Genotyping, Characterization and Preclinical Studies in Transgenic Murine Models of Colorectal Cancer

Abstract

Colorectal cancer is characterized by the aberrant proliferation of intestinal epithelial cells, driven by sequential accumulation of distinct genetic and epigenetic modifications, often progressing from benign adenomas to malignant carcinomas. Dysregulation of Wnt signaling pathway is the hallmark and driver of colorectal cancer. This signaling pathway is a fundamental regulatory pathway that govern embryonic development and maintains tissue homeostasis in normal physiology. APC, a tumor suppressor protein, is the key regulator of this pathway whose mutational inactivation causes hyperactivation of Wnt signaling, leading to development of numerous polyps in the colon that can initiate the onset of colorectal cancer. With the aim of understanding the mechanism behind initiation and progression of colorectal cancer, microarray analysis was conducted to identify significantly up/down-regulated genes in APC knockout murine models, through which many genes such as EphB4, CITED-1, c-Myc, MMPs with significant fold-differences have been identified. This project is focused on understanding CITED-1 gene’s role in the initiation and progression of colorectal cancer which is not fully understood. Two types of transgenic mouse models where CITED-1 gene is over/mis-expressed were created to investigate the role of this gene in deregulation of Wnt signaling and further development of CRC. Histological characterization of the intestine such as alcian, grimelius staining techniques revealed an elevation in the number of intestinal cells across all lineages in the transgenics compared to wild type. Immuno-histochemical analysis too highlighted several proliferation markers' upregulation and Wnt pathways’s activation in the transgenic mice. Pre-clinical studies of shRNA-based bio-drug in APC knockout murine models. Their efficacy in suppressing colorectal cancer and increasing the survival of treated mice were noted.