Characterisation of the DNA sequence specificity, cellular toxicity and cross-linking properties of novel bispyridine-based dinuclear platinum complexes

Abstract

BackgroundThe anti-tumour activity of cisplatin is thought to be a result of its capacity to form DNA adducts which prevent cellular processes such as DNA replication and transcription. These DNA adducts can effectively induce cancer cell death, however, there are a range of clinical side effects and drug resistance issues associated with its use. In this study, the biological properties of three novel dinuclear platinum-based compounds (that contain alkane bridging linkers of eight, ten and twelve carbon atoms in length) were characterised to assess their potential as anticancer agents.MethodsThe properties of these compounds were determined using a DNA template containing seven tandem telomeric repeat sequences. A linear amplification reaction was used in combination with capillary electrophoresis to quantify the sequence specificity of DNA adducts formed by these compounds at base pair resolution. The DNA cross-linking ability of these compounds was assessed using denaturing agarose gel electrophoresis and cytotoxicity was determined in HeLa cells using a colorimetric cell viability assay.ResultsThe dinuclear compounds were found to preferentially form DNA adducts at guanine bases and they exhibited different damage intensity profiles at the telomeric repeat sequences compared to that of cisplatin. The dinuclear compounds were found to exhibit a low level of cytotoxicity relative to cisplatin and their cytotoxicity increased as the linker length increased. Conversely, the interstrand cross-linking efficiency of the dinuclear compounds increased as the linker length decreased and the compound with the shortest alkane linker was six-fold more effective than cisplatin.ConclusionsSince the bifunctional compounds exhibit variation in sequence specificity of adduct formation and a greater ability to cross-link DNA relative to cisplatin they warrant further investigation towards the goal of developing new cancer chemotherapeutic agents.

The interactions of novel mononuclear platinum-based complexes with DNA

“…Following incubation, an ethanol precipitation was performed on all samples and the DNA pellets were re-dissolved in 20 μL of 10 mM Tris-HCl (pH 8.8), 0.1 mM Na 2 EDTA. The Pvu II-cleaved pUC19/T7 DNA samples were used in the LAR and interstrand cross-linking assays as previously described [33]. All assays were reproduced in triplicate to give consistent results, representative examples are shown.…”

Quantitative and systematic NMR measurements of sequence-dependent A-T Hoogsteen dynamics uncovers unique conformational specificity in the DNA double helix

“…Beyond these regulatory processes, many mutational processes linked to cancer strongly depend on the DNA sequence (6)(7)(8). Some DNA sequences are more susceptible to damage from environmental and endogenous factors (9)(10)(11)(12)(13)(14)(15)(16)(17), while others are more prone to replicative errors (18)(19)(20)(21)(22)(23)(24). The efficiency of damage repair can also vary depending on the sequence context of the damaged nucleotide (25)(26)(27)(28).…”

Role of Mouse Organic Cation Transporter 2 for Nephro- and Peripheral Neurotoxicity Induced by Chemotherapeutic Treatment with Cisplatin

“…The main mechanism of anticancer action of CDDP is the formation of intra-and inter-strand adducts with nuclear and mitochondrial DNA [9], which activate cellular DNAdamage responses and increase oxidative stress, ultimately leading to cell apoptosis [10]. However, CDDP cellular damage can also result from a direct interaction of CDDP with proteins, as has been shown, for example, for the CDDP adduct of the Iron Regulatory Protein 2 [11].…”