ABSTRACT
Glioblastoma multiforme (GBM) has been subdivided into two types based on clinical and genetic findings: primary tumors, which arise de novo, and secondary tumors, which progress from lower grade gliomas to GBMs. To analyse this dichotomy at the protein level, we employed selective tissue microdissection to obtain pure populations of tumor cells, which we studied using two-dimensional protein gel electrophoresis (2-DGE) and protein sequencing of select target proteins. Protein patterns were analysed in a blinded manner from the clinical and genetic data. 2-DGE clearly identified two distinct populations of tumors. 2-DGE was reproducible and reliable, as multiple samples analysed from the same patient gave identical results. In addition, we isolated and sequenced 11 proteins that were uniquely expressed in either the primary or the secondary GBMs, but not both. We demonstrate that specific proteomic patterns can be reproducibly identified by two-dimensional gel electrophoresis from limited numbers of selectively procured, microdissected tumor cells and that two patterns of GBMs, primary versus secondary, previously distinguished by clinical and genetic differences, can be recognized at the protein level. Proteins that are expressed distinctively may have important implications for the diagnosis, prognosis, and treatment of patients with GBM.
Subject(s)
Glioblastoma/classification , Glioblastoma/genetics , Neoplasm Proteins/isolation & purification , Base Sequence , DNA Primers , Electrophoresis, Gel, Two-Dimensional , Glioblastoma/pathology , Humans , Mutation/genetics , Neoplasm Proteins/genetics , Neoplasms, Second Primary/classification , Neoplasms, Second Primary/genetics , Neoplasms, Second Primary/pathology , PTEN Phosphohydrolase , Phosphoric Monoester Hydrolases/genetics , Polymerase Chain Reaction , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Proteins/geneticsABSTRACT
A systematic structure-activity relationship investigation of the lead compound 1 resulted the identification of several N-[(substituted alkyl)cycloalkanoyl]-4-[((2,6-dichlorophenyl)carbonyl)amino]-L-phenylalanine derivatives as potent VCAM/VLA-4 antagonists. The data are consistent with a model of these compounds in which these alkanoylphenylalanines reside in a compact gauche (-) bioactive conformation.
Subject(s)
Integrin alpha4beta1/antagonists & inhibitors , Phenylalanine/analogs & derivatives , Vascular Cell Adhesion Molecule-1/drug effects , Crystallography, X-Ray , Cycloparaffins/chemical synthesis , Cycloparaffins/pharmacology , Humans , Inhibitory Concentration 50 , Molecular Structure , Phenylalanine/pharmacology , Protein Binding , Structure-Activity RelationshipABSTRACT
A series of N-benzoyl-4-[(2,6-dichlorobenzoyl)amino]-L-phenylalanine derivatives was prepared in order to optimize the substitution on the N-benzoyl moiety for VCAM/VLA-4 antagonist activity. Disubstitution in the 2- and 6-positions is favored and a range of small alkyl and halogen are tolerated. A model of the bioactive conformation of these compounds is proposed.
Subject(s)
Integrin alpha4beta1/antagonists & inhibitors , Phenylalanine/analogs & derivatives , Vascular Cell Adhesion Molecule-1/drug effects , Heterocyclic Compounds/chemistry , Humans , Hydrocarbons, Aromatic , Inhibitory Concentration 50 , Models, Molecular , Molecular Mimicry , Phenylalanine/pharmacology , Protein Binding , Structure-Activity RelationshipABSTRACT
A structure-based focused library approach was employed in an effort to identify more lipophilic replacements for the N-benzylpyroglutamyl group of the VCAM/VLA-4 antagonist 2. This effort led to the discovery of two new classes of potent antagonists characterized by the N-(alpha-phenylcyclopentanoyl- and the N-(2,6-dimethylbenzoyl)-derivatives 60 and 64.
