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Updated: Jun 10, 2026
A Strategy to Identify Compounds that Affect Cell Growth and Survival in Cultured Mammalian Cells at Low-to-Moderate Throughput
Published on: September 22, 2019
A cellular viability assay to monitor drug toxicity
Abstract:
A central part of the research in protein misfolding and its associated disorders is the development of treatment strategies based on ensuring cellular protein homeostasis. This often includes testing chemical substances or drugs for their ability to counteract protein misfolding processes and to promote correct folding. Such investigations also include assessment of how the tested chemical substances affect cellular viability, that is, their cytotoxic effect. Investigations of cytotoxicity often require testing several different concentrations and drug exposure times using cells in culture. It is therefore attractive to use a viability test that permits the analysis of many samples with little handling time. This protocol describes a simple and fast methodology to analyze viability of lymphoblastoid cells and to test putative cytotoxic effects associated with exposure to a chemical substance, here exemplified by celastrol. The natural substance celastrol has been used for many years in traditional Chinese medicine and has subsequently been shown to induce transcription of genes encoding molecular chaperones (heat shock proteins) that are involved in promoting folding of cellular proteins. The well-described colorimetric tetrazolium salt (MTT) assay, which monitors metabolic activity of cultured cells, was adapted to analyze the viability of cells exposed to celastrol. After having established a suitable cell seeding density, the dose-dependence and time-course of viability reduction of lymphoblastoid cells treated with celastrol were determined. It was found that 4- and 24-h exposure to 0.8 microM celastrol reduced the viability of lymphoblastoid cells, with the most severe effect observed at 24 h with MTT reductions approaching 30% of non-exposed cells. For a series of incubations for 24 h, it was found that concentrations as low as 0.2 microM were sufficient to affect the viability, and celastrol concentrations of 0.5 microM reduced the MTT reduction rate to approximately half the level displayed by cells receiving vehicle alone.
Insights
This study adapted the MTT assay to quickly assess celastrol
Area of Science:
- Biochemistry
- Cell Biology
- Pharmacology
Background:
- Protein misfolding disorders necessitate treatments promoting cellular protein homeostasis.
- Assessing drug cytotoxicity, including effects on cellular viability, is crucial for developing new therapies.
- Efficient viability assays are needed for high-throughput screening of chemical substances.
Purpose of the Study:
- To establish a simple and fast methodology for analyzing lymphoblastoid cell viability.
- To test the cytotoxic effects of the natural compound celastrol on cellular viability.
- To adapt the tetrazolium salt (MTT) assay for assessing celastrol's impact on cell metabolism.
Main Methods:
- Lymphoblastoid cells were cultured and exposed to varying concentrations and durations of celastrol.
- The metabolic activity of cells was measured using the colorimetric tetrazolium salt (MTT) assay.
- Dose-dependence and time-course of viability reduction were determined.
Main Results:
- Celastrol exposure, even at low concentrations (0.2 microM) for 24 hours, reduced lymphoblastoid cell viability.
- A 24-hour exposure to 0.8 microM celastrol decreased cell viability by approximately 30%.
- Celastrol concentrations of 0.5 microM halved the MTT reduction rate compared to control cells.
Conclusions:
- The adapted MTT assay provides a rapid method for evaluating the cytotoxicity of chemical substances like celastrol.
- Celastrol exhibits dose- and time-dependent cytotoxic effects on lymphoblastoid cells.
- This methodology aids in the development of therapeutic strategies for protein misfolding disorders.
