Development of optimized drug-like small molecule inhibitors of the SARS-CoV-2 3CL protease for treatment of COVID-19.

The SARS-CoV-2 3CL protease is a critical drug target for small molecule COVID-19 therapy, given its likely druggability and essentiality in the viral maturation and replication cycle. Based on the conservation of 3CL protease substrate binding pockets across coronaviruses and using screening, we identified four structurally distinct lead compounds that inhibit SARS-CoV-2 3CL protease. After evaluation of their binding specificity, cellular antiviral potency, metabolic stability, and water solubility, we prioritized the GC376 scaffold as being optimal for optimization. We identified multiple drug-like compounds with <10 nM potency for inhibiting SARS-CoV-2 3CL and the ability to block SARS-CoV-2 replication in human cells, obtained co-crystal structures of the 3CL protease in complex with these compounds, and determined that they have pan-coronavirus activity. We selected one compound, termed coronastat, as an optimized lead and characterized it in pharmacokinetic and safety studies in vivo. Coronastat represents a new candidate for a small molecule protease inhibitor for the treatment of SARS-CoV-2 infection for eliminating pandemics involving coronaviruses.

Inhibitors of Coronavirus 3CL Proteases Protect Cells from Protease-Mediated Cytotoxicity.

We describe a mammalian cell-based assay to identify coronavirus 3CL protease (3CLpro) inhibitors. This assay is based on rescuing protease-mediated cytotoxicity and does not require live virus. By enabling the facile testing of compounds across a range of 15 distantly related coronavirus 3CLpro enzymes, we identified compounds with broad 3CLpro-inhibitory activity. We also adapted the assay for use in compound screening and in doing so uncovered additional severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) 3CLpro inhibitors. We observed strong concordance between data emerging from this assay and those obtained from live-virus testing. The reported approach democratizes the testing of 3CLpro inhibitors by developing a simplified method for identifying coronavirus 3CLpro inhibitors that can be used by the majority of laboratories, rather than the few with extensive biosafety infrastructure. We identified two lead compounds, GC376 and compound 4, with broad activity against all 3CL proteases tested, including 3CLpro enzymes from understudied zoonotic coronaviruses. IMPORTANCE Multiple coronavirus pandemics have occurred over the last 2 decades. This has highlighted a need to be proactive in the development of therapeutics that can be readily deployed in the case of future coronavirus pandemics. We developed and validated a simplified cell-based assay for the identification of chemical inhibitors of 3CL proteases encoded by a wide range of coronaviruses. This assay is reporter free, does not require specialized biocontainment, and is optimized for performance in high-throughput screening. By testing reported 3CL protease inhibitors against a large collection of 3CL proteases with variable sequence similarity, we identified compounds with broad activity against 3CL proteases and uncovered structural insights into features that contribute to their broad activity. Furthermore, we demonstrated that this assay is suitable for identifying chemical inhibitors of proteases from families other than 3CL proteases.

A simplified cell-based assay to identify coronavirus 3CL protease inhibitors.

We describe a mammalian cell-based assay capable of identifying coronavirus 3CL protease (3CLpro) inhibitors without requiring the use of live virus. By enabling the facile testing of compounds across a range of coronavirus 3CLpro enzymes, including the one from SARS-CoV-2, we are able to quickly identify compounds with broad or narrow spectra of activity. We further demonstrate the utility of our approach by performing a curated compound screen along with structure-activity profiling of a series of small molecules to identify compounds with antiviral activity. Throughout these studies, we observed concordance between data emerging from this assay and from live virus assays. By democratizing the testing of 3CL inhibitors to enable screening in the majority of laboratories rather than the few with extensive biosafety infrastructure, we hope to expedite the search for coronavirus 3CL protease inhibitors, to address the current epidemic and future ones that will inevitably arise.

Understanding health-related quality of life in adult women with metastatic cancer who have dependent children.

BACKGROUND: Cancer is a leading cause of death among women of parenting age in the United States. Women living with advanced or incurable cancer who have dependent children experience high rates of depression and anxiety as well as unique parenting challenges. To the authors' knowledge, few studies to date have examined the parenting factors associated with health-related quality of life (HRQOL) in women with advanced cancer. METHODS: The authors conducted a cross-sectional, Web-based survey of the psychosocial concerns of 224 women with a tumor-node-metastasis staging system of the AJCC stage IV solid tumor malignancy who had at least 1 child aged <18 years. Participants completed validated measures of HRQOL (Functional Assessment of Cancer Therapy-General [FACT-G]); depression and anxiety symptom severity; functional status; parenting concerns; and investigator-designed questions to assess demographic, communication, and parenting characteristics. Multiple linear regression models were estimated to identify factors associated with FACT-G total and subscale scores. RESULTS: The mean FACT-G score was 66 (standard deviation, 16). The mean Emotional Well-Being subscale scores were particularly low (13; standard deviation, 5). In multivariable linear regression models, parenting variables explained nearly 40% of the HRQOL model variance. In the fully adjusted model, parenting concerns and the absence of parental prognostic communication with children both were found to be significantly associated with HRQOL scores. For each 1-point increase in parenting concern severity, FACT-G scores decreased by 4 points (P = .003). CONCLUSIONS: Women with metastatic cancer who are parents of dependent children are at risk of high psychological distress and low HRQOL. Parenting factors may have a negative influence on HRQOL in this patient population. Cancer 2018;124:2629-36. © 2018 American Cancer Society.