The PARP inhibitor rucaparib blocks SARS-CoV-2 virus binding to cells and the immune reaction in models of COVID-19.

BACKGROUND AND PURPOSE: To date, there are limited options for severe Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2 virus. As ADP-ribosylation events are involved in regulating the life cycle of coronaviruses and the inflammatory reactions of the host; we have, here, assessed the repurposing of registered PARP inhibitors for the treatment of COVID-19. EXPERIMENTAL APPROACH: The effects of PARP inhibitors on virus uptake were assessed in cell-based experiments using multiple variants of SARS-CoV-2. The binding of rucaparib to spike protein was tested by molecular modelling and microcalorimetry. The anti-inflammatory properties of rucaparib were demonstrated in cell-based models upon challenging with recombinant spike protein or SARS-CoV-2 RNA vaccine. KEY RESULTS: We detected high levels of oxidative stress and strong PARylation in all cell types in the lungs of COVID-19 patients, both of which negatively correlated with lymphocytopaenia. Interestingly, rucaparib, unlike other tested PARP inhibitors, reduced the SARS-CoV-2 infection rate through binding to the conserved 493-498 amino acid region located in the spike-ACE2 interface in the spike protein and prevented viruses from binding to ACE2. In addition, the spike protein and viral RNA-induced overexpression of cytokines was down-regulated by the inhibition of PARP1 by rucaparib at pharmacologically relevant concentrations. CONCLUSION AND IMPLICATIONS: These results point towards repurposing rucaparib for treating inflammatory responses in COVID-19.

Mapping protein binding sites by photoreactive fragment pharmacophores.

Fragment screening is a popular strategy of generating viable chemical starting points especially for challenging targets. Although fragments provide a better coverage of chemical space and they have typically higher chance of binding, their weak affinity necessitates highly sensitive biophysical assays. Here, we introduce a screening concept that combines evolutionary optimized fragment pharmacophores with the use of a photoaffinity handle that enables high hit rates by LC-MS-based detection. The sensitivity of our screening protocol was further improved by a target-conjugated photocatalyst. We have designed, synthesized, and screened 100 diazirine-tagged fragments against three benchmark and three therapeutically relevant protein targets of different tractability. Our therapeutic targets included a conventional enzyme, the first bromodomain of BRD4, a protein-protein interaction represented by the oncogenic KRasG12D protein, and the yet unliganded N-terminal domain of the STAT5B transcription factor. We have discovered several fragment hits against all three targets and identified their binding sites via enzymatic digestion, structural studies and modeling. Our results revealed that this protocol outperforms screening traditional fully functionalized and photoaffinity fragments in better exploration of the available binding sites and higher hit rates observed for even difficult targets.

[Changes in radiotherapy indication for early-stage operated endometrial cancer. Revised staging, predictive factors. Conclusions from our own results]. / Változások a korai stádiumú operált méhtestcarcinoma sugárkezelésének indikációjában. Újabb stádiumbeosztás, prediktív tényezok. Tanulságok saját eredményeink alapján.

Optimal postoperative radiotherapy indications for early-stage operated endometrial cancers have drastically changed with the new imaging generation (magnetic resonance imaging, positron emission tomography/computed tomography) and more detailed pathomorphology. The depth and growth of tumor invasion, presence or absence of the lymph node metastases, grading and lymphovascular invasion are the most important factors to predict the progression and to influence the prognosis. In 2016, on the basis of these, the European Gynecologist Oncology and Radiotherapy Society published a report in which they proposed unanimously indications for postoperative radio- and/or radiochemotherapy. The basis of their work was prospective multilevel randomized investigations which could avoid over- or undertreatment hazards. The results obtained by the authors of this article from 164 operated patients in early-stage endometrium carcinoma seem to be acceptable, in spite of the fact that their earlier radiotherapy indication was different and in the pathological description lymphovascular invasion was not included and the grading was not always applied.