Evaluation of firefly luciferase biolurninescence mediated photodynarnic toxicity in cancer cells

Purpose: This work investigated whether fLuc-catalyzed oxidation Of D-luciferin generates sufficient light to induce photodynamic toxicity in cancer cells. Procedures: Light emission was assessed via cooled CCD (charge-coupled device) camera. Parental and fLuc expressing cancer cells were exposed to subtoxic concentrations of photosensitizers (Rose Bengal or hypericin) and D-luciferin, sunlight, or lamplight. Toxicity was assessed by MTT assay. Results: fLuc expressing cells emitted up to 500-fold higher levels of photons than parental cell lines. Although exposure to photosensitizer and sunlight reduced survival of various cell lines, survival of fLuc expressing cells incubated with photosensitizer and D-luciferin, or photosensitizer and lamplight, did not differ significantly from parental or untreated cells. Conclusions: Contesting recent reports, fLuc bioluminescence does not generate sufficient photons to induce Rose Bengal or hypericin photodynamic toxicity in a range of malignant and nonmalignant cell lines, and is not suitable as a generalizable approach to antineoplastic therapy.