astaxanthine and Cell-Transformation--Neoplastic

Nuclear factor erythroid-2-related factor-2 (Nrf2 or NFE2L2) is a master regulator of the anti-oxidative stress response, which is involved in the defense against many oxidative stress/inflammation-mediated diseases, including anticancer effects elicited by an increasing number of natural products. Our previous studies showed that the epigenetic modification of the Nrf2 gene plays a key role in restoring the expression of Nrf2. In this study, we aimed to investigate the epigenetic regulation of Nrf2 by astaxanthin (AST) and fucoxanthin (FX), carotenoids which are abundant in microalgae and seaweeds, in mouse skin epidermal JB6 P+ cells. FX induced the anti-oxidant response element (ARE)-luciferase and upregulated the mRNA and protein levels of Nrf2 and Nrf2 downstream genes in HepG2-C8 cells overexpressing the ARE-luciferase reporter. Both FX and AST decreased colony formation in 12-Otetradecanoylphorbol-13-acetate (TPA)-induced transformation of JB6 P+ cells. FX decreased the methylation of the Nrf2 promoter region in the JB6 P+ cells by the bisulfite conversion and pyrosequencing. Both FX and AST significantly reduced DNA methyltransferase (DNMT) activity but did not affect histone deacetylase (HDAC) activity in JB6 P+ cells. In summary, our results show that FX activates the Nrf2 signaling pathway, induces the epigenetic demethylation of CpG sites in Nrf2 and blocks the TPA-induced transformation of JB6 P+ cells, indicating the potential health-promoting effects of FX in skin cancer prevention.

Topics: Animals; Antioxidant Response Elements; Cell Transformation, Neoplastic; CpG Islands; DNA Demethylation; Epidermal Cells; Epigenesis, Genetic; Gene Knockdown Techniques; Hep G2 Cells; Humans; Mice; NF-E2-Related Factor 2; RNA, Small Interfering; Signal Transduction; Skin Neoplasms; Tetradecanoylphorbol Acetate; Xanthophylls

Astaxanthin captured peroxynitrite to form nitroastaxanthins. 15-Nitroastaxanthin was a major reaction product of astaxanthin with peroxynitrite. Here, the anti-oxidative, anti-tumor-promoting, and anti-carcinogensis activities of 15-nitroastaxanthin were investigated. In addition to astaxanthin, 15-nitroastaxanthin showed excellent singlet oxygen quenching activity. Furthermore, 15-nitroastaxanthin showed inhibitory effects of in vitro Epstein-Barr virus early antigen activation and two-stage carcinogensis on mouse skin papillomas. These activities were slightly higher than those of astaxanthin. Similar results were obtained for the 15-nitrolutein, a major reaction product of lutein with peroxynitrite.

Topics: Animals; Anticarcinogenic Agents; Antigens, Viral; Antineoplastic Agents; Antioxidants; Cell Transformation, Neoplastic; Female; Lutein; Mice; Mice, Inbred ICR; Papilloma; Peroxynitrous Acid; Skin Neoplasms; Tyrosine; Xanthophylls

The goal of this study was to investigate the effects of beta-carotene and astaxanthin (ASX) - carotenoid without provitamin A activity on the proliferation and differentiation of rat oval cells (OC) in vitro. Oval cells were isolated from two groups of animals: I - partial hepatectomised (PH) and II- diethylnitrosamine (DEN) treated rats. At various time points cell lysates were separated by PAGE. For immunodetection primary antibodies against CD-34, Ck19 and albumin were used. Medium concentration of fibrinogen and haptoglobin was measured. Mitochondrial competence of cells was expressed as the proliferation index. In comparison to HP- and DEN-obtained oval cells cultured without carotenoids, the addition of beta-carotene and ASX increased albumin expression during the experimental period. The same condition didn't reveal CK19 expression. CD34 expressed by oval cells was detected up to the 5(th) week of beta-carotene and ASX absence in the medium. beta-carotene addition resulted in a decrease of the proliferative activity of OC, with significant changes in 48 h, the 5(th) and 15(th) week of incubation. ASX (p < or = 0.05) inhibited the proliferation, especially in 24h and 5(th) week of cell culture. In respect to haptoglobin concentration, its maximum value after the 10(th) week was observed. The fibrinogen level obtained from DEN-oval cells incubated with beta-carotene elevated from 480+/-6.87 microg/ml after 24h to 5520+/-34,56 microg/ml after the 15(th) week. In a condition without carotenoids fibrinogen concentration did not exceed 2280+/-31.5 microg/ml after the 15(th) week of cell culture.

Topics: Animals; Anticarcinogenic Agents; beta Carotene; Cell Differentiation; Cell Proliferation; Cell Transformation, Neoplastic; Diethylnitrosamine; Female; Fibrinogen; Haptoglobins; Hepatectomy; Liver; Liver Neoplasms, Experimental; Rats; Rats, Wistar; Tumor Cells, Cultured; Xanthophylls

Carotenoids have been implicated in numerous epidemiological studies as being protective against cancer at many sites, and their chemopreventive properties have been confirmed in laboratory studies. Astaxanthin (AST), primarily a carotenoid of marine origin, responsible for the pink coloration of salmon, shrimp and lobster, has received relatively little attention. As with other carotenoids, its highly lipophilic properties complicate delivery to model systems. To overcome this issue we have synthesized a novel tetrasodium diphosphate astaxanthin (pAST) derivative with aqueous dispersibility of 25.21 mg/ml. pAST was delivered to C3H/10T1/2 cells in an aqueous/ethanol solution and compared with non-esterified AST dissolved in tetrahydrofuran. We show pAST to (i) upregulate connexin 43 (Cx43) protein expression; (ii) increase the formation of Cx43 immunoreactive plaques; (iii) upregulate gap junctional intercellular communication (GJIC); and (iv) cause 100% inhibition of methylcholanthrene-induced neoplastic transformation at 10(-6) M. In all these assays, pAST was superior to non-esterified AST itself; in fact, pAST exceeded the potency of all other previously tested carotenoids in this model system. Cleavage of pAST to non-esterified (free) AST and uptake into cells was also verified by HPLC; however, levels of free AST were approximately 100-fold lower than in cells treated with AST itself, suggesting that pAST possesses intrinsic activity. The dual properties of water dispersibility (enabling parenteral administration in vivo) and increased potency should prove extremely useful in the future development of cancer chemopreventive agents.

Topics: Animals; Anticarcinogenic Agents; Antineoplastic Agents; Benzoates; beta Carotene; Carotenoids; Cell Line; Cell Transformation, Neoplastic; Fibroblasts; Gap Junctions; Mice; Mice, Inbred C3H; Retinoids; Xanthophylls