Martine I. Abboud

We report the development of a potent and selective de novo cyclic peptide ligand for epigenetic methyllysine reader domain. The cyclic peptide binds at the aromatic cage of PHD-finger and modulates the JmjC lysine demethylase activity of KDM7.

Supplementary Table from JMJD6 Is a Druggable Oxygenase That Regulates AR-V7 Expression in Prostate Cancer

Supplementary Figure from JMJD6 Is a Druggable Oxygenase That Regulates AR-V7 Expression in Prostate Cancer

Supplementary Table from JMJD6 Is a Druggable Oxygenase That Regulates AR-V7 Expression in Prostate Cancer

Supplementary Figure from JMJD6 Is a Druggable Oxygenase That Regulates AR-V7 Expression in Prostate Cancer

Endocrine resistance (EnR) in advanced prostate cancer is fatal. EnR can be mediated by androgen receptor (AR) splice variants, with AR splice variant 7 (AR-V7) arguably the most clinically important variant. In this study, we determined proteins key to generating AR-V7, validated our findings using clinical samples, and studied splicing regulatory mechanisms in prostate cancer models. Triangulation studies identified JMJD6 as a key regulator of AR-V7, as evidenced by its upregulation with in vitro EnR, its downregulation alongside AR-V7 by bromodomain inhibition, and its identification as a top hit of a targeted siRNA screen of spliceosome-related genes. JMJD6 protein levels increased (P < 0.001) with castration resistance and were associated with higher AR-V7 levels and shorter survival (P = 0.048). JMJD6 knockdown reduced prostate cancer cell growth, AR-V7 levels, and recruitment of U2AF65 to AR pre-mRNA. Mutagenesis studies suggested that JMJD6 activity is key to the generation of AR-V7, with the catalytic machinery residing within a druggable pocket. Taken together, these data highlight the relationship between JMJD6 and AR-V7 in advanced prostate cancer and support further evaluation of JMJD6 as a therapeutic target in this disease.Significance:This study identifies JMJD6 as being critical for the generation of AR-V7 in prostate cancer, where it may serve as a tractable target for therapeutic intervention.

Hypoxia, that is, an inadequate oxygen supply, is linked to neurodegeneration and patients with cardiovascular disease are prone to Alzheimer's disease (AD). 2‐Oxoglutarate and ferrous iron‐dependent oxygenases (2OGDD) play a key role in the regulation of oxygen homeostasis by acting as hypoxia sensors. 2OGDD also have roles in collagen biosynthesis, lipid metabolism, nucleic acid repair, and the regulation of transcription and translation. Many biological processes in which the >60 human 2OGDD are involved are altered in AD patient brains, raising the question as to whether 2OGDD are involved in the transition from normal aging to AD. Here we give an overview of human 2OGDD and critically discuss their potential roles in AD, highlighting possible relationships with synapse dysfunction/loss. 2OGDD may regulate neuronal/glial differentiation through enzyme activity‐dependent mechanisms and modulation of their activity has potential to protect against synapse loss. Work linking 2OGDD and AD is at an early stage, especially from a therapeutic perspective; we suggest integrated pathology and in vitro discovery research to explore their roles in AD is merited. We hope to help enable long‐term research on the roles of 2OGDD and, more generally, oxygen/hypoxia in AD. We also suggest shorter term empirically guided clinical studies concerning the exploration of 2OGDD/oxygen modulators to help maintain synaptic viability are of interest for AD treatment.

The JmjC family of 2-oxoglutarate dependent oxygenases catalyse a range of hydroxylation and demethylation reactions in humans and other animals. Jumonji domain-containing 7 (JMJD7) is a JmjC (3S)-lysyl-hydroxylase that catalyses the modification of Developmentally Regulated GTP Binding Proteins 1 and 2 (DRG1 and 2); JMJD7 has also been reported to have histone endopeptidase activity. Here we report biophysical and biochemical studies on JMJD7 from Drosophila melanogaster (dmJMJD7). Notably, crystallographic analyses reveal that the unusual dimerization mode of JMJD7, which involves interactions between both the N- and C-terminal regions of both dmJMJD7 monomers and disulfide formation, is conserved in human JMJD7 (hsJMJD7). The results further support the assignment of JMJD7 as a lysyl hydroxylase and will help enable the development of selective inhibitors for it and other JmjC oxygenases.

Cancer linked isocitrate dehydrogenase (IDH) 1 variants, notably R132H IDH1, manifest a ‘gain-of-function’ to reduce 2-oxoglutarate to 2-hydroxyglutarate. High-throughput screens have enabled clinically useful R132H IDH1 inhibitors, mostly allosteric binders at the dimer interface. We report investigations on roles of divalent metal ions in IDH substrate and inhibitor binding that rationalise this observation. Mg²⁺/Mn²⁺ ions enhance substrate binding to wt IDH1 and R132H IDH1, but with the former manifesting lower Mg²⁺/Mn²⁺K_Ms. The isocitrate-Mg²⁺ complex is the preferred wt IDH1 substrate; with R132H IDH1, separate and weaker binding of 2-oxoglutarate and Mg²⁺ is preferred. Binding of R132H IDH1 inhibitors at the dimer interface weakens binding of active site Mg²⁺ complexes; their potency is affected by the Mg²⁺ concentration. Inhibitor selectivity for R132H IDH1 over wt IDH1 substantially arises from different stabilities of wt and R132H IDH1 substrate-Mg²⁺ complexes. The results reveal the importance of substrate-metal ion complexes in wt and R132H IDH1 catalysis and the basis for selective R132H IDH1 inhibition. Further studies on roles of metal ion complexes in TCA cycle and related metabolism, including from an evolutionary perspective, are of interest.