Title: UBXN2A represses migration and invasion of colorectal cancer cells. This project focuses on UBXN2A, which is a ubiquitin-like (UBX) domain-containing protein with potent tumor suppressor functions in colorectal cancer (CRC). We showed that induction of UBXN2A decreases colon xenograft growth rate by 50%, and heterozygous disruption of UBXN2A in mice is sufficient to promote tumorigenesis. At the cellular level, our results indicate that UBXN2A has a major inhibitory effect on tumor cell migration and invasion. Thus, UBXN2A may have a dominant anti-cancer effect by dual-targeting primary tumors as well as signaling pathways associated with tumor metastasis. The objective of this application is twofold; the first objective is to identify the UBXN2A's regulatory function in the mTORC2/pAKT signaling pathway during cancer cell migration and invasion. The second objective is to understand UBXN2A's anti- cancer mechanisms during colon cancer cell invasion/migration in an orthotopic colon cancer mouse model that mimics human CRC metastasis. Because our protein array data showed that 50% of CRC tumors have low levels of UBXN2A, the long-term goal of this proposal is to develop a new therapeutic strategy for patients with CRC using UBXN2A as a target for therapy. Based on our published results and preliminary data, our central hypothesis will be tested in two specific aims: 1) Determine whether loss of UBXN2A is sufficient to enhance migration and invasion in metastatic colon cancer cells in a mTORC2/pAKT-dependent manner, and 2) Examine the inhibitory effect of UBXN2A induction on human colorectal tumor invasion and metastasis in an orthotopic CRC mouse model. The designed in vitro and in vivo experiments and available Tet- on controllable expression cell lines as well as our 3D ultrasound imaging technique in live animals will be a powerful approach for gaining new mechanistic insight into the role of UBXN2A in the regulation of CRC metastasis and assessing the therapeutic potential of UBXN2A in patients with CRC.
Metastasis accounts for the vast majority of colon cancer deaths; thus, preventing tumor cell migration, invasion, and dissemination represents a major therapeutic challenge for this disease. Completion of this study can lead to the development and in vivo testing of a novel mTORC2/pAKT inhibitor in human colorectal cancer (CRC). The results obtained from this proposal will therefore have a significant impact on the treatment of CRC patients.