A Quantitative Bioassay to Determine the Inhibitory Potency of NGF–TrkA Antagonists

In this article, we demonstrate and validate a new bioassay named the NTAB [NGF–TrkA (nerve growth factor–tropomyosin receptor kinase A) antagonist bioassay] for the determination of the inhibitory potency of NGF–TrkA antagonists, based on the inhibition of NGF-dependent proliferation of the human TF1 erythroleukemic cell line. It is well known that NGF holds great therapeutic potential due to its neurotrophic and neuroprotective properties. NGF is also involved in some pathways, however, principally driven by TrkA that, if not correctly regulated, can lead to unwanted pathological outcomes linked to pain, angiogenesis, and cancer. Indeed, there is an increasing interest, from a therapeutic perspective, in designing new effective molecules (antibodies, antibody fragments, or small molecules) able to inhibit the undesired NGF–TrkA pathway. For these reasons, there is an interest to develop functional cell-based assays for determination of the inhibition potency of compounds inhibiting the NGF–TrkA axis. The NTAB presents significant advantages over other published NGF–TrkA functional bioassays, for these reasons: (1) It is quantitative, (2) it measures a pure TrkA response, (3) it is simpler, (4) it is based on a natural biological response, and (5) it is easily scalable from a lab scale to an automated industrial assay. The NTAB assay was validated with a panel of well-characterized NGF–TrkA inhibitors, yielding characteristic dose–response curves, from which the relative strength of the inhibitors was quantitatively determined and used for comparisons. This new bioassay will be very useful to assist in the validation and prioritization of the best inhibitors among a large number of candidates.

A New Bioassay Platform Design for the Discovery of Small Molecules with Anticancer Immunotherapeutic Activity

Immunotherapy takes advantage of the immune system to prevent, control, and eliminate neoplastic cells. The research in the field has already led to major breakthroughs to treat cancer. In this work, we describe a platform that integrates in vitro bioassays to test the immune response and direct antitumor effects for the preclinical discovery of anticancer candidates. The platform relies on the use of dendritic cells that are professional antigen-presenting cells (APC) able to activate T cells and trigger a primary adaptive immune response. The experimental procedure is based on two phenotypic assays for the selection of chemical leads by both a panel of nine tumor cell lines and growth factor-dependent immature mouse dendritic cells (D1). The positive hits are then validated by a secondary test on human monocyte-derived dendritic cells (MoDCs). The aim of this approach is the selection of potential immunotherapeutic small molecules from natural extracts or chemical libraries.

The heart of Varroa destructor: description, function and inhibition following acaricide application

This study examines the heart and its activity in the mite Varroa destructor. Through light microscopy, the duration and frequency of the beat of the mite’s heart, which is located over the synganglion, was recorded and analysed. The heart measured 165 μm by 60 μm, and consisted of two lateral trunks, inducing pulses with an average duration of 10 sec and an average frequency of 0.13 Hz. The use of cardiac activity as a new bioassay for accurate assessment of the effect of varroacide compounds was also examined.