A Comparative Analysis of the In Vitro Anticancer Activity of Iridium(III) {η<sup>5</sup>-C<sub>5</sub>Me<sub>4</sub>R} Complexes with Variable R Groups

Piano-stool iridium complexes based on the pentamethylcyclopentadienyl ligand (Cp*) have been intensively investigated as anticancer drug candidates and hold much promise in this setting. A systematic study aimed at outlining the effect of Cp* mono-derivatization on the antiproliferative activity is...

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Bibliographic Details
Main Authors: Alice De Palo, Dijana Draca, Maria Grazia Murrali, Stefano Zacchini, Guido Pampaloni, Sanja Mijatovic, Danijela Maksimovic-Ivanic, Fabio Marchetti
Format: Article
Language:English
Published: MDPI AG 2021-07-01
Series:International Journal of Molecular Sciences
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Online Access:https://www.mdpi.com/1422-0067/22/14/7422
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Summary:Piano-stool iridium complexes based on the pentamethylcyclopentadienyl ligand (Cp*) have been intensively investigated as anticancer drug candidates and hold much promise in this setting. A systematic study aimed at outlining the effect of Cp* mono-derivatization on the antiproliferative activity is presented here. Thus, the dinuclear complexes [Ir(η<sup>5</sup>-C<sub>5</sub>Me<sub>4</sub>R)Cl(μ-Cl)]<sub>2</sub> (R = Me, <b>1a</b>; R = H, <b>1b</b>; R = Pr, <b>1c</b>; R = 4-C<sub>6</sub>H<sub>4</sub>F, <b>1d</b>; R = 4-C<sub>6</sub>H<sub>4</sub>OH, <b>1e</b>), their 2-phenylpyridyl mononuclear derivatives [Ir(η<sup>5</sup>-C<sub>5</sub>Me<sub>4</sub>R)(k<i><sub>N</sub></i>,k<i><sub>C</sub></i>PhPy)Cl] (<b>2a–d</b>), and the dimethylsulfoxide complex [Ir{η<sup>5</sup>-C<sub>5</sub>Me<sub>4</sub>(4-C<sub>6</sub>H<sub>4</sub>OH)}Cl<sub>2</sub>(κ<i><sub>S</sub></i>-Me<sub>2</sub>S=O)] (<b>3</b>) were synthesized, structurally characterized, and assessed for their cytotoxicity towards a panel of six human and rodent cancer cell lines (mouse melanoma, B16; rat glioma, C6; breast adenocarcinoma, MCF-7; colorectal carcinoma, SW620 and HCT116; ovarian carcinoma, A2780) and one primary, human fetal lung fibroblast cell line (MRC5). Complexes <b>2b</b> (R = H) and <b>2d</b> (4-C<sub>6</sub>H<sub>4</sub>F) emerged as the most active ones and were selected for further investigation. They did not affect the viability of primary mouse peritoneal cells, and their tumoricidal action arises from the combined influence on cellular proliferation, apoptosis and senescence. The latter is triggered by mitochondrial failure and production of reactive oxygen and nitrogen species.
ISSN:1661-6596
1422-0067