The in vivo role of Grb7 in mammary gland development and tumorigenesis

Growth factor receptor-bound protein 7 (Grb7) is an adaptor protein that regulates tumor progression by integrating several important pathways for cell proliferation, invasion and survival. The role of Grb7 was intensively studied in breast cancer, since it is closely related to the oncogene ERBB2. Prior study from out lab has also indicated that knockdown the expression of Grb7 ablates the proliferation, migration and tumorigenesis of the SK-BR3 cell line in vitro. Since the normal development of mammary gland shares similar characteristics with the mammary gland tumorigenesis, we questioned whether Grb7 participates in the development of the normal mammary gland. Using CRISPR-Cas9 generated Grb7 knockout C57BL/6 mice, we have investigated the role of Grb7 in normal mammary gland development in vivo. According to our study, Grb7 knockout has slightly promote branching and delayed involution. Also, we applied the B16-F10 subcutaneous and lung metastasis models to see investigate the influence of Grb7 knockout on tumor progression. Grb7 knockout has affected the tumor colonization on lungs during metastasis. The results from this study will better illustrate the in vivo role of Grb7, which will further contribute to the drug development against cancers. Keywords: Growth factor receptor-bound protein (Grb7); mammary gland development; tumor growth; lung metastasis