ZEB1-mediated fibroblast polarization controls inflammation and sensitivity to immunotherapy in colorectal cancer.

The EMT-transcription factor ZEB1 is heterogeneously expressed in tumor cells and in cancer-associated fibroblasts (CAFs) in colorectal cancer (CRC). While ZEB1 in tumor cells regulates metastasis and therapy resistance, its role in CAFs is largely unknown. Combining fibroblast-specific Zeb1 deletion with immunocompetent mouse models of CRC, we observe that inflammation-driven tumorigenesis is accelerated, whereas invasion and metastasis in sporadic cancers are reduced.

Colorectal Cancer Organoid-Stroma Biobank Allows Subtype-Specific Assessment of Individualized Therapy Responses.

Unlabelled: In colorectal cancers, the tumor microenvironment plays a key role in prognosis and therapy efficacy. Patient-derived tumor organoids (PDTO) show enormous potential for preclinical testing; however, cultured tumor cells lose important characteristics, including the consensus molecular subtypes (CMS). To better reflect the cellular heterogeneity, we established the colorectal cancer organoid-stroma biobank of matched PDTOs and cancer-associated fibroblasts (CAF) from 30 patients.

Synthetic enforcement of STING signaling in cancer cells appropriates the immune microenvironment for checkpoint inhibitor therapy.

Immune checkpoint inhibitors (ICIs) enhance anticancer immunity by releasing repressive signals into tumor microenvironments (TMEs). To be effective, ICIs require preexisting immunologically "hot" niches for tumor antigen presentation and lymphocyte recruitment. How the mutational landscape of cancer cells shapes these immunological niches remains poorly defined.

Loss of SUV420H2-Dependent Chromatin Compaction Drives Right-Sided Colon Cancer Progression.

Background & Aims: Epigenetic processes regulating gene expression contribute markedly to epithelial cell plasticity in colorectal carcinogenesis. The lysine methyltransferase SUV420H2 comprises an important regulator of epithelial plasticity and is primarily responsible for trimethylation of H4K20 (H4K20me3). Loss of H4K20me3 has been suggested as a hallmark of human cancer due to its interaction with DNMT1.

Inflammatory fibroblasts mediate resistance to neoadjuvant therapy in rectal cancer.

Standard cancer therapy targets tumor cells without considering possible damage on the tumor microenvironment that could impair therapy response. In rectal cancer patients we find that inflammatory cancer-associated fibroblasts (iCAFs) are associated with poor chemoradiotherapy response. Employing a murine rectal cancer model or patient-derived tumor organoids and primary stroma cells, we show that, upon irradiation, interleukin-1α (IL-1α) not only polarizes cancer-associated fibroblasts toward the inflammatory phenotype but also triggers oxidative DNA damage, thereby predisposing iCAFs to p53-mediated therapy-induced senescence, which in turn results in chemoradiotherapy resistance and disease progression.

A Wnt-Induced Phenotypic Switch in Cancer-Associated Fibroblasts Inhibits EMT in Colorectal Cancer.

Tumor progression is recognized as a result of an evolving cross-talk between tumor cells and their surrounding nontransformed stroma. Although Wnt signaling has been intensively studied in colorectal cancer, it remains unclear whether activity in the tumor-associated stroma contributes to malignancy. To specifically interfere with stromal signals, we generated Wnt-independent tumor organoids that secrete the Wnt antagonist Sfrp1.

Pooled In Vitro and In Vivo CRISPR-Cas9 Screening Identifies Tumor Suppressors in Human Colon Organoids.

Colorectal cancer (CRC) is characterized by prominent genetic and phenotypic heterogeneity between patients. To facilitate high-throughput genetic testing and functional identification of tumor drivers, we developed a platform for pooled CRISPR-Cas9 screening in human colon organoids. Using transforming growth factor β (TGF-β) resistance as a paradigm to establish sensitivity and scalability in vitro, we identified optimal conditions and strict guide RNA (gRNA) requirements for screening in 3D organoids.

3D model for CAR-mediated cytotoxicity using patient-derived colorectal cancer organoids.

Immunotherapy using chimeric antigen receptor (CAR)-engineered lymphocytes has shown impressive results in leukemia. However, for solid tumors such as colorectal cancer (CRC), new preclinical models are needed that allow to test CAR-mediated cytotoxicity in a tissue-like environment. Here, we developed a platform to study CAR cell cytotoxicity against 3-dimensional (3D) patient-derived colon organoids.

Human colon organoids reveal distinct physiologic and oncogenic Wnt responses.

Constitutive Wnt activation upon loss of () acts as main driver of colorectal cancer (CRC). Targeting Wnt signaling has proven difficult because the pathway is crucial for homeostasis and stem cell renewal. To distinguish oncogenic from physiological Wnt activity, we have performed transcriptome and proteome profiling in isogenic human colon organoids.

Dynamic Formation of Microvillus Inclusions During Enterocyte Differentiation in -Deficient Intestinal Organoids.

Background & Aims: Microvillus inclusion disease (MVID) is a congenital intestinal malabsorption disorder caused by defective apical vesicular transport. Existing cellular models do not fully recapitulate this heterogeneous pathology. The aim of this study was to characterize 3-dimensional intestinal organoids that continuously generate polarized absorptive cells as an accessible and relevant model to investigate MVID.

Visualization of a short-range Wnt gradient in the intestinal stem-cell niche.

Mammalian Wnt proteins are believed to act as short-range signals, yet have not been previously visualized in vivo. Self-renewal, proliferation and differentiation are coordinated along a putative Wnt gradient in the intestinal crypt. Wnt3 is produced specifically by Paneth cells.