Parallel purification of microscale libraries via automated solid phase extraction

High-throughput experimentation (HTE) has become more widely utilized in drug discovery for rapid reaction optimization and generation of large synthetic compound arrays. While this has accelerated medicinal chemistry design, make, test (DMT) iterations, the bottleneck of purification persists, consuming time and resources. Herein we describe a general parallel purification approach based on solid phase extraction (SPE) that provides a more efficient and sustainable workflow producing compound libraries with significantly upgraded purity. This robust, user-friendly workflow is fully automated and integrated with HTE library synthesis, as demonstrated by its application to a diverse parallel library compound array generated via amide-bond coupling in HTE microscale format.

Heavily treatment-experienced people living with HIV in the OPERA® cohort: population characteristics and clinical outcomes

BACKGROUND

Multi-class resistance, intolerance, and drug-drug interactions can result in unique antiretroviral (ART) combinations for heavily treatment-experienced (HTE) people living with HIV (PLWH). We aimed to compare clinical outcomes between HTE and non-HTE PLWH.

METHODS

Eligible ART-experienced PLWH in care in the OPERA® Cohort were identified in a cross-sectional manner on December 31, 2016 and observed from the date of initiation of the ART regimen taken on December 31, 2016 until loss to follow up, death, study end (December 31, 2018), or becoming HTE (non-HTE group only). In the absence of resistance data, HTE was defined based on the ART regimens used (i.e., exposed to ≥ 3 core agent classes or regimen suggestive of HTE). Time to virologic undetectability, failure, and immunologic preservation were assessed using Kaplan-Meier methods; cumulative probabilities were compared between the two groups. Regimen changes, incident morbidities, and death were described.

RESULTS

A total of 24,183 PLWH (2277 HTE PLWH, 21,906 non-HTE) were followed for a median of 28 months (IQR 21, 38). Viremic HTE PLWH (viral load [VL] ≥ 50 copies/mL) were less likely to achieve undetectability (VL < 50 copies/mL; 24-month cumulative probability: 80% [95% Confidence Interval 77-82]) than their non-HTE counterparts (85% [84-86]). No difference was observed in the probability of maintaining VLs < 200 copies/mL over the first 48 months after achieving suppression (< 50 copies/mL). HTE PLWH were less likely than non-HTE PLWH to maintain CD4 cell counts ≥ 200 cells/µL (24-month cumulative probability: 95% HTE [91-93]; 97% non-HTE [97-97]), and more likely to change regimens (45% HTE; 41% non-HTE). Incident non-AIDS defining event (ADE) morbidities were common in both populations, though more likely among HTE PLWH (45%) than non-HTE PLWH (35%). Incident ADE morbidities and deaths were uncommon among HTE (ADEs 5%; deaths 2%) and non-HTE (ADEs 2%; deaths 1%) PLWH.

CONCLUSIONS

HTE PLWH were at greater risk of unfavorable treatment outcomes than non-HTE PLWH, suggesting additional therapeutic options are needed for this vulnerable population.

A Phenotypic Approach for the Identification of New Molecules for Targeted Protein Degradation Applications

Targeted protein degradation is an emerging new strategy for the modulation of intracellular protein levels with applications in chemical biology and drug discovery. One approach to enable this strategy is to redirect the ubiquitin-proteasome system to mark and degrade target proteins of interest (POIs) through the use of proteolysis targeting chimeras (PROTACs). Although great progress has been made in enabling PROTACs as a platform, there are still a limited number of E3 ligases that have been employed for PROTAC design. Herein we report a novel phenotypic screening approach for the identification of E3 ligase binders. The key concept underlying this approach is the high-throughput modification of screening compounds with a chloroalkane moiety to generate HaloPROTACs in situ, which were then evaluated for their ability to degrade a GFP-HaloTag fusion protein in a cellular context. As proof of concept, we demonstrated that we could generate and detect functional HaloPROTACs in situ, using a validated Von Hippel-Lindau (VHL) binder that successfully degraded the GFP-HaloTag fusion protein in living cells. We then used this method to prepare and screen a library of approximately 2000 prospective E3 ligase-recruiting molecules.

Why not integrate ethics in HTA: identification and assessment of the reasons

From the conception of HTA in the 1970s it has been argued that addressing ethical issues is an element of HTA, and many methods for integrating ethics in HTA have become available. However, despite almost 40 years with repeated intentions, only few HTA reports include ethical analysis. Why is this so? How come, ethics is a constituent part of HTA, there are many methods available, but ethics is rarely part of practical HTA work?

This is the key question of this article and several reasons why ethics is not a part of HTA are identified. A) Ethicists are professional strangers in HTA. B) A common agreed methodology for integrating ethics is lacking. Ethics methodology appears to be C) deficient, D) insufficient, or E) unsuitable. F) Integrating ethics in HTA is neither efficient nor needed for successful HTA. G) Most moral issues are general, and are not specific to a given technology. H) All relevant ethical issues can be handled within other frameworks, e.g., within economics. I) Ethics can undermine or burst the foundation of HTA.

Hence, there are many reasons why ethics is not an integrated part of HTA so many years after identifying ethics as constitutive to HTA. These reasons may all explain why it is so, but on closer scrutiny, they do not work as compelling arguments for not addressing ethical issues in HTA. Hence, the identified reasons may work well as explanations, but not as justifications.

In order to move on from a situation of failure we can:

Exclude ethics from definitions of HTA, and as a consequence, establish a separate kind of evaluation (Health Technology Evaluation – HTE).

Take the existing definition seriously and actually integrate ethics in the performance of HTA practice.

Amend, expand or change HTA so that ethics is more genuinely incorporated.

Which of these options to choose is open for discussion, but we need to move away from a situation where we have a definition of HTA which does not correspond with HTA practice.

Molecular functions of the iron-regulated metastasis suppressor, NDRG1, and its potential as a molecular target for cancer therapy

N-myc down-regulated gene 1 (NDRG1) is a known metastasis suppressor in multiple cancers, being also involved in embryogenesis and development, cell growth and differentiation, lipid biosynthesis and myelination, stress responses and immunity. In addition to its primary role as a metastasis suppressor, NDRG1 can also influence other stages of carcinogenesis, namely angiogenesis and primary tumour growth. NDRG1 is regulated by multiple effectors in normal and neoplastic cells, including N-myc, histone acetylation, hypoxia, cellular iron levels and intracellular calcium. Further, studies have found that NDRG1 is up-regulated in neoplastic cells after treatment with novel iron chelators, which are a promising therapy for effective cancer management. Although the pathways by which NDRG1 exerts its functions in cancers have been documented, the relationship between the molecular structure of this protein and its functions remains unclear. In fact, recent studies suggest that, in certain cancers, NDRG1 is post-translationally modified, possibly by the activity of endogenous trypsins, leading to a subsequent alteration in its metastasis suppressor activity. This review describes the role of this important metastasis suppressor and discusses interesting unresolved issues regarding this protein.

Evaluation of the light scattering and the turbidity microtiter plate-based methods for the detection of the excipient-mediated drug precipitation inhibition

The excipient-mediated precipitation inhibition is classically determined by the quantification of the dissolved compound in the solution. In this study, two alternative approaches were evaluated, one is the light scattering (nephelometer) and other is the turbidity (plate reader) microtiter plate-based methods which are based on the quantification of the compound precipitate. Following the optimization of the nephelometer settings (beam focus, laser gain) and the experimental conditions, the screening of 23 excipients on the precipitation inhibition of poorly soluble fenofibrate and dipyridamole was performed. The light scattering method resulted in excellent correlation (r>0.91) between the calculated precipitation inhibitor parameters (PIPs) and the precipitation inhibition index (PI(classical)) obtained by the classical approach for fenofibrate and dipyridamole. Among the evaluated PIPs AUC100 (nephelometer) resulted in only four false positives and lack of false negatives. In the case of the turbidity-based method a good correlation of the PI(classical) was obtained for the PIP maximal optical density (OD(max), r=0.91), however, only for fenofibrate. In the case of the OD(max) (plate reader) five false positives and two false negatives were identified. In conclusion, the light scattering-based method outperformed the turbidity-based one and could be reliably used for identification of novel precipitation inhibitors.