Synthesis of Cycloruthenated Compounds as Potential Anticancer Agents

Organometallic Pyridylnaphthalimide Complexes as Protein Kinase Inhibitors

A new metal-containing scaffold for the design of protein kinase inhibitors is introduced. Key feature is a 3-(2-pyridyl)-1,8-naphthalimide "pharmacophore chelate ligand" which is designed to form two hydrogen bonds with the hinge region of the ATP-binding site and is at the same time capable of serving as a stable bidentate ligand through C-H-activation at the 4-position of the electron-deficient naphthalene moiety. This C-H-activation leads to a reduced demand for coordinating heteroatoms and thus sets the basis for a very efficient three-step synthesis starting from 1,8-naphthalic anhydride. The versatility of this ligand is demonstrated with the discovery of a ruthenium complex that functions as a nanomolar inhibitor for myosin light-chain kinase (MYLK or MLCK).

Photocontrolled nucleobase binding to an organometallic Ru(II) arene complex

The complex [(p-cym)Ru(bpm)(py)][PF(6)](2) (where p-cym = para-cymene, bpm = 2,2'-bipyrimidine and py = pyridine) is the first ruthenium(ii) arene complex that can selectively photodissociate a monodentate ligand (py) when excited with visible light and form a reactive aqua derivative able to bind to a DNA base.

Excellent correlation between cathepsin B inhibition and cytotoxicity for a series of palladacycles

The reaction of the five- or six-membered C,N or C,S-palladacycles [(L)PdCl](2) with PTA (1,3,5-triaza-7-phosphaadamantane) led to the monomeric complexes [(L)Pd(PTA)Cl] 6a, 6b and 7 where LH= N,N-dimethyl-1-phenylmethanamine, benzyl(methyl)sulfane or 1-methyl-5-phenyl-1H-benzo[e][1,4]diazepin-2(3H)-one respectively. Dimeric complexes have also been synthesised: [Pd(2)L(2)(mu-dppe)Cl(2)], where LH = 1-methyl-5-phenyl-1H-benzo[e][1,4]diazepin-2(3H)-one (1a), (R)- or (S)-3-isopropyl-1-methyl-5-phenyl-1H-benzo[e][1,4]diazepin-2(3H)-one (1b, 1c), [Pd(2)L(2)(mu-dppf)Cl(2)], where L= 1-methyl-5-phenyl-1H-benzo[e][1,4]diazepin-2(3H)-one (4a) or (R)-3-isopropyl-1-methyl-5-phenyl-1H-benzo[e][1,4]diazepin-2(3H)-one (4b), respectively, and dppe = 1,2-bis(diphenylphosphino)ethane, dppf = 1,1'-bis(diphenylphosphino)ferrocene. The complexes were characterised in solution, by (1)H and (31)P NMR spectroscopy, and single crystals of complexes 6b and 7 were studied in the solid state by X-ray crystallography. The palladacycles were evaluated for in vitro activity as cytotoxic agents on A2780/S cells and also as cathepsin B inhibitors, an enzyme implicated in a number of cancer related events.

Antitumor and antimycobacterial activities of cyclopalladated complexes: X-ray structure of [Pd(C2,N-dmba)(Br)(tu)] (dmba=N,N-dimethylbenzylamine, tu=thiourea)

The reactions between [Pd(C(2),N-dmba)(micro-X)](2) (dmba=N,N-dimethylbenzylamine; X=Cl, Br) and thiourea (tu) in the 1:2 molar ratio at room temperature resulted in the mononuclear compounds [Pd(C(2),N-dmba)(Cl)(tu)] (1) and [Pd(C(2),N-dmba)(Br)(tu)] (2), which were characterized by elemental analyses and infrared (IR), (1)H- and (13)C{(1)H} NMR spectroscopies. The crystal and molecular structures of 2 were determined by single-crystal X-ray diffraction. In vitro cytotoxicity assays of the compounds 1, 2, tu, dmba and cisplatin were carried out using two murine tumor cell lines, namely mammary adenocarcinoma (LM3) and lung adenocarcinoma (LP07). The compounds 1, 2, tu and dmba were also tested against Mycobacterium tuberculosis and their MIC values were determined.

A ruthenium-containing organometallic compound reduces tumor growth through induction of the endoplasmic reticulum stress gene CHOP

Cisplatin-derived anticancer therapy has been used for three decades despite its side effects. Other types of organometallic complexes, namely, some ruthenium-derived compounds (RDC), which would display cytotoxicity through different modes of action, might represent alternative therapeutic agents. We have studied both in vitro and in vivo the biological properties of RDC11, one of the most active compounds of a new class of RDCs that contain a covalent bond between the ruthenium atom and a carbon. We showed that RDC11 inhibited the growth of various tumors implanted in mice more efficiently than cisplatin. Importantly, in striking contrast with cisplatin, RDC11 did not cause severe side effects on the liver, kidneys, or the neuronal sensory system. We analyzed the mode of action of RDC11 and showed that RDC11 interacted poorly with DNA and induced only limited DNA damages compared with cisplatin, suggesting alternative transduction pathways. Indeed, we found that target genes of the endoplasmic reticulum stress pathway, such as Bip, XBP1, PDI, and CHOP, were activated in RDC11-treated cells. Induction of the transcription factor CHOP, a crucial mediator of endoplasmic reticulum stress apoptosis, was also confirmed in tumors treated with RDC11. Activation of CHOP led to the expression of several of its target genes, including proapoptotic genes. In addition, the silencing of CHOP by RNA interference significantly reduced the cytotoxicity of RDC11. Altogether, our results led us to conclude that RDC11 acts by an atypical pathway involving CHOP and endoplasmic reticulum stress, and thus might provide an interesting alternative for anticancer therapy.

Structural and biological investigation of ferrocene-substituted 3-methylidene-1,3-dihydro-2H-indol-2-ones

The Knoevenagel condensation of 1,3-dihydro-2H-indol-2-one with ferrocene carboxaldehyde afforded an approximate 2:1 mixture of the geometrical isomers (E)- and (Z)-3-ferrocenylmethylidene-1,3-dihydro-2H-indol-2-one respectively in an overall 67% yield; the air and solution-stable isomers were readily separated by preparative thin layer chromatography and their structures were unequivocally elucidated in solution, by (1)H NMR spectroscopy, and in the solid phase, by X-ray crystallography; both isomers of displayed in vitro toxicity against B16 melanoma and Vero cell lines in the micromolar range and inhibited the kinase VEGFR-2 with IC(50) values of ca. 200 nM.