PROGRESS IN THE TECHNOLOGY OF ANIMAL CELLS CULTURES IN LARGE QUANTITIES.
After specific stimulation by the appropriate growth factors, tyrosine kinases phosphorylate themselves on tyrosine as the first step in the cascade of events ending in the promotion of deoxyribonucleic acid (DNA) synthesis and cell growth. To idenfity new growth factor receptors, antiphosphotyrosine antibodies have been produced and used to screen a variety of normal and tumour cell model systems. In 2 instances antiphosphotyrosine antibodies identified a new tyrosine kinase. One (p190met) turned out to be a growth factor receptor expressed by epithelial cells and tumours of the gastrointestinal tract. The other (p56lck) was found to a transmembrane signal transducer coupled to a lymphocyte receptor, involved in the immune response and deregulated in leukaemia cells. In response to their specific extracellular ligands, these cell membrane molecules activated their tyrosine kinase activity and transduced the mitogenic signal into the cell's internal machinery. Under physiological conditions, the process was tightly controlled by the exogenous ligand. Pathological constitutive autoactivation of the tyrosine kinase was observed only in the case of structural alterations of the receptor itself or in autocrine loops, where the same cell simultaneously expresses both the growth factor and the receptor.
INABILITY TO ADHERE TO THE CONVENTIONAL PLASTIC SURFACES AND LACK OF APPROPRIATE GROWTH FACTORS ARE THE MAIN REASONS FOR THE FAILURE TO ESTABLISH CELL LINES IN VITRO. THE STRATEGY OF THIS RESEARCH IS TO DEVELOP ASSAYS TO SELECT APPROPRIATE ADHESION AND GROWTH FACTORS FOR TUMOR CELLS EXPLANTS.
MAJOR STEPS OF THE RESEARCH :
- DEVELOPMENT OF RAPID ASSAYS TO ASSESS ADHESION REQUIREMENTS.
- RECONSTITUTION OF ARTIFICIAL MATRICES STARTING FROM PURIFIED COMPONENTS TO PROMOTE ADHESION OF CELLS THAT DO NOT RESPOND TO A SINGLE FACTOR.
- DEFINITION OF APPROPRIATE CONDITIONS TO STIMULATE CELLS TO PRODUCE THEIR OWN MATRIX.
- DEVELOPMENT OF RAPID ASSAYS TO SELECT GROWTH FACTORS FOR EACH CELL TYPES.
- DEFINITION OF OPTIMAL CELL GROWTH CONDITIONS.
Funding SchemeCSC - Cost-sharing contracts