In vitro biological characterization of innovative anticancer metal-based agents

Cancer is the second leading cause of death. Although it is already validated the use of techniques such as radiotherapy, immunotherapy and chemotherapy, in the last decade the medical community has focused on the research of less invasive drugs, through the identification of new anticancer agents, as well as by the design of an innovative system for the drug delivery, like the liposomes, that allow the protection of the active principle until the achievement of molecular target, reducing the toxic effects. Among the new anticancer agents currently in clinical trials, there are the ruthenium-based compounds, NAMI-A and KP1019. These have emerged as promising alternatives to platinum compounds (Cisplatin, Oxaliplatin, Carboplatin) that constitute still an important class of chemotherapeutics, whose limit is the high toxicity. Although ruthenium and platinum belong to the same chemical series, the ruthenium complexes showed anticancer and/or antimetastatic activity, associated with fewer side effects. The difference between the derivatives of ruthenium and platinum is probably due to their different pharmacodynamics that, if is well known for Cisplatin and its analogs, it is not yet completely clarified for the other metal complexes. Also, the chemical characteristics like the redox potential, the charges and the lipophilicity are very different among the various classes of metal-based compounds, reflecting their different biological effects. In this context, my Ph.D. aim was the validation of new metal-based agents for the cancer therapy; in particular I analyzed two different classes of compounds: - The ruthenium complex inspired to the drug NAMI-A, AziRu, prepared (designed and developed) by the Department of Chemical Sciences of the University Federico II, Naples (Prof. Luigi Paduano, Prof. Daniela Montesarchio). Its pharmacokinetic profile was improved by the inclusion in liposomes, which should provide, by a passive targeting, for the protection of AziRu and its delivery to cancer cells. - The C-N heterocyclic compounds Ruthenium-derived (RDC11) or Osmium-derived (ODC2, ODC16, ODC20), prepared (designed and developed) by the Department of Chemistry of University of Strasbourg (Prof. Michael Pfeffer). Therefore, my research had different focuses: first, the validation of a nanotechnological platform of metal-based compounds by evaluation of biocompatibility and cellular uptake of different types of liposomes, as innovative carriers for metal complexes. The second point was the analysis of cell death pathways induced by these compounds. Finally, the research evaluated the possible targets involved in the mechanism of action. In fact, even if these compounds are really largely characterized by biological investigations, their mechanism of action, that, as mentioned above, is also closely dependent on redox status and chemical ligands, needs further insights. This study was carried out in particular on the compounds of RDCs and ODCs families, during the period of my Ph.D. at INSERM (French Institute of Health and Medical Research) of Strasbourg (supervisor Dr. Christian Gaiddon); in particular, it concerned the evaluation of the epigenetic changes correlated with the activity of such compounds and the identification of their specific targets. All the results of this work are thus divided, according to the different chemical characteristics of the compounds, into four sections: - Ruthenium-based nanovectors: comparison between neutral and cationic liposomes - DOTAP-TothyCholRu: cholesterol improves the cellular uptake - de-LOS-POPC-TothyRu: an alternative liposome inspired to the bacterial wall - RDCs and ODCs: the role of epigenetic changes in their mechanism of actio