Possible Chemopreventive Role Of Eicosapentaenoic Acid In An In Vitro Model Of Inflammatory-Driven Colorectal Cancer.

Abstract

The Notch1 signaling pathway has a pivotal role in cell fate regulation and has been found to be critically deranged in different cancers, including colorectal cancer (CRC). Inflammation is known to play an important role in the pathogenesis of CRC and a prominent function of Notch1 during inflammation has been recently demonstrated. Epithelial to Mesenchymal Transition (EMT), a crucial process in the malignant transformation, is modulated by inflammation and Metalloproteinase-9 (MMP9) is involved in this interaction. Eicosapentaenoic Acid is an omega-3 polyunsaturated fatty acid (omega-3 PUFA) known for its anti-inflammatory properties as well as for its capability in preventing colon cancer development both in sporadic and in hereditary settings. In particular, our group has demonstrated that an extra-pure formulation of Eicosapentaenoic Acid as the free fatty acid (EPA-FFA) protects from CRC development in a mouse model of colitis-associated cancer (CAC) by modulating the Notch signaling pathway. In the present work, we re-created an in vitro model of inflammatory-driven CRC by exposing colon cancer cells to a cytokine-enriched conditioned medium (CM) obtained from THP-1-differentiated macrophages. We found, for the first time, that CM strongly induces Notch1 signaling and EMT markers, increasing the capability of cells to invade. Importantly we found that, upon CM exposure, Notch1 signaling is dependent on MMP9 expression. Finally, we show that a non-cytotoxic pre-treatment with 50 μM of EPA-FFA for 72h counteracts the effect of inflammation on Notch1 signaling and EMT, leading to a reduction of invasiveness. Taken together, our data demonstrate that in CRC inflammation up-regulates Notch1 signaling through MMP9 and that this mechanism can be effectively counteracted by EPA-FFA.