Basement membranes are important extracellular structures implicated in cellular adhesion, growth, differentiation, and cancer metastasis. The main structural components of basement membranes including Type IV collagen, laminin, fibronectin, proteoglycan, and entactin have been identified and their specific functions are now being investigated. Basement membrane components for these studies have been derived mainly from murine (EHS sarcoma) or rat (yolk sac tumor) sources, because there has not been a good source of human basement membranes. The main objective of this project is to establish human basement membrane producing tumors in both cell culture and in athymic (nude) mice as a perpetual source of human basement membrane components. A second objective of this project is to compare the structure and function of the human-derived basement membrane components with their murine-derived counterparts. Human tumors with the highest basement membrane producing capability will be identified by histologic and immunocytochemical methods using antibodies to Type IV collagen and laminin. Preliminary screening has indicated that the human tumors with the highest amounts of basement membrane synthesis include the adenoid cystic carcinoma of the salivary gland, the yolk sac (endodermal sinus) tumor of the testis, and adenocarcinoma of the kidney. Tumors of the above categories with the highest immunocytochemical demonstration of basement membrane will be established in both cell culture and as xenografts in athymic """"""""nude"""""""" mice. Laminin and Type IV collagen will be extracted from the human tumors by identical methods used in the extraction from the EHS sarcoma. The rate of synthesis of these components will be determined by using radiolabeling with C14 proline and S35 methionine and this will be compared to the synthesis rate of the EHS sarcoma. The basement membrane producing capability of the human tumors will be monitored over time with cell passage and xenograft transplantation. The structure and function of human laminin and Type IV collagen will be compared to their murine counterparts with SDS-PAGE, peptide mapping, rotary shadowing, attachment assays, and antibody cross-reactivation.
