G-Quadruplex Conformational Switching for miR-155-3p Detection Using a Ligand-Based Fluorescence Approach

Biomolecules, Год журнала: 2025, Номер 15(3), С. 410 - 410

Опубликована: Март 13, 2025

MicroRNA-155-3p (miR-155-3p) is an important biomarker in various pathological conditions, including cancer, making the development of sensitive and specific detection methods crucial. Here, we present a molecular beacon (MB-G4) that underwent conformational switch upon hybridization with miR-155-3p, enabling formation G-quadruplex (G4) structure. This G4 was recognized by fluorogenic ligand N-methyl mesoporphyrin IX (NMM), producing fluorescence signal proportional to target concentration, it new method. The dynamics MB-G4 were characterized through circular dichroism (CD) spectroscopy native polyacrylamide gel electrophoresis (PAGE), confirming transition from hairpin structure RNA–DNA hybrid duplex facilitated formation. optimization experimental potassium chloride (KCl) NMM concentrations, ensured selective minimal background signal. limit (LOD) determined be 10.85 nM, using linear response curve, specificity studies demonstrated clear distinction between miR-155-3p miR-155-5p. Furthermore, studied total RNA extracted lung cancer cell line A549 evaluate its more complex environment able detect target, validating potential for biological sample analysis.

Язык: Английский

Formation of the i-motif Structures by Human Telomeric c-Rich Sequences d(CCCTAA)n and Its Recognition by Bisbenzylisoquinoline Alkaloids

ACS Chemical Biology, Год журнала: 2025, Номер unknown

Опубликована: Март 27, 2025

The human telomeric repeat CCCTAA has been reported to form a higher-order structure called an intercalated motif (i-motif) that plays important roles in telomere function and telomerase activity regulation, small molecule ligands targeting i-motif (hTelo-iM) is promising therapeutic strategy for cancer treatment, yet the folding pattern of long repeats hTelo-iM ligand screening have not studied extensively. In this study, we systematically investigated structures formed by four eight C-rich d(CCCTAA)4 (hTeloC-24mer) d(CCCTAA)8 (hTeloC-48mer) under varied conditions found hTeloC-48mer probably forms unstacked tandem consisting two hTeloC-24mer monomers near physiological conditions. Moreover, natural bisbenzylisoquinoline (BBI) alkaloids, isofangchinoline, fangchinoline, cepharanthine, tetrandrine, were screened from 33 molecules effectively disrupt destabilize mainly through major groove hydrogen bonding van der Waals interactions. Further, repeated amplification protocol (TRAP) assay suggested selected BBI alkaloids can inhibit extension telomerase. These findings provide theoretical basis further research as well novel class compounds regulating activity, which may contribute anticancer drug design development taking target.

Язык: Английский