Phytochemicals from the genus Beta and their cytotoxic activity on Caco-2 colon cancer cells.

Introduction: Colon cancer is one of the most aggressive tumor. Caco-2 are colon cancer cells characterized by the mutated TP53 gene and over expression of Multi Drug Resistance (MDR) proteins. Beta vulgaris con-tains molecules able to inhibit the proliferation of Caco-2 [1], namely vitexin-2-O xyloside (VOX) purified from Swiss chard seeds and betalains (BLS) purified from red beetroot. The aim of this work was to study the individual and combined anticancer activity of VOX and BLS on Caco-2 cells as well as to identify their mechanisms of action.Materials and methods: Caco-2 colon cancer cells were grown in complete DMEM+NEAA and Sulforho-damine B assay was performed as described [1]; VOX was purified as described [2]; BLS were purified on DEAE FF anion exchange resin. Three fractions were obtained: R1 with 3 betaxanthins, R2 with 2 betacya-nins, R3 with 2 betaxanthins. In order to identify the involved apoptotic pathway, western blots for BAX, Bcl-2, PARP1/ARTD1 and Caspase 3 were performed as described [1].Results: Cells were incubated with phytochemicals at 24, 48 and 72 h and cytotoxicity was assessed. Indivi-dually VOX was the most cytotoxic compound (IC50: 25 μg/ml), whereas R1, R2, R3 showed a weaker, but significant cytotoxic effect. When combined in couples at concentrations: 25 μg/ml VOX plus 350 ng/ml R1, or 250 ng/ml R2 or 35 ng/ml R3, these phytochemicals showed a synergistic cytotoxic effect at 72h. Western blots showed an increase in the levels of BAX, cleaved PARP1/ARTD1, cleaved caspase 3 and a decrease of Bcl-2 levels in both individual and coupled treatments.Discussion: VOX and BLS exhibit on Caco-2 cells a significant cytotoxicity on Caco-2 cells, by means of the activation of intrinsic apoptotic pathway. When VOX and BLS were used in couples, a highest cytotoxicity was evident, probably due to remarkable cytotoxic effects of their metabolic products

Natural extracts from the genus Beta and their cytotoxic activity on T24 human bladder cancer cells

Introduction: The combination chemotherapies with methotrexate plus vinblastine, doxorubicin and cisplatin are often ineffective against bladder cancer [1]. Alternative regimens based on new anticancer compounds are therefore needed to overcome conventional drug resistance and optimize patients’ outcome. It has already been demonstrated that phytochemicals extracted from Beta vulgaris cicla (vitexin-2-O-xyloside) and Beta vulgaris rubra (betaxanthins and betacyanins) possess chemopreventive properties [2]. Cancer microen-vironment is pro-oxidant and pro-inflammatory and all those compounds able to worsen these conditions could fight cancer.Materials and methods: T24 bladder cancer cells were grown in complete DMEM and Sulforhodamine B as-say was performed to evaluate the cytotoxicity of vitexin-2-O-xyloside (VOX) and betalains (BLS) on cancer cells. COX-2 activity was evaluated on the samples of cytosol extracted from T24 cells by a spectrophotome-tric assay through the values of absorbance at 590 nm. Results: We tested VOX and BLS on T24 human bladder carcinoma cell line and we evaluated their cytotoxi-city in time-course experiments. We incubated T24 cells with individual compounds and their combinations for 24, 48 and 72h. We demonstrated that VOX and BLS, alone or in combination, are able to kill T24 cells, showing a synergistic effect after 48h treatment. We than evaluated the activity of COX-2, a key pro-inflam-matory enzyme, in the cytosol of T24 cells, which was incubated with VOX. We found an increase of the COX-2 activity in the presence of VOX, thus indicating a pro-inflammatory effect of this drug. Discussion: A mixture of VOX and BLS is able to kill efficiently chemoresistant T24 bladder cancer cells. These data underlie the importance of cocktails of phytochemicals in the therapy of human cancers that are resistant to conventional drugs. Molecular studies are in progress to detect the cellular network of signaling involved in this cytotoxic effect

ATP independent proteasomal degradation of NQO1 in BL cell lines

Abstract Human NAD(P)H: quinone oxidoreductase 1 (NQO1) catalyzes the obligatory two-electron reduction of quinones. For this peculiar catalytic mechanism, the enzyme is considered an important cytoprotector. The NQO1 gene is expressed in all human tissues, unless a polymorphism due to C609T point mutation is present. This polymorphism produces a null phenotype in the homozygous condition and reduced enzyme activity in the heterozygous one. We previously demonstrated that two cell lines of hematopoietic origin, HL60 and Raji cells, possess the same heterozygous genotype, but different phenotypes; as expected for an heterozygous condition the HL-60 cell line showed a low level of enzyme activity, while the Raji cell line appeared as null phenotype. The level of NQO1 mRNA was similar in the two cell lines and the different phenotype was not due to additional mutations or to expression of alternative splicing products. Here we show that in Raji BL-cell line with heterozygous genotype the null NQO1 phenotype is due to 20S proteasome degradation of wild-type and mutant protein isoforms and is not directly linked to C609T polymorphism. This finding may have important implications in B-cell differentiation, in leukemia risk evaluation and in chemotherapy based on proteasome inhibitors

Land System Science In Latin America: Challenges And Perspectives

This article reviews the current status, trends and challenges of land system science in Latin America. We highlight the advances in the conceptualization, analysis and monitoring of land systems. These advances shift from a focus on the relationships between forests and other land uses to include a greater diversity of land cover and land-use types and the processes and interactions that link them. We then provide a biome-level typology of social-ecological land systems (SELS) as an approach to help connect local-level realities to regional processes and we discuss how this approach can help to design more socially inclusive land systems. We also discuss the increased role of distant socio-economic and ecological interactions that connect these SELS to global processes. Combined, these insights support a research agenda for land system science in the region that can develop more accurate and integrative monitoring of land change and their social and ecological consequences, better understand different stakeholder perspectives within a context of livelihood diversification, and encourage institutional feedbacks to govern land systems influenced by distant drivers. © 201726-27374