Correction: In vitro and in vivo antiproliferative activity of organo-nickel SCS-pincer complexes on estrogen responsive MCF7 and MC4L2 breast cancer cells. Effects of amine fragment substitutions on BSA binding and cytotoxicity.

Correction for 'In vitro and in vivo antiproliferative activity of organo-nickel SCS-pincer complexes on estrogen responsive MCF7 and MC4L2 breast cancer cells. Effects of amine fragment substitutions on BSA binding and cytotoxicity' by Mahboubeh Hosseini-Kharat et al., Dalton Trans., 2018, 47, 16944-16957, https://doi.org/10.1039/c8dt03079k.

Cytotoxicity, anti-tumor effects and structure-activity relationships of nickel and palladium S,C,S pincer complexes against double and triple-positive and triple-negative breast cancer (TNBC) cells.

Triple-Negative Breast Cancer (TNBC) is a highly aggressive form of breast cancer. The high rate of metastasis associated with TNBC is attributed to its multidrug resistance, making the treatment of this metastatic condition difficult. The development of metal-based antitumor agents was launched with the discovery of cisplatin, followed by the development of related antitumor drugs such as carboplatin and oxaliplatin. Yet, the severe side effects of this approach represent a limitation for its clinical use. The current search for new metal-based antitumor agents possessing less severe side effects than these platinum-based complexes has focused on various complexes of nickel and palladium, the group 10 congeners of platinum. In this work, we have prepared a series of SCS-type pincer complexes of nickel and palladium featuring a stable meta-phenylene central moiety and two chelating but labile thioamide donor moieties at the peripheries of the ligand. We have demonstrated that the complexes in question, namely L1NiCl, L1NiBr, L1PdCl, L2PdCl, and L3PdCl, are active on the proliferation of estrogen-dependent breast tumor cells (MCF-7 and MC4L2) and triple-negative breast cancer (4 T1). Among the complexes studied, the palladium derivatives were found to be much safer anticancer agents than nickel counterparts; these were thus selected for further investigations for their effects on tumor cell adhesion and migration as well. The results of our studies show that palladium complexes are effective for inhibiting TNBC 4 T1 cells adhesion and migration. Finally, the HOMO and LUMO analysis was used to determine the reactivity and charge transfer within the compounds.

Improvement of Power Conversion Efficiency of Quantum Dot-Sensitized Solar Cells by Doping of Manganese into a ZnS Passivation Layer and Cosensitization of Zinc-Porphyrin on a Modified Graphene Oxide/Nitrogen-Doped TiO2 Photoanode.

It is vital to acquire power conversion efficiencies comparable to other emerging solar cell technologies by making quantum dot-sensitized solar cells (QDSSCs) competitive. In this study, the effect of graphene oxide (GO), nitrogen, manganese, and a porphyrin compound on the performance of QDSSCs based on a TiO2/CdS/ZnS photoanode was investigated. First, adding GO and nitrogen into TiO2 has a conspicuous impact on the cell efficacy. Both these materials reduce the recombination rate and expand the specific surface area of TiO2 as well as dye loading, reinforcing cell efficiency value. The maximum power conversion efficiency of QDSSC with a GO N-doped photoelectrode was 2.52%. Second, by employing Mn2+ (5 and 10 wt %) doping of ZnS, we have succeeded in considerably improving cell performance (from 2.52 to 3.47%). The reason for this could be for the improvement of the passivation layer of ZnS by Mn2+ ions, bringing about to a smaller recombination of photoinjected electrons with either oxidized dye molecules or electrolyte at the surface of titanium dioxide. However, doping of 15 wt % Mn2+ had an opposite effect and somewhat declined the cell performance. Finally, a Zn-porphyrin dye was added to the CdS/ZnS by a cosensitization method, widening the light absorption range to the NIR (near-infrared region) (>700 nm), leading to the higher short-circuit current density (J SC) and cell efficacy. Utilizing an environmentally safe porphyrin compound into the structure of QDSSC has dramatically enhanced the cell efficacy to 4.62%, which is 40% higher than that of the result obtained from the TiO2/CdS/ZnS photoelectrode without porphyrin coating.

Novel Palladium Complex: Cytotoxicity against Cisplatin-resistant K562 Cells.

Today, development of resistance to anticancer drugs (including cisplatin) is noticed as a major problem. Recently several studies demonstrated that palladium complexes showed remarkable cytotoxic effects against K562 cell line and could be used efficiently for treatment of many human cancers including leukemia. Hereof, K562 cells were made resistant to cisplatin using increasing concentration of cisplatin up to 4.5 mM and then cytotoxic effect of synthesized palladium complex was evaluated on this sub-line using MTT assay. Annexin V/PI staining using flow cytometry and scanning electron microscopy (SEM) were performed to find out the mechanism of the observed cytotoxicity. Results indicated that tested compounds had a noticeable cytotoxic effect on K562 cells 80 times more than cisplatin. Palladium complex also showed significant cytotoxicity on resistant K562 sub-line. Flow cytometry and SEM results revealed that these compounds exert their cytotoxic effect via apoptosis and it could be concluded that the novel synthesized palladium complex might be a good candidate for replacing cisplatin in case of treatment of cisplatin resistant tumors.

Antiproliferative activity of morpholine-based compounds on MCF-7 breast cancer, colon carcinoma C26, and normal fibroblast NIH-3T3 cell lines and study of their binding affinity to calf thymus-DNA and bovine serum albumin.

This report describes the results of a study on the antiproliferative activity of the morpholine-based ligand 1,3-bis(1-morpholinothiocarbonyl)benzene (HL) and its nickel(II) complex (NiL) against human breast cancer cells (MCF-7), colon carcinoma cells (C26), and normal fibroblast NIH-3T3 cells. NiL showed better cytotoxicity on both cancerous cells relative to normal cells in vitro with the highest selective index of 2.22 in MCF-7 cells. The interaction of both compounds with calf thymus DNA (CT DNA) and bovine serum albumin (BSA) was studied using various spectroscopic techniques and analytical methods such as UV - vis titrations, thermal denaturation, circular dichroism, competitive fluorescent intercalator displacement assays, as well as molecular modeling. The fluorescence intensity of the probe molecule increases clearly when HL and NiL are added to the methylene blue (MB)-DNA system. Furthermore, the binding of HL and NiL quenches the BSA fluorescence, revealing a 1:1 interaction with a binding constant of about 105 M-1. Communicated by Ramaswamy H. Sarma.

In vitro and in vivo antiproliferative activity of organo-nickel SCS-pincer complexes on estrogen responsive MCF7 and MC4L2 breast cancer cells. Effects of amine fragment substitutions on BSA binding and cytotoxicity.

A family of organonickel complexes has been prepared, fully characterized, and tested for their antiproliferative activity against estrogen-responsive human breast cancer cells (MCF7). The three SCS-type pincer ligands HL1, HL2, and HL3 and their corresponding Ni(ii) complexes NiL1, NiL2, and NiL3 have been synthesized and fully characterized, including by single crystal diffraction studies for the complexes. The complexes possess square planar geometry with two symmetrical 5-membered nickellacycles. Fluorescence spectroscopy, circular dichroism measurements, molecular modeling, colorimetric based assay and tumor transplantation studies were used to evaluate the protein binding and antiproliferative activities of these organometallic complexes both in vitro and in vivo. Fluorescence quenching was used to investigate bovine serum albumin (BSA) interaction at different temperatures (293, 303 and 313 K), and the results were analyzed using the classical Stern-Volmer equation, allowing us to propose a dynamic quenching mechanism. Studies in vitro on the antiproliferative activity of the three organonickel complexes against estrogen-responsive human breast cancer cells (MCF7) showed promising antitumor activity for NiL1 containing pyrrolidine fragments. In vivo administration of this compound significantly inhibits tumor growth in estrogen-dependent MC4L2 cancer cells in female BALB/c mice.

Synthesis, spectral characterization, crystal structure and in vitro DNA/protein binding studies of phosphorous ylide palladacyclic complexes containing azide group.

The reaction between (4-nitrobenzoylmethylene)triphenylphosphorane Pd(II) complex [Pd{κ(2)(C,C)-C6 H4PPh2C(H)CO(C6 H4NO2-4)}(µ-Cl)]2 and excess of NaN3 resulted in the µ-N3 bridged Pd(II) complex [Pd{κ(2)(C,C)-C6H4PPh2C(H)CO(C6 H4NO2-4)}(µ-N3)]2 (1), which underwent bridge cleavage reactions with monodentate ligands to afford the monomeric, neutral complexes [Pd{κ(2)(C,C)-C6 H4PPh2C(H)CO(C6 H4NO2-4)}N3(L)] (L=Me3Py (1a), PPh3 (1b)). The complexes were identified and characterized by elemental analyses, infrared (IR), ((1))H, ((13))C{((1))H} and ((31))P{((1))H} NMR spectroscopy. The molecular structure of 1b was determined by single-crystal X-ray diffraction. The interactions of complexes with FS-DNA were investigated using UV absorption and fluorescence spectra. The results suggested that both complexes could interact with FS-DNA through the intercalation mode and follow the binding affinity order of 1a>1b. The reactivity toward protein BSA revealed that the quenching of BSA fluorescence by the two complexes are static quenching, and complex 1a exhibits a higher BSA-binding ability than the complex 1b.

In vitro cytotoxicity studies of palladacyclic complexes containing the symmetric diphosphine bridging ligand. Studies of their interactions with DNA and BSA.

The reactions between [Pd2{(C,N)-C6H4CH2NH(Et)}2(µ-X)2] (X = Cl or Br) and 1,2-bis(diphenylphosphino)ethane (dppe) in the 1:1 molar ratio resulted in the dppe-bridged Pd(II) complexes, [Pd2{(C,N)-C6H4CH2NH(Et)}2(µ-dppe)(Cl)2] (1) and [Pd2{(C,N)-C6H4CH2NH(Et)}2(µ-dppe)(Br)2] (2), respectively, which were characterized by elemental analyses, infrared (IR), (1)H- and (31)P{(1)H} NMR spectroscopy. The molecular structure of 1 was determined by single-crystal X-ray diffraction. In vitro cytotoxicity of 1, 2, dppe, PhCH2NH(Et) and cisplatin were carried out against four human tumor cell lines. The interactions of complexes towards DNA and protein are investigated. The results suggested that both complexes could interact with FS-DNA through the intercalation mode. Moreover, the reactivity towards BSA revealed that the microenvironment and the secondary structure of BSA were changed in the presence of Pd(II) complexes.