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Chronic inflammation and angiogenesis are associated with colonic carcinogenesis. Enteric glia-derived S100B protein has been proposed as an "ideal bridge", linking colonic inflammation and cancer, given its dual ability to up-regulate nuclear factor-kappaB (NF-κB) transcription via receptor for advanced glycation end products (RAGE) signaling and to sequestrate wild type pro-apoptotic wild type ( wt )p53. However, its pro-angiogenic effects on cancer cells are still uninvestigated. To this aim, we evaluated the effect of exogenous S100B (0.05-5 µM) protein alone or in the presence of S100B blocking monoclonal antibody (mAb) (1:10 5 -1:10 4 v / v diluted) on (1) cultured Caco-2 cells proliferation, migration and invasiveness in vitro, respectively by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT)-formazan, wound healing and matrigel invasion assays and (2) its effect on the release of pro-angiogenic factors, such as vascular endothelial growth factor (VEGF) by ELISA and immunofluorescence analyses. The effect of S100B alone or in the presence of S100BmAb was then investigated on RAGE/pAkt/mammalian target of rapamycin (mTOR) signaling pathway by immunoblot analysis. Our results showed that S100B markedly increases proliferation and invasiveness of Caco-2 cells, through the release of pro-angiogenic VEGF and NO paralleled to a significant decrease of wt p53 expression mediated by RAGE-p38 mitogen-activated protein kinase (MAPK)/pAkt-mTOR and hypoxia-inducible factor 1-alpha (HIF1α) pathways. Such effects were counteracted by S100BmAb, indicating that S100B targeting is a potential approach to inhibit colon carcinoma proliferation and angiogenesis.

Because histamine is a modulator of cancer cell proliferation and invasiveness, this study aimed at investigating the effect of Lathyrus sativus-derived diamine oxidase (LSAO) and its mechanism of action on Caco-2 cell line, considering that LSAO catalizes the oxidative deamination of histamine to the corresponding aldehyde, NH 3 and H 2 O 2 . Histamine (0.01-1 μM) caused a proliferative effect on Caco-2 cells promoting cell migration, invasion and nitric oxide and vascular endothelial growth factor release. Histamine (1 μM) stimulus also down regulated occludin expression, favouring up regulation of pro-proliferative nuclear protein Ki67. Incubation with LSAO (0.004-0.4 μM) resulted in a significant inhibition of histamine-induced effects. LSAO rescued occludin expression and down regulated Ki67, and it inhibited histamine-induced increase of both MMP-2 and 9 expression. Histamine effects were mediated by RhoA-GTP down regulation and inversely related to phospho-p38MAPK/p50/65 up regulation. These effects were counteracted by LSAO incubation. Histamine catabolism by LSAO accounts for a significant down regulation of proliferation and invasiveness of Caco-2 cells. This study highlights the importance to control histamine levels in contrasting pro-angiogenic and metastatization capability of colon cancer cells and expands the knowledge about the diamine oxidase from L. sativus seeding as a phytotherapeutic approach for colon cancer., (© 2019 John Wiley & Sons, Ltd.)