Influence of arsenic trioxide on the expression of cyclin A in the Jurkat cel line

Improper expression of cell cycle regulators is characteristic for most cancer cells. Cyclins are a group of proteins, with concentration changing in time, which control progression through each phase of the cell cycle. Maximum cyclin A expression falls inside S and at the beginning of M phase. In the S phase cyclin A is responsible for a proper run of the replication process, and together with cyclin B conditions transition into the M phase. Arsenic trioxide (ATO) is an efficient drug used in acute promyelocytic leukemia (AML). Numerous reports point that arsenic trioxide can be applied in therapy of other types of cancer as well. The purpose of these study was to evaluate influence of arsenic trioxide on the expression and localization of cyclin A in Jurkat cell line. Additionally, we determined the effect of ATO on morphology and ultrastructure of the Jurkat cells. In order to reach this aim we applied classic light, florescence and electron transmission microscopy. A dose-dependent decrease in the percentage of viable cells was observed. Morphological and ultrastructural alterations suggest that apoptosis and autophagy are induced by ATO. Image-based cytometry showed high extent of necrotic cells after ATO treatment. A decrease in cyclin A level was observed, but without a change in protein nuclear localization.