A 2-(benzothiazol-2-yl)-phenolato platinum(II) complex as potential photosensitizer for combating bacterial infections in lung cancer chemotherapy†.

Cancer and antibiotic resistance are two global health threats that usually hamper clinical chemotherapeutic efficacy. Particularly for lung cancer, bacterial infections frequently arise thereby complicating the course of cancer treatment. In this sense, three new neutral luminescent cycloplatinated(II) photosensitizers of the type [Pt(dmba)(L)] (dmba = N,N-dimethylbenzylamine-κN,κC; L = 2-(benzo[d]oxazol-2-yl)-phenolato-κN,κO1, 2-(benzo[d]thiazol-2-yl)-phenolato-κN,κO2, and 2-(1-methyl-1H-benzo[d]imidazole-2-yl)phenolato-κN,κO3) have been characterized and developed to potentially eliminate both resistant bacteria and lung cancer cells.

Alcian blue pyridine variant interaction with DNA and RNA polynucleotides and G-quadruplexes: changes in the binding features for different biosubstrates.

This work concerns an analysis of the binding mechanism of a copper phthalocyanine (Alcian Blue-tetrakis(methylpyridinium) chloride, ABTP) to natural calf thymus DNA, G-quadruplexes (G4) and synthetic RNA polynucleotides in the form of double polyriboadenylic·polyribouridylic acid (poly(A)·poly(U)) or triple strands polyriboadenylic·2polyribouridylic acid (poly(A)·2poly(U)). ABTP is a well know dye that might undergo novel applications, but its interaction with DNA is scarcely studied and we lack information on possible RNA or G4 binding. This might be related to system complexity due to the presence of supramolecular dye-dye aggregates.

Biological activity and photocatalytic properties of a naphthyl-imidazo phenanthroline (HNAIP) ligand and its [Ir(ppy)(HNAIP)]Cl and [Rh(ppy)(HNAIP)]Cl complexes.

The synthesized 2-(hydroxy-1-naphtyl)imidazo-[4,5-f][1,10]phenanthroline (HNAIP) ligand and its new iridium ([Ir(ppy)(HNAIP)]Cl) and rhodium ([Rh(ppy)(HNAIP)]Cl) complexes, being ppy = 2-phenylpiridinate, show cytotoxic effects in SW480 (colon adenocarcinoma) and A549 (epithelial lung adenocarcinoma) cells. They all are cytotoxic in the tested cell lines. HNAIP and [Rh(ppy)(HNAIP)] are the most cytotoxic, whereas [Ir(ppy)(HNAIP)] displays negligible cytotoxicity towards A549 cells and moderate activity towards SW480.

Thiabendazole-based Rh(III) and Ir(III) biscyclometallated complexes with mitochondria-targeted anticancer activity and metal-sensitive photodynamic activity.

Two pairs of Rh(III) and Ir(III) biscyclometallated complexes with thiabendazole (L), named [Ir-a]Cl and [Rh-a]Cl, and N-benzyl-thiabendazole (L), named [Ir-b]Cl and [Rh-b]Cl, have been designed and synthesized to explore the photophysical and biological effects that arise from changing both the metal center and the ancillary ligand. In the dark, the four metal complexes exhibit greater cytotoxicity than cisplatin against human colon (SW480) and human lung (A549) adenocarcinoma cell lines. Moreover, the pair of complexes bearing the ligand L is markedly more cytotoxic and present higher uptake values than complexes with L, thereby their biological properties were studied further to determine their mechanism of action.

Binding Studies of Metal-Salphen and Metal-Bipyridine Complexes towards G-Quadruplex DNA.

The proposed in vivo formation of G-quadruplex DNA (G4 DNA) in promoter regions of oncogenes and in telomeres has prompted the development of small molecules with high affinity and selectivity for these structures. Herein we report the synthesis of a new di-substituted bipyridine ligand and the corresponding complexes with Ni and VO . Both these new complexes have been characterized spectroscopically and by X-ray crystallography.

Role of Seroalbumin in the Cytotoxicity of cis-Dichloro Pt(II) Complexes with (N^N)-Donor Ligands Bearing Functionalized Tails.

Given the potent anticancer properties of cis-diamminedichloroplatinum(II) and knowing its mode of action, we synthesized four new cis-[PtCl(N^N)] organoplatinum complexes, two with N-substituted pbi ligands (pbiR = 1-R-2-(2-pyridyl)benzimidazole) (namely, 1 and 2) and two more with 4,4'-disubstituted bpy ligands (bpy = 2,2'-bipyridine) (namely, 3 and 4). We explored their cytotoxicity and ability to bind to deoxyguanosine monophosphate (dGMP), DNA, and albumin models. By H NMR and UV-vis spectroscopies, circular dichroism, agarose gel electrophoresis, differential scanning calorimetry measurements, and density functional theory calculations, we verified that only 3 can form aquacomplex species after dimethyl sulfoxide solvation; surprisingly, 1, 2, and 3 can bind covalently to DNA, whereas 4 can form a noncovalent complex.

Kinetic evidence for interaction of TMPyP4 with two different G-quadruplex conformations of human telomeric DNA.

Background: Stabilization of G-quadruplex helices by small ligands has attracted growing attention because they inhibit the activity of the enzyme telomerase, which is overexpressed in >80% cancer cells. TMPyP4, one of the most studied G-quadruplex ligands, is used as a model to show that the ligands can exhibit different binding features with different conformations of a human telomeric specific sequence.

Methods: UV-Vis, FRET melting Assay, Isothermal Titration Calorimetry, Time-resolved Fluorescence lifetime, T-Jump and Molecular Dynamics.

New insights into the mechanism of the DNA/doxorubicin interaction.

Doxorubicin (DOX) is an important anthracycline antibiotic whose intricate features of binding to DNAs, not yet fully understood, have been the object of intense debate. The dimerization equilibrium has been studied at pH = 7.0, I = 2.