Kristallstruktur eines Cisplatin-(1,3-GTG)-Schadens im Komplex mit DNA-Polymerase η

Chromatin Regulates Genome Targeting with Cisplatin

Cisplatin derivatives can form various types of DNA lesions (DNA‐Pt) and trigger pleiotropic DNA damage responses. Here, we report a strategy to visualize DNA‐Pt with high resolution, taking advantage of a novel azide‐containing derivative of cisplatin we named APPA, a cellular pre‐extraction protocol and the labeling of DNA‐Pt by means of click chemistry in cells. Our investigation revealed that pretreating cells with the histone deacetylase (HDAC) inhibitor SAHA led to detectable clusters of DNA‐Pt that colocalized with the ubiquitin ligase RAD18 and the replication protein PCNA. Consistent with activation of translesion synthesis (TLS) under these conditions, SAHA and cisplatin cotreatment promoted focal accumulation of the low‐fidelity polymerase Polη that also colocalized with PCNA. Remarkably, these cotreatments synergistically triggered mono‐ubiquitination of PCNA and apoptosis in a RAD18‐dependent manner. Our data provide evidence for a role of chromatin in regulating genome targeting with cisplatin derivatives and associated cellular responses.

The selective synthesis of metallanucleosides and metallanucleotides: a new tool for the functionalization of nucleic acids

Nucleobases team up: the efficient and selective preparation of purine-derived metallanucleosides, metallanucleotides, and metalladinucleotides having M-C bonds (M=Ir(III), Rh(III)) is reported for the first time. The results presented may be applied to the synthesis of functionalized nucleic acids, or DNA/RNA-modified segments.

In vitro and in vivo antitumor activities and DNA binding mode of five coordinated cyclometalated organoplatinum(II) complexes containing biphosphine ligands

New complexes [Pt(C(∧)N)Cl(dppa)] (1), and [Pt(C(∧)N)Cl(dppm)] (2), (C(∧)N. deprotonated 2-phenylpyridine; dppa. bis(diphenylphosphino)amine; dppm. bis(diphenylphosphino)methane) were suggested to have pentacoordinated geometry as investigated by NMR and conductometry. Pharmacological effects of 1 and 2 were evaluated for their proteasome-inhibitory and apoptosis-inducing activities under in vitro and in vivo conditions, showing significant proteasome-inhibitory activity against purified 20S proteasome, while 2 demonstrated superior inhibitory activity against cellular 26S proteasome. Consistently, this effect was associated with higher levels of proteasome target proteins and apoptosis induction in breast cancer cells. Importantly, preliminary studies show 1 and 2 were able to exert a similar effect in vivo by inhibiting the growth of breast cancer xenografts in mice, which was associated with proteasome inhibition and apoptosis induction. Interaction of 1 and 2 with herring sperm DNA was investigated by fluorimeteric emission, suggesting that Pt(II)-containing biphosphine complexes with DNA binding capabilities can also target and inhibit the tumor proteasome.

Aromatic rings in chemical and biological recognition: energetics and structures

This review describes a multidimensional treatment of molecular recognition phenomena involving aromatic rings in chemical and biological systems. It summarizes new results reported since the appearance of an earlier review in 2003 in host-guest chemistry, biological affinity assays and biostructural analysis, data base mining in the Cambridge Structural Database (CSD) and the Protein Data Bank (PDB), and advanced computational studies. Topics addressed are arene-arene, perfluoroarene-arene, S⋅⋅⋅aromatic, cation-π, and anion-π interactions, as well as hydrogen bonding to π systems. The generated knowledge benefits, in particular, structure-based hit-to-lead development and lead optimization both in the pharmaceutical and in the crop protection industry. It equally facilitates the development of new advanced materials and supramolecular systems, and should inspire further utilization of interactions with aromatic rings to control the stereochemical outcome of synthetic transformations.