EFFECT OF PLANT HORMONES ON THE COMPONENTS OF SECRETORY PATHWAY
IN HUMAN NORMAL AND TUMOR CELLS
M.S. Vildanova,1 M.A. Savitskaya, G.E. Onishchenko, E.A. Smirnova
M.V. Lomonosov Moscow State University;
1 e-mail: vch41048@mail.ru
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.
Key words: Golgi apparatus, plant hormones, abscisic acid, gibberellic acid
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