Cytotoxic activity, cell imaging and photocleavage of DNA induced by a Pt(ii) cyclophane bearing 1,2 diamino ethane as a terminal ligand

Abstract

A Pt II complex [{Pt(en)L} 2 ]$4PF 6 (Ptcyp) (LH 2 ¼ N,N 0 -bis(salicylidene)-p-phenylenediamine, en ¼ 1,2diamino ethane) shows high cytotoxicity against HeLa cells (IC 50 -11.5 mM) and against Dalton's lymphoma (DL) cells (IC 50 -0.65 nM); UV-vis titration of Ptcyp with calf thymus DNA (CT-DNA) demonstrated its DNA binding, which could be further quantified by competitive fluorescence titration of DNA, Ptcyp and ethidium bromide. Circular dichroism studies suggest that Ptcyp interacts with CT-DNA by intercalation in an aqueous medium containing a minimum amount of DMSO. Agarose gel electrophoresis showed that Ptcyp is able to convert a supercoiled pBR322 plasmid DNA into a nicked circular DNA in DMSO, but to a much lower extent in an aqueous medium. However, with UV irradiation, Ptcyp is able to cause concentration-dependent nicking of supercoiled DNA in an aqueous medium. These findings indicate the DNA binding and UV exposure-dependent DNA cleavage properties of Ptcyp. Cell imaging studies using the HeLa cell line carried out in the presence of Ptcyp represent one of the first examples of Pt complexes applied as fluorophores in cell imaging and strongly support its interaction with DNA.

Synthesis of 4-aminoquinoline–pyrimidine hybrids as potent antimalarials and their mode of action studies

“…Also, the bathochromic shift of w3 nm was observed for both the absorptions. The observed hyperchromic as well as hypochromic shifts in absorption bands of 5b upon addition of DNA results from the intercalation of 5b with CT DNA as suggested in the literature [42]. The intercalative nature of interaction of compound 5b with CT DNA was additionally supported by thermal denaturation experiment.…”

Synthesis, structures, nuclease activity, cytotoxicity, DFT and molecular docking studies of two nitrato bridged homodinuclear (Cu-Cu, Zn-Zn) complexes containing 2,2′-bipyridine and a chalcone derivative

“…It is noteworthy that complex 1 has a better IC50 value than complex 2 in topoisomerase inhibition study. As compared to cisplatin, as well as some recently reported copper and zinc complexes, the IC50 value of complex 1 against HeLa cells suggests a stronger cytotoxic action of this complex than that of cisplatin and other complexes [58,59]. Both complexes showed potential cytotoxicity as compared to recently reported copper and zinc complxes of aminonaphthoquinone derivative [60].…”

When self-assembly meets biology: luminescent platinum complexes for imaging applications

“…Mishra and coworkers reported on complex [{Pt(en)L} 2 ]Á4PF 6 , 8, where LH 2 is N,N 0 -bis(salicylidene)-p-phenylenediamine and en is 1,2-diamino-ethane (see Chart 1 for the chemical structure). 113 The complex is internalized by HeLa cells and its toxicity is evaluated by the MTT assay study. Complex 8 was 2-and 10-fold more toxic than cisplatin towards HeLa and Dalton's Lymphoma (DL) cell lines, respectively.…”