Creating a 3D Engineered Tissue Model to Mimic Colorectal Cancer Microenvironment for Studying Chemokine and Fibroblast in Cancer Progression

Abstract

Colorectal cancer (CRC) is the second leading cause of cancer-related death worldwide with a higher incidence in US. Among its subtypes, the consensus molecular subtype 4 (CMS4) is known to be the most aggressive, characterized by high stromal infiltration and an abundance of fibroblasts. CRC progression is heavily influenced by the tumor microenvironment (TME), particularly through secreted chemokines that regulate inflammation, angiogenesis, and tissue remodeling. One such chemokine, CXCL7, has emerged as a key factor in promoting pro-tumorigenic signaling. In our initial study, the role of CXCL7 was investigated in HT29 CRC progression within a three-dimensional (3D) culture environment. Elevated CXCL7 expression was associated with increased cell proliferation, larger colony size, and greater tissue growth and survival in the 3D construct. These results reinforce the role of CXCL7 as a critical mediator in colorectal cancer progression and highlight its potential as a therapeutic target in modulating the inflammatory and proliferative components of the TME. Additionally, 3D colon cancer tissues were engineered using HT29 cells in coculture with BJ5ta fibroblasts at varying ratios (1:0, 1:1, and 1:5) to better recapitulate the 3D TME and to evaluate the impact of fibroblasts on tumor progression, particularly whether CMS3-like cancer could transition toward a more aggressive cancer subtype. The engineered tissues were used to study the morphological changes, colony formation, mechanical properties, and proliferation. The results showed that coculture with fibroblasts, especially at a 1:5 ratio, significantly altered the tissue structure, leading to more compact and larger colonies along with increased stiffness compared to monoculture. These outcomes aligned with the hypothesis and suggest that fibroblast-induced changes in the TME may play an important role in CRC progression, offering future potential for use in testing therapeutic targeting.