A Novel CD44-binding Peptide from the Pro-Matrix Metalloproteinase-9 Hemopexin Domain Impairs Adhesion and Migration of Chronic Lymphocytic Leukemia (CLL) Cells

• Published in: The Journal of biological chemistry 2014-05, Vol.289 (22), p.15340-15349
• Main Authors: Ugarte-Berzal, Estefanía, Bailón, Elvira, Amigo-Jiménez, Irene, Albar, Juan Pablo, García-Marco, José A., García-Pardo, Angeles
• Format: Article
• Language: English
• Subjects: Aged; Amino Acid Sequence; CD44; Cell Adhesion; Cell Adhesion - physiology; Cell Migration; Cell Movement - physiology; Disease Progression; Drug Design; Enzyme Precursors - chemistry; Enzyme Precursors - metabolism; Female; Hemopexin - chemistry; Hemopexin - metabolism; Humans; Hyaluronan Receptors - metabolism; Leukemia; Leukemia, Lymphocytic, Chronic, B-Cell - drug therapy; Leukemia, Lymphocytic, Chronic, B-Cell - metabolism; Leukemia, Lymphocytic, Chronic, B-Cell - pathology; Male; Matrix Metalloproteinase 9 - chemistry; Matrix Metalloproteinase 9 - metabolism; Metalloprotease; Middle Aged; Molecular Bases of Disease; Molecular Sequence Data; Peptides - chemical synthesis; Peptides - metabolism; Protein Binding - physiology; Protein Structure, Tertiary
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M114.559187

(pro)MMP-9 binds to CLL cells through the PEX9 domain and contributes to CLL progression. To biochemically characterize this interaction and identify potential therapeutic targets, we prepared GST-PEX9 forms containing structural blades B1B2 or B3B4. We recently described a sequence in blade B4 (P3 sequence) that bound α4β1 integrin and partially impaired cell adhesion and migration. We have now studied the possible contribution of the B1B2 region to cell interaction with PEX9. CLL cells bound to GST-B1B2 and CD44 was the primary receptor. GST-B1B2 inhibited CLL cell migration as effectively as GST-B3B4. Overlapping synthetic peptides spanning the B1B2 region identified the sequence FDAIAEIGNQLYLFKDGKYW, present in B1 and contained in peptide P6, as the most effective site. P6 inhibited cell adhesion to PEX9 in a dose-dependent manner and with an IC50 value of 90 μm. P6 also inhibited cell adhesion to hyaluronan but had no effect on adhesion to VCAM-1 (α4β1 integrin ligand), confirming its specific interaction with CD44. Spatial localization analyses mapped P6 to the central cavity of PEX9, in close proximity to the previously identified P3 sequence. Both P6 and P3 equally impaired cell adhesion to (pro)MMP-9. Moreover, P6 synergistically cooperated with P3, resulting in complete inhibition of CLL cell binding to PEX9, chemotaxis, and transendothelial migration. Thus, P6 is a novel sequence in PEX9 involved in cell-PEX9/(pro)MMP-9 binding by interacting with CD44. Targeting both sites, P6 and P3, should efficiently prevent (pro)MMP-9 binding to CLL cells and its pathological consequences. proMMP-9 binds to CLL cells through the hemopexin domain (PEX9), contributing to disease progression. A 20-residue sequence (P6) within PEX9 inhibits CD44-mediated CLL-proMMP-9 interaction and cell migration. P6 cooperates with the previously identified sequence P3, also located in PEX9. P6 is a CD44-binding site and impairs proMMP-9 effects on CLL. P6 may be a novel therapeutic target in CLL.