High-content analysis in preclinical drug discovery

High-Content Analysis (HCA) has developed into an established tool and is used in a wide range of academic laboratories and pharmaceutical research groups. HCA is now routinely proving to be effective in providing functionally relevant results. It is essential to select the appropriate HCA application with regard to the targeted compound's cellular function. The cellular impact and compound specificity as revealed by HCA analysis facilitates reaching definitive conclusions at an early stage in the drug discovery process. This technology therefore has the potential to substantially improve the efficiency of pharmaceutical research. Recent advances in fluorescent probes have significantly boosted the success of HCA. Auto-fluorescent proteins which minimally hinder the functioning of the living cell have been playing a decisive role in cell biology research. For companies the severely restricted license conditions regarding auto-fluorescent proteins hamper their general use in pharmaceutical research. This has opened the field for other solutions such as self-labeling protein technology, which could potentially replace the well established methods that utilize auto-fluorescent proteins. In addition, direct labeling techniques have improved considerably and may supersede many of the approaches based on fusion proteins. Following sample preparation, treated cells are imaged and the resulting multiple fluorescent signals are subjected to contextual and statistical analysis. The extraordinary advantage of HCA is that it enables the large-scale and simultaneous quantification and correlation of multiple phenotypic responses and physiological reactions using sophisticated software solutions that permit assay-specific image analysis. Hence, HCA once more has demonstrated its outstanding potential to significantly support establishing effective pharmaceutical research processes in order to both advance research projects and cut costs.     

Synthesis of optically enriched 1,2-aminoalcohols by [2,3]-Wittig rearrangements of 3-aza-allylic alcohol derivatives

[2,3]-Wittig rearrangements of (E)-3-aza-allylic alcohol derivatives can provide access to syn or anti optically enriched 1,2-aminoalcohols by using a chirality transfer or a chiral auxiliary.     

Synthesis of 4‐(Isothiazol‐3‐yl)morpholines and 1‐(Isothiazol‐3‐yl)piperazines,and Their Inhibitory Activity towards Acetylcholinesterase

The synthesis of novel triaryl‐substituted 4‐(isothiazol‐3‐yl)morpholines 7 and 8 , and 1‐(isothiazol‐3‐yl)piperazines 9 – 13 by reaction of the corresponding isothiazolium salts 5 and 6 with secondary amines in the presence of t‐BuOK in absolute THF is described. Some representatives of the isothiazoles were evaluated as inhibitors of acetylcholinesterase from Electrophorus electricus.     

Breast Cancer Stem Cell Potent Copper(II)–Non‐Steroidal Anti‐Inflammatory Drug Complexes

The breast cancer stem cell (CSC) potency of a series of copper(II)–phenanthroline complexes containing the nonsteroidal anti‐inflammatory drug (NSAID), indomethacin, is reported. The most effective copper(II) complex in this series, 4 , selectivity kills breast CSC‐enriched HMLER‐shEcad cells over breast CSC‐depleted HMLER cells. Furthermore, 4 reduces the formation, size, and viability of mammospheres, to a greater extent than salinomycin, a potassium ionophore known to selectively inhibit CSCs. Mechanistic studies revealed that the CSC‐specificity observed for 4 arises from its ability to generate intracellular reactive oxygen species (ROS) and inhibit cyclooxygenase‐2 (COX‐2), an enzyme that is overexpressed in breast CSCs. The former induces DNA damage, activates JNK and p38 pathways, and leads to apoptosis.     

Total synthesis of herbimycin A

[structure: see text] Hsp90 has recently emerged as a promising biological target for treatment of cancer. Herbimycin A and other members of the benzoquinoid ansamycin class of natural products are known to inhibit Hsp90 activity. The total synthesis of herbimycin A was achieved from the commercially available Roche ester 1 by using allylmetals to control the stereogenic centers at C6, C7, C10, C11, and C12 and a ring-closing metathesis to control the (Z)-double bond of the (E,Z)-dienic moiety.     

Development of a receptor-based microplate assay for the detection of beta-lactam antibiotics in different food matrices

The penicillin-binding protein PBP 2x* from Streptococcus pneumoniae has been utilised to develop a novel microplate assay for the detection and determination of penicillins and cephalosporins with intact beta-lactam structure in milk, bovine and porcine muscle juice, honey and egg. In the assay, the receptor protein is immobilised to a microplate in the first step. To each sample a bifunctional reagent is added, with ampicillin and digoxigenin as functional groups (DIG-AMPI). The amount of bifunctional reagent, which is bound via its ampicillin part to the receptor protein, decreases with increasing beta-lactam concentration in the sample. The detection step uses anti-digoxigenin F(ab) fragments marked with horseradish peroxidase. The more bifunctional reagent is bound to the receptor protein, the more antibody fragments are bound via the digoxigenin part of the reagent. A maximum colour development with tetramethylbenzidine as chromogen for the peroxidase reaction is achieved, when no beta-lactam residues are present. A fractional factorial design was applied to detect chemometrically effects and interactions of the assay parameters. For optimisation of the significant parameters a Box-Behnken design was used. The assay has been developed for various food matrices as screening test with the option for a quantitative assay, when the identity of the residual beta-lactam is known (e.g. elimination studies). Cefoperazon, cefquinome, cefazolin, cloxacillin, ampicillin and benzylpenicillin could be detected at levels corresponding to 1/2 EU maximum residue limit (MRL) in milk, meat juice from muscle tissue of different species, egg and honey (where applicable) without needing lengthy and elaborate sample pre-treatment. Matrix calibration curves are presented, which show that quantitative analyses are possible.     

Highly enantioselective synthesis of beta-amino alcohols: a catalytic version

Highly enantioselective rearrangement of beta-amino alcohols was realized by using a catalytic amount of trifluoroacetic anhydride.