A large animal model to elucidate the role of LGR5 stem cells in cancer

Project Summary In the United States, colorectal cancer (CRC) is the 3rd leading cause of cancer death among women and men combined, with of 1 in 20 people being diagnosed with CRC each year.

Yet, understanding factors controlling disease progression and metastasis has been hampered by the lack of a suitable animal model of CRC.

At present, there is considerable information regarding candidate genes that are mutated in CRC and contribute to tumor locations, tumor phenotype and patient response to treatment1.

While candidate genes can be studied in mice by use of transgenic lines carrying gain-of-function and loss-of function genetic modifications, mutations in candidate genes such as Apc, result in lesions in mice that differ from those seem in humans. As a result, modifications of the traditional transgenic model have been required to advance our understanding of CRC.

In contrast, an analogous APC-/- pig model demonstrates predominantly colon tumors, which are remarkably similar to the human disease.

We propose to combine the strengths of an existing gene edited LGR5-H2B-GFP pig line with the power of a Cre-inducible Cas9 system to generate a novel line that will allow a careful dissection both in vivo and in vitro of the molecular pathways associated with the behavior of LGR5 cells in colon cancer.

This proposal will allow for the generation and the initial in vitro and in vivo validation of the model.

This highly relevant large animal model will greatly improve our understanding of how LGR5 cells behavior is controlled at the molecular level during oncogenic transformation and will be of great use to develop novel strategies to treat human colorectal cancer, as well as other cancers.