Statistical analysis Data were expressed as the mean6S.D. Statistical analysis was performed using one-way analysis of variance (ANOVA), followed by Duncan’s test, using the statistical program, SPSS11.0 for Windows. The values obtained in the assays were considered statistically different when P,0.05. References 1. Li B, Lu F, Wei X, Zhao R (2008) Fucoidan: structure and bioactivity. Molecules. 13: 1671–1695. 2. Bilan MI, Grachev AA, Ustuzhanina NE, Shashkov AS, Nifantiev NE, et al. (2002) Structure of a fucoidan from the brown seaweed Fucus evanescens C. Ag. Carbohydrate research. 337: 719–730. 3. Bilan MI, Grachev AA, Shashkov AS, Nifantiev NE, Usov AI (2006) Structure of a fucoidan from the brown seaweed Fucus serratus L. Carbohydrate research. 341: 238–245. 4. Wang J, Zhang Q, Zhang Z, Li Z (2008) Antioxidant activity of sulfated polysaccharide fractions extracted from Laminaria japonica. Int J Biol Macromol. 42: 127–132. 5. Alekseyenko TV, Zhanayeva SY, Venediktova AA, Zvyagintseva TN, Kuznetsova TA, et al. (2007) Antitumor and antimetastatic activity of fucoidan, a sulfated polysaccharide isolated from the Okhotsk Sea Fucus evanescens brown alga. Bull Exp Biol Med. 143: 730–732. 6. Maruyama H, Tamauchi H, Iizuka M, Nakano T (2006) The role of NK cells in antitumor activity of dietary fucoidan from Undaria pinnatifida sporophylls (Mekabu). Planta Med. 72: 1415–1417. 7. Simon M, Grandage VL, Linch DC, Khwaja A (2005) Constitutive activation of the Wnt/beta-catenin signalling pathway in acute myeloid leukaemia. Oncogene. 24: 2410–2420. 8. Ishii H, Iwatsuki M, Ieta K, Ohta D, Haraguchi N, et al. (2008) Cancer stem cells and chemoradiation resistance. Cancer Sci. 99: 1871–1877. 9. Itoh H, Noda H, Amano H, Zhuaug C, Mizuno T, et al. (1993) Antitumor activity and immunological properties of marine algal polysaccharides, especially fucoidan, prepared from Sargassum thunbergii of Phaeophyceae. Anticancer Res. 13: 2045–2052. 10. Zhuang C, Itoh H, Mizuno T, Ito H (1995) Antitumor active fucoidan from the brown seaweed, umitoranoo (Sargassum thunbergii). Biosci Biotechnol Biochem. 59: 563–567. 11. Coombe DR, Parish CR, Ramshaw IA, Snowden JM (1987) Analysis of the inhibition of tumour metastasis by sulphated polysaccharides. Int J Cancer. 39: 82–88. 12. Riou D, Colliec-Jouault S, Pinczon du Sel D, Bosch S, Siavoshian S, et al. (1996) Antitumor and antiproliferative effects of a fucan extracted from ascophyllum nodosum against a non-small-cell bronchopulmonary carcinoma line. Antican- cer Res. 16: 1213–1218. 13. Aisa Y, Miyakawa Y, Nakazato T, Shibata H, Saito K, et al. (2005) Fucoidan induces apoptosis of human HS-sultan cells accompanied by activation of caspase-3 and down-regulation of ERK pathways. Am J Hematol. 78: 7–14. 14. Ye J, Li Y, Teruya K, Katakura Y, Ichikawa A, et al. (2005) Enzyme-digested Fucoidan Extracts Derived from Seaweed Mozuku of Cladosiphon novae- caledoniae kylin Inhibit Invasion and Angiogenesis of Tumor Cells. Cytotech- nology. 47: 117–126. 15. Philchenkov A, Zavelevich M, Imbs T, Zvyagintseva T, Zaporozhets T (2007) Sensitization of human malignant lymphoid cells to etoposide by fucoidan, a brown seaweed polysaccharide. Exp. Oncol. 29: 181–185. 16. Boo HJ, Hyun JH, Kim SC, Kang JI, Kim MK, et al. (2011) Fucoidan from Undaria pinnatifida Induces Apoptosis in A549 Human Lung Carcinoma Cells. Phytother Res. Mar 31. doi: 10.1002/ptr.3489. Anticancer Effect of Fucoidan on Breast Cancer Author Contributions Conceived and designed the experiments: YG JZ MX YL. Performed the experiments: MX YL. Analyzed the data: MX QL. Contributed reagents/ materials/analysis tools: LH QW LS. Wrote the paper: MX. 17. Kim EJ, Park SY, Lee JY, Park JH (2010) Fucoidan present in brown algae induces apoptosis of human colon cancer cells. BMC Gastroenterol. 10: 96. 18. Teruya T, Konishi T, Uechi S, Tamaki H, Tako M (2007) Antiproliferative activity of oversulfated fucoidan from commercially cultured Cladosiphon okamuranus Tokida in U937 cells. Int. J. Biol. Macromol. 41: 221–226. 19. Haneji K, Matsuda T, Tomita M, Kawakami H, Ohshiro K, et al. (2005) Fucoidan extracted from Cladosiphon okamuranus Tokida induces apoptosis of human T-cell leukemia virus type 1-infected T cell lines and primary adult T-cell leukemia cells. Nutr. Cancer. 52: 189–201. 20. Hanahan D, Weinberg RA (2000) The hallmarks of cancer. Cell. 100: 57–70. 21. Donovan M, Cotter TG (2004) Control of mitochondrial integrity by Bcl-2 family members and caspase-independent cell death. BiochimBiophys Acta. 1644: 133–147. 22. Oltvai ZN, Milliman CL, Korsmeyer SJ (1993) Bcl-2 heterodimerizes in vivo with a conserved homolog, Bax, that accelerates programmed cell death. Cell. 74: 609–619. 23. Li F (2003) Survivin study: what is the next wave? J Cell Physiol. 197: 8–29. 24. Li F, Ling X (2006) Survivin study: an update of ‘‘What is the next wave’’? J Cell Physiol. 208: 476–486. 25. Shakibaei M, Schulze-Tanzil G, SouzaP JohnT, Rahmanzadeh M, et al. (2001) Inhibition of mitogen-activated protein kinase kinase induces apoptosis of human chondrocytes. J. Biol. Chem. 276: 13289–13294. 26. Zhang Z, Teruya K, Eto H, Shirahata S (2011) Fucoidan extract induces apoptosis in MCF-7 cells via a mechanism involving the ROS-dependent JNK activation and mitochondria-mediated pathways. PLoS One. 6: e27441. 27. Poulaki V, Qin W, Joussen AM, Hurlbut P, Wiegand SJ, et al. (2002) Acute intensive insulin therapy exacerbates diabetic bloodretinal barrier breakdown via hypoxia-inducible factor-1alpha and VEGF. J. Clin. Invest. 109: 805–815. 28. Mehlen P, Puisieux A(2006). Metastasis: a question of life or death. Nat Rev Cancer. 6: 449–458. 29. Koyanagi S, Tanigawa N, Nakagawa H, Soeda S, Shimeno H (2003) Oversulfation of fucoidan enhances its anti-angiogenic and antitumor activities. Biochem Pharmacol. 65: 173–179. 30. Carmichael J, DeGraff WG, Gazdar AF, Minna JD, Mitchell JB (1987) Evaluation of a tetrazolium-based semiautomated colorimetric assay: assessment of radiosensitivity. Cancer Res. 47: 943–946. 31. Montanaro F, Liadaki K, Schienda J, Flint A, Gussoni E, et al. (2004) Demystifying SP cell purification: viability, yield, and phenotype are defined by isolation parameters. Exp Cell Res. 298: 144–154. 32. Chevolot L, Mulloy B, Ratiskol J, Foucault A, Colliec-Jouault S (2001) A disaccharide repeat unit is the major structure in fucoidans from two species of brown algae. Carbohydr Res. 330: 529–535. 33. Pulaski BA, Ostrand-Rosenberg S (2001) Mouse 4T1 breast tumor model. Curr Protoc Immunol. Chapter 20: Unit 20.2. 34. Zhang X, Deng HX, Zhao X, Su D, Chen XC, et al. (2009) RNA interference- mediated silencing of the phosphatidylinositol 3-kinase catalytic subunit attenuates growth of human ovarian cancer cells in vitroand in vivo. Oncology. 77: 22–32. PLOS ONE | www.plosone.org 9 August 2012 | Volume 7 | Issue 8 | e43483