsequent characterization of both homotypic (TC) and heterotypic (TC + F) spheroidsecretomes was performed using label-free liquid chromatography-mass spectrometry (LC-MS).Results Through bioinformatic analysis using the NCI-Pathway Interaction Database (NCI-PID) we found that the HIF-1signaling pathway was most highly enriched among the proteins whose secretion was enhanced in the heterotypic spheroids.Previously, we found that HIF-1 may be associated with resistance of colorectal cancer cells to photodynamic therapy (PDT), anantitumor therapy that combines photosensitizing agents, O2and light to create a harmful photochemical reaction. Here, wefound that the presence of fibroblasts considerably diminished the sensitivity of colorectal cancer cells to photodynamic activity.Although the biological significance of the HIF-1 pathway of secretomes was decreased after photosensitization, this decreasewas partially reversed in heterotypic 3D-spheroids. HIF-1 pathway modulation by both PDT and stromal fibroblasts wasconfirmed through expression assessment of the HIF-target VEGF, as well as through HIF transcriptional activity assessment.Conclusion Collectively, our results delineate a potential mechanism by which stromal fibroblasts may enhance colorectal cancercell survival and photodynamic treatment resistance via HIF-1 pathway modulation.