Fucoidan Inhibits the Proliferation of Leiomyoma Cells and Decreases Extracellular Matrix-Associated Protein Expression

Background/Aims: Uterine leiomyomas (ULs) are benign uterine tumors, and the most notable pathophysiologic feature of ULs is excessive accumulation of extracellular matrix (ECM). Fucoidan is a polysaccharide extracted from brown seaweeds that has a wide range of pharmacological properties, including anti-fibrotic effects. We aimed to study the effect of fucoidan on the growth of ULs activated by transforming growth factor beta (TGFβ). Methods: We used ELT-3 (Eker rat leiomyoma tumor-derived cells) and HUtSMC (human uterine smooth muscle cells) as in vitro models. Cell viability was determined by the MTT assay. Cell colony formation was stained using crystal violet. The side population, cell cycle and apoptosis were analyzed using flow cytometry. Protein expression was assayed by western blot analysis. We also conducted in vivo experiments to confirm the inhibitory effects of fucoidan in nude mouse xenograft models. Tumor tissues were assayed by immunohistochemistry analysis. Results: In our study, fucoidan caused a 50% growth inhibition using a dose of 0.5 mg/ml and decreased the stem cell activity after 48 h. In addition, fucoidan induced sub-G1 cell cycle arrest and apoptosis. Fucoidan down-regulated fibronectin, vimentin, α-SMA and the COL1A1 protein levels in TGFβ3-induced ELT-3 cells. In the cellular mechanism, fucoidan abrogated TGFβ3-induced levels of p-Smad2 and p-ERK1/2, as well as β-catenin translocation into the nucleus. Furthermore, fucoidan suppressed xenograft tumor growth in vivo. Conclusion: Fucoidan displays anti-proliferation and anti-fibrotic effects and exerts protective effects against ULs development.

A role for matrix stiffness in the regulation of cardiac side population cell function

The mechanical properties of the local microenvironment may have important influence on the fate and function of adult tissue progenitor cells, altering the regenerative process. This is particularly critical following a myocardial infarction, in which the normal, compliant myocardial tissue is replaced with fibrotic, stiff scar tissue. In this study, we examined the effects of matrix stiffness on adult cardiac side population (CSP) progenitor cell behavior. Ovine and murine CSP cells were isolated and cultured on polydimethylsiloxane substrates, replicating the elastic moduli of normal and fibrotic myocardium. Proliferation capacity and cell cycling were increased in CSP cells cultured on the stiff substrate with an associated reduction in cardiomyogeneic differentiation and accelerated cell ageing. In addition, culture on stiff substrate stimulated upregulation of extracellular matrix and adhesion proteins gene expression in CSP cells. Collectively, we demonstrate that microenvironment properties, including matrix stiffness, play a critical role in regulating progenitor cell functions of endogenous resident CSP cells. Understanding the effects of the tissue microenvironment on resident cardiac progenitor cells is a critical step toward achieving functional cardiac regeneration.