ABSTRACT
Bcl-2 homologues (such as Bcl-x(L)) promote survival in part through sequestration of "activator" BH3-only proteins (such as Puma), preventing them from directly activating Bax. It is thus assumed that inhibition of interactions between activators and Bcl-x(L) is a prerequisite for small molecules to antagonize Bcl-x(L) and induce cell death. The biological properties, described here of a terphenyl-based alpha-helical peptidomimetic inhibitor of Bcl-x(L) attest that displacement of Bax from Bcl-x(L) is also critical. Terphenyl 14 triggers Bax-dependent but Puma-independent cell death, disrupting Bax/Bcl-x(L) interactions without affecting Puma/Bcl-x(L) interactions. In cell-free assays, binding of inactive Bax to Bcl-x(L), followed by its displacement from Bcl-x(L) by terphenyl 14, produces mitochondrially permeabilizing Bax molecules. Moreover, the peptidomimetic kills yeast cells that express Bax and Bcl-x(L), and it uses Bax-binding Bcl-x(L) to induce mammalian cell death. Likewise, ectopic expression of Bax in yeast and mammalian cells enhances sensitivity to another Bcl-x(L) inhibitor, ABT-737, when Bcl-x(L) is present. Thus, the interaction of Bcl-x(L) with Bax paradoxically primes Bax at the same time it keeps Bax activity in check, and displacement of Bax from Bcl-x(L) triggers an apoptotic signal by itself. This mechanism might contribute to the clinical efficiency of Bcl-x(L) inhibitors.
Subject(s)
bcl-2-Associated X Protein/metabolism , bcl-X Protein/metabolism , Amino Acid Sequence , Animals , Apoptosis Regulatory Proteins/genetics , Apoptosis Regulatory Proteins/metabolism , Binding Sites , Biphenyl Compounds/pharmacology , Cell Death/drug effects , Cell Death/genetics , Cell Death/physiology , Cell Line, Tumor , Cell-Free System , Cells, Cultured , Gene Knockdown Techniques , HeLa Cells , Humans , In Vitro Techniques , Mice , Mice, Knockout , Mitochondria/metabolism , Models, Biological , Molecular Mimicry , Molecular Sequence Data , Mutation , Nitrophenols/pharmacology , Piperazines/pharmacology , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins/metabolism , RNA, Small Interfering/genetics , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Sulfonamides/pharmacology , Terphenyl Compounds/pharmacology , Tumor Suppressor Proteins/genetics , Tumor Suppressor Proteins/metabolism , Two-Hybrid System Techniques , bcl-2-Associated X Protein/deficiency , bcl-2-Associated X Protein/genetics , bcl-X Protein/deficiency , bcl-X Protein/geneticsABSTRACT
Modulations of alpha and aryl substitutions on 3-aryloxy propionic acid hydroxamates led to novel and potent inhibitors of MMP-2,3,9 and 13, and selectivity versus MMP-1.
Subject(s)
Matrix Metalloproteinase Inhibitors , Propionates/pharmacology , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacokinetics , Antineoplastic Agents/pharmacology , Antirheumatic Agents/chemical synthesis , Antirheumatic Agents/pharmacokinetics , Antirheumatic Agents/pharmacology , Biological Availability , Cartilage/drug effects , Combinatorial Chemistry Techniques , Drug Stability , Humans , Mice , Microsomes, Liver , Neoplasm Metastasis/drug therapy , Neoplasms, Experimental/drug therapy , Propionates/chemical synthesis , Propionates/pharmacokinetics , Proteoglycans/drug effects , Proteoglycans/metabolism , Structure-Activity Relationship , Substrate Specificity , Tumor Cells, CulturedABSTRACT
Modified deoxynucleosides 2'-deoxy-beta-L-uridine, beta-L-thymidine, alpha-L-thymidine, 2'-deoxy-beta-L-adenosine and 2'-deoxy-alpha-L-adenosine were synthesized and assembled as homooligomers, respectively: octa-beta-L-deoxyuridylates, octa beta-L and alpha-L-thymidylates and tetra beta-L and alpha-L-deoxyadenylates. These unnatural oligomers were then substituted with an acridine derivative. The binding studies of these modified oligonucleotides with D-ribo- and D-deoxyribopolynucleotides were carried out by absorption spectroscopy. While beta-L-d(Up)8m5Acr, beta-L-(Tp)8m5Acr, alpha-L-(Tp)8m5Acr did not interact with poly(rA) and poly(dA), beta-L-d(Ap)4m5Acr and alpha-L-d(Ap)4m5Acr did form double and triple helices with poly(rU) and poly(dT), respectively. Their stability towards nuclease digestion was studied through comparison with that of octa-beta-D-thymidylate and tetra beta-D-deoxyadenylate covalently linked to an acridine derivative. One endonuclease (nuclease P1 from Penicillium citrinum) and two exonucleases (a 3'-exonuclease from Crotalus durissus venom and a 5'-exonuclease extracted from calf thymus) were employed. beta-L- and alpha-L-oligomers demonstrate a high resistance toward nuclease digestion.
