Lysosomotropic-related limitations of the BALB/c 3T3 cell-based neutral red uptake assay and an alternative testing approach for assessing e-liquid cytotoxicity.

Lysosomotropic-related limitations of the BALB/c 3T3 cell-based neutral red uptake assay and an alternative testing approach for assessing e-liquid cytotoxicity. Toxicol In Vitro. 2019 Sep 10;:104647 Authors: Cudazzo G, Smart DJ, McHugh D, Vanscheeuwijck P Abstract Cytotoxicity assays are used to quantify the cytotoxic potential of chemicals. The neutral red uptake (NRU) assay is one of these assays and routinely used in the pharmaceutical, cosmetic, and tobacco industries. In the context of e-cigarette development, an NRU assay-based screen was implemented to evaluate the cytotoxic potential of e-liquids. E-liquids induced a biphasic response in the BALB/c 3T3-based assay. NRU initially increased in a concentration-dependent manner before decreasing following treatment with higher concentrations until NRU was abolished. Experiments were performed to characterize the mechanism underlying this biphasic signal. Nicotine alone was found to induce the same biphasic effects, while inducing concentration-dependent decreases in relative cell counts (RCC). Imaging and flow cytometry data revealed that the increases in NRU likely resulted from nicotine-induced vacuolization via a lysosomotropic mechanism. In support of this, two lysosomotropic agents, chloroquine and lapatinib, induced similar profiles. Nicotine's effects were also translatable, as brain-, lung-, bone marrow-, and smooth muscle-derived mammalian cells responded with the bipha...
Source: Toxicology in Vitro - Category: Toxicology Authors: Tags: Toxicol In Vitro Source Type: research