Study of the role of visceral adipose tissue in colon cancer

Abstract

[eng] Obesity is strongly linked to a higher risk of developing colon cancer, and both pathologies are growing on an international scale. However, the underlying mechanism of this association is poorly understood. While biomedical research conventionally tried to explain the dysfunctions in cancerous epithelial colonocytes, an interest for the role of visceral adipose tissue (VAT) in this problematic has recently emerged. Firstly, because VAT is anatomically localized in proximity to colon, so colon cancer metastasizes primarily in this tissue; and secondly, because obesity causes fat cells hypertrophy, leading to an excessive secretion of adipokines and fatty acids, and a chronic lowgrade inflammation in the tumor microenvironment, finally prompting colon cancer cells malignization. The objective of our study was to examine whether the lipidomic profile of distal mesenteric VAT (mVAT) adipocytes was altered at pT3 stage, and whether colon cancer infiltration into peritumoral VAT (pVAT) influences the immunologic signature of this fat-depot. Hence, we described fatty acids composition of mVAT adipocytes of 11 colon cancer patients at pT2 and pT3 stages using gas chromatography-mass spectrometry (GC-MS). We did not observe differences in fatty acids profile and average proportion between both groups. Then, we performed flow cytometry analysis of immune cells in pVAT and mVAT. Although only three patients were analyzed, we identified a consistent increase of T and B lymphocytes and pro-inflammatory macrophages in peritumoral fat. Our preliminary data indicate that colon cancer stage did not affect the lipid content of adipocytes in the mVAT, and that colon cancer was associated with a change in the inflammatory status of pVAT, suggesting a crosstalk between colon cancer cells and immune cells.