ABSTRACT
A library of 14-helical hexa ß(3)-peptides was synthesized in order to determine the influence of sequence variation as well as staple size and location on conformational stability. From this study we show that appropriately stapled hexa-ß(3)-peptides can allow for a number of variations without significant perturbation of the 14-helix.
Subject(s)
Peptide Library , Alkenes/chemistry , Circular Dichroism , Molecular Conformation , Protein StabilityABSTRACT
JQ1 is a BET-bromodomain inhibitor that has immunomodulatory effects. However, the precise molecular mechanism that JQ1 targets to elicit changes in antibody production is not understood. Our results show that JQ1 induces apoptosis, reduces cell proliferation, and as a consequence, inhibits antibody-secreting cell differentiation. ChIP-sequencing reveals a selective displacement of Brd4 in response to acute JQ1 treatment (<2 h), resulting in specific transcriptional repression. After 8 h, subsequent alterations in gene expression arise as a result of the global loss of Brd4 occupancy. We demonstrate that apoptosis induced by JQ1 is solely attributed to the pro-apoptotic protein Bim (Bcl2l11). Conversely, cell-cycle regulation by JQ1 is associated with multiple Myc-associated gene targets. Our results demonstrate that JQ1 drives temporal changes in Brd4 displacement that results in a specific transcriptional profile that directly affects B cell survival and proliferation to modulate the humoral immune response.
Subject(s)
Bcl-2-Like Protein 11/metabolism , Nuclear Proteins/metabolism , Transcription Factors/metabolism , Animals , Apoptosis/drug effects , Azepines/pharmacology , B-Lymphocytes/metabolism , Bcl-2-Like Protein 11/physiology , Cell Cycle Checkpoints/drug effects , Cell Differentiation/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Female , Gene Expression Regulation, Neoplastic/drug effects , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Nuclear Proteins/genetics , Nuclear Proteins/physiology , Proto-Oncogene Proteins c-myc/metabolism , Transcription Factors/genetics , Transcription Factors/physiology , Triazoles/pharmacology , Xenograft Model Antitumor AssaysABSTRACT
The key tricyclic intermediate 3a, for the total synthesis of the C(20)-nor analogue of salvinorin A, was prepared in seven steps from 3-furaldehyde. Key steps involved a highly regio- and diastereoselective Lewis acid assisted Diels-Alder reaction followed by base-promoted epimerization and a completely stereoselective conjugate reduction.
Subject(s)
Diterpenes, Clerodane/chemical synthesis , Heterocyclic Compounds, 3-Ring/chemical synthesis , Furaldehyde/chemistry , StereoisomerismABSTRACT
The first synthesis of carbon-stapled beta(3)-peptides is reported. The precursor beta(3)-peptides, with O-allyl beta-serines located in an i/i+3 relationship, were prepared on solid phase. We show that efficient ring-closing metathesis (RCM) of these new beta(3)-peptides proceeds smoothly either in solution or on an appropriate solid support. All products were generated with high selectivity for the E-isomer.