Targeted Antitumoral Dehydrocrotonin Nanoparticles With L-ascorbic Acid 6-stearate

Tumoral cells are known to have a higher ascorbic acid uptake than normal cells. Therefore, the aim of this study was to obtain polymeric nanoparticles containing the antitumoral compound trans-dehydrocrotonin (DHC) functionalized with L-ascorbic acid 6-stearate (AAS) to specifically target this system tumoral cells. Nanoparticle suspensions (NP-AAS-DHC) were prepared by the nanoprecipitation method. The systems were characterized for AAS presence by thin-layer chromatography and for drug loading (81-88%) by UV-Vis spectroscopy. To further characterize these systems, in vitro release kinetics, size distribution (100-140 nm) and Zeta potential by photon-correlation spectroscopic method were used. In vitro toxicity against HL60 cells was evaluated by tetrazolium reduction and Trypan blue exclusion assays. Cell death by apoptosis was quantified and characterized by flow cytometry and caspase activity. Zeta potential analyses showed that the system has a negatively charged outer surface and also indicate that AAS is incorporated on the external surface of the nanoparticles. In vitro release kinetics assay showed that DHC loaded in nanoparticles had sustained release behavior. In vitro toxicity assays showed that NP-AAS-DHC suspension was more effective as an antitumoral than free DHC or NP-DHC and increased apoptosis induction by receptor-mediated pathway. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association.981247964807Ziegler, D.S., Kung, A.L., Therapeutic targeting of apoptosis pathways in cancer (2008) Curr Opin Oncol, 20, pp. 97-103http://www.who.int, last access: 20/02/2008Sofou, S., Surface-active liposomes for targeted cancer therapy (2007) Nanomedicine, 2 (5), pp. 711-724. , http://www.futuremedicine.com/doi/pdf/10.2217/17435889.2.5.711, DOI 10.2217/17435889.2.5.711Castro, M.A., Pozo, M., Cortes, C., Garcia, M.D.L.A., Concha, I.I., Nualart, F., Intracellular ascorbic acid inhibits transport of glucose by neurons, but not by astrocytes (2007) Journal of Neurochemistry, 102 (3), pp. 773-782. , DOI 10.1111/j.1471-4159.2007.04631.xSavona, M., Talpaz, M., Getting to the stem of chronic myeloid leukaemia (2008) Nature Reviews Cancer, 8 (5), 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Nanocytotoxicity: Violacein And Violacein-loaded Poly (d, L-lactide-co-glycolide) Nanoparticles Acting On Human Leukemic Cells

Violacein is a compound obtained from Chromobacterium violaceum, a bacterium found in the Amazonian region. Violacein-loaded poly (D, L-lactide-co-glycolide) nanoparticles has a similar inhibitory effect evaluated by trypan blue assay on leukemic HL60 cells than the free form. However, the cytotoxic effects evaluated by phosphatase activity and MTT reduction assays were lower for the encapsulated form than for free violacein. Based on morphological changes, violacein and violacein entrapped in nanoparticles were found to induce terminal differentiation (assessed by nitro blue tetrazolium reduction) in HL60 cells. Thus, both formulations inhibit HL60 cell growth in vitro, partly by inducing cytotoxic effects and cell differentiation. Flow cytometric analysis of HL60 cells after treatment for 12 h showed that violacein-loaded PLGA induced apoptosis, with maximum cell death at a concentration of 2 μM. Violacein and violacein/PLGA induced opposite effects on the mitochondrial swelling which indicates altered mitochondrial function. The mitochondrial activity was also checked by flow cytometry studies. Labelled cells with the probe JC1 displayed a basal hypopolarized status of the mitochondria in treated cells. Based on morphological changes, alterations in phospholipid asymmetry and changes in mitochondrial polarization, violacein and nanoparticles containing violacein were found to trigger cell death by apoptosis. These methodologies are promising as diagnostic and mechanistic effects of nanoparticles in cell cultures. Copyright © 2009 American Scientific Publishers All rights reserved.52192201Durán, N., Menck, C.F.M., Chromobacterium violaceum: A review of pharmacological and industrial perspectives (2001) Crit. Rev. 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Diterpenes From Xylopia Langsdorffiana Inhibit Cell Growth And Induce Differentiation In Human Leukemia Cells

Two new diterpenes were isolated from stems and leaves of Xylopia langsdorffiana, entatisane-7α,16α-diol (xylodiol) and ent-7α-acetoxytrachyloban-18-oic acid (trachylobane), along with the known 8(17),12E,14-labdatrien-18-oic acid (labdane). We investigated their antitumour effects on HL60, U937 and K562 human leukemia cell lines. We found that xylodiol was the most potent diterpene in inhibiting cell proliferation of HL60, U937 and K562 cells, with mean IC 50 values of 90, 80 and 50 μM, respectively. Based on the nitroblue tetrazolium (NBT) reduction assay, all the diterpenes were found to induce terminal differentiation in HL60 and K562 cells, with xylodiol being the most effective. NBT reduction was increased by almost 120% after 12 h exposure of HL60 cells to xylodiol at a concentration lower than the IC 50 (50 μM). Thus, xylodiol inhibited human leukemia cell growth in vitro partly by inducing cell differentiation, and merits further studies to examine its mechanism of action as a potential antitumoural agent. © 2009 Verlag der Zeitschrift für Naturforschung, Tübingen.649-10650656Denizot, F., Lang, R., Rapid colorimetric assay for cell growth and survival, modifications to the tetrazolium dye procedure giving improved sensitivity and reliability (1986) J. Immunol. Methods, 89, pp. 271-277Dimas, K., Demetzos, C., Vãos, V., Ioannidis, P., Trangas, T., Labdane type diterpenes down-regulate the expression of c-Myc protein, but not of Bcl2, in human leukemia T-cells undergoing apoptosis (2001) Leukemia Res, 25, pp. 449-454Faulkner, D.F., Lebby, V., Waterman, P.G., Further diterpenes from stem bark of Xylopia aethiopica (1985) Planta Med, 4, pp. 354-355Graikou, K., Aligiannis, N., Skaltsounis, A.L., Chinou, I., Michel, S., Tillequin, F., Litaudon, M., New diterpenes from Croton insularis (2004) J. Nat. Prod, 67, pp. 685-688Jiang, H., Lin, J., Fisher, P.B., A molecular definition of terminal cell differentiation in human melanoma cells (1994) Mol. Cell Differ, 2, pp. 221-239Kohroki, J., Muto, N., Tanaka, T., Itoh, N., Inada, A., Tanaka, K., Induction of differentiation and apoptosis by dithizone in human myeloid leukemia cell lines (1998) Leukemia Res, 22, pp. 405-412Kondoh, M., Suzuki, I., Sato, M., Nagashima, F., Simizu, S., Harada, M., Fujii, M., Watanabe, Y., Kaurene diterpene induces apoptosis in human leukemia cells partly through a caspase-8-dependent pathway (2004) J. Pharmacol. Exp. Ther, 311, pp. 115-122Leszczyniecka, M., Roberts, T., Dent, P., Grant, S., Fisher, P.B., Differentiation therapy of human cancer: Basic science and clinical applications (2001) Pharmacol. Ther, 90, pp. 105-156Li, W.-X., Cui, C.-B., Cai, B., Yao, X.-S., Labdane-type diterpenes as new cell cycle inhibitors and apoptosis inducers from Vitex trifolia L (2005) J. Asian Nat. Prod. Res, 7, pp. 95-105Maas, P.J.M., Kamer, H.M.V., Junikka, L., Silva, R.M., Rainer, H., Annonnaceae from centraleastern Brazil (2001) Rodriguésia, 80, pp. 65-98Morais, M.P.L., Roque, N.F., Diterpenes from the fruits of Xylopia aromatica (1988) Phytochemistry, 27, pp. 3205-3208Newman, D.J., Cragg, G.M., Snader, K.M., Natural products as sources of new drugs over the period 1981-2002 (2003) J. Nat. Prod, 66, pp. 1022-1037Oliveira, A.P., Furtado, F.F., Silva, M.S., Tavares, J.F., Mafra, R.A., Araújo, D.A.M., Cruz, J.S., Medeiros, I.A., Calcium channel blockade as a target for the cardiovascular effects induced by the 8(17),12E,14-labdatrien-18-oic acid (labdane-302) (2006) Vasc. Pharmacol, 44, pp. 338-344Perry, N.B., Burgess, E.J., Baek, S.-H., Weavers, R.T., The first atisane diterpenoids from a liverwort: Polyols from Lepidolaena clavigera (2001) Org. Lett, 3, pp. 4243-4245Sun, I.C., Kashiwada, Y., Morris-Natschke, S.L., Lee, K.H., Plant-derived terpenoids and analogues as anti-HIV agents (2003) Curr. Top. Med. Chem, 3, pp. 155-169Tavares, J.F., Queiroga, K.F., Silva, M.V.B., Diniz, M.F.F.M., Barbosa-Filho, J.M., Da-Cunha, E.V.L., Simone, C.A., Silva, M.S., Ent-Trachylobane diterpenoids from Xylopia langsdorffiana (2006) J. Nat. Prod, 69, pp. 960-962Tavares, J.F., Silva, M.V.B., Queiroga, K.F., Diniz, M.F.F.M., Barbosa-Filho, J.M., Haun, M., Melo, P.S., Silva, M.S., Xylodiol, a new atisane diterpenoid from Xylopia langsdorffiana St.-Hil. & Tul. (Annonaceae) (2007) Z. Naturforsch, 62 c, pp. 742-74