New 2,9-disubstituted-1,10-phenanthroline derivatives with anticancer activity by selective targeting of telomeric G-quadruplex DNA

Synthesis of 1,10-Phenanthroline-2,9-bistriazoles: Evaluation as G-Quadruplex Binders and Anti-Tumor Activity

Novel 1,10-phenanthroline-2,9-bistriazoles derivatives have been synthesized by copper-catalyzed azide/alkyne cycloaddition reactions and assessed for their ability to bind and stabilize G-quadruplex (G4) structures. Ten novel compounds were evaluated using Förster resonance energy transfer (FRET) melting, circular dichroism (CD), and fluorescence spectroscopy on several G4 sequences. Biophysical characterization led to the identification of compounds 4 a, 4 b, and 5 b as good G4 ligands of KRAS G4 sequences. The impact on cell viability of all derivatives was also assessed, revealing weak effects. However, compound 2 a exhibited cytotoxicity activity on A549 and H1299 cancer cells and low cytotoxicity towards MRC-5 non-malignant cells MRC-5 not connected with its G4-binding ability. Flow cytometry showed that 2 a induced a cell viability decrease in S and G2/M phases for A549 and H1299; thus, more studies should be performed to explore the proteins involved in cell cycle regulation.

Study of nitrogen heterocycles as DNA/HSA binder, topoisomerase inhibitors and toxicological safety

Four new nitrogen-containing heterocyclic derivatives (acridine, quinoline, indole, pyridine) were synthesized and their biological properties were evaluated. The compounds showed affinity for DNA and HSA, with CAIC and CAAC displaying higher binding constants (Kb) of 9.54 × 104 and 1.06 × 106, respectively. The fluorescence quenching assay (Ksv) revealed suppression values ranging from 0.34 to 0.64 × 103 M-1 for ethidium bromide (EB) and 0.1 to 0.34 × 103 M-1 for acridine orange (AO). Molecular docking confirmed the competition of the derivatives with intercalation probes at the same binding site. At 10 μM concentrations, the derivatives inhibited topoisomerase IIα activity. In the antiproliferative assays, the compounds demonstrated activity against MCF-7 and T47-D tumor cells and nonhemolytic profile. Regarding toxicity, no acute effects were observed in the embryos. However, some compounds caused enzymatic and cardiac changes, particularly the CAIC, which increased SOD activity and altered heart rate compared to the control. These findings suggest potential antitumor action of the derivatives and indicate that substituting the acridine core with different cores does not interfere with their interaction and topoisomerase inhibition. Further investigations are required to assess possible toxicological effects, including reactive oxygen species generation.

Harnessing G-quadruplex ligands for lung cancer treatment: A comprehensive overview

Lung cancer (LC) remains a leading cause of mortality worldwide, and new therapeutic strategies are urgently needed. One such approach revolves around the utilization of four-stranded nucleic acid secondary structures, known as G-quadruplexes (G4), which are formed by G-rich sequences. Ligands that bind selectively to G4 structures present a promising strategy for regulating crucial cellular processes involved in the progression of LC, rendering them potent agents for lung cancer treatment. In this review, we offer a summary of recent advancements in the development of G4 ligands capable of targeting specific genes associated with the development and progression of lung cancer.

Exploring Pyrrolo-Phenanthrolines as Semiconductors for Potential Implementation in Organic Electronics

This paper describes the synthesis and characterization of new organic semiconductors based on pyrrolo[1,2-i][1,7]phenanthrolines in the form of thin layers. The thin layers, produced via the spin coating method (with a thickness of 10-11 μm), were investigated for their electrical and optical properties. After heat treatment at temperatures ranging from 210 to 240 °C, the layers displayed consistent and reproducible properties. The layers exhibited n-type semiconductor behavior, with a thermal activation energy (E_a) in the range of 0.75-0.78 eV. Additionally, the layers showed transmittance values of 84-92% in the visible and near-infrared spectral ranges, with a direct optical band gap (E_go^d) ranging from 3.13 to 4.11 eV. These thin layers have potential applications in electronic devices such as thermistors, as well as in nanoelectronics and optoelectronics. Overall, these new organic semiconductors show promising properties for practical implementation in various electronic applications.

Schiff-base ligands containing phenanthroline terminals: Synthesis, characterization, biological activities and molecular docking study

Three new phenanthroline-derived ligands were synthesized by the Schiff base condensation method. The first ligand was the result of 1,10-phenanthroline-2-carboxyaldehyde reaction with 1,4-diaminobutane (L1). The other ligands were obtained 1,6-diaminohexane (L2) and 1,8-diaminooctane (L3) with the phenanthroline aldehyde in separate reactions. The structures of all ligands were elucidated using spectral techniques such as FT-IR, ¹³C NMR, ¹H NMR and LC ESI/MS. The geometric properties of ligands such as bond lengths, bond angles, dihedral angles, electronic properties, HOMO and LUMO energies were calculated by using the Gaussian 09w programme. Ligands were optimized with B3LYP and 6-311++G(2d,p) basis set and NMR and FT-IR spectra were calculated. Experimental and theoretical spectrum data were compared. All of the ligands showed antibacterial activity against Staphylococcus aureus ATCC 25923 and Bacillus cereus ATCC 11778. The anticancer activities of the ligands were also determined against human breast cancer (MCF7) and prostate cancer (DU145) cell lines. In addition, which conformation of the ligands was determined by the theoretical calculations. Docking studies of ligands with bovine serum albumin (BSA) were performed using Autock Tools 1.5.6 programme.