Studying arsenic trioxide-induced apoptosis of Colo-16 cells with two-photon and confocal laser scanning microscopy

Abstract

With two-photon and confocal laser scanning microscopy in combination with fluorescent probes Hoechst 33342, 2′,7′-dichlorofluorescin diacetate (DCFH-DA) and Fluo 3-AM, we simultaneously observed arsenic trioxide (As₂O₃)-induced changes in nuclear morphology, reactive oxygen species (ROS) and intracellular calcium concentration (Ca²⁺)i within human skin squamous carcinoma cells (Colo-16 cells). Our results indicated that As₂O₃ induced (Ca²⁺)i elevation and ROS production within Colo-16 cells, and both (Ca²⁺)i elevation and ROS production were involved in the apoptosis of Colo-16 cells. These results suggested that two-photon and confocal laser scanning microscopy might provide a real-time, sensitive and noninvasive method for simultaneously multi-parameter observation of As₂O₃- induced apoptosis at the single cell level.

Key words: Two-photon laser scanning microscopy, confocal laser scanning microscopy, human skin squamous carcinoma cells (Colo-16 cells), arsenic trioxide, apoptosis