Differential nuclear staining assay for high-throughput screening to identify cytotoxic compounds

Area of Science:

• Cell Biology
• Drug Discovery
• Assay Development

Background:

• Identifying novel therapeutic agents with cytotoxic activity is crucial but challenging.
• High-throughput screening (HTS) methods are needed to efficiently evaluate large compound libraries.

Purpose of the Study:

• To develop and validate a novel Differential Nuclear Staining (DNS) assay for live-cell imaging.
• To adapt the DNS assay for high-throughput screening (HTS) of compounds with cytotoxic activity.

Main Methods:

• The DNS assay utilizes two fluorescent DNA intercalators: Hoechst 33342 (stains all cells) and Propidium iodide (stains dead cells).
• The assay was validated using known cytotoxic agents and assessed for HTS suitability (Z' factors).
• Eighty diverse compounds were screened, and hits were validated using MTS and flow cytometry assays.

Main Results:

• The DNS assay demonstrated suitability for HTS with good Z' factors in 96 and 384-well formats.
• Assay quality metrics (signal-to-noise, signal-to-background, coefficient of variation) were adequate.
• Six cytotoxic compounds were identified from a library of eighty, with results confirmed by MTS and flow cytometry.

Conclusions:

• The Differential Nuclear Staining (DNS) assay is a reliable and robust method for identifying cytotoxic compounds.
• The assay is suitable for both primary and secondary screening in drug discovery initiatives.
• DNS assay facilitates dose-response studies and determination of CC50 values.