CRISPRa_screen_in_mice_to_identify_membrane_protein_regulators_of_melanoma_metastasis. CRISPRa_screen_in_mice_to_identify_membrane_protein_regulators_of_melanoma_metastasis

Metastasis is the spread of cancer cells to a secondary site within the body, and is the leading cause of death for cancer patients. The lung is a common site of metastasis for many cancer types, including melanoma. In order for better treatments to be developed, identifying the genes involved in aiding metastasis of melanoma cells to the lungs is critical. As the accessibility of cell surface proteins make them attractive therapeutic targets, we performed a CRISPR activation screen using a library of guide RNAs (gRNAs) targeting the transcription start sites of 2,195 membrane protein-encoding genes, to identify those whose upregulated expression aided pulmonary metastasis. Immunodeficient mice were subcutaneously injected in the flank with murine B16-F0 melanoma cells carrying dCas9 and the membrane protein library gRNAs, and their lungs collected 14-21 days later. Analysis was performed to identify the gRNAs enriched in the lungs, relative to those present in the cells at the time of administration (day 0) to identify genes whose increased expression promoted metastasis of the melanoma cells to the lung.