The gut microbiota plays a critical role in human health, influencing immune responses, efficacy and toxicity of pharmacological treatments, including chemotherapy. Despite its recognized importance, the precise mechanisms by which the microbiota modulates chemotherapy efficacy and contributes to drug-induced gastrointestinal toxicity (DIGIT) remain unclear. This gap in knowledge mainly due to the poor availability of fully humanized, physiologically relevant multiorgan in vitro models.

Building on existing evidence, this work aims to develop a novel triculture human gut model fluidically connected to a 3D breast cancer model, using a multi-compartmental multiorgan on chip platform, resembling both the gut lumen and the circulatory circuit, where cisplatin, a commonly used chemotherapeutic drug, circulates. The 3D intestinal barrier model consists of a Gelatin Methacryloyl (GelMA) hydrogel scaffold embedded with human dermal fibroblasts (HDFs) to simulate the lamina propria. This structure supports a co-culture of Caco- 2 and HT-29 cells, forming a functional intestinal epithelial barrier. Escherichia coli was introduced to mimic microbiota interactions. A downstream tumor-on-chip model with MDA-MB-231 triple-negative breast cancer cells in alginate hydrogels enabled the study of drug penetration, tumor response, and DIGIT mechanisms.

This microbiota-Gut-Cancer on- Chip Model has been fully characterized in terms of cellular viability, epithelial barrier integrity measurements, permeability tests, and histological evaluations. Furthermore, the study evaluates the effect of cisplatin on cancer cell death (i.e. drug efficacy) as well as its impact on the epithelial barrier integrity, cell apoptosis ad mucus alteration in the gut tissue.

The integration of gut-microbiota-on-chip with cancer-on-chip models offers a promising platform for future preclinical assessments, contributing to precision medicine and more effective, individualized cancer treatments.