Khoruzhenko A. Features of subcellular localization of proteinkinases S6K1 and S6K2 in rat thyrocytes in cell culture conditions in vitro

The aim of this work was to investigate subcellular localization of S6K1 and S6K2 in thyrocytes at different terms of cultivations and to define possible connection of processes of proliferation, migrations and changes of functional activity of cells with subcellular relocalization of the indicated forms of S6K. For this purpose terms are developed for the obtaining of two- and three-dimensional cultures without a maintainance (monolayer and spheroid cultures) and with the maintainance of follicle organization (aggregates of follicles) of thyrocytes. Determination of thyroglobulin content found out the decrease of functional activity of human and rat thyrocytes in monolayer and spheroid cultures by comparison to the aggregates of follicles. On the model of thyrocyte monolayer culture it was revealed subcellular relocalization of S6K1/2, important link of PI3K signal transduction pathway which mediates regulator influence of TSH on thyroid cells. Unlike normal tissue, in monolayer conditions along with a cytoplasm found out nuclear localization of S6K1/2, which is observed in the process of cultivation and accompanied by the decrease of thyroglobulin content, reflecting the functional state of thyrocytes. Correlation between appearance S6K1/2-positive nuclei of thyrocytes and localization of proliferating cells not exposed. From other hand, the increase of S6K1/2 content is marked in Ki-67 positive cells. Connection between the process of thyrocyte migration and change of subcellular localization of S6K1/2 was not revealed. Correlation was however exposed between thyroglobulin content in thyrocytes of aggregates of follicles and by cytoplasm localization S6K1/2. Thus, it was revealed the connection between subcellular localization of S6K1/2 and by the level of functional activity of thyrocytes, cultivated in the conditions of two- and three-dimensional culture.