Herein we report the identification of a novel class of HDAC6 and HDAC8 selective inhibitors through a unique chemistry and phenotypic screening strategy. Tetrahydroisoquinoline 12 was identified as a potent HDAC6 and HDAC8 dual inhibitor from a focused library through cellular tubulin acetylation and p21 induction screening assays. Scaffold hopping from 12 led to the discovery of an aminotetralin class of HDAC inhibitors. In particular, the 3-R stereoisomer 32 showed highly potent inhibition against HDAC6 and HDAC8 with IC50 values of 50 and 80 nM, respectively. Treatment of neuroblastoma BE(2)C cells with 32 resulted in elevated levels of acetylated tubulin, TrkA, and neurite outgrowth with only marginal effects on p21 induction and histone H3 acetylation. Consistent with its weak enzymatic inhibition of HDAC1, 32 showed significantly less cytotoxicity than SAHA and moderately inhibited the growth of myeloma NCI-H929 and OPM-2 cells.
The YAP-TEAD protein-protein interaction (PPI) mediates the oncogenic function of YAP, and inhibitors of this PPI have potential usage in treatment of YAP-involved cancers. Here we report the design and synthesis of potent cyclic peptide inhibitors of the YAP-TEAD interaction. A truncation study of YAP interface 3 peptide identified YAP(84-100) as a weak peptide inhibitor (IC50 = 37 ?M), and an alanine scan revealed a beneficial mutation, D94A. Subsequent replacement of a native cation-? interaction with an optimized disulfide bridge for conformational constraint and synergistic effect between macrocyclization and modification at positions 91 and 93 greatly boosted inhibitory activity. Peptide 17 was identified with an IC50 of 25 nM, and the binding affinity (K d = 15 nM) of this 17mer peptide to TEAD1 proved to be stronger than YAP(50-171) (K d = 40 nM).
Study Design. A human cadaveric biomechanical study of a novel, prefabricated autogenous bone interbody fusion (ABIF) cage.Objective. To evaluate the biomechanical properties of the ABIF cage in a single-level construct with and without transpedicular screw and rod fixation.Summary of Background Data. In current practice, posterior lumbar interbody fusion (PLIF) is generally carried out using synthetic interbody spacers or corticocancellous iliac crest bone graft (ICBG) in combination with posterior instrumentation. However, questions remain concerning the use of synthetic intervertebral implants as well as the morbidity ICBG harvesting. Therefore, ABIF cage has been developed to obviate some of the challenges in conventional PLIF instrumentation and to facilitate the fusion process.Methods. Eighteen adult cadaveric lumbosacral (L3-S1) specimens were tested. Test conditions included single lumbosacral segments across (1) intact, (2) decompressed, (3) intervertebral cage alone, and (4) intervertebral cage with bilateral transpedicular fixation. Range of motion (ROM), neutral zone (NZ) and axial failure load were tested for each condition.Resluts. The ICBG, PEEK cage or ABIF cage alone exhibited a significantly lower (p<0.05) ROM and NZ compared to the decompressed spine. In comparison with the intact spine, all three test conditions without supplemental fixation was able to decrease ROM and NZ to near intact levels. When stabilized with pedicle screws, the ROM was significantly less and the NZ significantly lower (p<0.05) for each group both compared to the intact spine. In axial compression testing, the failure load of PEEK cage was the highest, with no significant difference between the ICBG and the ABIF cage.Conclusion. These data suggest the novel ABIF cage can bear the physiologic intervertebral peak load, similar to ICBG. When combined with pedicle screw and rod fixation, it exhibits similar biomechanical properties as the PEEK cage plus posterior instrumentation. Based on the biomechanical properties of ABIF cage, the prospect of these cages in clinical practice is expected.
Novel 2-aminoanilide histone deacetylase (HDAC) inhibitors were designed to increase their contact with surface residues surrounding the HDAC active site compared to the contacts made by existing clinical 2-aminoanilides such as SNDX-275, MGCD0103, and Chidamide. Their HDAC selectivity was assessed using p21 and klf2 reporter gene assays in HeLa and A204 cells, respectively, which provide a cell-based readout for the inhibition of HDACs associated either with the p21 or klf2 promoter. A subset of the designed compounds selectively induced p21 over klf2 relative to the clinical reference compound SNDX-275. A representative lead compound from this subset had antiproliferative effects in cancer cells associated with induction of acetylated histone H4, endogenous p21, cell cycle arrest, and apoptosis. The p21- versus klf2-selective compounds described herein may provide a chemical starting point for developing clinically-differentiated HDAC inhibitors for cancer therapy.
According to the docking studies and the analysis of a co-crystal structure of GW4064 with FXR, a series of 3-aryl heterocyclic isoxazole analogs were designed and synthesized. N-Oxide pyridine analog (7b) was identified as a promising FXR agonist with potent binding affinity and good efficacy, supporting our hypothesis that through an additional hydrogen bond interaction between the pyridine substituent of isoxazole analogs and Tyr373 and Ser336 of FXR, binding affinity and functional activity could be improved.
Herein, we describe the pharmacokinetic optimization of a series of class-selective histone deacetylase (HDAC) inhibitors and the subsequent identification of candidate predictive biomarkers of hepatocellular carcinoma (HCC) tumor response for our clinical lead using patient-derived HCC tumor xenograft models. Through a combination of conformational constraint and scaffold hopping, we lowered the in vivo clearance (CL) and significantly improved the bioavailability (F) and exposure (AUC) of our HDAC inhibitors while maintaining selectivity toward the class I HDAC family with particular potency against HDAC1, resulting in clinical lead 5 (HDAC1 IC?? = 60 nM, mouse CL = 39 mL/min/kg, mouse F = 100%, mouse AUC after single oral dose at 10 mg/kg = 6316 h·ng/mL). We then evaluated 5 in a biomarker discovery pilot study using patient-derived tumor xenograft models, wherein two out of the three models responded to treatment. By comparing tumor response status to compound tumor exposure, induction of acetylated histone H3, candidate gene expression changes, and promoter DNA methylation status from all three models at various time points, we identified preliminary candidate response prediction biomarkers that warrant further validation in a larger cohort of patient-derived tumor models and through confirmatory functional studies.
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