THE EFFECT OF DISULPHIRAM, GOSSYPOL, SPERMINE AND THEIR COMBINATIONS ON HUMAN PROSTATE CANCER CELLS in vitro

Abstract

Summary. Aim: to study the effect of tetraethylthiuram disulfide (disulfiram, DS) and gossypol (Gos) on the viability, electrokinetic and cytomorphological properties of prostate cancer (PCa) cells and modifications in these features of spermine (Spn) action when combined with these inhibitors. Object and methods: the test objects of the study were highly differentiated androgen-sensitive cells of the LNCaP line and poorly differentiated androgenresistant cells of the DU-145 line; the latter phylogenetically originate from a tumor with a more aggressive course of the disease. Cell survival was determined using trypan blue, the effect of the studied compounds on proliferative activity was assessed colorimetrically, staining live cells with crystal violet, the extinction value of the samples was measured at λ = 544 nm. Electrokinetic parameters (ζ-potential, density of total surface charge (TSC) and its sign) were determined by cell microelectrophoresis. Cytomorphological changes were examined using an optical microscope on fixed preparations of cells grown on coverslips and stained with hematoxylin and eosin. Results: inhibitory concentrations (IC50) of DS used in pure form for LNCaP and DU-145 cells were almost the same. In the case of combined use of DS and Spn, the IC50 of DS for both cell lines also differed little. At the same time, the presence of DS in the active mixture potentiated the antiproliferative properties of Spn both in the case of androgen-sensitive LNCaP and androgenresistant DU-145 PCa cells. The decrease in the negative TSC of LNCaP cells under the influence of DS makes it possible to assume competition between DS and Spn for binding receptors, since the increase in the positive TSC caused by the action of pure Spn was not observed when they were combined. Androgen-sensitive LNCaP cells cultured in the presence of Gos or its combination with Spn did not move at all in an electric field due to the fact that the cations and anions of the cell surface were mutually balanced. In contrast, androgen- resistant DU-145 cells retained on their surface the cation-anion imbalance necessary for movement in an electric field. This indicated a different ionic arrangement of their surface. The proapoptotic effect of ALDH inhibitors on human PCa cells in vitro and the enhancement of the cytotoxic effect of Spn in the case of their combined use can be explained by the accumulation in the cells of toxic aldehydes that arise during the metabolism of polyamines and oxidation of ALDH itself. Conclusions: Gos exerts a proapoptotic effect on both androgen-sensitive human PCa cells of the LNCaP line and androgen-resistant DU-145 lines. When combined, Gos and Spn induced apoptosis in a culture of highly differentiated LNCaP cells. In a culture of DU-145 cells, the combined use of DS and Spn potently stimulated apoptosis. Androgen-sensitive and androgen-resistant prostate cancer cells have different ionic arrangements: in LNCaP cells, DS and Spn compete for the same binding sites on their surface, which does not occur in DU-145 cells.