Mucin-1 C-terminal subunit (MUC1-C) (MUC1-C)

The Mucin-1 C-terminal subunit (MUC1-C) is a transmembrane oncoprotein that results from the proteolytic cleavage of the MUC1 precursor protein (UniProt: P15941). While the larger N-terminal subunit (MUC1-N) is heavily glycosylated and serves a protective role on the cell surface, MUC1-C is a signaling-active component that is frequently overexpressed and mislocalized in various human cancers, including breast, lung, and pancreatic carcinomas (Kufe, 2013, Cancer Biol Ther). MUC1-C functions as a critical node in oncogenic signaling by localizing to the cell membrane, mitochondria, and nucleus, where it interacts with key proteins such as beta-catenin, NF-kappaB, and various receptor tyrosine kinases (Raina et al., 2009, Cancer Research). These interactions drive the epithelial-mesenchymal transition (EMT), promote cancer stem cell phenotypes, and facilitate immune evasion (Hasegawa et al., 2016, Scientific Reports). Consequently, MUC1-C has emerged as a high-priority therapeutic target, with development efforts focusing on peptide inhibitors that block its oligomerization, as well as monoclonal antibodies and CAR-T cell therapies designed to exploit its tumor-specific expression (Kufe, 2017, Trends in Cancer).

Other names

CD227MUC1-CTMUC1 cytoplasmic tailMucin 1 transmembrane subunitEMAH23AGKL-6MAM6PEMPUMMUC1-C

The primary mechanism of action for drugs targeting the MUC1-C subunit involves the inhibition of its oligomerization, which is mediated by a specific CQC motif in its cytoplasmic domain (Raina et al., 2009, Cancer Research). By blocking this homodimerization, inhibitors prevent the translocation of MUC1-C to the nucleus and mitochondria, thereby disrupting its ability to act as a transcriptional co-activator for oncogenic pathways like Wnt/beta-catenin and NF-kappaB (Kufe, 2013, Cancer Biol Ther). Additionally, immunotherapeutic approaches such as CAR-T cells and monoclonal antibodies target the extracellular portion of MUC1-C to induce direct cytotoxic effects or antibody-dependent cellular cytotoxicity (ADCC) against tumor cells (Kufe, 2017, Trends in Cancer).