A tumor suppressor function of laminin-binding alpha-dystroglycan

Interaction of epithelial cells with basement membrane (BM) is mediated by cell-adhesion molecules, which regulate cell proliferation, motility, and differentiation by integrating signals from extracellular matrix and soluble factors. alpha-Dystroglycan (alpha-DG) is one of the most important adhesion molecules in epithelial cell-BM interaction. alpha-DG serves as the cell surface receptor for several major BM proteins, including laminin, perlecan, and agrin. The laminin G-like domain in all these proteins binds to a unique glycan structure, so-called laminin-binding glycan, attached to alpha-DG with high affinity. Formation of the laminin-binding glycan is required for the BM assembly, and loss or deficiency of the glycan causes muscular dystrophy. We studied the role of this alpha-DG-specific glycan modification in tumor development, and identified a tumor suppressor function of the laminin-binding alpha-DG. In this chapter, we describe methods used to isolate the cell populations from human prostate cancer cell line PC3 and characterize their potentials in tumor formation and metastasis in vitro and in vivo.