Functional Characterization of Nsfl1c Using Comprehensive Proteomic Approaches: Implication in Oral Cancer Metastasis

Oral cavity squamous cell carcinoma (OSCC) is a leading cause of cancer-related death worldwide. In Taiwan, OSCC is the fifth most common malignancy and causes more than 2500 deaths per year. Despite significant advances in treatment over the recent decades, approximately 50% of OSCC patients die within 5 years of diagnosis, mostly ascribed to lymphatic metastasis and/or local recurrence. Only 25-40% of OSCC patients with lymph node metastasis at initial diagnosis achieve 5-year survival, compared to approximately 90% of patients without metastasis. Thus, it is critical to identify the molecules involved in OSCC development and improve the ability of predicting lymph node metastasis to optimize tailored therapies for individual patients. Toward this end, we have quantitatively profiled the proteome of tissue interstitial fluids (TIFs) from cancerous and adjacent non-cancerous tissues in oral cavities. Among the proteins over-expressed in OSCC TIFs, NSFL1 cofactor p47 (NSFL1C) has been selected for further investigation as a metastasis-associated molecule, based on the finding that the expression of NSFL1C was significantly elevated in OSCC TIFs with lymphatic metastasis comparing with that without lymphatic metastasis. NSFL1C is a major adaptor of p97, a cytosolic ATPase associated with various cellular activities. The NSFL1C/p97 complex is involved in the reassembly of Golgi stacks at the end of mitosis. However, the expressional profiling and the functional characterization of NSFL1C in human cancer remain limited to date. Our preliminary data have revealed that NSFL1C, as a migration-promoting protein in OSCC cells, is over-expressed in OSCC tissues compared to adjacent non-cancerous counterparts. Given that OSCC is a highly metastatic head and neck cancer, discovery of the role of NSFL1C in OSCC cells will accelerate the understanding of lymphatic metastasis in OSCC. In the present proposal, we attempt to conduct a comprehensive, proteome-wide analysis of NSFL1C function in OSCC cells. We aim to (1) systemically identify the components of NSFL1C-associated protein complexes, (2) comparatively profile the proteome isolated respectively from NSFL1C-depleted and control cells to discover the components which are potentially regulated by NSFL1C, and (3) focus on validation of candidates which appear to be involved in NSFL1C-mediated promotion of cell migration. This study could then lead to therapeutic targets and the development of drugs to limit or eradicate the spreading of OSCC.

Project ID:PC10507-0280
External Project ID:MOST105-2320-B182-025