The basement membrane plays a key role in the metastasis of tumor cells. During the complex, multi-step process of metastasis, tumor cells must disseminate from the primary tumor mass, migrate through the basement membrane, enter the bloodstream or lymphatic system, arrest in a capillary bed, adhere, degrade, and migrate through the basement membrane, proliferate, and become vascularized. The basement membrane serves as a barrier for tumor cells and is critically important in phenotypic modulation of malignant cells. Laminin promotes adhesion, migration by haptotaxis, and invasion of metastatic cells. The proposal will focus on discrete peptide sequences of the B1, B2, and A chains of laminin that promote adhesion. Migration and invasion of metastatic tumor cells. These peptides will be tested for the ability to modify experimental tumor metastasisor colony formation in vitro. The binding conditions of peptides for cells and heparin and other glycosaminoglycans will be determined. A structural functional analysis of peptides will be performed to: (a) discern the minimal functional sequence and (b) the critical amino acids necessary for function. Antibodies, polyclonal and monoclonal of functionally active peptides will be generated to attempt to block the function of the particular sequence in the intact, native molecule, relative to adhesion, migration, invasion, binding of laminin to tumor cells and heparin binding. The next studies will isolate """"""""receotors"""""""" from metastaric cells for the biologically active laminin synthetic peptides derived from 81' 82' or A chains. These receptors will be identified by one of the following methods: 1) affinity purification on laminin columns. Followed by elution with specific peptides; 2) affinity purification on peptide columns or 3) a complimentary peptide/ antiidiotypic antibody approach. Any putative receptors would be casted for similarity co the 67 KD receptor or integrins. Polyclonal and monoclonal antibodies receptor molecules would be generated and tested for their ability to modify novel a) cell adhesion and spreading. b) cell migration. c) cell invasion and do experimental tumor metastasis. These studies floresent a molecular approach towards understanding and modulating the phenotypic behavior of metastatic cells and potentially designing reagents for therapeutic uses in cancer treatment.
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