Synthesis of OSW‑1 Derivatives by Site-Selective Acylation and Their Biological Evaluation

A strategy to site-selectively monoacylate an antitumor saponin OSW-1 was developed using an organotin reagent to rapidly access its derivatives that are useful as chemical probes. 4″-<i>O</i>-Acylated OSW-1 derivatives bearing a fluorophore, an alkyne tag, or biotin were prepared in good yields and were shown to maintain highly cytotoxic activity

<i>In Vitro</i> Selection of a DNA-Templated Small-Molecule Library Reveals a Class of Macrocyclic Kinase Inhibitors

DNA-templated organic synthesis enables the translation of DNA sequences into synthetic small-molecule libraries suitable for <i>in vitro</i> selection. Previously, we described the DNA-templated multistep synthesis of a 13 824-membered small-molecule macrocycle library. Here, we report the discovery of small molecules that modulate the activity of kinase enzymes through the <i>in vitro</i> selection of this DNA-templated small-molecule macrocycle library against 36 biomedically relevant protein targets. DNA encoding selection survivors was amplified by PCR and identified by ultra-high-throughput DNA sequencing. Macrocycles corresponding to DNA sequences enriched upon selection against several protein kinases were synthesized on a multimilligram scale. <i>In vitro</i> assays revealed that these macrocycles inhibit (or activate) the kinases against which they were selected with IC₅₀ values as low as 680 nM. We characterized in depth a family of macrocycles enriched upon selection against Src kinase, and showed that inhibition was highly dependent on the identity of macrocycle building blocks as well as on backbone conformation. Two macrocycles in this family exhibited unusually strong Src inhibition selectivity even among kinases closely related to Src. One macrocycle was found to activate, rather than inhibit, its target kinase, VEGFR2. Taken together, these results establish the use of DNA-templated synthesis and <i>in vitro</i> selection to discover small molecules that modulate enzyme activities, and also reveal a new scaffold for selective ATP-competitive kinase inhibition

Additional file 1 of Impact of upper and lower respiratory symptoms on COVID-19 outcomes: a multicenter retrospective cohort study

Additional file 1. Supplemental Figure 1. Study flow chart of patient identification and selectionStudy flow chart of patient identification and selection. A total of 117 records were excluded from the 3431 cases registered in the coronavirus disease 2019 (COVID-19) taskforce database owing to lack of essential clinical information. Ultimately, 3314 patients met the eligibility criteria, of which 2709 had respiratory symptoms. Supplemental Figure 2. Frequency of assisted respiration therapy and death in all four groups (a) Univariate analysis of the proportion of high-flow oxygen therapy with COVID-19 in each group. (b) Univariate analysis of the proportion of use of invasive mechanical ventilation (IMV) with COVID-19 in each group. (c) Univariate analysis of the proportion of use of extracorporeal membrane oxygenation (ECMO) with COVID-19 in each group. (d) Univariate analysis of the proportion of death with COVID-19 in each group. Supplemental Table 1.　Common non-respiratory symptoms in each group