Citrus seeds are full of phenolic compounds, such as flavonoids. The aims of this study were to identify the types of flavonoids in Citrus seed extracts, the cytotoxic effect, mode of cell death, and signaling pathway in human hepatic cancer HepG2 cells. The flavonoids contain anticancer, free radical scavenging, and antioxidant activities. Neohesperidin, hesperidin, and naringin, active flavanone glycosides, were identified in Citrus seed extract. The cytotoxic effect of three compounds was in a dose-dependent manner, and IC₅₀ levels were determined. The sensitivity of human HepG2 cells was as follows: hesperidin > naringin > neohesperidin > naringenin. Hesperidin induced HepG2 cells to undergo apoptosis in a dose-dependent manner as evidenced by the externalization of phosphatidylserine and determined by annexin V-fluorescein isothiocyanate and propidium iodide staining using flow cytometry. Hesperidin did not induce the generation of reactive oxygen species, which was determined by using 2′,7′-dichlorohydrofluorescein diacetate and flow cytometry method. The number of hesperidin-treated HepG2 cells with the loss of mitochondrial transmembrane potential increased concentration dependently, using 3,3′-dihexyloxacarbocyanine iodide employing flow cytometry. Caspase-9, -8, and -3 activities were activated and increased in hesperidin-treated HepG2 cells. Bcl-xL protein was downregulated whereas Bax, Bak, and tBid protein levels were upregulated after treatment with hesperidin in a dose-dependent manner. In conclusion, the bioflavanone from Citrus seeds, hesperidin, induced human HepG2 cell apoptosis via mitochondrial pathway and death receptor pathway. Citrus seed flavonoids are beneficial and can be developed as anticancer drug or food supplement, which still needs further in vivo investigation in animals and human beings.

We have developed an antibody-based method to assess plasma uptake of a proprietary Undaria-derived fucoidan galactofucan sulfate (GFS(TM)) after oral ingestion by human volunteers. Fucoidans have high-molecular-weights but exert biological effects in experimental animals after oral intake. By using a novel antibody raised against sulfated polysaccharides, we carried out a competitive ELISA to quantitate GFS in plasma samples from healthy volunteers who ingested 3 g/day of whole Undaria containing 10% GFS fucoidan, purified 75% GFS fucoidan, or 3 g of a nonsulfated placebo polysaccharide over 12 days. Increased reactivity to the novel antibody, as measured against preingestion levels, was detected at all time points. Assuming the measured material to be intact GFS, the concentration detected (median) was 4.002 and 12.989 mg/l when 3 g of 10% or 75% pure fucoidan was ingested orally over a period of 12 days, respectively. High-molecular-weight fucoidan can be detected in plasma using an ELISA competitive assay based on a novel antibody to sulfated polysaccharides.

Versican/PG-M is a large chondroitin sulfate proteoglycan in the extracellular matrix, which is transiently expressed in mesenchymal condensation areas during tissue morphogenesis. Here, we generated versican conditional knock-out mice Prx1-Cre/Vcan(flox/flox), in which Vcan is pruned out by site-specific Cre recombinase driven by the Prx1 promoter. Although Prx1-Cre/Vcan(flox/flox) mice are viable and fertile, they develop distorted digits. Histological analysis of newborn mice reveals hypertrophic chondrocytic nodules in cartilage, tilting of the joint, and a slight delay of chondrocyte differentiation in digits. By immunostaining, whereas the joint interzone of Prx1-Cre/Vcan(+/+) shows an accumulation of TGF-beta, concomitant with versican, that of Prx1-Cre/Vcan(flox/flox) without versican expression exhibits a decreased incorporation of TGF-beta. In a micromass culture system of mesenchymal cells from limb bud, whereas TGF-beta and versican are co-localized in the perinodular regions of developing cartilage in Prx1-Cre/Vcan(+/+), TGF-beta is widely distributed in Prx1-Cre/Vcan(flox/flox). These results suggest that versican facilitates chondrogenesis and joint morphogenesis, by localizing TGF-beta in the extracellular matrix and regulating its signaling.

The cancer stem cell (CSC) model suggests that a small subpopulation of cancer cells possesses the ability to self-renew and give rise to malignant progeny that drive cancer progression. Recent reports have also proposed the existence of certain extra- or intracellular signals that allow cancer progenitors to dynamically revert to a stem cell state. However, the mechanisms underlying cancer cell plasticity and CSC expansion are not entirely clear. Our previous studies using a hyaluronan synthase 2 (Has2) transgenic mouse model demonstrated that hyaluronan overproduction caused rapid development of aggressive breast carcinoma at a high incidence. Thus, we hypothesize that hyaluronan overproduction may accelerate cancer progression by expanding CSC subpopulations during cancer development. Primary cancer cells were established from mammary tumors developed in the transgenic mice and subjected to the Hoechst 33342 dye exclusion assay to sort side population (SP) from non-side population (non-SP) cells. Flow cytometric analysis demonstrated the enrichment of CD44(high)/CD24(low) CSC-like cells in the SP fraction of hyaluronan-overproducing cancer cells. This subpopulation exhibited several characteristics that were similar to CSCs, including cancer-initiating and mammosphere-forming abilities. Excess hyaluronan production drove the epithelial-to-mesenchymal transition process defined as the loss of epithelial phenotypes, up-regulation of transforming growth factor β (TGF-β), and induction of the epithelial-to-mesenchymal transition-related transcriptional factors Snail and Twist. Inhibition of TGF-β-Snail signaling or silencing of Twist expression abrogated the entrance into a stem cell state. Taken together, our findings suggest that hyaluronan overproduction allows plastic cancer cell populations to revert to stem cell states via Twist and the TGF-β-Snail signaling axis.