Intestinal organoids: a model to study the role of microbiota in the colonic tumor microenvironment

The inhibitory effects of the novel Lactobacillus cocktail on colorectal cancer development through modulating BMP signaling pathway: In vitro and in vivo study

This study investigates the impact of a five-strain Lactobacillus cocktail (comprising two strains of L. plantarum, and one strain each of L. brevis, L. reuteri, and L. rhamnosus) on colorectal cancer (CRC) modulation by targeting the bone morphogenetic proteins (BMP) signaling pathway. Both in vitro and in vivo (models were employed. The antiproliferative effects of the Lactobacillus cocktail on HT-29 cells were assessed via the MTT assay. Mice were divided into three groups: a negative control (treated with PBS), a positive control (treated with azoxymethane (AOM)/dextran sulfate sodium (DSS) + PBS), and a test group (treated with AOM/DSS + Lactobacillus cocktail in PBS). The role of the Lactobacillus cocktail in inhibiting the BMP signaling pathway was evaluated using qRT-PCR for gene expression analysis and western blotting for β-catenin protein assessment in both models. The MTT assay results demonstrated a significant, time-dependent reduction in HT-29 cell proliferation. qRT-PCR indicated downregulation of the BMP signaling pathway in treated cells, which subsequently led to decreased expression of the hes1 gene, crucial for cell differentiation and proliferation control. This inhibitory effect was corroborated in the mice model, showing significant downregulation of BMP pathway genes and hes1 in the AOM/DSS/Lactobacillus cocktail-treated group. Additionally, western blotting revealed a marked decrease in β-catenin expression in both in vitro and in vivo experiments. Collectively, these findings suggest that the Lactobacillus cocktail may aid in CRC prevention by downregulating the BMP signaling pathway.

Advances in the use of 3D colorectal cancer models for novel drug discovery

INTRODUCTION

Colorectal cancer (CRC) is one of the most common and deadly tumors worldwide. CRC in vitro and in vivo models that recapitulate key features of human disease are essential to the development of novel and effective therapeutics. However, two-dimensional (2D) in vitro culture systems are considered too simple and do not represent the complex nature of the human tumor. However, three-dimensional (3D) models have emerged in recent years as more advanced and complex cell culture systems, able to closely resemble key features of human cancer tissues.

AREAS COVERED

The authors' review the currently established in vitro cell culture models and describe the advances in the development of 3D scaffold-free models to study CRC. The authors also discuss intestinal spheroids and organoids. As well as in vitro models for drug screening and metastatic CRC (mCRC).

EXPERT OPINION

The ideal CRC in vitro model is not yet established. Spheroid-based 3D models represent one of the most used approaches to recapitulate the tumor environment, overcoming some limitations of 2D models. Mouse and patient-derived organoids are more advanced models that can mimic more closely the characteristics and properties of CRC, with the possibility of including cells derived from patients with metastatic CRC.

Advances on colorectal cancer 3D models: The needed translational technology for nanomedicine screening

Colorectal cancer (CRC) is a heterogeneous and molecularly complex disease, associated with high mortality worldwide, exposing the urgent need for novel therapeutic approaches. Their development and translation to the clinic have been hampered, partially due to the absence of reliable cellular models that resemble key features of the human disease. While traditional 2D models are not able to provide consistent and predictive responses about the in vivo efficiency of the formulation, animal models frequently fail to recapitulate cancer progression and to reproduce adverse effects. On its turn, multicellular 3D systems, by mimicking key genetic, physical and mechanical cues of the tumor microenvironment, constitute a promising tool in cancer research. In addition, they constitute more physiological and relevant environment for anticancer drugs screening and for predicting patient's response towards personalized approaches, bridging the gap between simplified 2D models and unrepresentative animal models. In this review, we provide an overview of CRC 3D models for translational research, with focus on their potential for nanomedicines screening.

Organoids and Colorectal Cancer

Organoids were first established as a three-dimensional cell culture system from mouse small intestine. Subsequent development has made organoids a key system to study many human physiological and pathological processes that affect a variety of tissues and organs. In particular, organoids are becoming very useful tools to dissect colorectal cancer (CRC) by allowing the circumvention of classical problems and limitations, such as the impossibility of long-term culture of normal intestinal epithelial cells and the lack of good animal models for CRC. In this review, we describe the features and current knowledge of intestinal organoids and how they are largely contributing to our better understanding of intestinal cell biology and CRC genetics. Moreover, recent data show that organoids are appropriate systems for antitumoral drug testing and for the personalized treatment of CRC patients.

Hydrogels to engineer tumor microenvironments in vitro

Illustration of engineered hydrogel to recapitulate aspects of the tumor microenvironment.