Nazarov, A. A. | Search bioRxiv

bioRxiv2025

Tuning Histone Site Selectivity in the Nucleosome with Organometallic Agents

Platinum anticancer drugs tend to target DNA whereas certain ruthenium and osmium organometallic compounds, including those with known anticancer activity, preferentially bind histone proteins in chromatin. We earlier found that Ru/Os arene 2-pyridinecarbothioamide antitumor agents display unique or partially overlapping profiles of histone protein binding in the nucleosome compared to Ru arene phosphaadamantane (RAPTA) antimetastasis drugs, but the basis for this difference is unclear. Here we structurally characterized the nucleosome binding effects of arene ligand substitutions and carried out a multiscale simulation analysis, which reveals that the interplay between metal cation and non-leaving ligand identity dictates adduct stability and whether complexes target electronegative surface patches, internal crevices, or both. We show that the nucleosome superhelical crevice acts as a small molecule selectivity filter and that multi-site binding profiles can be expanded or reduced through defined ligand substitutions, which modulate dynamic and steric attributes. Our findings suggest new avenues for rationally developing Ru/Os organometallics that could help expand the scope of chromatin-targeting therapeutics. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=79 SRC="FIGDIR/small/688318v2_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@188bc1dorg.highwire.dtl.DTLVardef@1f619d5org.highwire.dtl.DTLVardef@1a0ebaorg.highwire.dtl.DTLVardef@bd0abb_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2024

Study on the mechanism of action of the Pt(IV) complex with lonidamine ligands by ultrafast chemical proteomics

Platinum (II) complexes such as cisplatin among the few others are well-known and approved for clinical use as anticancer metal-based drugs. In spite of their successful and wide acceptance, the respective chemotherapy is associated with severe side effects and the ability of tumors to quickly develop resistance. To overcome these drawbacks the novel strategy is considered, which is based on the use of platinum complexes with bioactive ligands attached to act in synergy with platinum and further improve its pharmacological properties. Among the recently introduced such multi-action prodrugs is Pt(IV) complex with two lonidamine ligands, the latter selectively inhibiting hexokinase and, thus, the glycolysis in cancer cells. While platinum based multi-action prodrugs are exhibiting increased levels of activity towards cancer cells and, thus, considered as potent to overcome the resistance to cisplatin, there is a crucial need to uncover their mechanism of action by revealing all possibly affected processes and targets across the whole cellular proteomes. These are the challenging tasks in proteomics requiring high-throughput analysis of hundreds of samples for just a single drug-to-proteome system. In this work we performed these analyses for 8-azaguanine and experimental Pt(IV)-lonidamine complex applied to ovarian cancer cell line A2780, using both mechanism- and compound-centric chemical proteomics approaches based on ultrafast expression proteomics and thermal proteome profiling, respectively. Analysis of data obtained for Pt(IV)-lonidamine complex revealed regulation of proteins involved in glucose metabolic process associated with lonidamine further supporting the multi-action mechanism of this prodrug action.

pharmacology and toxicology↗