Effects Of Integrinα5β1-mediated Signal Transduction Pathways On The Proliferation And Apoptosis Of K562 Cells

Objective: Chronic myeloid leukemia (CML) is a common malignant hematopoietic disease. More than 90% of patients with CML have the Philadelphia (Ph) chromosome which produces a specific oncoprotein known as BCR/ABL (P210) protein. Having strong tyrosine kinase activity, the P210 oncoprotein can trigger some signal transduction pathways of CML progenitors, and inhibit the normal signal transduction pathways. It is the reason that Ph+ cells proliferate excessively and escape apoptosis. Integrin blongs to the adhesion molecule family, which is an important ligand and expresses widely on many kinds of cells. Presenting on cell surface, integrin mediates the adhesive action between cell and cell or cell and extra cellular matrix (ECM). Focal adhesion kinase (FAK) is the medium that connects integrin and the downstream signal molecules in integrin-signal transduction pathway, and is the convergence of many signal pathways. In the integrin-signal transduction pathway which FAK is central, except for the ras-MAPK pathway, there are also phosphatidylinositol-3-kinase (PI3K) and protein kinase B (serine/threonrine kinase, AKT) signal molecules. It takes part in many physiological and pathological processes such as signaling transduction and activation of cellular function, cell growth, development, differentiation, migration, proliferation and apoptosis. The expression, structure and function of integrin were often abnormal on tumor cells. Studies proved that the normal signal transduction process was often inhibited and some abnormal signal transduction pathways mediated by integrin were activated in tumor cells. And these abnormal signal transduction pathways could induce the proliferation of tumor cells and made them avoid apoptosis. Integrin antibody could inhibit the proliferation of tumor cells and induce the apoptosis.