Characterization and Efficacy of a Nanomedical Radiopharmaceutical for Cancer Treatment.

Although much progress has been made over the last decades, there is still a significant clinical need for novel therapies to manage cancer. Typical problems are that solid tumors are frequently inaccessible, aggressive, and metastatic. To contribute to solving some of these issues, we have developed a novel radioisotope-labeled 27 nm nanoparticle, 177Lu-SN201, to selectively target solid tumors via the enhanced permeability and retention effect, allowing irradiation intratumorally. We show that 177Lu-SN201 has robust stealth properties in vitro and anti-tumor efficacy in mouse mammary gland and colon carcinoma models. The possible clinical application is also addressed with single photon emission computed tomography imaging, which confirms uptake in the tumor, with an average activity of 19.4% injected dose per gram (ID/g). The properties of 177Lu-SN201 make it a promising new agent for radionuclide therapy with the potential to target several solid tumor types.

Novel multi-target compounds in the quest for new chemotherapies against Alzheimer's disease: An experimental and theoretical study.

The lack of any effective therapy along with the aging world population anticipates a growth of the worldwide incidence of Alzheimer's disease (AD) to more than 100 million cases by 2050. Accumulation of extracellular amyloid-ß (Aß) plaques, intracellular tangles in the brain, and formation of reactive oxygen species (ROS) are the major hallmarks of the disease. In the amyloidogenic process, a ß-secretase, known as BACE 1, plays a fundamental role in the production of Aß fragments, and therefore, inhibition of such enzymes represents a major strategy for the rational design of anti-AD drugs. In this work, a series of four multi-target compounds (1-4), inspired by previously described ionophoric polyphenols, have been synthesized and studied. These compounds have been designed to target important aspects of AD, including BACE 1 enzymatic activity, Aß aggregation, toxic concentrations of Cu2+ metal ions and/or ROS production. Two other compounds (5 and 6), previously reported by some of us as antimalarial agents, have also been studied because of their potential as multi-target species against AD. Interestingly, compounds 3 and 5 showed moderate to good ability to inhibit BACE 1 enzymatic activity in a FRET assay, with IC50's in the low micromolar range (4.4 ±â€¯0.3 and 1.7 ±â€¯0.3 µM, respectively), comparable to other multi-target species, and showing that the observed activity was in part due to a competitive binding of the compounds at the active site of the enzyme. Theoretical docking calculations overall agreed with FRET assay results, displaying the strongest binding affinities for 3 and 5 at the active site of the enzyme. In addition, all compounds selectively interacted with Cu2+ metal ions forming 2:1 complexes, inhibited the production of Aß-Cu2+ catalyzed hydroxyl radicals up to a ∼100% extent, and scavenged AAPH-induced peroxyl radical species comparably to resveratrol, a compound used as reference in this work. Our results also show good anti-amyloidogenic ability: compounds 1-6 inhibited both the Cu2+-induced and self-induced Aß(1-40) fibril aggregation to an extent that ranged from 31% to 77%, while they disaggregated pre-formed Aß(1-40) mature fibrils up to a 37% and a 69% extent in absence and presence of Cu2+, respectively. Cytotoxicity was additionally studied in Tetrahymena thermophila and HEK293 cells, and compared to that of resveratrol, showing that compounds 1-6 display lower toxicity than that of resveratrol, a well-known non-toxic polyphenol.

Gold(I) complex of 1,1'-bis(diphenylphosphino) ferrocene-quinoline conjugate: a virostatic agent against HIV-1.

HIV infection is known for replicating in proliferating CD(+) T-cells. Treatment of these cells with cytostatic (anti-proliferation) compounds such as hydroxyurea interferes with the cells's ability support HIV replication. Combinations of such cytostatic compounds with proven anti-retroviral drugs (like ddI) are known as virostatic, and have been shown to aid in the control of the infection. The use of two different drugs in virostatic combinations however, carries the risk of adverse effects including drug-drug interactions, which could lead to augmented toxicities and reduced efficacy. Here, a novel digold(I) complex of ferrocene-quinoline (3) was investigated for cytostatic behaviour as well as anti-viral activity which if demonstrated would eliminate concerns of drug-drug interactions. The complex was synthesized and characterized by NMR, FT-IR and mass spectroscopy and the molecular structure was confirmed by X-ray crystallography. Bio-screening involved viability dyes, real time electronic sensing and whole virus assays. The complex showed significant (p = 0.0092) inhibition of virus infectivity (83 %) at 10 ug/mL. This same concentration caused cytostatic behaviour in TZM-bl cells with significant (p < 0.01) S and G2/M phase cell cycle arrest. These data supports 3 as a virostatic agent, possessing both anti-viral and cytostatic characteristics. In the absence of 3, TZM-bl cells were infected by a pseudovirus and this was demonstrated through luminescence in a luciferase assay. Pre-incubation of the virus with 3 decreased luminescence, indicating the anti-viral activity of 3. Complex 3 also showed cytostatic behavior with increased S-phase and G2/M phase cell cycle arrest.

Pentamethylcyclopentadienyl-rhodium and iridium complexes containing (N

The synthesis and characterization of twenty new pentamethylcyclopentadienyl-rhodium and iridium complexes containing N^N and N^O-chelating chloroquine analogue ligands are described. The in vitro antimalarial activity of the new ligands as well as the complexes was evaluated against the chloroquine sensitive (CQS) NF54 and the chloroquine resistant (CQR) Dd2 strains of Plasmodium falciparum. The antimalarial activity was found to be good to moderate; although all complexes are less active than artesunate, some of the ligands and complexes showed better activity than chloroquine (CQ). In particular, rhodium complexes were found to be considerably more active than iridium complexes against the CQS NF54 strain. Salicylaldimine Schiff base ligands having electron-withdrawing groups (F, Cl, Br, I and NO2) in para position of the salicyl moiety and their rhodium complexes showed good antiplasmodial activity against both the CQS-NF54 and the CQR-Dd2 strains. The crystal structures of (η(5)-pentamethylcyclopentadienyl){N(1)-(7-chloroquinolin-4-yl)-N(2)-(pyridin-2-ylmethyl)ethane-1,2-diamine)} chlororhodium(III) chloride and (η(5)-pentamethylcyclopentadienyl){(4-chloro-2-(((2-((7-chloroquinolin-4-yl)amino)ethyl)imino)methyl)phenolate)}chlororhodium(III) chloride are reported. The crystallization of the amino-pyridyl complex (η(5)-pentamethylcyclopentadienyl){(N(1)-(7-chloroquinolin-4-yl)-N(2)-(pyridin-2-ylmethyl)ethane-1,2-diamine)}chloroiridium(III) chloride in acetone resulted in the formation of the imino-pyridyl derivative (η(5)-pentamethylcyclopentadienyl){(N1-(7-chloroquinolin-4-yl)-N2-(pyridin-2-ylmethylene)ethane-1,2-diamine)}chloroiridium(III) chloride, the crystal structure of which is also reported.

Antimalarial activity of ruthenium(II) and osmium(II) arene complexes with mono- and bidentate chloroquine analogue ligands.

Eight new ruthenium and five new osmium p-cymene half-sandwich complexes have been synthesized, characterized and evaluated for antimalarial activity. All complexes contain ligands that are based on a 4-chloroquinoline framework related to the antimalarial drug chloroquine. Ligands HL(1-8) are salicylaldimine derivatives, where HL(1) = N-(2-((2-hydroxyphenyl)methylimino)ethyl)-7-chloroquinolin-4-amine, and HL(2-8) contain non-hydrogen substituents in the 3-position of the salicylaldimine ring, viz. F, Cl, Br, I, NO2, OMe and (t)Bu for HL(2-8), respectively. Ligand HL(9) is also a salicylaldimine-containing ligand with substitutions in both 3- and 5-positions of the salicylaldimine moiety, i.e. N-(2-((2-hydroxy-3,5-di-tert-butylphenyl)methyl-imino)ethyl)-7-chloroquinolin-4-amine, while HL(10) is N-(2-((1-methyl-1H-imidazol-2-yl)methylamino)ethyl)-7-chloroquinolin-4-amine) The half sandwich metal complexes that have been investigated are [Ru(η(6)-cym)(L(1-8))Cl] (Ru-1-Ru-8, cym = p-cymene), [Os(η(6)-cym)(L(1-3,5,7))Cl] (Os-1-Os-3, Os-5, and Os-7), [M(η(6)-cym)(HL(9))Cl2] (M = Ru, Ru-HL(9); M = Os, Os-HL(9)) and [M(η(6)-cym)(L(10))Cl]Cl (M = Ru, Ru-10; M = Os, Os-10). In complexes Ru-1-Ru-8 and Ru-10, Os-1-Os-3, Os-5 and Os-7 and Os-10, the ligands were found to coordinate as bidentate N,O- and N,N-chelates, while in complexes Ru-HL(9) and Os-HL(9), monodentate coordination of the ligands through the quinoline nitrogen was established. The antimalarial activity of the new ligands and complexes was evaluated against chloroquine sensitive (NF54 and D10) and chloroquine resistant (Dd2) Plasmodium falciparum malaria parasite strains. Coordination of ruthenium and osmium arene moieties to the ligands resulted in lower antiplasmodial activities relative to the free ligands, but the resistance index is better for the ruthenium complexes compared to chloroquine. Overall, osmium complexes appeared to be less active than the corresponding ruthenium complexes.