Platinum(IV) Complexes Featuring Axial Michael Acceptor Ligands - Synthesis, Characterization, and Cytotoxicity

Fluorinated Cycloplatinated(II) Complexes Bearing Bisphosphine Ligands as Potent Anticancer Agents

A family of cationic cycloplatinated(II) complexes [Pt(dfppy)(P^P)]Cl, dfppy = 2-(2,4-difluorophenyl)pyridine, incorporating bisphosphine ligands, P^P = bis(diphenylphosphino)methane (1, dppm), 1,2-bis(diphenylphosphino)ethane (2, dppe) and 1,2-bis(diphenylphosphino)benzene (3, dppbz), was prepared. The complexes were characterized by means of several analytical and spectroscopic methods. These complexes displayed acceptable stability in the biological environments which was confirmed by NMR, HR ESI-MS and UV-vis techniques. The antiproliferative properties of these complexes were evaluated by National Cancer Institute (NCI) at National Institutes of Health (NIH) against 60 different human tumor cell lines such as leukemia, melanoma, lung, colon, brain, ovary, breast, prostate and kidney. These complexes showed higher cytotoxicity than cisplatin against a wide variety of cancer cell lines such as K-562 (leukemia), HOP-92 (lung), HCT-116 (colon), OVCAR-8 (ovarian), PC-3 (prostate), MDA-MB-468 (breast), and melanoma cancer cell lines. Complex 3 as the most potent compound in this study furnished an excellent anti-proliferative activity compared to the cisplatin against Hela, SKOV3, and MCF-7 cancer cell lines. The main mode of the interaction of 1-3 with DNA was also determined using molecular docking studies.

Recent Advances in the Chemistry of Metal Carbamates

Following a related review dating back to 2003, the present review discusses in detail the various synthetic, structural and reactivity aspects of metal species containing one or more carbamato ligands, representing a large family of compounds across all the periodic table. A preliminary overview is provided on the reactivity of carbon dioxide with amines, and emphasis is given to recent findings concerning applications in various fields.

Stability, Reduction, and Cytotoxicity of Platinum(IV) Anticancer Prodrugs Bearing Carbamate Axial Ligands: Comparison with Their Carboxylate Analogues

Platinum(IV) complexes containing carboxylate and carbamate ligands at the axial position have been reported previously. A better understanding of the similarity and difference between the two types of ligands will provide us with new insights and more choices to design novel Pt(IV) complexes. In this study, we systematically investigated and compared the properties of Pt(IV) complexes bearing the two types of ligands. Ten pairs of unsymmetric Pt(IV) complexes bearing axial carbamate or carboxylate ligands were synthesized and characterized. The stability of these Pt(IV) complexes in a PBS buffer with or without a reducing agent was investigated, and most of these complexes exhibited good stability. Besides, most Pt(IV) prodrugs with carbamate axial ligands were reduced faster than the corresponding ones with carboxylate ligands. Furthermore, the aqueous solubilities and lipophilicities of these Pt(IV) complexes were tested. All the carbamate complexes showed better aqueous solubility and decreased lipophilicity as compared to those of the corresponding carboxylate complexes, due to the increased polarity of carbamate ligands. Biological properties of these complexes were also evaluated. Many carbamate complexes showed cytotoxicity similar to that of the carboxylate complexes, which may derive from the lower cellular accumulation but faster reduction of the former. Our research highlights the differences between the Pt(IV) prodrugs containing carbamate and carboxylate axial ligands and may contribute to the future rational design of Pt-based anticancer prodrugs.

The impact of whole human blood on the kinetic inertness of platinum(iv) prodrugs - an HPLC-ICP-MS study

The potential advantage of platinum(iv) complexes as alternatives to classical platinum(ii)-based drugs relies on their kinetic stability in the body before reaching the tumor site and on their activation by reduction inside cancer cells. In this study, an analytical workflow has been developed to investigate the reductive biotransformation and kinetic inertness of platinum(iv) prodrugs comprising different ligand coordination spheres (respectively, lipophilicity and redox behavior) in whole human blood. The distribution of platinum(iv) complexes in blood pellets and plasma was determined by inductively coupled plasma-mass spectrometry (ICP-MS) after microwave digestion. An analytical approach based on reversed-phase (RP)-ICP-MS was used to monitor the parent compound and the formation of metabolites using two different extraction procedures. The ligand coordination sphere of the platinum(iv) complexes had a significant impact on their accumulation in red blood cells and on their degree of kinetic inertness in whole human blood. The most lipophilic platinum(iv) compound featuring equatorial chlorido ligands showed a pronounced penetration into blood cells and a rapid reductive biotransformation. In contrast, the more hydrophilic platinum(iv) complexes with a carboplatin- and oxaliplatin-core exerted kinetic inertness on a pharmacologically relevant time scale with notable amounts of the compound accumulated in the plasma fraction.

Metallomic study on the metabolism of RAPTA-C and cisplatin in cell culture medium and its impact on cell accumulation

The different extracellular speciation of cisplatin and the organoruthenium developmental anticancer agent RAPTA-C impacts the accumulation in cancer cells.

C-Glycosylation in platinum-based agents: a viable strategy to improve cytotoxicity and selectivity

The glycosylation of five-coordinate Pt(ii) compounds through a Pt–C linkage can be a very effective strategy for attacking cancer cells, while preserving the survival of the healthy ones.