MicroRNAs (miRNAs) are involved in the modulation of pathogenic genes by binding to their mRNA sequences’ 3′ untranslated regions (3′UTR). Interleukin-6 (IL-6) is known to promote cancer progression and treatment resistance. In this study, we aimed to explore the therapeutic effects of gold nanoparticles (GNP) against IL-6 overexpression and the modulation of miRNA-26a-5p in breast cancer (BC) cells. GNP were synthesized using the trisodium citrate method and characterized through UV-Vis spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). To predict the binding of miR-26a-5p in the IL-6 mRNA’s 3′UTR, we utilized bioinformatics algorithms. Luciferase reporter clone assays and anti-miRNA-26a-5p transfection were employed to validate the binding of miR26a-5p in the IL-6 mRNA’s 3′UTR. The activity of RelA and NF-κBp50 was assessed and confirmed using Bay 11-7082. The synthesized GNP were spherical with a mean size of 28.3 nm, exhibiting high stability, and were suitable for BC cell treatment. We found that miR-26a-5p directly regulated IL-6 overexpression in MCF-7 cells activated with PMA. Treatment of MCF-7 cells with GNP resulted in the inhibition of IL-6 overexpression and secretion through the increase of miR26a-5p. Furthermore, GNP deactivated NF-κBp65/NF-κBp50 transcription activity. The newly engineered GNP demonstrated safety and showed promise as a therapeutic approach for reducing IL-6 overexpression. The GNP suppressed IL-6 overexpression and secretion by deactivating NF-κBp65/NF-κBp50 transcription activity and upregulating miR-26a-5p expression in activated BC cells. These findings suggest that GNP have potential as a therapeutic intervention for BC by targeting IL-6 expression and associated pathways.

This work describes the synthesis of a new unsymmetrical tetradentate copper(ii) Schiff base complex Cu(L)(Py)(ClO4) containing N₃O donor atoms.

Objective: Schiff bases are versatile chemical compounds extensively used in various applications, including as catalysts, polymer stabilizers, pigments, dyes, and building blocks for organic synthesis. In addition, they exhibit a wide range of biological activities, such as antifungal, antibacterial, antiviral, antiproliferative, antiinflammatory, and antipyretic effects. Methods: A novel Schiff base ligand (HL) was synthesized by condensing isatin with 2,6-diaminopyridine and isoleucine, followed by the preparation of transition metal complexes. The ligand and complexes were characterized using techniques such as elemental analysis, IR, 1H-NMR, UV-vis spectroscopy, mass spectrometry, and thermal analysis. Antimicrobial, antiproliferative activities, and structural investigations through X-ray diffraction and scanning electron microscopy were also evaluated. Results: The complexes were identified as [Cr(L)Cl(H2O)]Cl2H(2)O, [Fe(L)Cl-2], [M(L)]ClnH(2)O, and [M(L)(H2O)(2)]Cl, where M represents Mn(II), Cu(II), Cd(II), Co(II), Zn(II), and Ni(II). Thermogravimetric analysis showed initial water loss, followed by decomposition of anionic compounds and ligands. The ligand forms a uninegative-tetradentate bond with the metal ions, and all complexes, except Fe(III), exhibit electrolytic behavior. Most complexes displayed tetrahedral geometry, while Ni(II), Co(II), and Zn(II) had octahedral geometry. The metal complexes showed enhanced antibacterial, antifungal, and antiproliferative activity against MCF-7 breast cancer cells compared to the free ligand. Molecular docking studies indicated inhibitory potential against receptors 1GS4, 2HQ6, 3DJD, and 5JPE. Conclusion: These newly synthesized ligands and complexes show promise as therapeutic agents against infections and cancer, though further studies are needed to understand their mechanisms.