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Updated: May 27, 2026
A Semi-Quantitative Drug Affinity Responsive Target Stability (DARTS) assay for studying Rapamycin/mTOR interaction
Published on: August 27, 2019
Evaluation of rapamycin-induced cell death
Lorenzo Galluzzi1, Eugenia Morselli, Oliver Kepp
1INSERM, U848, Villejuif, France.
Abstract:
Mammalian target of rapamycin (mTOR) is an evolutionarily conserved kinase that integrates signals from nutrients and growth factors for the coordinate regulation of many cellular processes, including proliferation and cell death. Constitutive mTOR signaling characterizes multiple human malignancies, and pharmacological inhibitors of mTOR such as the immunosuppressant rapamycin and some of its nonimmunosuppressive derivatives not only have been ascribed with promising anticancer properties in vitro and in vivo but are also being extensively evaluated in clinical trials. mTOR inhibition rapidly leads to the activation of autophagy, which most often exerts prosurvival effects, although in some cases it accompanies cell death. Thus, depending on the specific experimental setting (cell type, concentration, stimulation time, and presence of concurrent stimuli), rapamycin can activate/favor a wide spectrum of cellular responses/phenotypes, ranging from adaptation to stress and survival to cell death. The (at least partial) overlap among the biochemical and morphological responses triggered by rapamycin considerably complicates the study of cell death-associated variables. Moreover, rapamycin presumably triggers acute cell death mainly via off-target mechanisms. Here, we describe a set of assays that can be employed for the routine quantification of rapamycin-induced cell death in vitro, as well as a set of guidelines that should be applied for their correct interpretation.
Insights
This study details assays for quantifying rapamycin-induced cell death, crucial for understanding mTOR inhibitor anticancer effects. Proper interpretation guidelines are provided for reliable results in cancer research.
Area of Science:
- Cellular Biology
- Molecular Oncology
Background:
- Mammalian target of rapamycin (mTOR) signaling is vital for cell growth and survival, and its dysregulation is implicated in human cancers.
- mTOR inhibitors, like rapamycin, show anticancer potential but induce complex cellular responses, including autophagy and cell death.
- The precise mechanisms and quantification of rapamycin-induced cell death remain challenging due to overlapping cellular responses.
Purpose of the Study:
- To establish reliable in vitro assays for quantifying rapamycin-induced cell death.
- To provide guidelines for the accurate interpretation of these cell death assays.
- To aid in the evaluation of mTOR inhibitors as anticancer agents.
Main Methods:
- Description of a set of assays for routine quantification of rapamycin-induced cell death in vitro.
- Development of guidelines for the correct interpretation of assay results.
- Focus on in vitro experimental settings for rapamycin treatment.
Main Results:
- The study outlines specific assays suitable for measuring cell death induced by rapamycin.
- Guidelines are presented to ensure accurate interpretation of the complex cellular responses to mTOR inhibition.
- The findings facilitate a clearer understanding of rapamycin's impact on cell viability.
Conclusions:
- Standardized assays and interpretation guidelines are essential for studying rapamycin-induced cell death.
- Accurate quantification aids in assessing the therapeutic potential of mTOR inhibitors in oncology.
- This work provides a framework for reproducible research on mTOR pathway-targeted cancer therapies.
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