A Simple LC-MS/MS Method for the Quantification of PDA-66 in Human Plasma.

The treatment of cancer is one of the most important pharmacotherapeutic challenges. To this end, chemotherapy has for some time been complemented by targeted therapies against specific structures. PDA-66, a structural analogue of the inhibitor of serine-threonine kinase glycogen synthase kinase 3ß SB216763, has shown preclinical antitumour effects in various cell lines, with the key pathways of its anticancer activity being cell cycle modulation, DNA replication and p53 signalling. For the monitoring of anticancer drug treatment in the context of therapeutic drug monitoring, the determination of plasma concentrations is essential, for which an LC-MS/MS method is particularly suitable. In the present study, a sensitive LC-MS/MS method for the quantification of the potential anticancer drug PDA-66 in human plasma with a lower limit of quantification of 2.5 nM is presented. The method was successfully validated and tested for the determination of PDA-66 in mouse plasma and sera.

Supported Cobalt Nanoparticles for Hydroformylation Reactions.

Hydroformylation of olefins has been studied in the presence of specific heterogeneous cobalt nanoparticles. The catalytic materials were prepared by pyrolysis of preformed cobalt complexes deposited onto different inorganic supports. Atomic absorption spectroscopy (AAS) measurements indicated a correlation of catalyst activity and cobalt leaching as well as a strong influence of the heterogeneous support on the productivity. These new, low-cost, easy-to-handle catalysts can substitute more toxic, unstable and volatile cobalt carbonyl complexes for hydroformylations on a laboratory scale.

The novel arylindolylmaleimide PDA-66 displays pronounced antiproliferative effects in acute lymphoblastic leukemia cells.

BACKGROUND: Prognosis of adult patients suffering from acute lymphoblastic leukemia (ALL) is still unsatisfactory. Targeted therapy via inhibition of deregulated signaling pathways appears to be a promising therapeutic option for the treatment of ALL. Herein, we evaluated the influence of a novel arylindolylmaleimide (PDA-66), a potential GSK3ß inhibitor, on several ALL cell lines. METHODS: ALL cell lines (SEM, RS4;11, Jurkat and MOLT4) were exposed to different concentrations of PDA-66. Subsequently, proliferation, metabolic activity, apoptosis and necrosis, cell cycle distribution and protein expression of Wnt and PI3K/Akt signaling pathways were analyzed at different time points. RESULTS: PDA-66 inhibited the proliferation of ALL cells significantly by reduction of metabolic activity. The 72 h IC50 values ranged between 0.41 to 1.28 µM PDA-66. Additionally, caspase activated induction of apoptosis could be detected in the analyzed cell lines. PDA-66 influenced the cell cycle distribution of ALL cell lines differently. While RS4;11 and MOLT4 cells were found to be arrested in G2 phase, SEM cells showed an increased cell cycle in G0/1 phase. CONCLUSION: PDA-66 displays significant antileukemic activity in ALL cells and classifies as candidate for further evaluation as a potential drug in targeted therapy of ALL.

A convenient palladium-catalyzed carbonylative synthesis of 2-aminbenzoxazinones from 2-bromoanilines and isocyanates.

Mon ami(ne)! A general and convenient methodology for 2-aminobenzoxazinone synthesis has been developed (see scheme). Readily available 2-bromoanilines and isocyanates were used as substrates and various products have been prepared in good yields. Notably, [Mo(CO)6] as a solid CO source was applied instead of gas.

Efficient and simple zinc-mediated synthesis of 3-amidoindoles.

A general synthesis of 3-amidoindoles from easily available arylhydrazines and acylated propargylamines is described. In the presence of inexpensive Zn salts, alkyne amination and subsequent Fischer indole-cyclization took place in good yields with excellent regioselectivity providing an interesting scaffold for potentially bio-active compounds.

Platinum-catalyzed cyclization reaction of alkynes: synthesis of azepino[3,4-b]indol-1-ones.

Novel azepino[3,4-b]indol-1-ones were synthesized from alkyne-substituted indole-2-carboxamides by catalytic intramolecular cyclization in the presence of PtCl(2). The scope and limitations of this straightforward protocol are reported.

A new facile synthesis of 3-amidoindole derivatives and their evaluation as potential GSK-3beta inhibitors.

3-Amidoindoles were synthesized from commercially available arylhydrazines and propargylamines over Zn-salt mediated one pot procedure in excellent regioselectivity and up to 94% yield.

Novel indolylmaleimide acts as GSK-3beta inhibitor in human neural progenitor cells.

The Wnt pathway is involved in cellular processes linked to either proliferation or differentiation. Therefore small molecules offer an attractive opportunity to modulate this pathway, whereas the key enzyme GSK-3beta is of special interest. In this study, non-symmetrically substituted indolylmaleimides have been synthesized and their ability to function as GSK-3beta inhibitors has been investigated in a human neural progenitor cell line. Among the newly synthesized compounds, the substance IM-12 showed a significant activity in several biological tests which was comparable or even outplayed the effects of the known GSK-3beta inhibitor SB-216763. Furthermore the treatment of human neural progenitor cells with IM-12 resulted in an increase of neuronal cells. Therefore we conclude that indolylmaleimides act via the canonical Wnt signalling pathway by inhibition of the key enzyme GSK-3beta.

PDA Indolylmaleimides Induce Anti-Tumor Effects in Prostate Carcinoma Cell Lines Through Mitotic Death.

Castrate resistant prostate cancer in men shares several characteristics with canine prostate cancer (PCa). Due to current insufficient therapies, evaluating novel therapeutic agents for late-stage PCa is of considerable interest for both species. PDA indolylmaleimides showed anticancer effects in several neoplastic cell lines. Herein, a comparative characterization of PDA-66 and PDA-377 mediated effects was performed in human and canine PCa cell lines, which is also the first detailed characterization of these agents on cells derived from solid tumors in general. While PDA-377 showed only weak growth inhibition on human PCa cell lines, PDA-66 inhibited proliferation and induced apoptosis in human and canine cell lines with concentrations in the low micromolar range. Morphological characterization and whole transcriptome sequencing revealed that PDA-66 induces mitotic death through its microtubule-depolymerizing ability. PDA-66 appears to be a worthwhile anti-mitotic agent for further evaluation. The similarities in cellular and molecular response observed in the cell lines of both origins form a solid basis for the use of canine PCa in vivo models to gain valuable interchangeable data to the advantage of both species.

An enantioselective chiral Brønsted acid catalyzed imino-azaenamine reaction.

The enantioselective Brønsted acid catalyzed addition of methyleneaminopyrrolidine to N-Boc imines has been achieved in the presence of chiral phosphoric acids derived from 3,3'-di(phenanthryl)-H8-BINOL. The corresponding aminohydrazones have been isolated in good yields with enantiomeric excesses up to 90%. [reaction: see text]

Characterization of the novel indolylmaleimides' PDA-66 and PDA-377 effect on canine lymphoma cells.

Protein kinase inhibitors are widely used in chemotherapeutic cancer regimens. Maleimide derivatives such as SB-216763 act as GSK-3 inhibitor targeting cell proliferation, cell death and cell cycle progression.Herein, the two arylindolylmaleimide derivatives PDA-66 and PDA-377 were evaluated as potential chemotherapeutic agents on canine B-cell lymphoma cell lines. Canine lymphoma represents a naturally occurring model closely resembling the human high-grade non-Hodgkin's lymphoma (NHL). PDA-66 showed more pronounced effects on both cell lines. Application of 2.5µM PDA-66 resulted in a significant induction of apoptosis (approx. 11 %), decrease of the metabolic activity (approx. 95 %), anti-proliferative effect (approx. 85 %) and cell death within 48h. Agent induced mode of action was characterized by whole transcriptome sequencing, 12 h and 24 h post-agent exposure. Key PDA-66-modulated pathways identified were cell cycle, DNA replication and p53 signaling. Expression analyses indicated that the drug acting mechanism is mediated through DNA replication and cycle arrest involving the spindle assembly checkpoint.In conclusion, both PDA derivatives displayed strong anti-proliferation activity in canine B-cell lymphoma cells. The cell and molecular PDA-induced effect characterization and the molecular characterization of the agent acting mechanism provides the basis for further evaluation of a potential drug for canine lymphoma serving as model for human NHL.

Synthesis of new diphosphine ligands and their application in Pd-catalyzed alkoxycarbonylation reactions.

Carbocyclic and N-heterocyclic analogues of the industrially applied ligand bis(di-tert-butylphosphinomethyl)benzene (1) have been synthesized in moderate to very good yields. The new ligands are based on benzene, tetralin, lutidine, pyrazine, quinoxaline, and maleimide backbones. Electronic and steric variations of the phosphorous donor sites were performed. As a benchmark reaction, the palladium-catalyzed methoxycarbonylation of 1-octene has been tested. Ester yields up to 64% and high linear selectivities up to 92% were achieved.

Interference of a novel indolylmaleimide with microtubules induces mitotic arrest and apoptosis in human progenitor and cancer cells.

Indolylmaleimides display a broad spectrum of biological activity and offer great opportunity to influence several aspects of cell fate, as proliferation and differentiation. In this study we describe the effect of PDA-66, a newly synthesised indolylmaleimide, showing a strong dose dependent anti-proliferative effect on immortalised human progenitor and cancer cells. We demonstrated a highly depolymerizing effect on in vitro tubulin assembly and conclude that PDA-66 acts as microtubule destabilising agent. In addition we found that PDA-66 induces mitotic arrest of cells in the G2/M phase of the cell cycle. Subsequently cells undergo apoptosis, indicating the major mechanism of the anti-proliferative effect. To prove a potential anti-cancer activity of PDA-66 we examined the effect of PDA-66 on human SH-SY5Y neuroblastoma and A-459 lung cancer cells, showing a significant reduction in cancer cell proliferation in a dose dependent manner. Thus PDA-66 is a new anti-mitotic compound with an indole-core with the potential to be used for cancer therapy.

A novel Zn-catalyzed hydroamination of propargylamides: a general synthesis of di- and tri-substituted imidazoles.

Starting from commercially available amines and propargylamides a variety of substituted imidazoles were synthesized via a novel hydroamination-cyclization sequence. The target compounds are obtained in good to excellent yields in the presence of catalytic amounts of zinc triflate.

Efficient palladium-catalyzed synthesis of 3-aryl-4-indolylmaleimides.

Improved palladium catalysts for the Suzuki coupling of 3-bromo-1-methyl-4-(2-methyl-3-indolyl)maleimide have been developed. The coupling of both aryl- and heteroarylboronic acids proceeds smoothly in good to excellent yields at low catalyst loading.