Mimicking Tumor Cell Heterogeneity of Colorectal Cancer in a Patient-derived Organoid-Fibroblast Model.

BACKGROUND & AIMS: Patient-derived organoid cancer models are generated from epithelial tumor cells and reflect tumor characteristics. However, they lack the complexity of the tumor microenvironment, which is a key driver of tumorigenesis and therapy response. Here, we developed a colorectal cancer organoid model that incorporates matched epithelial cells and stromal fibroblasts. METHODS: Primary fibroblasts and tumor cells were isolated from colorectal cancer specimens. Fibroblasts were characterized for their proteome, secretome, and gene expression signatures. Fibroblast/organoid co-cultures were analyzed by immunohistochemistry and compared with their tissue of origin, as well as on gene expression levels compared with standard organoid models. Bioinformatics deconvolution was used to calculate cellular proportions of cell subsets in organoids based on single-cell RNA sequencing data. RESULTS: Normal primary fibroblasts, isolated from tumor adjacent tissue, and cancer associated fibroblasts retained their molecular characteristics in vitro, including higher motility of cancer associated compared with normal fibroblasts. Importantly, both cancer-associated fibroblasts and normal fibroblasts supported cancer cell proliferation in 3D co-cultures, without the addition of classical niche factors. Organoids grown together with fibroblasts displayed a larger cellular heterogeneity of tumor cells compared with mono-cultures and closely resembled the in vivo tumor morphology. Additionally, we observed a mutual crosstalk between tumor cells and fibroblasts in the co-cultures. This was manifested by considerably deregulated pathways such as cell-cell communication and extracellular matrix remodeling in the organoids. Thrombospondin-1 was identified as a critical factor for fibroblast invasiveness. CONCLUSION: We developed a physiological tumor/stroma model, which will be vital as a personalized tumor model to study disease mechanisms and therapy response in colorectal cancer.

Requirement of DNMT1 to orchestrate epigenomic reprogramming for NPM-ALK-driven lymphomagenesis.

Malignant transformation depends on genetic and epigenetic events that result in a burst of deregulated gene expression and chromatin changes. To dissect the sequence of events in this process, we used a T-cell-specific lymphoma model based on the human oncogenic nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) translocation. We find that transformation of T cells shifts thymic cell populations to an undifferentiated immunophenotype, which occurs only after a period of latency, accompanied by induction of the MYC-NOTCH1 axis and deregulation of key epigenetic enzymes. We discover aberrant DNA methylation patterns, overlapping with regulatory regions, plus a high degree of epigenetic heterogeneity between individual tumors. In addition, ALK-positive tumors show a loss of associated methylation patterns of neighboring CpG sites. Notably, deletion of the maintenance DNA methyltransferase DNMT1 completely abrogates lymphomagenesis in this model, despite oncogenic signaling through NPM-ALK, suggesting that faithful maintenance of tumor-specific methylation through DNMT1 is essential for sustained proliferation and tumorigenesis.

Care of patients with non-small-cell lung cancer stage III - the Central European real-world experience.

Background Management of non-small-cell lung cancer (NSCLC) is affected by regional specificities. The present study aimed at determining diagnostic and therapeutic procedures including outcome of patients with NSCLC stage III in the real-world setting in Central European countries to define areas for improvements. Patients and methods This multicentre, prospective and non-interventional study collected data of patients with NSCLC stage III in a web-based registry and analysed them centrally. Results Between March 2014 and March 2017, patients (n=583) with the following characteristics were entered: 32% females, 7% never-smokers; ECOG performance status (PS) 0, 1, 2 and 3 in 25%, 58%, 12% and 5%, respectively; 21% prior weight loss; 53% squamous carcinoma, 38% adenocarcinoma; 10% EGFR mutations. Staging procedures included chest X-ray (97% of patients), chest CT (96%), PET-CT (27%), brain imaging (20%), bronchoscopy (89%), endobronchial ultrasound (EBUS) (13%) and CT-guided biopsy (9%). Stages IIIA/IIIB were diagnosed in 55%/45% of patients, respectively. N2/N3 nodes were diagnosed in 60%/23% and pathologically confirmed in 29% of patients. Most patients (56%) were treated by combined modalities. Surgery plus chemotherapy was administered to 20%, definitive chemoradiotherapy to 34%, chemotherapy only to 26%, radiotherapy only to 12% and best supportive care (BSC) to 5% of patients. Median survival and progression-free survival times were 16.8 (15.3;18.5) and 11.2 (10.2;12.2) months, respectively. Stage IIIA, female gender, no weight loss, pathological mediastinal lymph node verification, surgery and combined modality therapy were associated with longer survival. Conclusions The real-world study demonstrated a broad heterogeneity in the management o f stage III NSCLC in Central European countries and suggested to increase the rates of PET-CT imaging, brain imaging and invasive mediastinal staging.

Systemic treatment of advanced non-small cell lung cancer: controversies and perspectives.

Patients with advanced non-small cell lung cancer receive first-line therapy with chemotherapy, targeted therapies in case of tumors with driver mutations, and more recently also immune checkpoint inhibitors. Important controversies include the role of targeted therapies in combination with chemotherapy, optimal sequencing of treatments, treatment guidance by means of predictive biomarkers, and value-based judgements of treatments.