Synthesis, crystal structure, DFT calculation and DNA binding studies of new water-soluble derivatives of dppz

Phenazine Cations as Anticancer Theranostics†

The biological properties of two water-soluble organic cations based on polypyridyl structures commonly used as ligands for photoactive transition metal complexes designed to interact with biomolecules are investigated. A cytotoxicity screen employing a small panel of cell lines reveals that both cations show cytotoxicity toward cancer cells but show reduced cytotoxicity to noncancerous HEK293 cells with the more extended system being notably more active. Although it is not a singlet oxygen sensitizer, the more active cation also displayed enhanced potency on irradiation with visible light, making it active at nanomolar concentrations. Using the intrinsic luminescence of the cations, their cellular uptake was investigated in more detail, revealing that the active compound is more readily internalized than its less lipophilic analogue. Colocalization studies with established cell probes reveal that the active cation predominantly localizes within lysosomes and that irradiation leads to the disruption of mitochondrial structure and function. Stimulated emission depletion (STED) nanoscopy and transmission electron microscopy (TEM) imaging reveal that treatment results in distinct lysosomal swelling and extensive cellular vacuolization. Further imaging-based studies confirm that treatment with the active cation induces lysosomal membrane permeabilization, which triggers lysosome-dependent cell-death due to both necrosis and caspase-dependent apoptosis. A preliminary toxicity screen in the Galleria melonella animal model was carried out on both cations and revealed no detectable toxicity up to concentrations of 80 mg/kg. Taken together, these studies indicate that this class of synthetically easy-to-access photoactive compounds offers potential as novel therapeutic leads.

A new palladium-based antiproliferative agent: synthesis, characterization, computational calculations, cytotoxicity, and DNA binding properties

A new palladium(II) complex entitled [Pd(phendione)(8Q)]NO₃, (PdPQ), where phendione is N,N-donor heterocyclic 1,10-phenanthroline-5,6-dion and 8Q is 8-hydroxyquinolinate, has been synthesized and then characterized by molar conductivity, CHN analysis and spectral data (UV-Vis, FT-IR, NMR). DFT/ TDDFT procedures were also performed to determine the electronic structure and the nature of the electronic transitions of PdPQ. Moreover, the affinity and binding properties of DNA to the desired complex have been studied in details using electronic absorption, fluorescence, circular dichroism spectroscopies, and viscosity measurement in combination with molecular docking technique. The obtained results exhibit relatively high DNA binding values with a static quenching mechanism, which suggest that an intercalative mode plays a peridominate role in interaction process concluded by experimental/theoretical measurements. As a result of drug exposure, in vitro cytotoxicity assay demonstrated the antiproliferative activity of the PdPQ against leukemia cancer cell line, K562.