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Effects of polyamine (PA) synthesis inhibitors--alpha-difluoromethylornithinchloride (DFMO) and alpha-methylornithinchloride (MO)--separately or in combination with the epidermal growth factor (EGF)--on lysosome-phagosome fusion (P-LF) and F-actin content in murine peritoneal macrophages were studied using fluorescent dye Acridine orange for lysosome labelling, FITC-phalloidin for F-actin, and yeast cells as a target. DFMO and MO significantly inhibited P-LF and decreased F-actin content in murine peritoneal macrophages. A combination of DFMO and MO with EGF failed to inhibit P-LF or to decrease F-actin content in these cells. The results obtained with DFMO and MO suggested new cellular targets of their effects. These results may be extended to cancer research to provide a rationale for clinical trials using combinations of EGF with DFMO or MO.

Effect of DNA-intercalators ethidium bromide (EB, 0.005 and 0.015 mM) and dimidium bromide (DB, 0.005 and 0.010 mM) and antioxidative compounds acetylsalicylic acid (ASA, 0.05 and 0.50 mM) and beta-carotene (0.01, 0.02, 0.05 mM) on the phagosome-lysosome (P-L) fusion and F-actin content in murine peritoneal macrophages were studied. EB, DB, ASA and beta-carotene were found to stimulate P-L fusion and the effect depending on the concentration of compounds tested. The strongest influence as evoked by 0.5 mM of ASA and 0.05 mM of beta-carotene. The compounds tested enhanced the F-actin content in macrophages, especially by the action of beta-carotene (0.05 mM). The obtained data indicate a correlation between P-L fusion stimulation and F-actin content under the influence of compounds tested in murine peritoneal macropheages.

Effects of biologically active compounds bilirubin (BR, 0.1 and 0.2 mM), chelerythrine (CR, 0.1 and 0.5 mM) and farmorubicin (FR, 0.6 and 6.0 mM) on the phagosome-lysosome fusion (P-LF) were studied using fluorescent dye acridine orange for lysosomal labelling and yeast cells as a target. To investigate mechanisms of these effects, changes in fluidity of lysosomal membranes from murine liver were studied by measuring of fluorescence intensity, lifetime and polarization of the fluorescent membrane probes: DPH (1,6-diphenyl-1,3,5-hexatriene) and TMA-DPH [1-(4-triphenylamino)-6-phenyl-1,3,5-hexatriene] incorporated in isolated murine liver lysosomes. In order to characterize the induced cytoskeleton changes, the F-actin content in murine peritoneal macrophages was determined. It was found that all three compounds tested enhanced P-LF. Our results demonstrate that BR induces a decrease in DPH and TMA-DPH fluorescence polarization, FR increases DPH and TMA-DPH fluorescence polarization, and CR causes an increase in TMA-DPH fluorescence polarization in lysosomal membranes. All the three compounds increase F-actin content in peritoneal macrophages. Thus, the action of BR extended on P-LF is associated with increasing lysosomal membranes fluidity and cytoskeleton changes. The enhancement of P-LF under the action of FR and CR can be most likely explained by changes of cytoskeleton.

Effects of various antituberculosis remedies (ATR)--isoniazid (INA), saluzid (SA), streptosaluzid (SS), ethambutol (EB), sodium para-aminosalicylate (SPAS) on phagosome-lysosome (PL) fusion, on F-actin content in mouse macrophages and on G-actin polymerization in vitro were studied. The ATR of choice have been shown to stimulate the PL fusion. INA (0.2 mM), SA (0.02 mM), SS (0.05 mM), EB (0.08 mM) and SPAS (0.5 mM) increased the F-actin content and changed its localization within macrophages. ATR changed the character of G-actin polymerization in vitro. Possible mechanisms of interrelation between cytoskeleton (actin part) changes and PL fusion are discussed. The results obtained suggest to use the ATR-induced changes in PL fusion and F-actin content in the cells for estimating therapeutic effects of respective antituberculosis remedies.