Suppressive effects of lycopene and ß-carotene on the viability of the human esophageal squamous carcinoma cell line EC109.

The molecular mechanisms underlying the chemopreventive effects of carotenoids in different types of cancer are receiving increasing attention. In the present study, the role of peroxisome proliferator-activated receptor γ (PPARγ) in the effect of lycopene and ß-carotene on the viability of EC109 human esophageal squamous carcinoma cells was investigated. The viability of EC109 cells was evaluated using MTT assays. The effects of lycopene and ß-carotene on the expression of PPARγ, p21WAF1/CIP1, cyclin D1 and cyclooxygenase-2 (COX-2) were analyzed by western blotting. Lycopene and ß-carotene (5-40 µM) dose- and time-dependently reduced the viability of the EC109 cells. GW9662, an irreversible PPARγ antagonist, partly attenuated the decrease in EC109 cell viability induced by these carotenoids. Lycopene and ß-carotene treatments upregulated the expression of PPARγ and p21WAF1/CIP1, and downregulated the expression of cyclin D1 and COX-2. These modulatory effects of the carotenoid treatments were suppressed by GW9662, suggesting that the inhibition of EC109 cell viability by lycopene and ß-carotene involves PPARγ signaling pathways and the modulation of p21WAF1/CIP1, cyclin D1 and COX-2 expression.

Separation and purification and in vitro anti-proliferative activity of leukemia cell K562 of Galium aparine L. petroleum ether phase.

To explore material basis of in vitro anti-proliferative activity of leukemia cell K562 of petroleum ether phase of product resulting from Galium aparine L. 60% ethanol extraction, the experiment adopts column chromatography combined with thin layer preparation, isolates and purifies petroleum ether, conducts structural identification of obtained single compound and applies MTT method for viability assay of in vitro anti-proliferative activity of leukemia cell K562. Experimental results show that G. aparine L. petroleum ether contains mainly ß-sitosterol, daucosterol and dibutyl phthalate and other substances. Under experimental conditions, the three could inhibit the proliferation of leukemia cell K562 with dose-effect and time-effect relationship, of which dibutyl phthalate has strongest activity. Dibutyl phthalate with excellent activity, ß-sitosterol with rich content and moderate effect should be the main contributor to its biological activity.

Changes in carotenoid profiles and in the expression pattern of the genes in carotenoid metabolisms during fruit development and ripening in four watermelon cultivars.

Changes in carotenoid profiles during fruit ripening were investigated in four watermelon cultivars: red-fleshed "CN66", pink-fleshed "CN62", yellow-fleshed "ZXG381" and white-fleshed "ZXG507". The expression pattern of twelve genes (GGPS, PSY, PSY-A, PDS, ZDS, CRTISO, LCYB, CHYB, ZEP, NCED1, NCED2 and NCED3) was analysed. In "CN66" and "CN62", lycopene appeared at 12 DAP and became a main carotenoid increased at the later stages. The transcript levels of carotenogenic genes in "CN66" sharply increased during 18-30 DAP, and concomitantly, fruit accumulated the massive amounts of carotenoids. In "ZXG381", violaxanthin and lutein contents were positively correlated, respectively, with CHYB and ZEP transcript levels during fruit ripening. The trace amounts of carotenoids in "ZXG507" were accompanied with the low transcript levels of most biosynthetic genes. The results suggest that differential transcriptional regulation of carotenoid metabolic genes is very important in determining the amount and type of specific carotenoids accumulated during fruit development and ripening.

(2-Chloro-pyrimidin-4-yl)ferrocene.

In the title compound, [Fe(C5H5)(C9H6ClN2)], the two cyclo-penta-dienyl rings are almost parallel, subtending a dihedral angle of 3.01 (5)°. The dihedral angle between the substituted cyclo-penta-dienyl ring and the pyrimidinyl ring is 12.02 (1)°. The conformation of the two cyclopentadienyl rings in the ferrocenyl moiety is eclipsed.

(6-Chloropyridazin-3-yl)ferrocene.

The asymmetric unit of the title compound, [Fe(C5H5)(C9H6ClN2)], contains two independent mol-ecules in which the cyclo-penta-dienyl rings are almost parallel, making dihedral angles of 2.16 (4) and 2.71 (5), and the dihedral angles between the pyridazinyl and substituted cyclo-penta-dienyl rings are 9.65 (5) and 11.53 (8)°. In the crystal, mol-ecules are linked by C-H⋯N hydrogen bonds into chains along the c-axis direction.

PPARγ-dependent pathway in the growth-inhibitory effects of K562 cells by carotenoids in combination with rosiglitazone.

BACKGROUND: Carotenoids have been found to play roles in the prevention and therapy of some cancers which PPARγ was also discovered to be involved in. The present studies were directed to determine the inhibitory effects of carotenoids in combination with rosiglitazone, a synthetic PPARγ agonist, on K562 cell proliferation and elucidate the contribution of PPARγ-dependent pathway to cell proliferation suppression. METHODS: The effects of carotenoid and rosiglitazone combination on K562 cell proliferation were evaluated by trypan blue dye exclusion assay and MTT assay. When PPARγ has been inhibited by GW9662 and siRNA, cycle-related regulator expression in K562 cells treated with carotenoid and rosiglitazone combination was analyzed by Western blotting. RESULTS: Rosiglitazone inhibited K562 cell proliferation and augmented the inhibitory effects of carotenoids on the cell proliferation greatly. Specific PPARγ inhibition attenuated the cell growth suppression induced by carotenoid and rosiglitazone combination. GW9662 pre-treatment attenuated the enhanced up-regulation of PPARγ expression caused by the combination treatment. Moreover, GW9662 and PPARγ siRNA also significantly attenuated the up-regulation of p21 and down-regulation of cyclin D1 caused by carotenoids and rosiglitazone. CONCLUSIONS: PPARγ signaling pathway, via stimulating p21 and inhibiting cyclin D1, may play an important role in the anti-proliferative effects of carotenoid and rosiglitazone combination on K562 cells. GENERAL SIGNIFICANCE: Carotenoids in combination with rosiglitazone are hopeful to provide attractive dietary or supplementation-based and pharmaceutical strategies to treat cancer diseases.

Carotenoids inhibit proliferation and regulate expression of peroxisome proliferators-activated receptor gamma (PPARγ) in K562 cancer cells.

As one of the main micronutrients in vegetables and fruit carotenoids are almost daily intaken in significant quantity. Although the pharmacological roles of carotenoids in the prevention and reduction of cancer incidence have received more and more attention, the exact molecular mechanisms underlying anticancer effects of carotenoids remain unclear yet. Activated peroxisome proliferator-activated receptor gamma (PPARγ) plays an inhibitory role in cancer cell proliferation and growth. Involvement of PPARγ in the growth inhibition of leukemia K562 cells by carotenoids was investigated in the present study. The results demonstrated that ß-carotene, astaxanthin, capsanthin, and bixin inhibited the proliferation and decreased the viability of leukemia K562 cells in dose- and time-dependent manners, induced cell apoptosis, and interfered with cell cycle progression. Pretreatment with GW9662, a potent antagonist of PPARγ, partly attenuated the inhibition of K562 cell proliferation by the four carotenoids at 8µM. These carotenoids up-regulated the expression of PPARγ and p21 and down-regulated the expression of cyclin D1 in a dose-dependent manner. In addition, ß-carotene, astaxanthin, capsanthin and bixin also up-regulated the expression of Nrf2, an important transcription factor in Keap1-Nrf2/EpRE/ARE signaling pathway. It appears to us that PPARγ signaling pathways and Keap1-Nrf2/EpRE/ARE signaling pathway were involved in the inhibition of K562 cell proliferation by carotenoids and the up-regulation of PPARγ expression at least partly contributed to the antiproliferative effects of ß-carotene, astaxanthin, capsanthin, and bixin on K562 cells.

beta-Carotene induces apoptosis and up-regulates peroxisome proliferator-activated receptor gamma expression and reactive oxygen species production in MCF-7 cancer cells.

Although the pharmacological role of beta-carotene in the prevention and treatment of many cancer cells has received increasing attention, the molecular mechanisms underlying such chemopreventive activity are not clear. Since peroxisome proliferator-activated receptor gamma (PPAR-gamma) has been implicated in regulating breast cancer cell differentiation and apoptosis, the effects of beta-carotene on the PPAR-gamma-mediated pathway and its association with reactive oxygen species production in MCF-7 cells were investigated in the present study. The results demonstrated that beta-carotene significantly increased PPAR-gamma mRNA and protein levels in time-dependent manner. In addition, beta-carotene increased the cyclin-dependent kinase inhibitor p21(WAF1/CIP1) expression and decreased the prostanoid synthesis rate-limiting enzyme cyclooxygenase-2 expression. 2-chloro-5-nitro-N-phenylbenzamide (GW9662), an irreversible PPAR-gamma antagonist, partly attenuated the cell death caused by beta-carotene. Further, reactive oxygen species (ROS) production was induced by beta-carotene, resulting in mitochondrial dysfunction and cytochrome C release. Reduced glutathione (GSH) treatment decreases the intracellular ROS and prevents cytochrome C release and cell apoptosis induced by beta-carotene. In total, these observations suggest that the synergistic effect of PPAR-gamma expression and ROS production may account for beta-carotene-mediated anticancer activities.