Antiproliferative and Cytotoxic Effects of Exopolisaccharides from Arthronema africanum on Panel of Human Cell Lines

Exopolysaccharides (EPS) isolated from the cyanobacteria Arthronema africanum were examined for antiproliferative activity. The effects of EPS on the human cancer cell lines of lung (A549), cervical (HeLa), colon (HCT), hepatocellular (HepG-2), and mammary (MDA-MB-231) carcinoma were determined using NRU-test. Non-tumour cell line HaCaT was used as control to assess the selectivity towards the cancer cells. EPS influence on the distribution of cells in different phases of the cell cycle was analyzed using flow cytometry. Acridine orange/ethidium bromide and DAPI staining were carried out to determine the ability of EPS to induce apoptosis. EPS-treatment caused decrease in cell viability of all types of cancer cells, with the strong inhibition against HeLa cells. The significantly lower cytotoxicity in non-tumour HaCaT cells demonstrated the selectivity of the cytotoxicity effects. EPS did not induce any changes in the cell cycle distribution. The fluorescence microscopy analysis revealed cytomorphological changes associated with the induction of apoptotic cell death after EPS treatment. The presented results show significant antiproliferative activity of the studied EPS and demonstrate that Arthronema africanum is a promising source of bioactive compounds with potential for use in cancer therapy.