title: Rapid discovery of death ligands with one-bead-two-compound combinatorial library methods.
abstract: The one-bead-one-compound (OBOC) technology enables one to generate thousands to millions of chemical molecules on resin beads (90 μm diameter) such that each bead displays 10(13) copies of the same chemical entity. Whole-cell binding assays have been developed to screen OBOC combinatorial libraries for ligands that bind to specific cell surface receptors. While very powerful, this screening method does not address the downstream cell signaling properties of the binding ligand. We have modified the OBOC technology by introducing a fixed known cell adhesion ligand to the outer layer of each bead. This one-bead-two-compound (OB2C) library configuration allows the bound cells to interact with the random immobilized chemical molecules on each bead. The bound cells can then be probed for specific cellular responses such as apoptosis and activation or inhibition of a specific cell signaling pathway. To validate this concept, an OB2C combinatorial library was created such that a random hexapeptide plus a high affinity lymphoma targeting ligand LLP2A were displayed on each bead. This LLP2A-X(6) OB2C library was then screened with human T-cell leukemia cells (Molt-4) for cell death responses. After 5 days of incubation, propidium iodide was added to the bead library to stain dead cells. Beads coated by red fluorescent cells were isolated for sequence analysis. Two ligands identified by this method, when added to the lymphoid cancer cells, were able to induce cell death.
authors.affiliation: Department of Biochemistry and Molecular Medicine, Division of Hematology & Oncology, and Department of Internal Medicine, UC Davis Cancer Center, University of California Davis, Sacramento, California 95817, United States. pappanaicken.kumaresan@ucdmc.ucdavis.edu
authors.forename: Pappanaicken R
authors.initials: PR
authors.lastname: Kumaresan
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Mary
authors.initials: M
authors.lastname: Saunders
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Maeda
authors.forename: Ruiwu
authors.initials: R
authors.lastname: Liu
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Wang
authors.forename: Kit Sang
authors.initials: KS
authors.lastname: Lam
mesh_terms: D045744:Cell Line, Tumor; D020650:Combinatorial Chemistry Techniques; D006801:Humans; D015458:Leukemia, T-Cell / Q000473:pathology*; D008024:Ligands
chemical_list: D008024:Ligands