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Apoptosis assays for quantifying the bioactivity of anticancer drug products
Joslyn K Brunelle1, Baolin Zhang
1Division of Therapeutic Proteins, Office of Biotechnology Products, Center for Drug Evaluation and Research, Food and Drug Administration, USA.
Abstract:
The goal of cancer therapy is to kill cancer cells. Many anticancer drugs are designed to kill cells by inducing apoptosis. However, the potency assays used for measuring the bioactivity of these products are generally cell viability assays which do not distinguish between cell death and growth inhibition. There are a number of commercial assays available to measure apoptosis; however, many of these assays are not appropriate for use in high-throughput screening formats preferred by industry to measure drug activity, also known as potency, due to their inherent low robustness and/or high variability. This review outlines the strengths and weaknesses of current apoptosis assays and highlights new promising assay developments for evaluation of anticancer therapeutics, such as the design of fluorescent and luminescent constructs to be applied as caspase substrates.
Insights
Measuring anticancer drug potency requires assays that specifically detect apoptosis (programmed cell death), not just cell viability. This review examines current apoptosis assays and highlights new, robust methods for high-throughput screening of cancer therapeutics.
Area of Science:
- Oncology
- Biochemistry
- Pharmacology
Background:
- Cancer therapy aims to eliminate cancer cells, often by inducing apoptosis.
- Current potency assays primarily measure cell viability, failing to distinguish cell death from growth inhibition.
- Existing apoptosis assays often lack the robustness and reproducibility needed for high-throughput screening (HTS).
Purpose of the Study:
- To review the strengths and weaknesses of existing apoptosis assays for anticancer drug evaluation.
- To highlight novel assay developments suitable for HTS in the pharmaceutical industry.
- To improve the accuracy of potency measurements for anticancer therapeutics.
Main Methods:
- Literature review of current apoptosis detection methods.
- Analysis of assay suitability for high-throughput screening (HTS).
- Discussion of emerging technologies, including fluorescent and luminescent caspase substrates.
Main Results:
- Cell viability assays are insufficient for accurate anticancer drug potency determination.
- Many commercial apoptosis assays exhibit low robustness and high variability, limiting their HTS applicability.
- Novel assay designs, such as caspase substrate constructs, show promise for robust apoptosis measurement.
Conclusions:
- Accurate measurement of apoptosis is critical for evaluating anticancer drug efficacy.
- Development of robust, HTS-compatible apoptosis assays is essential for pharmaceutical research.
- Emerging caspase-based assays offer improved solutions for potency determination in cancer drug discovery.
