Carrageenan delays cell cycle progression in human cancer cells in vitro demonstrated by FUCCI imaging.

BACKGROUND: Carrageenan is a sulfated polysaccharide that exists in red seaweeds recently shown to have anticancer properties. Previous findings show various effects of carrageenan suppressing tumor cell growth. One of the hallmarks of cancer is uncontrolled proliferation, a consequence of loss of normal cell-cycle control, that underlies tumor growth. Recently there is an increasing interest in potential anticancer agents that affect cell cycle in cancer cells. Thus, in this study we investigated the effects of carrageenan on the tumor cell cycle. METHODS: Using human cervical carcinoma cells (HeLa) cells as and human umbilical vein endothelial cells (HUVEC), the cytotoxic effects of kappa carrageenan (k-CO) and lambda carrageenan (λ-CO) at the concentrations of 250-2500 µg/mL were observed. Cell viability was determined using the MTT assay while cell death rates were determined using staining with calcein-AM/propidium iodide. Cell-cycle profile and progression were demonstrated with HeLa cells expressing FUCCI (fluorescence ubiquitination-based cell-cycle indicator) probes (HeLa-FUCCI). RESULTS: Carrageenan had no significant effect on HUVEC (normal cells). In contrast both forms of carrageenan were cytotoxic towards HeLa cells (cancer cells). Furthermore, according to cell-cycle analysis with FUCCI cells, the cell cycle of HeLa cells was delayed in specific phases due to different carrageenan treatments. CONCLUSION: Considering these results, it could be suggested that carrageenan affects the cell-cycle of HeLa cells not only by arresting the cell cycle in specific phases but also by delaying the time needed for the cell to progress through the cell cycle. Additionally, different types of carrageenans have different effects on cell cycle progression. This effect of carrageenan towards cancer cells could possibly be developed into a tumor cell-specific anticancer agent.

Safflower seed polyphenols (N-(p-coumaroyl)serotonin and N-feruloylserotonin) ameliorate atherosclerosis and distensibility of the aortic wall in Kurosawa and Kusanagi-hypercholesterolemic (KHC) rabbits.

Pulse wave velocity (PWV) has been used clinically as a direct measure of arterial stiffness. We investigated the inhibitory effects of defatted safflower seed extract (SSE) and serotonin derivatives (N-(p-coumaroyl)serotonin, N-feruloylserotonin; CS+FS), which are the active components in SSE, on hypercholesterolemia and atherosclerosis, using PWV in Kurosawa and Kusanagi-hypercholesterolemic (KHC) rabbits. SSE and CS+FS were supplemented with a commercial diet containing 0.5% cholesterol for 8 weeks in male KHC rabbits, aged 2 months. Pulse waves were recorded at different aortic positions using two catheters with micromanometers under pentobarbital anesthesia. The atherosclerotic lesioned area in the aorta was significantly reduced in the SSE and CS+FS groups, without significant changes in serum cholesterol and triglyceride levels among the three groups after supplementation. Local PWV (LPWV) in the middle thoracic and distal abdominal aortas was significantly smaller in the SSE and CS+FS groups than in the control group. PWV in the entire aorta was also significantly lower in the SSE and CS+FS groups, compared with that in the control group. Pressure-strain elastic modulus, an index of wall distensibility, was significantly lower in the middle thoracic and middle abdominal aortas in the SSE and CS+FS groups than in the control group. Wall thickness was also significantly smaller in the middle thoracic aorta in the SSE and CS+FS groups compared with that in the control group. Serotonin derivatives inhibited the progress of atherosclerosis and ameliorated wall distensibility, which contributed, in part, to the lowering of LPWV. Serotonin derivatives may be beneficial in improving vascular distensibility and in reducing cardiovascular risk.