Testing therapeutics in cell-based assays: Factors that influence the apparent potency of drugs

Abstract

Identifying effective antivirals for treating Ebola virus disease (EVD) and minimizing transmission of such disease is critical. A variety of cell-based assays have been developed for evaluating compounds for activity against Ebola virus. However, very few reports discuss the variable assay conditions that can affect the results obtained from these drug screens. Here, we describe variable conditions tested during the development of our cell-based drug screen assays designed to identify compounds with anti-Ebola virus activity using established cell lines and human primary cells. The effect of multiple assay readouts and variable assay conditions, including virus input, time of infection, and the cell passage number, were compared, and the impact on the effective concentration for 50% and/ or 90% inhibition (EC50, EC90) was evaluated using the FDA-approved compound, toremifene citrate. In these studies, we show that altering cell-based assay conditions can have an impact on apparent drug potency as measured by the EC50. These results further support the importance of developing standard operating procedures for generating reliable and reproducible in vitro data sets for potential antivirals.

Discovery and development of safe-in-man broad-spectrum antiviral agents

“…Primary cell cultures give more accurate images of drug responses (Alves et al, 2018;Denisova et al, 2012;Koban et al, 2018;Postnikova et al, 2018). They have a low population doubling level and therefore more closely recapitulate the physiological conditions observed in vivo.…”

Trends and targets in antiviral phototherapy

“…General overviews on methods for determining antiviral efficacy are available in the literature. 116,118 A very comprehensive overview and compilation of the in vitro methods used for testing antivirals is given in the recent review by Rumlová and Ruml. 118 Information on in vivo models for assessing the antiviral efficacy is also given in reviews 15b,119 as well as in the discussion of the compound classes below.…”

Discovery and Development of Safe-in-Man Broad-Spectrum Antiviral Agents

“…Thereby, novel antiviral activities of BSAAs should be further validated in primary human cells using different viral strains (including wild-type viruses), different viral loads, different times of compound addition, different endpoint measurements and compound concentration range. Primary cell cultures give more accurate images of drug responses (48)(49)(50)(51). They have a low population doubling level and therefore more closely recapitulate the physiological conditions observed in vivo.…”