title: Online Measurement of Real-Time Cytotoxic Responses Induced by Multi-Component Matrices, such as Natural Products, through Electric Cell-Substrate Impedance Sensing (ECIS).
abstract: Natural products are complex matrices of compounds that are prone to interfere with the label-dependent methods that are typically used for cytotoxicity screenings. Here, we developed a label-free Electric Cell-substrate Impedance Sensing (ECIS)-based cytotoxicity assay that can be applied in the assessment of the cytotoxicity of natural extracts. The conditions to measure the impedance using ECIS were first optimized in mice immortalized hypothalamic neurons GT1-7 cells. The performance of four natural extracts when tested using three conventional cytotoxicity assays in GT1-7 cells, was studied. Betula pendula (silver birch tree) was found to interfere with all of the cytotoxicity assays in which labels were applied. The silver birch extract was also proven to be cytotoxic and, thus, served as a proof-of-concept for the use of ECIS. The extract was fractionated and the ECIS method permitted the distinction of specific kinetic patterns of cytotoxicity on the fractions as well as the extract's pure constituents. This study offers evidence that ECIS is an excellent tool for real-time monitoring of the cytotoxicity of complex extracts that are difficult to work with using conventional (label-based) assays. Altogether, it offers a very suitable cytotoxicity-screening assay making the work with natural products less challenging within the drug discovery workflow.
authors.affiliation: Discipline of Pharmaceutical Biology, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 Helsinki, Finland. adyary.fallarero@helsinki.fi.
authors.forename: Adyary
authors.initials: A
authors.lastname: Fallarero
authors.affiliation: Department of Microbiology and Immunology, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA. ana.batista@einstein.yu.edu.
authors.forename: Ana E
authors.initials: AE
authors.lastname: Batista-González
authors.affiliation: Discipline of Pharmaceutical Biology, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 Helsinki, Finland. anna.k.hiltunen@helsinki.fi.
authors.forename: Anna K
authors.initials: AK
authors.lastname: Hiltunen
authors.affiliation: Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, University of Turku, 20014 Turku, Finland. jh.liimatainen@gmail.com.
authors.forename: Jaana
authors.initials: J
authors.lastname: Liimatainen
authors.affiliation: Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, University of Turku, 20014 Turku, Finland. maarit.karonen@utu.fi.
authors.forename: Maarit
authors.initials: M
authors.lastname: Karonen
authors.affiliation: Discipline of Pharmaceutical Biology, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 Helsinki, Finland. pia.vuorela@helsinki.fi.
authors.forename: Pia M
authors.initials: PM
authors.lastname: Vuorela
mesh_terms: D000818:Animals; D001688:Biological Products / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D015374:Biosensing Techniques; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004353:Drug Evaluation, Preclinical; D017097:Electric Impedance; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio
chemical_list: D001688:Biological Products
keywords: ECIS; cytotoxicity; impedance; label-free; natural extracts; screening