Inhibitors of thiol-mediated uptake

Abstract

Thiol-reactive inhibitors for the cellular entry of cyclic oligochalcogenide (COC) transporters and SARS-CoV-2 spike pseudo-lentivirus are reported.

Oligonucleotide Phosphorothioates Enter Cells by Thiol‐Mediated Uptake

“…The less reactive AspA [10, 12] 9 was also less impressive as inhibitor. The cyclic thiosulfonate COC 8 was of interest mostly because, among other activities, [14] it best inhibited the cellular entry of SARS‐CoV‐2 virus models [20] . In agreement with the importance of adaptive networks from exchange cascades, inorganic polysulfide 7 was recorded as good inhibitor, while ebselen analog 11 as well as MMTS 12 were inactive.…”

“…Traditionally, this has been done with Ellman's reagent. Weak and unreliable, this single inhibitor has been replaced recently by a collection of inhibitors which are up to 5000 times more active and cover at least some of the different uptake pathways involved [20] …”

“…From this collection, inhibitor candidates 3 – 12 were selected to explore interference with the uptake of OPS 1 , a random 18‐mer labelled with Cy5 at its 5′‐terminus (Figure 1, Figure 2; Table S1) [20] . If needed, inhibitors were prepared by multistep synthesis following reported procedures (see the Supporting Information).…”

“…A recent automated high‐content high‐throughput (HCHT) screening assay [20] was used to secure data from multiwell plates with thousands of HeLa Kyoto cells. They were first preincubated for 1 h with 3 – 12 at various concentrations below their toxicity limit [20] and then, after inhibitor removal, incubated for 2 h with Cy5‐OPS 1 . The dependence of the uptake of 1 on the concentration of 3 – 12 (Figure 2 A) was then used to determine the MIC OPS (Figure 2 B) and, if accessible, also the IC 50 , i.e., the concentration to observe ≈15 % and 50 % inhibition, respectively (Figures 1, 2, S10–S19, Table S2).…”

“…I T : Average fluorescence intensities per cell ± SEM, normalized against that without the addition of an inhibitor ( I T(0) =1), with fit to Hill equation. B) Comparison of MICs against OPS 1 and ETP 6 a [20] (upward and rightward arrows: MIC > c MAX ; downward arrow: MIC< c MIN ), with trend line to guide the eye.…”