Biology subjects

Arrowsmith, C. H.

Publications and source records attributed to Arrowsmith, C. H..

42 records · Page 3Linked to original sources

bioRxiv2019

A Chemical Probe of CARM1 Alters Epigenetic Plasticity against Breast Cancer Cell Invasion

CARM1 is a cancer-relevant protein arginine methyltransferase that regulates many aspects of transcription. Its pharmacological inhibition is a promising anti-cancer strategy. Here SKI-73 is presented as a CARM1 chemical probe with pro-drug properties. SKI-73 can rapidly penetrate cell membranes and then be processed into active inhibitors, which are retained intracellularly with 10-fold enrichment for days. These compounds were characterized for their potency, selectivity, modes of action, and on-target engagement. SKI-73 recapitulates the effect of CARM1 knockout against breast cancer cell invasion. Single-cell RNA-seq analysis revealed that the SKI-73-associated reduction of invasiveness act via altering epigenetic plasticity and suppressing the invasion-prone subpopulation. Interestingly, SKI-73 and CARM1 knockout alter the epigenetic plasticity with remarkable difference, arguing distinct modes of action between the small-molecule and genetic perturbation. We therefore discovered a CARM1-addiction mechanism of cancer metastasis and developed a chemical probe to target this process.

biochemistry↗

bioRxiv2019

Structural basis of HMCES interactions with DNA reveals multivalent substrate recognition

HMCES can covalently crosslink to abasic sites in single-stranded DNA at stalled replication forks to prevent genome instability. Here, we report crystal structures of the HMCES SRAP domain in complex with DNA-damage substrates, revealing interactions with both single-stranded and duplex segments of 3 overhang DNA. HMCES may also bind gapped DNA and 5 overhang structures to align single stranded abasic sites for crosslinking to the conserved Cys2 of its catalytic triad.

biochemistry↗

bioRxiv2018

Pharmacological inhibition of PRMT7 links arginine monomethylation to the cellular stress response

Protein arginine methyltransferases (PRMTs) regulate diverse biological processes and are increasingly being recognized for their potential as drug targets. Here we report the discovery of a potent, selective and cell active chemical probe for PRMT7. SGC3027 is a cell permeable prodrug, which in cells, is converted to SGC8158, a potent, SAM-competitive PRMT7 inhibitor. Inhibition or knockout of cellular PRMT7 resulted in drastically reduced levels of arginine monomethylation of HSP70 family members and other stress-associated proteins. Structural and biochemical analysis revealed that PRMT7-driven in vitro methylation of HSP70 at R469 requires an ATP-bound, open conformation of HSP70. In cells, SGC3027 inhibited methylation of both constitutive and inducible forms of HSP70, and led to decreased tolerance for perturbations of proteostasis including heat shock and proteasome inhibitors. These results demonstrate a role for PRMT7 and arginine methylation in stress response.

biochemistry↗

bioRxiv2018

A Chemical Toolbox for the Study of Bromodomains and Epigenetic Signaling

Bromodomains (BRDs) are evolutionary conserved epigenetic protein interaction modules which recognize (\"read\") acetyl-lysine, however their role(s) in regulating cellular states and their potential as targets for the development of targeted treatment strategies is poorly understood. Here we present a set of 25 chemical probes, selective tool small molecule inhibitors, covering 29 human bromodomain targets. We comprehensively evaluate the selectivity of this probe-set using BROMOscan(R) and demonstrate the utility of the set using studies of muscle cell differentiation and triple negative breast cancer (TNBC). We identified cross talk between histone acetylation and the glycolytic pathway resulting in a vulnerability of TNBC cell lines to inhibition of BRPF2/3 BRDs under conditions of glucose deprivation or GLUT1 inhibition. This chemical probe set will serve as a resource for future applications in the discovery of new physiological roles of bromodomain proteins in normal and disease states, and as a toolset for bromodomain target validation.

cell biology↗

bioRxiv2018

MLL1 minimal catalytic complex is a dynamic conformational ensemble susceptible to pharmacological allosteric disruption

Histone H3K4 methylation is an epigenetic mark associated with actively transcribed genes. This modification is catalyzed by the mixed lineage leukaemia (MLL) family of histone methyltransferases including MLL1, MLL2, MLL3, MLL4, SET1A and SET1B. Catalytic activity of MLL proteins is dependent on interactions with additional conserved proteins but the structural basis for subunit assembly and the mechanism of regulation is not well understood. We used a hybrid methods approach to study the assembly and biochemical function of the minimally active MLL1 complex (MLL1, WDR5 and RbBP5). A combination of small angle X-ray scattering (SAXS), cross-linking mass spectrometry (XL-MS), NMR spectroscopy, and computational modeling were used to generate a dynamic ensemble model in which subunits are assembled via multiple weak interaction sites. We identified a new interaction site between the MLL1 SET domain and the WD40 repeat domain of RbBP5, and demonstrate the susceptibility of the catalytic function of the complex to disruption of individual interaction sites.

biophysics↗

bioRxiv2018

A Chemical Biology Toolbox for the Study of Protein Methyltransferases and Epigenetic Signaling

Protein methyltransferases (PMTs) comprise a major class of epigenetic regulatory enzymes with therapeutic relevance. Here we present a collection of chemical probes and associated reagents and data to elucidate the function of human and murine PMTs in cellular studies. Our collection provides inhibitors and antagonists that together modulate most of the key regulatory methylation marks on histones H3 and H4, providing an important resource for modulating cellular epigenomes. We describe a comprehensive and comparative characterization of the probe collection with respect to their potency, selectivity, and mode of inhibition. We demonstrate the utility of this collection in CD4+ T cell differentiation assays revealing the remarkable potential of individual probes to alter multiple T cell subpopulations with important implications for T cell-mediated processes such as inflammation and immuno-oncology. In particular, we demonstrate a role for DOT1L in limiting Th1 cell differentiation and maintaining lineage integrity.

biochemistry↗