Positive Health Online

Abstract

HOU and COLLEAGUES,  (1)Institute of Chemical Biology, Henan University, Kaifeng 475004, China investigated the effects and the molecular mechanisms of fucoxanthin, a major carotenoid found in edible seaweed, on HeLa cells.

Background

Fucoxanthin is a major carotenoid found in edible seaweed.

Methodology

The cytotoxicity of fucoxanthin was evaluated using MTT assay. Cell cycle and apoptosis were evaluated using flow cytometric analysis. Autophagy was detected with acridine orange staining and transient transfection of the GFP-LC3 plasmid into the cells. Protein expression was detected with Western blotting.

Results

Treatment of HeLa cells with fucoxanthin (10-80 μmol/L) for 48 h caused dose-dependent cytotoxicity with an IC50 value of 55.1±7.6 μmol/L. Fucoxanthin (10, 20, and 40 μmol/L) dose-dependently induced G0/G1 arrest, but did not change the apoptosis of HeLa cells. The same concentrations of fucoxanthin dose-dependently increased the protein expression of LC3 II (the autophagosome marker) and Beclin 1 (the initiation factor for autophagosome formation) in HeLa cells. Moreover, fucoxanthin dose-dependently decreased the levels of phosphorylated Akt and its downstream proteins p53, p70S6K, and mTOR, and increases the expression of PTEN in HeLa cells. Pre-treatment of HeLa cells with 3-methyladenine (5 mmol/L) blocked the cytotoxic effect of fucoxanthin as well as fucoxanthin-induced autophagy.

Conclusion

Fucoxanthin exerts autophagy-dependent cytotoxic effect in HeLa cells via inhibition of Akt/mTOR signalling pathway.

References

Hou LL(1), Gao C, Chen L, Hu GQ, Xie SQ. Essential role of autophagy in fucoxanthin-induced cytotoxicity to human epithelial cervical cancer HeLa cells. Acta Pharmacol Sin. 34(11):1403-10. Nov 2013. doi: 10.1038/aps.2013.90. Epub Aug 26 2013.