Delayed Luminescence Spectroscopy to Monitor Mitochondrially Targeted Effects of Cell Proliferation Inhibitors

To gain new insights into the biochemical mechanisms responsible for the low-level photoinduced Delayed Luminescence (DL) of living cells, as well as to provide new data regarding the relation between DL and the cell status, a new set of experimental data was performed. In this study the relation between DL induced by UVA-laser excitation and the effects of agents that inhibit cell proliferation and induce apoptosis in various cancer cell types were investigated. DL measurements, in the time interval 10 μs – 10 ms after the switching off of the illumination source, were performed on liquid suspension of cultured cells; the response of treated and untreated samples was compared. Data showed to be consistent with an important role of the Mitochondrial Respiratory Chain in DL. In particular the role of MRC Complex I in DL of human leukemia Jurkat T cells was probed by using Complex I targeting agents like rotenone, menadione and quercetin. In addition, the effects of berberine, which is known to be selectively accumulated by mitochondria, on follicular and anaplastic thyroid cancer cells were studied. Moreover results show the possibility of using DL to reveal the activation of the apoptotic pathway and monitor the effects of anticancer treatments.