Optimization of a high content screening assay for studying the cytotoxicity of new psychoactive substances – First results for the synthetic cannabinoid A-796260

Introduction and Aims: New psychoactive substances (NPS) are usually brought onto the drugs of abuse market without any safety testing, hence knowledge about their potential cytotoxicity is sparce or even unknown. Therefore, a health risk for consumers could not be excluded. Also, some case reports associate their ingestion with an acute organ toxicity [1,2]. There exist different in vitro approaches to measure cytotoxicity parameters such as cell viability, leakage of lactate dehydrogenase, mitochondrial membrane potential, mitochondrial redox activity, or apoptosis. However, many previous studies only investigated isolated parameters as single endpoints [3,4], which could lead to false negative or positive results. By using a high content screening assay (HCSA), this major drawback could be avoided, since several parameters are monitored simultaneously within the same experiment [5]. Therefore, the present study aimed to improve an existing HCSA, to study the cytotoxic potential of NPS using the hepatoma cell line HepG2 [6]. The model compound fluvastatin was used for method optimization to achieve a simplified use, increased sample throughput, and improved reproducibility. Afterwards, the applicability of the method was exemplified for the synthetic cannabinoid (SC) A-796260 (structure see Figure).