In vitro effects of suramin on Trypanosoma cruzi.

Suramin has been previously reported to inhibit distinct cellular enzymes and to affect the synthesis and distribution of cytoskeleton proteins, cell differentiation and proliferation. The present study indicates that prolonged incubation of Trypanosoma cruzi-infected cells in the presence of 500 microM suramin during intracellular development of the parasite causes morphological changes in amastigote and trypomastigote forms related to the cell division and differentiation process. Our results also show that trypomastigotes obtained from suramin-treated host cells were significantly less infective than control parasites and that amastigotes derived from those trypomastigote forms were less proliferative.

Effect of suramin on trypomastigote forms of Trypanosoma cruzi: changes on cell motility and on the ultrastructure of the flagellum-cell body attachment region.

Suramin has been previously reported to inhibit distinct cell enzymes and to affect the synthesis and distribution of cytoskeleton proteins. Our study indicates that prolonged incubation of Trypanosoma cruzi infected-LLC-MK2 cells in the presence of 500 microM suramin during the intracellular development of the parasite caused morphological changes on trypomastigote forms characterized by a partial or complete detachment of the flagellum from the cell body, besides an accentuated decrease on parasite motility. Immunofluorescence analysis of the region of adhesion between the cell body and the flagellum on trypomastigotes obtained from suramin-treated host cells after the completion of cell cycle did not show any difference in the localization of FAZ antigens recognized by 4D9 and L3B2 monoclonal antibodies despite the presence of a detached flagellum.

Ecto-ATPase activity on the surface of Trypanosoma cruzi and its possible role in the parasite-host cell interaction.

This study describes the possible role of Mg(2+)-dependent ecto-ATPase activity on the Trypanosoma cruzi-host cell interaction. Mg(2+)-dependent ecto-ATPase activity is observed on the cell body and flagellar membranes of the parasite and is about 20 times greater in trypomastigotes, as compared with epimastigotes. Suramin (a competitive antagonist of P2 receptors) and the impermeant agent 4,4'-diisothiocyanostylbene 2',2'-disulfonic acid (DIDS), both inhibitors of ecto-ATPases, strongly inhibited ATPase activity and the adhesion and internalization of both evolutive forms by mouse resident macrophages.