Water-soluble platinum phthalocyanines as potential antitumor agents.

Breast cancer represents the second cause of death in the European female population. The lack of specific therapies together with its high invasive potential are the major problems associated to such a tumor. In the last three decades platinum-based drugs have been considered essential constituents of many therapeutic strategies, even though with side effects and frequent generation of drug resistance. These drugs have been the guide for the research, in last years, of novel platinum and ruthenium based compounds, able to overcome these limitations. In this work, ruthenium and platinum based phthalocyanines were synthesized through conventional techniques and their antiproliferative and/or cytotoxic actions were tested. Normal mammary gland (MCF10A) and several models of mammarian carcinoma at different degrees of invasiveness (BT474, MCF-7 and MDA-MB-231) were used. Cells were treated with different concentrations (5-100 µM) of the above reported compounds, to evaluate toxic concentration and to underline possible dose-response effects. The study included growth curves made by trypan blue exclusion test and scratch assay to study cellular motility and its possible negative modulation by phthalocyanine. Moreover, we investigated cell cycle and apoptosis through flow cytometry and AMNIS Image Stream cytometer. Among all the tested drugs, tetrasulfonated phthalocyanine of platinum resulted to be the molecule with the best cytostatic action on neoplastic cell lines at the concentration of 30 µM. Interestingly, platinum tetrasulfophtalocyanine, at low doses, had no antiproliferative effects on normal cells. Therefore, such platinum complex, appears to be a promising drug for mammarian carcinoma treatment.

Linking Pd(II) and Ru(II) phthalocyanines to single-walled carbon nanotubes.

The preparation of new Pc-SWCNT hybrid materials is described. The synthesis of both Pd(ii)Pc-SWCNT and Ru(ii)bis(pyridine)Pc-SWCNT was carried out by esterification reaction between modified SWCNTs and the corresponding unsymmetric Pcs and , both endowed with three solubilizing tert-butyl groups and a hydroxymethyl function. Compound was prepared following the straightforward, statistical condensation of the corresponding phthalonitriles. However the preparation of Ru(ii)bis(pyridine)Pc required a multistep procedure relying on consecutive cyclotetramerization, protection, metallation and deprotection reactions. Modified SWCNT was prepared, as previously described, by the Prato reaction between HiPCo nanotubes, N-methylglycine and 4-formylbenzoic acid. The COOH-containing material was successfully reacted with Pd(ii)Pc to give Pd(ii)Pc-SWCNT , which was fully characterized by different techniques. However, the incorporation of Ru(ii)bis(pyridine)Pc did not take place when applying the above-mentioned conditions. The preparation of SWCNT endowed with 4-carboxyphenyl moieties was found to be essential to covalently link Ru(bis(pyridine))Pc to the nanotube material by ester bond formation. Although spectroscopic characterization supports the covalent binding of Pc molecules to the modified SWCNT sidewalls, direct evidence of the presence of Ru(ii) in the hybrid material could not be obtained.