Understanding the interaction of an antitumoral platinum(II) 7-azaindolate complex with proteins and DNA

Functionalized azobenzene platinum(II) complexes as putative anticancer compounds

The synthesis and characterization of four platinum(II) complexes using azobenzenes conveniently functionalized as ligands has been carried out. The characteristic photochemical behavior of the complexes due to the presence of azobenzene-type ligands and the role of the ligands in the activation of the complexes has been studied. Their promising cytotoxicity observed in HeLa cells prompted us to study the mechanism of action of these complexes as cytostatic agents. The interaction of the compounds with DNA, studied by circular dichroism, revealed a differential activity of the Pt(II) complexes upon irradiation. The intercalation abilities of the complexes as well as their reactivity with common proteins present in the blood stream allows to confirm some of the compounds obtained as good anticancer candidates.

Affinity of a mononuclear monofunctional anticancer Pt(II) complex to human serum albumin: a spectroscopic approach

The interaction of a mononuclear monofunctional anticancer Pt(II) complex, [PtLCl]Cl (L = 4′-bis(pyridine-2-ylmethyl)amino-2-phenylbenzothiazole) (1), and human serum albumin (HSA) was investigated under physiological conditions using UV–Vis absorption, circular dichroism, fluorescence, and synchronous fluorescence. The experimental results suggested that the Pt(II) complex could bind to HSA, induce conformation and microenvironmental changes of HSA with a moderate binding affinity, and quench the intrinsic fluorescence of HSA through a static quenching mechanism. The thermodynamic parameters, ΔG°, ΔH°, and ΔS°, calculated at different temperatures, indicated that the binding reaction was spontaneous and hydrophobic forces and π–π stacking played major roles in the association. Based on the number of binding sites, it was considered that one molecule of complex 1 could bind to a single site of HSA. In view of the results of site marker competition experiments, the reactive site of HSA to complex 1 mainly located in subdomain IIA (site I). Moreover, the binding distance, r, between donor (HSA) and acceptor (complex 1) was 4.69 nm according to Förster nonradiation energy transfer theory. The present study provides relevant and useful information that can be used for the design and application of mononuclear monofuctional Pt(II) complexes in biomedical sciences.

Efficient one-pot synthesis of trans-Pt(ii)(salicylaldimine)(4-picoline)Cl complexes: effective agents for enhanced expression of p53 tumor suppressor genes

One-pot synthesizedtrans-Pt(ii)(salicylaldimine)(4-picoline)Cl complexes showed promisingin vitrocytotoxicity in MCF-7 and A549 cancer cell lines.

Rhenium and technetium tricarbonyl, {M(CO)3} (+) (M = Tc, Re), binding to mammalian metallothioneins: new insights into chemical and radiopharmaceutical implications

This paper deals with the binding of the four mammalian metallothioneins (MTs) to the organometallic metal fragment {fac-M(CO)3}(+) (M = (99)Tc, Re), which is highly promising for the preparation of second-generation radiopharmaceuticals. The study of the transmetallation reaction between zinc and rhenium in Zn7-MT1 by means of UV-vis and CD spectroscopy demonstrated the incorporation of the {fac-Re(CO)3}(+) fragment to the MTs. This reaction should be performed at 70 °C to accelerate the reaction rate, a result that is consistent with the reported reactivity of the rhenium fragment. ESI-TOF MS demonstrated the formation of mixed-metal species as Zn6,{Re(CO)3}-MT, Zn6,{Re(CO)3}2-MT, and Zn5,{Re(CO)3}3-MT, as well as the different reactivity of the four MT isoforms. Hence, Zn-MT3 showed the highest reactivity, in agreement with its high Cu-thionein character, whereas Zn-MT2 exhibited the lowest reactivity, in line with its high Zn-thionein character. The reactivity of the Zn-loaded forms of MT1 and MT4 is intermediate between those of MT3 and MT2. The study of the binding of the {fac-(99)Tc(CO)3}(+) fragment to MTs showed a significant and very interesting different reactivity in relation to rhenium. The transmetallation reaction is much more effective with technetium than with rhenium and significant amounts of mixed Zn x ,{(99)Tc(CO)3} y -MT species were formed with the four MT isoforms whereas only MT3 rendered similar amounts of rhenium derivatives. The results obtained in this study support the possible use of technetium for labelling mammalian metallothioneins and also for possible radiopharmaceutical applications.