Morphological and Functional Changes in the Peritumoral Adipose Tissue of Colorectal Cancer Patients.

OBJECTIVE: The role of peritumoral adipose tissue (AT) has not been extensively studied in colorectal cancer (CRC). METHODS: This study was conducted in 20 male subjects undergoing elective surgery for CRC. The differences between the peritumoral visceral adipose tissue (P-VAT), visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) of the patients were described via immunohistochemistry and molecular biology analyses. The interactions between adipocytes and a colon cancer cell line were also investigated by using an in vitro coculture system. RESULTS: The analyses revealed that adipocytes near the tumor were significantly smaller than the adipocytes from other sites. The P-VAT was preferentially infiltrated by a CD68+/CD163+/IDO- macrophage subset with a prevalent reparative inflammatory response, while the macrophages identified in VAT and SAT mainly presented inflammatory features. Furthermore, the P-VAT presented a higher expression of adiponectin compared with other sites. Morphological analysis in vitro showed that after a few days of coculture, 3T3-L1 adipocytes were reduced in number and size with an increase in lipolysis rate and dedifferentiation phenomena. CONCLUSIONS: This study reveals important morphological and functional changes in the AT surrounding the tumor as an increase in lipolysis and in adiponectin-producing adipocytes, preferentially infiltrated by a macrophage subset, with prevalent reparative inflammatory response.

Adipocytes WNT5a mediated dedifferentiation: a possible target in pancreatic cancer microenvironment.

A significant epidemiological association between obesity and pancreatic ductal adenocarcinoma (PDAC) has previously been described, as well as a correlation between the degree of pancreatic steatosis, PDAC risk and prognosis. The underlying mechanisms are still not completely known.After co-culture of 3T3-L1 adipocytes and MiaPaCa2 with an in vitro transwell system we observed the appearance of fibroblast-like cells, along with a decrease in number and size of remaining adipocytes. RT-PCR analyses of 3T3-L1 adipocytes in co-culture showed a decrease in gene expression of typical markers of mature adipocytes, in parallel with an increased expression of fibroblast-specific and reprogramming genes. We found an increased WNT5a gene and protein expression early in MiaPaCa2 cells in co-culture. Additionally, EMSA of c-Jun and AP1 in 3T3-L1 demonstrated an increased activation in adipocytes after co-culture. Treatment with WNT5a neutralizing antibody completely reverted the activation of c-Jun and AP1 observed in co-cultured adipocytes.Increasing doses of recombinant SFRP-5, a competitive inhibitor for WNT5a receptor, added to the co-culture medium, were able to block the dedifferentiation of adipocytes in co-culture.These data support a WNT5a-mediated dedifferentiation process with adipocytes reprogramming toward fibroblast-like cells that might profoundly influence cancer microenvironment.

Iron primes 3T3-L1 adipocytes to a TLR4-mediated inflammatory response.

OBJECTIVE: Iron participates in several mechanisms involving inflammation and innate immunity, yet the dysregulation of its homeostasis is a major cause of metabolic syndrome. Adipocytes should play a major role in iron metabolism, as an impairment in iron turnover is closely related to insulin resistance, obesity, and type 2 diabetes. The aim of this study was to investigate the role of iron in an in vitro-inflamed adipocyte model. METHODS: Gene expression of tumor necrosis factor-α, interleukin-6, inflammatory chemokines (CCL3, CCL4, and CXCL12), and molecules involved in iron metabolism were evaluated in an in vitro mouse 3T3-L1 cell model. Cells underwent treatment with FeSO4 heptahydrate and lipopolysaccharide (LPS) stimulation. Toll-like receptor 4 (TLR4) membrane expression, lipid droplet immunohystochemistry, and lipolysis were also evaluated. RESULTS: Iron sulphate heptahydrate elicited gene expression of hepcidin, hemojuvelin, and ferroportin at different time courses. Additionally, it activated lipolysis but did not trigger any adipokine gene expression. When cells treated with physiological doses of iron were also stimulated with LPS, an enhancement in the LPS-induced gene expression of cytokines and chemokines was observed. The enhancement occurred with different patterns depending on different time courses and investigated genes, showing its maximal effect for IL-6 gene expression. CONCLUSIONS: FeSO4 heptahydrate at a relatively physiological dose, induced gene expression of iron modulatory proteins and also enhanced RNA transcripts of several inflammatory cytokines and chemokines through a priming/synergistic mechanism involving membrane TLR4.

Effect of high-frequency electromagnetic fields on trophoblastic connexins.

Connexins (Cx) are membrane proteins able to influence trophoblast functions. Here we investigated the effect of high-frequency electromagnetic fields (HF-EMF) on Cx expression and localization in extravillous trophoblast cell line HTR-8/SVneo. We also analysed cell ultrastructural changes induced by HF-EMF exposure. Samples were exposed to pulse-modulated 1817 MHz sinusoidal waves (GSM-217 Hz; 1h: SAR of 2 W/kg). Cx mRNA expression was assessed through semi-quantitative RT-PCR, protein expression by Western blotting, protein localization by indirect immunofluorescence, cell ultrastructure using electron microscopy. HF-EMF exposure significantly and selectively increased Cx40 and Cx43, without altering protein expression. Nevertheless, Cx40 and Cx43 lost their punctuate fluorescence within the cell membrane, becoming diffuse after HF-EMF exposure. Electron microscopy evidenced a sharp decrease in intercellular gap junction-like structures. This study is the first to indicate that exposure of extravillous trophoblast to GSM-217 Hz signals can modify Cx gene expression, Cx protein localization and cellular ultrastructure.