"If you're strung out and female, they will take advantage of you": A qualitative study exploring drug use and substance use service experiences among women in Boston and San Francisco.

BACKGROUND: Significant disparities in substance use severity and treatment persist among women who use drugs compared to men. Thus, we explored how identifying as a woman was related to drug use and treatment experiences. METHODS: The study recruited participants for a qualitative interview study in Boston and San Francisco from January-November 2020. Self-identified women, age ≥ 18 years, with nonprescribed opioid use in the past 14 days were eligible for inclusion. The study team developed deductive codes based on intersectionality theory and inductive codes generated from transcript review, and identified themes using grounded content analysis. RESULTS: The study enrolled thirty-six participants. The median age was 46; 58 % were White, 16 % were Black, 14 % were Hispanic, and 39 % were unstably housed. Other drug use was common with 81 % reporting benzodiazepine, 50 % cocaine, and 31 % meth/amphetamine use respectively. We found that gender (i.e., identifying as a woman) intersected with drug use and sex work practices and exacerbated experiences of marginalization. Violence was ubiquitous in drug use environments. Some women reported experiences of gender-based violence in substance use service settings that perpetuated cycles of trauma and reinforced barriers to care. Substance use services that were women-led, safe, and responsive to women's needs were valued and sought after. CONCLUSION: Women reported a cycle of trauma and drug use exacerbated by oppression in substance use services settings. In addition to increasing access to gender-responsive care, our study highlights the need for greater research and examination of practices within substance use service settings that may be contributing to gender-based violence.

Histone deacetylase inhibitors derived from 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine and related heterocycles selective for the HDAC6 isoform.

Acyl derivatives of 4-(aminomethyl)-N-hydroxybenzamide are potent sub-type selective HDAC6 inhibitors. Constrained heterocyclic analogs based on 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine show further enhanced HDAC6 selectivity and inhibitory activity in cells. Homology models suggest that the heterocyclic spacer can more effectively access the wider catalytic channel of HDAC6 compared to other HDAC sub-types.

Potent histone deacetylase inhibitors derived from 4-(aminomethyl)-N-hydroxybenzamide with high selectivity for the HDAC6 isoform.

A screen for HDAC6 inhibitors identified acyl derivatives of 4-(aminomethyl)-N-hydroxybenzamide as potent leads with unexpected selectivity over the other subtypes. We designed and synthesized constrained heterocyclic analogues such as tetrahydroisoquinolines that show further enhanced HDAC6 selectivity and inhibitory activity in cellular assays. Selectivity may be attributed to the benzylic spacer more effectively accessing the wider channel of HDAC6 compared to other HDAC subtypes as well as hydrophobic capping groups interacting with the protein surface near the rim of the active site.

Discovery of a potent and orally bioavailable benzolactam-derived inhibitor of Polo-like kinase 1 (MLN0905).

This article describes the discovery of a series of potent inhibitors of Polo-like kinase 1 (PLK1). Optimization of this benzolactam-derived chemical series produced an orally bioavailable inhibitor of PLK1 (12c, MLN0905). In vivo pharmacokinetic-pharmacodynamic experiments demonstrated prolonged mitotic arrest after oral administration of 12c to tumor bearing nude mice. A subsequent efficacy study in nude mice achieved tumor growth inhibition or regression in a human colon tumor (HT29) xenograft model.

Optimization of a series of dipeptides with a P3 threonine residue as non-covalent inhibitors of the chymotrypsin-like activity of the human 20S proteasome.

Starting from a tripeptide screening hit, a series of dipeptide inhibitors of the proteasome with Thr as the P3 residue has been optimized with the aid of crystal structures in complex with the ß-5/6 active site of y20S. Derivative 25, (ß5 IC(50)=7.4 nM) inhibits only the chymotryptic activity of the proteasome, shows cellular activity against targets in the UPS, and inhibits proliferation.

Characterization of a new series of non-covalent proteasome inhibitors with exquisite potency and selectivity for the 20S beta5-subunit.

The mammalian 26S proteasome is a 2500 kDa multi-catalytic complex involved in intracellular protein degradation. We describe the synthesis and properties of a novel series of non-covalent di-peptide inhibitors of the proteasome based [corrected] on a capped tri-peptide that was first identified by high-throughput screening of a library of approx. 350000 compounds for inhibitors of the ubiquitin-proteasome system in cells. We show that these compounds are entirely selective for the beta5 (chymotrypsin-like) site over the beta1 (caspase-like) and beta2 (trypsin-like) sites of the 20S core particle of the proteasome, and over a panel of less closely related proteases. Compound optimization, guided by X-ray crystallography of the liganded 20S core particle, confirmed their non-covalent binding mode and provided a structural basis for their enhanced in vitro and cellular potencies. We demonstrate that such compounds show low nanomolar IC50 values for the human 20S beta5 site in vitro, and that pharmacological inhibition of this site in cells is sufficient to potently inhibit the degradation of a tetra-ubiquitin-luciferase reporter, activation of NFkappaB (nuclear factor kappaB) in response to TNF-alpha (tumour necrosis factor-alpha) and the proliferation of cancer cells. Finally, we identified capped di-peptides that show differential selectivity for the beta5 site of the constitutively expressed proteasome and immunoproteasome in vitro and in B-cell lymphomas. Collectively, these studies describe the synthesis, activity and binding mode of a new series of non-covalent proteasome inhibitors with unprecedented potency and selectivity for the beta5 site, and which can discriminate between the constitutive proteasome and immunoproteasome in vitro and in cells.

Configuration of a scintillation proximity assay for the activity assessment of recombinant human adenine phosphoribosyltransferase.

Adenine phosphoribosyltransferase plays a role in purine salvage by catalyzing the direct conversion of adenine to adenosine monophosphate. The involvement of the purine salvage pathway in tumor proliferation and angiogenesis makes adenine phosphoribosyltransferase a potential target for oncology drug discovery. We have expressed and characterized recombinant, N-terminally His-tagged human adenine phosphoribosyltransferase. Two assay formats were assessed for use in a high throughput screen: a spectrophotometric-based enzyme-coupled assay system and a radiometric ionic capture scintillation proximity bead assay format. Ultimately, the scintillation proximity assay format was chosen because of automated screening compatibility limitations of the coupled assay. We describe here the biochemical characterization of adenine phosphoribosyltransferase and the development of a robust, homogeneous, 384-well assay suitable for high throughput screening.

pH Dependence of inhibitors targeting the occluding loop of cathepsin B.

Potent and selective cathepsin B inhibitors have previously been synthesized based upon the natural product cysteine protease inhibitor E-64. X-ray crystal data indicates that these compounds interact through their free carboxylate with the positively charged histidine residues located on the prime-side of the active site within the occluding loop of cathepsin B. Herein, we examine the pH dependence of two prime-side-binding compounds. In each case there is a dramatic decrease in k(inact)/K(I) as the pH is raised from 4 to 7.8 corresponding to a single ionization of pK(a) 4.4. These results suggest that targeting of the occluding loop of cathepsin B may be a poor inhibitor design strategy if the enzyme environment has a pH greater than 5.5. However, this type of inhibitor may be a useful tool to help elucidate the role and the environment of cathepsin B in invading tumors.