Isabella Rimoldi

Promising antiproliferative platinum(II) complexes based on imidazole moiety: Synthesis, evaluation in HCT-116 cancer cell line and interaction with Ctr-1 Met-rich domain

A series of imidazole based platinum(II) complexes were synthesised and evaluated for their cytotoxicity in HCT-116 cancer cell line, known for being partially resistant to cisplatin but sensitive to oxaliplatin. Lipophilicity was modulated by introducing differently long saturated and unsaturated chains at the N1 of the imidazole moiety. Pt-I displayed the higher cytotoxic effect achieving a IC50=38.0±14.1μM, comparable to the oxaliplatin value. The interaction between the imidazole platinum(II) complexes and the octapeptide called Mets7, the methionine-rich motif mimicking the N-terminal domain of the yCtr-1, was evaluated in order to have a major insight of the uptake and the eventual resistance mechanisms for the so-synthesised novel platinum compounds.

Vibrational circular dichroism and chiroptical properties of chiral Ir(III) luminescent complexes

The octahedral ionic Ir(iii) complex with a dual stereogenic centre of general formula Δ,Λ-(R,S)-[(ppy)2Ir(Me-Campy)]X, where ppy = 2-phenylpyridine and Me-Campy = 2-methyl-5,6,7,8-tetrahydroquinolin-8-amine, and the complex Λ-(R,S)-[(ppy)2Ir(H-Campy)]X, where ppy = 2-phenylpyridine, H-Campy = 8-amino-5,6,7,8-tetrahydroquinolines and X(-) = Cl(-) as a counterion in both cases, have been characterized by vibrational circular dichroism (VCD), which turns out to be efficacious in diastereomeric discrimination. Moreover, the single crystal X-ray structure of the complex Δ-(R)-[(ppy)2Ir(Me-Campy)]Cl is reported here. Density functional theory (DFT) calculations allow us to conclude that the most important doublet feature in the VCD spectra is associated with a clear vibrational exciton structure located on the two dissymmetrically disposed phenylpyridine ligands. The features in the VCD spectra associated with the (R) or (S)-central chirality configuration are identified and commented on. DFT calculations provide also the interpretation of electronic circular dichroism (ECD) spectra. Finally, circularly polarized luminescence (CPL) spectra are presented as an additional chiroptical characterization of these luminescent iridium complexes.

Simple 1,3-diamines and their application as ligands in ruthenium(II) catalysts for asymmetric transfer hydrogenation of aryl ketones

In this research work simple unsymmetrical 1,3-diamines were studied. The synthesis of the diamines started from non-commercial available compounds. S-5a and S,S-5c were obtained by biocatalysis with non conventional yeast, Rhodotorula rubra MIM 147, with excellent 99% e.e. and d.e. up to 90%. Different approaches of synthesis were applied to the same backbone to study both the steric and electronic effects of the ligands. The reactivity of the corresponding ruthenium complexes was evaluated in the asymmetric hydrogen transfer reduction of acetophenone as a standard substrate and of other different aryl ketones, highlighting the flexibility of the six membered chelating ring. A screening of the reaction conditions indicated aqueous media in the presence of HCOONa as a hydrogen donor to be the best system for overcoming the lack of stereocontrol thus allowing us to obtain 56% e.e. in the reduction of acetophenone with the complex in which the ligand was diamine 1, revealed as the best in terms of reactivity and stereoselectivity also in the reduction of the other different aryl ketones, in particular for α-tetralone, i (63% e.e.).

Electropolymerized highly photoconductive thin films of cyclopalladated and cycloplatinated complexes.

The complete characterization of novel electropolymerizable organometallic complexes is presented. These are newly synthesized cyclometalated complexes of general formula (PPy)M(O ∧ N)(n) (H(PPy) = 2-phenylpyridine, M = Pd(II) or Pt(II), H(O ∧ N)(n) = Schiff base). Polymeric thin films have been obtained from these complexes by electropolymerization of the triphenylamino group grafted onto the H(O ∧ N)(n) ancillary ligand. The redox behavior and the photoconductivity of both of the monomers (PPy)M(O ∧ N)(n) and the electropolymerized species have been investigated. The polymeric films of (PPy)M(O ∧ N)(n) have shown a very significant enhancement of photoconductivity when compared to their monomeric amorphous counterparts. The high stability of the obtained films strongly suggests that electropolymerization of cyclometalated complexes represents a viable deposition technique of quality thin films with improved photoconduction properties, hence opening the door to a new class of materials with suitable properties for optoelectronic applications.

In vitro anticancer activity evaluation of new cationic platinum(II) complexes based on imidazole moiety

The development and the synthesis of cationic platinum(II) complexes were realized and their cytotoxic activity was tested on triple negative breast cancer MDA-MB-231 cell line and in two cell lines poorly responsive to cisplatin (DLD-1 and MCF-7). The complex 2c resulted the most potent cytotoxic agent in MDA-MB-231 (IC50=61.9µM) and more effective than cisplatin on both DLD-1 (IC50=57.4µM) and MCF-7 (IC50=79.9µM) cell lines. 2c showed different cellular uptake and pharmacodynamic properties than cisplatin, interfering with the progression of the M phase of the cell cycle. Thus, 2c represents a lead compound of a new class of cytotoxic agents with promising antitumor activity.

Evaluation of Chemical Diversity of Biotinylated Chiral 1,3‐Diamines as a Catalytic Moiety in Artificial Imine Reductase

The possibility of obtaining an efficient artificial imine reductase was investigated by introducing a chiral cofactor into artificial metalloenzymes based on biotin–streptavidin technology. In particular, a chiral biotinylated 1,3‐diamine ligand in coordination with iridium(III) complex was developed. Optimized chemogenetic studies afforded positive results in the stereoselective reduction of a cyclic imine, the salsolidine precursor, as a standard substrate with access to both enantiomers. Various factors such as pH, temperature, number of binding sites, and steric hindrance of the catalytic moiety have been proved to affect both efficiency and enantioselectivity, underlining the great flexibility of this system in comparison with the achiral system. Computational studies were also performed to explain how the metal configuration, in the proposed system, might affect the observed stereochemical outcome.

Malignant Pleural Mesothelioma: State of the art and advanced cell therapy

Malignant Pleural Mesothelioma (MPM) is an aggressive malignancy highly resistant to chemotherapy, with a response rate of 20% of patients and for this reason an efficient treatment is still a challenge. Platinum-based chemotherapy in association with a third-generation antifolate is the front-line standard of care whereas any second-line treatment was approved for MPM thus making it a pathology that evokes the need for new therapeutic agents. Different platinum-drugs were synthesised and tested as an option for patients who are not candidates to cisplatin-based therapy. Among these, monofunctional cationic antineoplastic platinum compounds received a special attention in the last decade. Alternative strategies to the commonly used combination-therapy resulted from the use of Mesenchymal Stromal Cells (MSC) widely used in the field of regenerative medicine and recently proposed as natural carriers for a selective delivery of chemotherapeutic agents and from the use of immune checkpoint and kinase inhibitors. The present short review shed light on the recent state of art and the future perspectives relative to MPM therapy.

Uptake-release by MSCs of a cationic platinum(II) complex active in vitro on human malignant cancer cell lines

In this study, the in vitro stability of cisplatin (CisPt) and cationic platinum(II)-complex (caPt(II)-complex) and their in vitro activity (antiproliferative and anti-angiogenic properties) were investigated against three aggressive human tumor cell lines. caPt(II)-complex shown a high stability until 9 days of treatment and displayed a significant and higher activity than CisPt against both NCI-H28 mesothelioma (19.37 ± 9.57 μM versus 34.66 ± 7.65 μM for CisPt) and U87 MG glioblastoma (19.85 ± 0.97 μM versus 54.14 ± 3.19 for CisPt). Mesenchymal Stromal Cells (AT-MSCs) showed a significant different sensitivity (IC50 = 71.9 ± 15.1 μM for caPt(II)-complex and 8.7 ± 4.5 μM for CisPt) to the antiproliferative activity of caPt(II)-complex and CisPt. The ability of MSCs to uptake both the drugs in a similar amount of 2.49 pM /cell, suggested a possible development of new therapies based on cell mediated drug delivery.

Mesenchymal Stromal Cells for Antineoplastic Drug Loading and Delivery

Mesenchymal stromal cells are a population of undifferentiated multipotent adult cells possessing extensive self-renewal properties and the potential to differentiate into a variety of mesenchymal lineage cells. They express broad anti-inflammatory and immunomodulatory activity on the immune system and after transplantation can interact with the surrounding microenvironment, promoting tissue healing and regeneration. For this reason, mesenchymal stromal cells have been widely used in regenerative medicine, both in preclinical and clinical settings. Another clinical application of mesenchymal stromal cells is the targeted delivery of chemotherapeutic agents to neoplastic cells, maximizing the cytotoxic activity against cancer cells and minimizing collateral damage to non-neoplastic tissues. Mesenchymal stem cells are home to the stroma of several primary and metastatic neoplasms and hence can be used as vectors for targeted delivery of antineoplastic drugs to the tumour microenvironment, thereby reducing systemic toxicity and maximizing antitumour effects. Paclitaxel and gemcitabine are the chemotherapeutic drugs best loaded by mesenchymal stromal cells and delivered to neoplastic cells, whereas other agents, like pemetrexed, are not internalized by mesenchymal stromal cells and therefore are not suitable for advanced antineoplastic therapy. This review focuses on the state of the art of advanced antineoplastic cell therapy and its future perspectives, emphasizing in vitro and in vivo preclinical results and future clinical applications.

Novel platinum agents and mesenchymal stromal cells for thoracic malignancies: state of the art and future perspectives

ABSTRACT Introduction: Non-small cell lung cancer and malignant pleural mesothelioma represent two of the most intriguing and scrutinized thoracic malignancies, presenting interesting perspectives of experimental development and clinical applications. Areas covered: In advanced non-small cell lung cancer, molecular targeted therapy is the standard first-line treatment for patients with identified driver mutations; on the other hand, chemotherapy is the standard treatment for patients without EGFR mutations or ALK rearrangement or those with unknown mutation status. Once considered an ineffective therapy in pulmonary neoplasms, immunotherapy has been now established as one of the most promising therapeutic options. Mesenchymal stromal cells are able to migrate specifically toward solid neoplasms and their metastatic localizations when injected intravenously. This peculiar cancer tropism has opened up an emerging field to use them as vectors to deliver antineoplastic drugs for targeted therapies. Expert opinion: Molecular targeted therapy and immunotherapy are the new alternatives to standard chemotherapy. Mesenchymal stromal cells are a new promising tool in oncology and—although not yet utilized in the clinical practice, we think they will represent another main tool for cancer therapy and will probably play a leading role in the field of nanovectors and molecular medicine.