Comparative Study of Organoids from Patient-Derived Normal and Tumor Colon and Rectal Tissue.

Alba Costales-Carrera,Aurora Burgos,Antonio Barbáchano,Alberto Muñoz,Laura Guerra-Pastrián,Luis Del Peso,Pilar Bustamante-Madrid,Ramón Cantero,Orlando Domínguez,Asunción Fernández-Barral

doi:10.3390/cancers12082302

Abstract

Colon and rectal tumors, often referred to as colorectal cancer, show different gene expression patterns in studies that analyze whole tissue biopsies containing a mix of tumor and non-tumor cells. To better characterize colon and rectal tumors, we investigated the gene expression profile of organoids generated from endoscopic biopsies of rectal tumors and adjacent normal colon and rectum mucosa from therapy-naive rectal cancer patients. We also studied the effect of vitamin D on these organoid types. Gene profiling was performed by RNA-sequencing. Organoids from a normal colon and rectum had a shared gene expression profile that profoundly differed from that of rectal tumor organoids. We identified a group of genes of the biosynthetic machinery as rectal tumor organoid-specific, including those encoding the RNA polymerase II subunits POLR2H and POLR2J. The active vitamin D metabolite 1α,25-dihydroxyvitamin D3/calcitriol upregulated stemness-related genes (LGR5, LRIG1, SMOC2, and MSI1) in normal rectum organoids, while it downregulated differentiation marker genes (TFF2 and MUC2). Normal colon and rectum organoids share similar gene expression patterns and respond similarly to calcitriol. Rectal tumor organoids display distinct and heterogeneous gene expression profiles, with differences with respect to those of colon tumor organoids, and respond differently to calcitriol than normal rectum organoids.

Highlights

Colorectal cancer (CRC) is no longer considered a single disease
Our study shows that human SC-derived organoids from a normal colon and rectum have highly similar morphology and gene expression profiles, whereas they differ greatly between organoids derived from a normal rectum and rectal tumors
We found that normal colon and rectum organoids respond very to calcitriol, whereas the calcitriol responses of a normal rectum and rectal tumor organoids are different

Summary

Introduction

Colorectal cancer (CRC) is no longer considered a single disease. The colon and rectum differ in their ontogeny, anatomy, microbiome, and function, and this is reflected in differences in risk factors and epidemiological and clinicopathological features between colon and rectal tumors [1,2,3,4,5].The two types of cancer differ in their patterns of metastases and chemosensitivity [6,7,8], and this underlies the different clinical management of colon and rectal cancer patients [3,9]. Colon and rectal carcinomas have different mutational landscapes and cytogenetic aberrations, as is the case for tumors affecting different colon segments [10,11,12,13]. This has led to the idea that molecular-genetic features change gradually along the colorectum, known as linearity [1]. Differences in gene expression patterns have been found between a normal colon and rectum and between colon and rectal tumors [14,15] These genetic studies were performed with whole tissue biopsies containing a mix of tumor and non-tumor epithelial and stromal cells, including fibroblasts, immune cells, pericytes, adipocytes, blood, and lymphatic endothelial cells. It has been impossible to assign the expression of a given gene to a particular cell type

Methods

Results

Conclusion