Design and in vitro anticancer assessment of a click chemistry-derived dinuclear copper artificial metallo-nuclease.

Copper compounds with artificial metallo-nuclease (AMN) activity are mechanistically unique compared to established metallodrugs. Here, we describe the development of a new dinuclear copper AMN, Cu2-BPL-C6 (BPL-C6 = bis-1,10-phenanthroline-carbon-6), prepared using click chemistry that demonstrates site-specific DNA recognition with low micromolar cleavage activity. The BPL-C6 ligand was designed to force two redox-active copper centres-central for enhancing AMN activity-to bind DNA, via two phenanthroline ligands separated by an aliphatic linker.

Correction: Re-pairing DNA: binding of a ruthenium phi complex to a double mismatch.

[This corrects the article DOI: 10.1039/D4SC01448K.].

Re-pairing DNA: binding of a ruthenium phi complex to a double mismatch.

We report a crystal structure at atomic resolution (0.9 Å) of a ruthenium complex bound to a consecutive DNA double mismatch, which results in a TA basepair with flipped out thymine, together with the formation of an adenine bulge. The structure shows a form of metalloinsertion interaction of the Λ-[Ru(phen)phi] (phi = 9,10-phenanthrenediimine) complex at the bulge site.

Thiazole orange-carboplatin triplex-forming oligonucleotide (TFO) combination probes enhance targeted DNA crosslinking.

We report a new class of carboplatin-TFO hybrid that incorporates a bifunctional alkyne-amine nucleobase monomer called AP-C3-dT that enables dual 'click' platinum(ii) drug conjugation and thiazole orange fluorophore coupling. Thiazole orange enhances the binding of Pt(ii)-TFO hybrids and provides an intrinsic method for monitoring triplex formation. These hybrid constructs possess increased stabilisation and crosslinking properties in comparison to earlier Pt(ii)-TFOs, and demonstrate sequence-specific binding at neutral pH.

Probing a Major DNA Weakness: Resolving the Groove and Sequence Selectivity of the Diimine Complex Λ-[Ru(phen) phi].

The grooves of DNA provide recognition sites for many nucleic acid binding proteins and anticancer drugs such as the covalently binding cisplatin. Here we report a crystal structure showing, for the first time, groove selectivity by an intercalating ruthenium complex. The complex Λ-[Ru(phen) phi] , where phi=9,10-phenanthrenediimine, is bound to the DNA decamer duplex d(CCGGTACCGG) .

A copper(ii) peptide helicate selectively cleaves DNA replication foci in mammalian cells.

The use of copper-based artificial nucleases as potential anticancer agents has been hampered by their poor selectivity in the oxidative DNA cleavage process. An alternative strategy to solve this problem is to design systems capable of selectively damaging noncanonical DNA structures that play crucial roles in the cell cycle. We designed an oligocationic Cu peptide helicate that selectively binds and cleaves DNA three-way junctions (3WJs) and induces oxidative DNA damage a ROS-mediated pathway both and , specifically at DNA replication foci of the cell nucleus, where this DNA structure is transiently generated.

Analysis of non-canonical three- and four-way DNA junctions.

The development of compounds that can selectively bind with non-canonical DNA structures has expanded in recent years. Junction DNA, including three-way junctions (3WJs) and four-way Holliday junctions (HJs), offer an intriguing target for developmental therapeutics as both 3WJs and HJs are involved in DNA replication and repair processes. However, there are a limited number of assays available for the analysis of junction DNA binding.

A Click Chemistry-Based Artificial Metallo-Nuclease.

Artificial metallo-nucleases (AMNs) are promising DNA damaging drug candidates. Here, we demonstrate how the 1,2,3-triazole linker produced by the Cu-catalysed azide-alkyne cycloaddition (CuAAC) reaction can be directed to build Cu-binding AMN scaffolds. We selected biologically inert reaction partners tris(azidomethyl)mesitylene and ethynyl-thiophene to develop TC-Thio, a bioactive C -symmetric ligand in which three thiophene-triazole moieties are positioned around a central mesitylene core.

Antitumor copper(II) complexes with hydroxyanthraquinones and N,N-heterocyclic ligands.

Five ternary copper(II) complexes, [Cu(phen)(L1)(ClO)] (1), [Cu(phen)(L1)(DMSO)](PF6) (2), [Cu(bpy)(L1)(ClO)(HO)] (3), [Cu(dmp)(L1)(ClO)(HO)] (4), and [Cu(phen)(L2)](ClO) (5), in which phen = 1,10-phenanthroline, bpy = 2,2'-bipyridine, dmp = 2,9-dimethyl-1,10-phenanthroline, HL1 = 1,4-dihydroxyanthracene-9,10-dione and HL2 = 1-hydroxyanthracene-9,10-dione, DMSO = dimethylsulfoxide, were synthesized and fully characterized. Complex 2 was obtained through the substitution of perchlorate for DMSO. When two hydroxyquinone groups are present, L1 makes a bridge between two Cu(II) ions, which also bind two nitrogens of the respective diimine ligand.

Two-Photon Polymerization: Fundamentals, Materials, and Chemical Modification Strategies.

Two-photon polymerization (TPP) has become a premier state-of-the-art method for microscale fabrication of bespoke polymeric devices and surfaces. With applications ranging from the production of optical, drug delivery, tissue engineering, and microfluidic devices, TPP has grown immensely in the past two decades. Significantly, the field has expanded from standard acrylate- and epoxy-based photoresists to custom formulated monomers designed to change the hydrophilicity, surface chemistry, mechanical properties, and more of the resulting structures.

Third-Generation Sequencing of Epigenetic DNA.

The discovery of epigenetic bases has revolutionised the understanding of disease and development. Among the most studied epigenetic marks are cytosines covalently modified at the 5 position. In order to gain insight into their biological significance, the ability to determine their spatiotemporal distribution within the genome is essential.

Gamified innovation to teach patient disadvantage.

Background: Disadvantages such as social distress, safety, economic status and educational levels can significantly impact health risk factors, health care access and health outcomes. Teaching of disadvantage is critical for medical students to understand impact of disadvantages on patient health and facilitate patient-centred care. Disadvantage was initially taught through one tutorial to third year medical students.

Enzymatic Synthesis of Chemical Nuclease Triplex-Forming Oligonucleotides with Gene-Silencing Applications.

Triplex-forming oligonucleotides (TFOs) are short, single-stranded oligomers that hybridise to a specific sequence of duplex DNA. TFOs can block transcription and thereby inhibit protein production, making them highly appealing in the field of antigene therapeutics. In this work, a primer extension protocol was developed to enzymatically prepare chemical nuclease TFO hybrid constructs, with gene-silencing applications.

Mapping the DNA Damaging Effects of Polypyridyl Copper Complexes with DNA Electrochemical Biosensors.

Several classes of copper complexes are known to induce oxidative DNA damage that mediates cell death. These compounds are potentially useful anticancer agents and detailed investigation can reveal the mode of DNA interaction, binding strength, and type of oxidative lesion formed. We recently reported the development of a DNA electrochemical biosensor employed to quantify the DNA cleavage activity of the well-studied [Cu(phen)] chemical nuclease.

Copper(II) and silver(I)-1,10-phenanthroline-5,6-dione complexes interact with double-stranded DNA: further evidence of their apparent multi-modal activity towards Pseudomonas aeruginosa.

Tackling microbial resistance requires continuous efforts for the development of new molecules with novel mechanisms of action and potent antimicrobial activity. Our group has previously identified metal-based compounds, [Ag(1,10-phenanthroline-5,6-dione)]ClO (Ag-phendione) and [Cu(1,10-phenanthroline-5,6-dione)](ClO).4HO (Cu-phendione), with efficient antimicrobial action against multidrug-resistant species.

A Click Chemistry Approach to Targeted DNA Crosslinking with cis-Platinum(II)-Modified Triplex-Forming Oligonucleotides.

Limitations of clinical platinum(II) therapeutics include systemic toxicity and inherent resistance. Modern approaches, therefore, seek new ways to deliver active platinum(II) to discrete nucleic acid targets. In the field of antigene therapy, triplex-forming oligonucleotides (TFOs) have attracted interest for their ability to specifically recognise extended duplex DNA targets.

Click and Cut: a click chemistry approach to developing oxidative DNA damaging agents.

Metallodrugs provide important first-line treatment against various forms of human cancer. To overcome chemotherapeutic resistance and widen treatment possibilities, new agents with improved or alternative modes of action are highly sought after. Here, we present a click chemistry strategy for developing DNA damaging metallodrugs.

Barriers and Facilitators to Integrative Oncology Services in Australia: A Changed Mind Set Required.

This study aimed to explore barriers and facilitators to integrative oncology (IO) service provision and access in Australia. The study design was mixed method with two substudies: a cross-sectional national cancer service survey of public and private sectors; and focus group interviews and an online survey of cancer survivors. Triangulation analysis of qualitative and quantitative data was used to identify and interrogate meta-themes.

DNA-Targeted Metallodrugs: An Untapped Source of Artificial Gene Editing Technology.

DNA binding metal complexes are synonymous with anticancer drug discovery. Given the array of structural and chemical reactivity properties available through careful design, metal complexes have been directed to bind nucleic acid structures through covalent or noncovalent binding modes. Several recognition modes - including crosslinking, intercalation, and oxidation - are central to the clinical success of broad-spectrum anticancer metallodrugs.

Development of Gene-Targeted Polypyridyl Triplex-Forming Oligonucleotide Hybrids.

In the field of nucleic acid therapy there is major interest in the development of libraries of DNA-reactive small molecules which are tethered to vectors that recognize and bind specific genes. This approach mimics enzymatic gene editors, such as ZFNs, TALENs and CRISPR-Cas, but overcomes the limitations imposed by the delivery of a large protein endonuclease which is required for DNA cleavage. Here, we introduce a chemistry-based DNA-cleavage system comprising an artificial metallo-nuclease (AMN) that oxidatively cuts DNA, and a triplex-forming oligonucleotide (TFO) that sequence-specifically recognises duplex DNA.

A Click Chemistry Approach to Developing Molecularly Targeted DNA Scissors.

Nucleic acid click chemistry was used to prepare a family of chemically modified triplex forming oligonucleotides (TFOs) for application as a new gene-targeted technology. Azide-bearing phenanthrene ligands-designed to promote triplex stability and copper binding-were 'clicked' to alkyne-modified parallel TFOs. Using this approach, a library of TFO hybrids was prepared and shown to effectively target purine-rich genetic elements in vitro.

Polypyridyl-Based Copper Phenanthrene Complexes: Combining Stability with Enhanced DNA Recognition.

We report a series of copper(II) artificial metallo-nucleases (AMNs) and demonstrate their DNA damaging properties and in-vitro cytotoxicity against human-derived pancreatic cancer cells. The compounds combine a tris-chelating polypyridyl ligand, di-(2-pycolyl)amine (DPA), and a DNA intercalating phenanthrene unit. Their general formula is Cu-DPA-N,N' (where N,N'=1,10-phenanthroline (Phen), dipyridoquinoxaline (DPQ) or dipyridophenazine (DPPZ)).

Efficient DNA Condensation by a C -Symmetric Codeine Scaffold.

A novel tripodal codeine scaffold (CC3) was rationally designed using computational methods as a DNA condensing alkaloid. Separation of the piperidine nitrogen atoms in CC3 is considerably larger at 14.36 Å than previously reported tripodal opioids allowing for enhanced aggregation of larger DNA plasmids (>4,000 bp).

Copper -Dipyridoquinoxaline Is a Potent DNA Intercalator that Induces Superoxide-Mediated Cleavage via the Minor Groove.

Herein, we report the synthesis, characterisation, X-ray crystallography, and oxidative DNA binding interactions of the copper artificial metallo-nuclease [Cu(DPQ)(NO)](NO), where DPQ = dipyrido[3,2-:2',3'-]quinoxaline. The cation [Cu(DPQ)] (Cu-DPQ), is a high-affinity binder of duplex DNA and presents an intercalative profile in topoisomerase unwinding and viscosity experiments. Artificial metallo-nuclease activity occurs in the absence of exogenous reductant but is greatly enhanced by the presence of the reductant Na--ascorbate.