Direct consequences of chromosomal instability in pre-malignant human adenoma

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Chromosomal instability (CIN) occurs in 85% of colorectal cancer (CRC) cases and represents an important CRC hallmark. Importantly, CIN is an early event in CRC development and the type of adenomatous polyposis coli (APC) mutation decides about CIN occurrence at early tumor stages. Recent data suggest CIN directly promotes cell growth and cellular transformation, and CIN might be a prerequisite for tumors to develop a metastatic potential at later disease stages. However, our understanding of the molecular consequences and downstream signaling pathways directly triggered by CIN in early tumor lesions and transformed colorectal cancer cells is incomplete. Using state-of-the-art 3-dimensional colonic stem cell culture systems and CRISPR/Cas9-mediated genome editing, we aim to model and further characterize the direct effects of CIN in APC-mutated human colonic organoids (=adenoma), AURKA overexpressing genomic instable organoids, and their checkpoint-deficient derivatives. Next generation sequencing (NGS), quantitative proteomic analysis of the cell surface proteome and secretome of CIN-affected human colon adenoma cells will shed new light on the CIN event and its role in human CRC progression. Moreover, considering the critical role of the microenvironment in CRC initiation and progression, we hypothesize that a pro-tumorigenic effect of CIN goes beyond cell autonomous mechanisms and likely contributes to the re-programming of associated fibroblasts towards a pro-tumorigenic state. To show this, we will generate human tumoroids ex vivo that contain human primary epithelial cells affected by CIN + primary colonic fibroblasts via magnetic levitation technique. This will allow us to study the differential effects of pre-malignant human adenoma cells suffering from CIN on adjacent stroma cells. Deciphering the CIN-induced signaling pathways in human adenoma cells and the cross-signaling between early human colorectal tumor lesions and their associated microenvironment will reveal novel drug targets and innovative strategies for cancer prevention and curative cancer therapy.