Mesenteric fibrosis in small intestinal neuroendocrine tumors (SI-NETs): Pathogenesis and therapeutic targets (B02)

Introduction: Mesenteric fibrosis (MF) affects up to 50% of small intestine neuroendocrine tumor (SI-NET) patients, causing significant morbidity and mortality. MF pathophysiology is poorly understood, limiting treatment development and biomarker identification.

Aim(s): This project aims to improve the understanding of MF and identify useful diagnostic and predictive molecular markers.

Materials and methods: Tissue was collected from 45 SI-NET patients, classified into 4 groups according to severity of mesenteric fibrosis. Genome-wide DNA methylation and RNA sequencing were performed. Primary fibroblasts were isolated from normal intestine tissue, normal mesentery, primary tumor, and mesenteric metastasis of SI-NET patients. Human normal intestine was decellularized, processed to obtain an extracellular matrix (ECM) powder, solubilised with nanocellulose, and mixed with SI-NET primary fibroblasts and/or GOT1 cells (SI-NET cell line). Bioengineered gels were cultured for 14 days and cell viability assessed by PrestoBlue. The distribution of cells in the gels was assessed using histological staining.

Results: Genomic analysis highlighted several fibrosis-associated genes with significantly altered methylation and expression in the mesenteric mass of MF patients. GOT1 and primary fibroblasts showed good viability in mono- and co-culture over 14 days of culture.

Conclusion: Epigenetic and transcriptomic differences highlighted pathways with relevance to disease pathophysiology which provides insight into development of MF. SI-NET cells and SI-NET primary fibroblasts can be cultured in a 3D model using human SI-NET-derived ECM intestine. This model will be used as a platform to better understand MF pathophysiology in SI-NET patients and to test candidate anti-fibrotic drugs targeting MF.

Keywords: fibrosis, small intestine, 3d model, cell crosstalk, microenvironment, cancer-associated fibroblast