Real-time cell viability assays using a new anthracycline derivative DRAQ7®.

Area of Science:

• Cell Biology
• Biotechnology
• Pharmacology

Background:

• Cell viability assays commonly rely on excluding charged fluorescent dyes from intact cells.
• There is a need for noninvasive fluorescent probes for real-time, long-term monitoring of cell death.

Purpose of the Study:

• To evaluate DRAQ7, a novel anthracycline derivative, as a fluorescent probe for real-time cell death detection.
• To assess the safety and efficacy of DRAQ7 in various cancer cell lines and its impact on drug response studies.

Main Methods:

• Utilized laser scanning microscopy and flow cytometry to analyze DRAQ7's cell penetration, DNA binding, and toxicity.
• Assessed cell death induced by hypoxia, starvation, and cytotoxic drugs in the presence of DRAQ7.
• Developed a microflow cytometric assay combining DRAQ7 with TMRM to analyze mitochondrial membrane potential.

Main Results:

• DRAQ7 did not penetrate intact cell membranes and was nontoxic to cancer cell lines for up to 72 hours.
• DRAQ7 did not induce DNA damage signaling and accurately reported cell death from various stressors.
• The presence of DRAQ7 did not alter cellular responses to anticancer agents or pharmacological dose-response profiles.
• A novel microflow cytometry assay combining DRAQ7 and TMRM provided multiparameter kinetic fingerprints of drug action.

Conclusions:

• DRAQ7 is a safe and effective noninvasive fluorescent probe for real-time cell death monitoring.
• DRAQ7 enables sensitive detection of cell death and does not interfere with anticancer drug efficacy studies.
• The combined DRAQ7 and TMRM assay offers a powerful tool for characterizing anticancer drug mechanisms.