SPOCC resin 1, a novel, highly permeable, polar support for chemical and enzymatic solid-phase methods, is presented. The synthesis of SPOCC resin is based on the cross-linking of long-chain poly(ethylene glycol) (PEG) terminally substituted with oxetane by cationic ring-opening polymerization, affording a polymer containing only primary ether and alcohol C−O bonds. The polymer was prepared using Et2O·BF3 as initiator either via bulk polymerization in solution or via suspension polymerization in silicon oil, the latter yielding a beaded resin. The polymerization reaction was investigated with respect to the effects of PEG chain length, the fraction of bisoxetanylated PEG, initiator amount, and temperature in order to vary the swelling, loading, and mechanical stability of the resin. Furthermore, the resin was derivatized with various functional groups and subsequently applied to peptide synthesis and organic reactions in both organic solvents and water. An N-terminal peptide aldehyde was generated on the solid phase and employed to synthesize peptide isosteres by nucleophilic addition of various ylides. Solid-phase glycosylation of peptides and enzymatic reactions were successfully performed with SPOCC resin. Enzymatic proteolytic cleavage of a resin-bound decapeptide on treatment with the 27 kDa protease subtilisin BNP‘ demonstrated the accessibility of the interior of the SPOCC resin for enzymes.
Förster resonance energy transfer (FRET) using fluorescent base analogues is a powerful means of obtaining high-resolution nucleic acid structure and dynamics information that favorably complements techniques such as NMR and X-ray crystallography. Here, we expand the base-base FRET repertoire with an adenine analogue FRET-pair. Phosphoramidite-protected quadracyclic 2'-deoxyadenosine analogues qAN1 (donor) and qA (acceptor) were synthesized and incorporated into DNA by a generic, reliable, and high-yielding route, and both constitute excellent adenine analogues. The donor, qAN1, has quantum yields reaching 21% and 11% in single- and double-strands, respectively. To the best of our knowledge, this results in the highest average brightness of an adenine analogue inside DNA. Its potent emissive features overlap well with the absorption of qA and thus enable accurate FRET-measurements over more than one turn of B-DNA. As we have shown previously for our cytosine analogue FRET-pair, FRET between qAN1 and qA positioned at different base separations inside DNA results in efficiencies that are highly dependent on both distance and orientation. This facilitates significantly enhanced resolution in FRET structure determinations, demonstrated here in a study of conformational changes of DNA upon binding of the minor groove binder netropsin. Finally, we note that the donor and acceptor of our cytosine FRET-pair, tC and tC, can be conveniently combined with the acceptor and donor of our current adenine pair, respectively. Consequently, our base analogues can now measure base-base FRET between 3 of the 10 possible base combinations and, through base-complementarity, between all sequence positions in a duplex.
Drug repositioning has gained attention from both academia and pharmaceutical companies as an auxiliary process to conventional drug discovery. Chemotherapeutic agents have notorious adverse effects that drastically reduce the life quality of cancer patients so drug repositioning is a promising strategy to identify non-cancer drugs which have anti-cancer activity as well as tolerable adverse effects for human health. There are various strategies for discovery and validation of repurposed drugs. In this review, 25 repurposed drug candidates are presented as result of different strategies, 15 of which are already under clinical investigation for treatment of prostate cancer (PCa). To date, zoledronic acid is the only repurposed, clinically used, and approved non-cancer drug for PCa. Anti-cancer activities of existing drugs presented in this review cover diverse and also known mechanisms such as inhibition of mTOR and VEGFR2 signaling, inhibition of PI3K/Akt signaling, COX and selective COX-2 inhibition, NF-κB inhibition, Wnt/β-Catenin pathway inhibition, DNMT1 inhibition, and GSK-3β inhibition. In addition to monotherapy option, combination therapy with current anti-cancer drugs may also increase drug efficacy and reduce adverse effects. Thus, drug repositioning may become a key approach for drug discovery in terms of time- and cost-efficiency comparing to conventional drug discovery and development process.
A highly fluorescent, non-perturbing, pentacyclic adenine analog was designed, synthesized, incorporated into DNA and photophysical evaluated.
Ultrasensitive detection of DNA is achieved via two-photon excitation of a fluorescent base analogue.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.