title: Antibody fragments directed against different portions of the human neural cell adhesion molecule L1 act as inhibitors or activators of L1 function.
abstract: The neural cell adhesion molecule L1 plays important roles in neuronal migration and survival, neuritogenesis and synaptogenesis. L1 has also been found in tumors of different origins, with levels of L1 expression correlating positively with the metastatic potential of tumors. To select antibodies targeting the varied functions of L1, we screened the Tomlinson library of recombinant human antibody fragments to identify antibodies binding to recombinant human L1 protein comprising the entire extracellular domain of human L1. We obtained four L1 binding single-chain variable fragment antibodies (scFvs), named I4, I6, I13, and I27 and showed by enzyme-linked immunosorbent assay (ELISA) that scFvs I4 and I6 have high affinity to the immunoglobulin-like (Ig) domains 1-4 of L1, while scFvs I13 and I27 bind strongly to the fibronectin type III homologous (Fn) domains 1-3 of L1. Application of scFvs I4 and I6 to human SK-N-SH neuroblastoma cells reduced proliferation and transmigration of these cells. Treatment of SK-N-SH cells with scFvs I13 and I27 enhanced cell proliferation and migration, neurite outgrowth, and protected against the toxic effects of H(2)O(2) by increasing the ratio of Bcl-2/Bax. In addition, scFvs I4 and I6 inhibited and scFvs I13 and I27 promoted phosphorylation of src and Erk. Our findings indicate that scFvs reacting with the immunoglobulin-like domains 1-4 inhibit L1 functions, whereas scFvs interacting with the fibronectin type III domains 1-3 trigger L1 functions of cultured neuroblastoma cells.
authors.affiliation: Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong Province, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Gabriele
authors.initials: G
authors.lastname: Loers
authors.forename: Hong-Chao
authors.initials: HC
authors.lastname: Pan
authors.forename: Ricardo
authors.initials: R
authors.lastname: Gouveia
authors.forename: Wei-Jiang
authors.initials: WJ
authors.lastname: Zhao
authors.forename: Yan-Qin
authors.initials: YQ
authors.lastname: Shen
authors.forename: Ralf
authors.initials: R
authors.lastname: Kleene
authors.forename: Julia
authors.initials: J
authors.lastname: Costa
authors.forename: Melitta
authors.initials: M
authors.lastname: Schachner
mesh_terms: D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D039842:Neural Cell Adhesion Molecule L1 / Q000819:agonists* / Q000037:antagonists & inhibitors* / Q000378:metabolism; D016501:Neurites / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D057127:Single-Chain Antibodies / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D039842:Neural Cell Adhesion Molecule L1; D011994:Recombinant Proteins; D057127:Single-Chain Antibodies; D006861:Hydrogen Peroxide; D019061:src-Family Kinases