Antiproliferative activity of sulfated polysaccharide isolated from an enzymatic digest of Ecklonia cava on the U-937 cell line

Abstract

A sulfated polysaccharide purified from a brown alga Ecklonia cava, having high anticoagulant activity was investigated for its antiproliferative effect on murine colon carcinoma (CT-26), human leukemic monocyte lymphoma (U-937), human promyelocytic leukemia (HL-60), and mouse melanoma (B-16) cell lines. The sulfated polysaccharide isolated and purified from an enzymatic extract of E. cava had a good selective tumor cell growth inhibition effect; its effect on HL-60 and U-937 was especially promising. The IC 50 value for the sulfated polysaccharide from E. cava (ECSP) on U-937 was 43.9 μg mL −1 . The presence of the sample in the cell culture media stimulated the induction of apoptosis, revealed by nuclear staining with Hoechst 33342. The apoptosis induction was confirmed by the cell cycle analysis, while pronounced sub-G1 phase arrests of 9.5% and 13.8% were also clearly observed when the cells were treated at 15 and 30 μg mL −1 of ECSP in the U-937 cell line, respectively. After a 24-h incubation period, ECSP dose-dependently enhanced the DNA fragmentation on the U-937 cell line as observed in the agarose gel electrophoresis assay. To rule out the action mechanism of ECSP for its anticancer activity, some western blot analyses were conducted with several antibodies (caspase-7, caspase-8, Bax, Bcl-xL, and PARP) and ECSP had a clear effect on the caspase -7 and 8 which cleave protein substrates, including PARP, an inducer of apoptosis responsible for DNA cleavage. Moreover, ECSP controlled the cellular transmembrane molecules like Bax and Bcl-xL. Taken together, the above results demonstrate that the apoptosis for antiproliferative effect of ECSP was clearly induced on U-937 cells.

Effect of enzyme-assisted extract of Sargassum coreanum on induction of apoptosis in HL-60 tumor cells

“…Our results showed that the inhibitory effect of >30-kDa fractions on the viability of HL-60 cells was remarkable compared with other fractions. In the previous study, the >30-kDa molecular weight of the enzymatic extract from Ecklonia cava evidenced profound cytotoxic activities against cancer cells (Athukorala et al 2009). …”

“…Flow cytometry is a rapid cell cycle analysis technique. Cells that have lost DNA take up less stain and will appear to the left of the G 1 peak; hence, the size of the G 1 peak of the histogram is directly proportional to the induced apoptosis of a given treatment (Athukorala et al 2009). The cytotoxicity of CPS on HL-60 cells was due to the induction of apoptosis, so cell cycle analysis was performed.…”

“…According to previous studies, the bioactive substances contained in seaweeds differ from those in land plants as these constituents have been shown to exhibit antioxidant, antitumor, anticoagulant, and antibacterial effects (e.g., Kashiwagi et al 1980;Gonzalez et al 1982;Kosovel et al 1998). In particular, polysaccharides have been broadly employed as a source of fucoidan, alginates, laminaran, and carageenans, all of which have been shown to exhibit anticancer, anticoagulant, antiadhesive, immunomodulatory, and antiinflammatory activities (Matsuda et al 2003;Cumashi et al 2007;Athukorala et al 2009Athukorala et al , 2006Guzman et al 2003).…”

“…However, some controversy surrounds this approach, largely with regard to the extremely low recovery and strict regulations for the use of organic solvents in the food industry and the limited recovery of water-soluble components in water extractions (Park et al 2005). An enzyme-assisted extraction technique using food-grade digestive enzymes such as proteases and carbohydrases has been previously used to extract products evidencing a variety of bioactivities, including antioxidant, anti-inflammatory, and antiproliferative effects (Kim et al 2008a, b;Ahn et al 2008;Athukorala et al 2009). These enzymes work principally by macerating the tissues and breaking down the cell walls and complex interior storage materials (Siriwardhana et al 2005).…”

Antioxidant Activity and Proximate Analysis of Dry Powder from Brown Seaweed Sargassum hystrix

“…was about 800 ppm (Ale et al, 2011), sulphated polysaccharides of Fucus vesiculosus was about 800 ppm (Suresh et al, 2013), sulphated polysaccharides of S. pallidum was about 1,000 ppm , and sulphated polysaccharides of S. plagiophyllum was about 700 ppm (Suresh et al, 2013). IC 50 value of S. hystrix dry powder was lower than sulphated polysaccharides of Ecklonia cava was about 43.9-100 ppm (Athukorala et al, 2009), sulphated polysaccharides of Cladosiphon okamuranus was about 100 ppm (Teruya et al, 2007), and S. hystrix extract was about 0.33±0.03 mg/ml (Budhiyanti et al, 2011).…”