Plant hormones play a key role in plant growth and differentiation. Many
hormones are known as potential
antitumor agents, yet others appear to affect the secretory activity and are produced by mammalian cells as pro-inflammatory
cytokines. The goal of this research was to study the effect of abscisic and gibberellic
acids on the secretory system of human cultured
epidermoid carcinoma cells A431 and keratinocytes HaCat. Immunocytochemical and morphometric analysis demonstrated that subtoxic concentration of
plant hormones induced the broadening of the ER network and increased the size of Golgi complex. Electron microscopy studies confirmed the hypertrophic changes of the Golgi apparatus, specifically, the swelling of cisternae in the trans-compartment of dictyosomes after exposure to
abscisic acid, and swelling of cis- and trans-compartment of dictyosomes after exposure to
abscisic acid, and swelling of cis- and trans-compartments of dictyosomes after exposure to
gibberellic acid. Using of Click-iT technique allowed to detect the elevation of the total
protein synthesis only in A431 cells exposed to
abscisic acid. Cumulative data suggests that, under these conditions, the
hypertrophy of Golgi apparatus may reflect the enhanced secretory activity of cells. In other experiments, the
hypertrophy of Golgi is not related to increased
protein synthesis and therefore may suggest the stress-related changes of ER and Golgi apparatus. Our results demonstrate that morphologically similar reaction of cellular organelles, such as
hypertrophy of Golgi apparatus, is the result of different functional activities, and that molecular mechanisms underlying the changes induced in cells need further investigations.